Introduction
The clinical course of both acute rheumatic fever (ARF) and rheumatic heart disease (RHD) may be complicated by acute life-threatening conditions. This chapter will focus on: (1) the clinical evaluation, diagnosis, and management of acute heart failure (AHF); (2) infective endocarditis (IE); and (3) the management of overanticoagulation and bleeding in patients receiving oral anticoagulation. The etiology and pathophysiology of AHF in rheumatic carditis is discussed in Chapter 3 . Chronic heart failure (HF) is discussed in detail in Chapter 5, Chapter 6 and the management of RHD and HF in pregnancy is discussed in Chapter 9 .
1: Acute Heart Failure
Definition and Classification
The main clinical syndrome resulting in death and disability in both ARF and RHD is HF, the natural history of which is characterized by episodes of acute decompensation (AHF). AHF is broadly defined as a potentially life-threatening syndrome, characterized by a rapid onset of new or worsening signs and symptoms of HF that typically requires urgent medical attention.
The development of AHF as a consequence of ARF or RHD is challenging. Some patients develop an acute deterioration in valvular function, where the presentation is usually dramatic and potentially life threatening. In certain cases, however, clinical features suggesting a valvular cause of AHF may be subtle, for example, the regurgitant murmur in acute severe mitral or aortic regurgitation is often soft and difficult to hear. Successful management requires maintaining a high index of suspicion, appropriate hemodynamic assessment, and timely initiation of therapeutic options. In most cases, however, AHF results from chronic valvular disease with progressive deterioration in ventricular function, often culminating in repeated subacute presentations requiring hospitalization. Treatment may be challenging, particularly in resource-limited populations as patients are often deprived of access to valve surgery, the only intervention that improves outcomes. Despite this, optimal medical treatment will usually provide symptomatic improvement in the short term.
Although characterized by a common set of signs and symptoms, AHF is a syndrome rather than a single disease entity, and patients exhibit a wide spectrum of features ( Box 16.1 ). Moreover, while our understanding of chronic HF has improved considerably over the last 20–30 years, the presentation and management of AHF is less well understood. Nonetheless, admission to hospital with AHF is a significant prognostic event in the natural history of ARF or RHD, indicating that not only is the valve lesion important but also that an additional factor may have contributed to the clinical picture. For many patients, it also indicates a poor prognosis, with a high risk of readmission and death postdischarge.
AHF may present as a first occurrence ( de novo AHF) or as a consequence of acute decompensation of chronic HF (ADHF).
De Novo Acute Heart Failure
- •
Occurs in patients with advanced RHD
- •
Constitutes 70% of patients hospitalized for AHF in nonendemic populations
- •
Causes: (1) primary cardiac dysfunction (usually worsening left ventricular function); (2) precipitated by extrinsic factors
- •
Typical presentation: with mild-to-moderate signs and symptoms of congestion and fluid retention
- •
Acuity: subacute over days to weeks (chronic neurohormonal compensatory mechanisms and preexisting medical therapy help ameliorate the severity of presentation)
Acute Decompensated Heart Failure
- •
In ARF:
- –
Usually subacute presentation with some cardiac enlargement and compensation
- –
Sometimes presents as fulminant carditis (see Chapter 3 , Chapter 4 ). In acute severe MR, the LA is noncompliant and acute pulmonary edema occurs within days
- –
- •
In RHD: as a first presentation of chronic valve disease
Epidemiology
A global epidemiological profile for AHF has emerged over the last 2 decades. Although most of the data originate from high-income countries (HICs), little is known about AHF in low- and middle-income countries (LMICs), where ARF and RHD are endemic.
In the landmark 1950s publication by Bland and Duckett Jones, a 20-year analysis of 1000 patients showed HF to account for 80% of all deaths from RHD. Cardiac enlargement early in life (presumably during the phase of ARF) had the strongest correlate with mortality, suggesting that the development of HF during ARF carries an extremely poor prognosis. In the contemporary REMEDY study (prospective registry, 3343 patients with RHD), congestive HF was the most frequent complication, and was seen in 33.4% of the patients. In addition, 25% of adults and 5.3% of children had reduced ejection fraction, and left ventricular (LV) dilatation occurred in 23% and 14.1%, respectively. Sixty percent of patients had multivalvular disease, and 66.7% of these were severely affected.
The sub-Saharan African Study of Heart Failure (THESUS-HF) was the first (and to date, only) prospective, observational survey that characterized the causes and short-term outcomes of African adult patients with AHF. Here, 1006 patients with AHF (mean age 52 years) were recruited from 12 university hospitals in nine African countries between 2007 and 2010. In contrast to data from HICs, the etiology of AHF in these patients was predominantly nonischemic, with hypertension (45.4%), idiopathic dilated cardiomyopathy (18.8%), and RHD (14.3%) accounting for 75.5% of cases. AHF presented around 2 decades earlier than in those patients from Europe and the United States. In-hospital mortality was 4.2% and estimated 180-day mortality was 17.8%, which were comparable to non-African registries. In a subanalysis of patients enrolled in THESUS-HF with RHD from South Africa, the 60-day mortality after admission with AHF due to RHD was 24.8% (95% CI 13.6%–42.5%) and 180-day mortality was 35.4% (95% CI 21.6%–54.4%). The epidemiology of HF due to RHD is discussed further in Chapter 1 .
Etiology of Acute Heart Failure
Acute rheumatic fever
A full discussion on the mechanisms of AHF in rheumatic carditis is presented in Chapter 3 . In brief, acute severe mitral or mitral and aortic regurgitation (all secondary to valvulitis) are by far the most common causes of AHF in those who develop ARF. Rarely, chordae tendineae rupture (causing acute severe mitral regurgitation) or cardiac tamponade are the primary cause of AHF. Rheumatic myocarditis does not on its own cause significant myocardial dysfunction and AHF, unlike other forms of myocarditis ( Table 16.1 ).
| Acute Rheumatic Carditis | Acute Viral Myocarditis | |
|---|---|---|
| Age (years) | Usually 5–15 | Any age |
| Epidemiology | Usually in areas where ARF is endemic | Anywhere |
| Prodrome | Sore throat | Headache, myalgia, skin rash, gastroenteritis, coryza |
| Cardiac murmurs | Murmurs of MR, AR | Nil or flow murmur |
| Hypotension | Unusual | Common |
| ECG | Prolonged PR interval or advanced AV block Accelerated junctional tachycardia | Low-voltage QRS complexes Bundle branch block Tachyarrhythmias, including ventricular tachycardia Risk of sudden cardiac death |
| Echocardiography | Significant mitral and/or aortic regurgitation | Mild to moderate secondary mitral regurgitation |
| LV Ejection Fraction | Normal or increased | Decreased |
| Troponin T | Normal | Elevated |
| Serology or PCR | ASOT positive Anti-DNAse B positive | Parvovirus, Coxsackie, Echo, Herpes, adenovirus, influenza, parechovirus, enterovirus |
| Cardiac magnetic resonance | Minimal changes | Often abnormal especially on T2 mapping |
| Endomyocardial biopsy | Nonspecific. May have aschoff bodies | Myocarditis Lymphocytic inflammation, myocyte degeneration |
Rheumatic heart disease
In contrast to those with ARF, patients with established RHD have chronic valvular heart disease. When the valve disease is significant, this is often accompanied by varying degrees of LV dysfunction and remodeling similar to that seen in nonrheumatic disease. The valvular lesions in RHD patients also tend to be more complex than those seen in ARF, with mixed and multivalve disease being the most common phenotype. RHD patients are also usually older and may suffer from significant comorbidities. They may require long-term medical therapy and have undergone mechanical or surgical valvular intervention.
The causes of AHF in those with RHD are therefore broad and are detailed in Box 16.2 . In many patients, an episode of AHF is often the result of numerous interlinked factors but in 40%–50% of all admissions, no clear precipitant is found.
Valve-related
- •
Natural history of chronic, severe valve regurgitation causing myocardial (pump) failure
- •
Recurrent acute rheumatic fever
- •
Infective endocarditis
- •
Acute prosthetic valve syndrome
- •
Dehiscence (e.g., infective endocarditis)
- •
Thrombosis (most often causing stenosis)
- •
Structural failure (e.g., tear or perforation of a bioprosthetic valve)
- •
- •
Iatrogenic mitral regurgitation following percutaneous mitral balloon commissurotomy
Nonvalvular
- •
Tachyarrhythmia (e.g., atrial fibrillation, ventricular tachycardia)
- •
Acute rise in blood pressure or chronic hypertension
- •
Worsening renal failure
- •
Infection (e.g., pneumonia, sepsis, influenza)
- •
Anemia
- •
Pregnancy and peripartum-related disorders
- •
Nonadherence (e.g., medications, salt/fluid intake)
- •
Acute coronary syndrome
- •
Cerebrovascular insult
- •
Pulmonary embolism
- •
Heavy alcohol consumption
- •
Noncardiac surgery and perioperative complications
Evaluation and Management of the Patient With Acute Heart Failure
The diagnostic work-up of AHF should start in the prehospital setting and continue in the emergency department. Given the potentially life-threatening nature of AHF, establishing a definitive diagnosis of the underlying cause, with initiation of appropriate therapy as rapidly and efficiently as possible, are of key importance as time to initiation of treatment is linked to outcome.
In all acutely unwell patients, a systematic approach is essential. Fig. 16.1 presents an algorithmic approach to the initial evaluation of patients with suspected AHF from the latest HF guidelines of the European Society of Cardiology (ESC). This algorithm highlights four phases, detailed later:
- (1)
early recognition, treatment, and triage of life-threatening conditions (i.e., respiratory failure and cardiogenic shock)
- (2)
early recognition and treatment of any acute etiology or relevant triggers requiring specific treatment (e.g., acute valvular regurgitation, arrhythmia, pericardial tamponade)
- (3)
completing the diagnostic work-up of AHF once the patient is stable
- (4)
defining the clinical profile of the patient to rapidly select the most appropriate therapy
Each of these phases will be discussed in order in the following sections. However, as stated in Box 16.1 , most patients with ARF or RHD that develop AHF will present subacutely and many of the therapeutic strategies in phases I and II will not be necessary. Most patients will therefore enter the treatment algorithm at phase III.
Phase I: Early recognition, treatment, and triage of life-threatening conditions
Initial evaluation begins with an ABC assessment (airway, breathing, and circulation) while simultaneously taking a focused history and progressing toward diagnosis and treatment ( Box 16.3 ).
Complete the ABC Assessment While Taking a Focused History:
- •
Any chest pain, dizziness, palpitations?
- •
Symptoms of AHF and duration
- •
Severity of breathlessness (NYHA class—see Chapter 5 )
- •
Previous history of ARF/RHD/HF; previous cardiac surgery or hospitalizations
- •
Drug history, including any recent changes and adherence
- •
Any dietary change, including salt and water intake?
- •
Any change in urine output?
Airway
- •
Look for and treat any evidence of airway obstruction (simple airway maneuvers, airway adjuncts, intubation)
Breathing
- •
Look for signs of increased respiratory effort and/or ineffective respiration (e.g., inability to complete sentences, confusion)
- •
Tachypnea (>upper limit of normal for age of patient) is a sensitive and reliable marker of critical illness
- •
Give oxygen only if S p O 2 is <90% (in all adults or children with respiratory distress) or if S p O 2 is <94% in children with signs of shock ± respiratory distress
- •
Examine the chest for signs of cardiac congestion (crackles, cardiac wheeze, pleural effusion)
- •
Order an urgent CXR (and ABG if unable to acquire a reliable S p O 2 reading)
- •
Consider lung ultrasound (interstitial edema, pleural effusion)
Circulation
- •
Assess the limbs for temperature (warm or cool) and check central capillary refill time in the sternal area (prolonged if >2 s in adults or >3 s in children)
- •
Palpate the pulse rate and rhythm, measure the blood pressure, and examine the JVP
- •
Listen to the heart sounds, record an ECG, and attach a cardiac monitor
- •
Assess for peripheral congestion (e.g., sacral and lower limb edema, hepatomegaly)
- •
Insert one or more wide-bore (depending on the age of the patient) cannulae and send urgent labs
- •
Monitor urine output, use catheter if necessary (aim >0.5 mL/kg/h)
The key elements of airway and breathing assessment are ensuring airway patency and determining the need for supplemental oxygen and respiratory support ( Table 16.2 ). Continuous pulse oximetry (S p O 2 ) is mandatory. Although some degree of pulmonary edema is common in AHF, severe pulmonary edema only occurs in <3% of all AHF presentations. Oxygen should not be used routinely in AHF as it may cause hyperoxia-induced vasoconstriction and reduced cardiac output. Oxygen is a treatment for hypoxemia and not breathlessness and does not consistently alter the sensation of breathlessness in nonhypoxemic patients. Intravenous (IV) morphine (for patients with severe anxiety or distress) should be used cautiously (if at all), particularly in those with hypotension, bradycardia, advanced heart block, or hypercapnia. Where concern arises, senior anesthetic/intensive care input is required.
| Treatment | Indications | Comment |
|---|---|---|
| Oxygen | Hypoxemia:
| Target S p O 2 : 90%–96%:
|
| Continuous positive airway pressure (CPAP) | Oxygenation failure: S p O 2 <90% (or S p O 2 <94% in shocked children), despite adequate oxygen therapy (F i O 2 >40%) | Initiate at a PEEP of 5–7.5 cmH 2 O and titrate to 10 cmH 2 O as needed |
| Non-invasive ventilation (NIV) | Ventilatory failure: P a CO 2 >6.1 KPa (>46 mmHg) and pH < 7.35 | Initiate at an IPAP 8–10 cmH 2 O and EPAP 4 cmH 2 O. Increase IPEP in 2–3 cmH 2 O increments to a maximum of 25 cmH 2 O |
| Endotracheal intubation and mechanical ventilation | Impending respiratory arrest (reduced GCS, pH <7.25, RR >35) or if oxygenation or ventilatory failure cannot be managed noninvasively | May not be appropriate if cardiac disorder is not remediable or patient is not a candidate for CPR |
a Settings need to be standardized according to weight and age of the patient. Close observation and repeated re-evaluation of the patient are important, with timely escalation or deescalation of therapy as appropriate.
b Severe heart failure in children should also be treated with high flow nasal prong therapy, either in the ward or intensive care setting.
If hypoxemia persists despite adequate oxygen therapy (F i O 2 >40%), continuous positive airway pressure (CPAP) or noninvasive ventilation (NIV), delivered through tight-fitting face masks, should be given ( Table 16.2 ). Both improve respiratory mechanics and unload the left ventricle (LV) by decreasing afterload. Because CPAP provides less inspiratory support (i.e., it is not a true ventilation modality) than NIV, the latter is more useful in the most severe patients (hypercapnic pulmonary edema, or respiratory fatigue). Meta-analyses and randomized controlled trials have shown that both CPAP and NIV decrease the need for intubation and improve physiological parameters (heart rate, dyspnea, hypercapnia, and acidemia), although there is conflicting evidence regarding their impact on mortality. Both should be used cautiously if the patient is hypotensive (systolic blood pressure (SBP) <90 mmHg) and should be avoided in cardiogenic shock.
Assessment of the circulation is aimed at identifying hemodynamic instability and evidence of cardiogenic shock. Only a minority of adult patients with AHF present with an SBP <90 mmHg (<8%) or cardiogenic shock (<3%); most present with a preserved (90–140 mmHg) or elevated (≥140 mmHg) SBP. ESC guidelines define cardiogenic shock in adults as an SBP <90 mmHg (with adequate volume) with clinical (cold extremities, oliguria, mental confusion, dizziness, and narrow pulse pressure) or laboratory (metabolic acidemia, elevated serum lactate, elevated serum creatinine) evidence of hypoperfusion.
In children, the clinical diagnosis of shock can be challenging, particularly in resource-limited settings. The 2016 emergency triage, assessment, and treatment guidelines developed by the World Health Organization (specifically for use in resource-limited settings) define shock as cold extremities with a capillary refill time >3 s and a weak, fast pulse (all signs must be present). When only one of these signs is present (i.e., capillary refill time >3 s or a weak, fast pulse or cold extremities), the patient meets the definition of “severely impaired circulation.” Patients with ARF (e.g., acute severe valvular regurgitation) or RHD (e.g., low output advanced end-stage chronic HF) may present with cardiogenic shock.
The initial management of adults and children with cardiogenic shock is summarized in Box 16.4 . Fluid resuscitation in patients with cardiogenic shock should only be indicated in those without pulmonary edema. Isotonic crystalloids such as normal saline or Lactated Ringer’s should be administered slowly to decrease the likelihood of exacerbating HF.
Adults
- 1.
IV fluid challenge only if no evidence of pulmonary edema
- •
Give 500 mL isotonic crystalloid over 15 min
- •
Repeat once if SBP remains <90 mmHg without evidence of pulmonary edema
- •
- 2.
IV vasoactive agents only if SBP remains <90 mmHg despite adequate filling and treatment of immediately reversible causes (see phase II)
- •
See Tables 16.3 and 16.4 for type and indication of vasoactive agent
- •
- 3.
IV diuretics should be considered if evidence of fluid overload once cardiac input has improved
- •
Give furosemide 40 mg IV bolus if the renal function is normal (consider higher doses if renal dysfunction)
- •
Other patients that might benefit from diuretics are those who are “wet and cold” (see phase IV) and with a “normal” BP, that is, not meeting the definition of cardiogenic shock
- •
Children
- 1.
IV fluid challenge: same principles as for adults
- •
Give 5–10 mL/kg over 10–20 min
- •
Target Perfusion and SBP: 70 mmHg + [2 × age in years] in children 1 month–10 years; ≥90 mmHg in children ≥10 years old
- •
- 2.
IV vasoactive agents: same principles as for adults (with age-adjusted BP targets)
- •
See Tables 16.3 and 16.4 for type and indication of vasoactive agent
- •
- 3.
IV diuretics: same principles as for adults
- •
Give 1 mg/kg IV bolus
- •
Vasoactive agents ( Tables 16.3 and 16.4 ) represent “rescue therapy” in cardiogenic shock. They are used to stabilize and salvage, or as a bridge to nonpharmacological management such as mechanical circulatory support (MCS), surgery, or transplantation. None of these agents improve outcomes and some may increase mortality. Because of these concerns, ESC guidelines restrict their use only in those who fulfill the definition of cardiogenic shock or in those who are symptomatically hypotensive. Given that there is no robust evidence base, choice of vasoactive agent often differs between institutions.
| Medication | Usual Infusion Dose | Receptor Binding | Hemodynamic Effects | |||
|---|---|---|---|---|---|---|
| α 1 | β 1 | β 2 | Dopamine | |||
| Inotropes/Vasopressors | ||||||
| Dopamine | 0.5–2 μg/kg/min | – | + | – | +++ | ↑ CO |
| 5–10 μg/kg/min | + | +++ | + | ++ | ↑↑ CO, ↑ SVR | |
| 10–20 μg/kg/min | +++ | ++ | – | ++ | ↑↑ SVR, ↑ CO | |
| Norepinephrine | 0.05–0.4 μg/kg/min | ++++ | ++ | + | – | ↑↑ SVR, ↑ CO |
| Epinephrine | 0.01–0.5 μg/kg/min | ++++ | ++++ | +++ | – | ↑↑ CO, ↑↑ SVR |
| Phenylephrine | 0.1–10 μg/kg/min | +++ | – | – | – | ↑↑ SVR |
| Vasopressin | 0.02–0.04 U/min | Stimulates V 1 receptors in VSM | ↑↑ SVR | |||
| Inodilators (Inotrope That Reduces Peripheral Vascular Resistance) | ||||||
| Dobutamine | 2.5–20 μg/kg/min | + | ++++ | ++ | – | ↑↑ CO, ↓ SVR, ↓ PVR |
| Isoproterenol | 2–20 μg/min | – | ++++ | +++ | – | ↑↑CO, ↓ SVR, ↓ PVR |
| Milrinone | 0.125–0.75 μg/kg/min | PDE III inhibitor | ↑CO, ↓ SVR, ↓ PVR | |||
| Levosimendan | 0.05–0.2 μg/kg/min | Myofilament Ca 2+ sensitizer, PD-3 inhibitor | ↑CO, ↓ SVR, ↓ PVR | |||
Diuretics are relatively ineffective in cardiogenic shock and should generally be avoided. However, diuretics can be used in fluid-overloaded patients receiving vasoactive agents who demonstrate evidence of improved cardiac output (e.g., improved SBP >90 mmHg, mental state, skin perfusion). Vasodilators are also often contraindicated in cardiogenic shock, although can be considered if the SBP has improved to ≥100 mmHg following treatment. The use of diuretics and vasodilators in AHF are discussed in detail in phase IV.
Immediate echocardiography is mandatory in patients with suspected cardiogenic shock (see also phase II). In addition to helping to confirm the underlying diagnosis, it can also help guide the need for IV fluids (preload insufficiency) and triage to more targeted medical therapy ( Table 16.4 ) or surgical intervention (e.g., emergency surgery for chordal rupture with a flail leaflet). A standard 12-lead ECG and continuous telemetry are also essential and may reveal a tachy- or bradyarrhythmia or myocardial ischemia, warranting an early invasive approach such as electrical cardioversion, pacing, or primary percutaneous coronary intervention. ECG and blood pressure monitoring are also recommended during inotrope/vasopressor use as they can cause arrhythmias and myocardial ischemia. Urine output should always be measured because it provides an assessment of the effectiveness of therapy, and an indirect measure of cardiac and renal function.
| Cause of Cardiogenic Shock | Vasoactive Management | Hemodynamic Rationale |
|---|---|---|
| Left Ventricular Dysfunction | Dobutamine or milrinone or other PDE III inhibitor Norepinephrine or higher dose dopamine (>5 μg/kg/min) Temporary MCS | Inodilator is used to increase cardiac output, increase BP, improve peripheral perfusion, and maintain end-organ perfusion Vasopressor added to inodilator if ongoing hypotension |
| Mitral Regurgitation | Norepinephrine or dopamine Dobutamine or milrinone Temporary MCS, including IABP | Vasopressor, although 1st line, may worsen degree of MR by increasing afterload If impaired LV contractility and ongoing hypotension, add inodilator IABP may reduce regurgitation fraction by reducing afterload and increasing CI |
| Mitral Stenosis | Phenylephrine or vasopressin Esmolol or amiodarone Electrical cardioversion PMBC | Shock resulting from MS is a preload-dependent state Aim to slow the HR and maintain atrioventricular synchrony Avoid agents that increase HR |
| Aortic Regurgitation | Dopamine Temporary pacing | Maintain an elevated HR (to shorten diastolic filling time and reduce LVEDP) |
| Aortic Stenosis | Phenylephrine or vasopressin If LVEF reduced, echo- or PAC-guided dobutamine titration | Shock caused by AS is an afterload-dependent state Inotropes may not improve hemodynamics if LVEF is preserved |
| Bradycardia | Chronotropic agents (atropine, isoproterenol, dopamine) Temporary pacing | Advanced heart block due to rheumatic carditis rarely (if ever) requires temporary pacing |
| Pericardial Tamponade | Fluid bolus Norepinephrine | Pericardiocentesis or surgical pericardial window required for definitive therapy |
Routine invasive hemodynamic evaluation, arterial line, or central venous line for diagnostic purposes are not indicated, but may be helpful in selected patients who are hemodynamically unstable with an unknown mechanism of deterioration.
Early warning scores, for both adults and children, are used in many HICs and some LMICs to identify deranged physiology as early as possible, thus prompting review by senior medical staff and/or admission to an intensive care setting ( Box 16.5 ). A combination of heart rate, respiratory rate, oxygen saturations, capillary refill time, and level of consciousness are more useful than a single parameter. In units where high-flow respiratory therapy is restricted to ICU, this would also be an indication for earlier transfer.
Need for intubation (or already intubated)
Signs and symptoms of hypoperfusion
S p O 2 <90%, despite supplemental oxygen
Use of accessory muscles for breathing, respiratory rate >25 breaths/min
Heart rate <40 beats/min or >130 beats/min, systolic blood pressure <90 mmHg
In those who remain critically unwell despite respiratory and pharmacological intervention, MCS, if available, such as the intraaortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), or ventricular assist devices can help achieve temporary stabilization before emergency surgery for valve repair or replacement. ECMO has been used successfully in the treatment of respiratory failure or cardiogenic shock resulting from fulminant rheumatic valvulitis. IABP is contraindicated in those with significant (more than mild) aortic regurgitation (AR) because it augments aortic diastolic pressures and worsens the severity of the regurgitant volume.
In many resource-limited settings, access to most of these monitoring and treatment modalities is not available. Patients are also more likely to present late in their illness, thus requiring more intensive and specialized intervention early in the management course. Malnourishment, severe anemia, and an increased background prevalence of infectious agents, such as falciparum malaria and tuberculous, often complicate management. These factors must be taken into consideration when tailoring the administration of fluids, blood products, and vasoactive medications. First-line vasoactive agents in resource-limited settings will vary depending on local protocols and drug availability, although a useful consideration is that dobutamine can be given through a peripheral line in settings where central line access is not available.
Phase II: Identification and treatment of acute etiologies or relevant triggers of AHF
As mentioned earlier, in patients presenting with suspected AHF secondary to ARF, it is important to consider acute valvular regurgitation. Factors that may trigger AHF in patients with RHD are summarized in Box 16.2 . Immediate bedside echocardiography is necessary in patients who are either hemodynamically unstable or in patients with a suspected life -threatening mechanical pathology. Box 16.6 summarizes the key elements in the echocardiographic evaluation of the acutely unwell patient with suspected AHF. Transthoracic echocardiography is usually sufficient for diagnosis by demonstrating the underlying mechanism. If inconclusive, transesophageal echocardiography usually clarifies the diagnosis and underlying mechanism and may be used in the planning of operative repair.
- •
Assess LV systolic function (and ideally LV size, presence of RWMAs)
- •
Valves
- •
exclude MR, MS, or AR
- •
exclude IE, flail leaflet
- •
assess prosthetic valve function
- •
- •
Exclude pericardial effusion
- •
Assess right ventricular size and function
- •
Estimate right atrial and pulmonary artery pressures
Acute valvular regurgitation
The medical management for organic causes of acute MR and acute AR leading to AHF is broadly similar. Diuretics and bed rest may be all that is required in patients with AHF secondary to severe valvular regurgitation as a consequence of acute rheumatic valvulitis. Most of these patients will stabilise over hours to days. Some experts also recommend corticosteroids in these patients, despite the absence of high-quality evidence (see Chapter 4 ). Diuretics and vasodilators (discussed in phase IV, later) help reduce left-ventricular end-diastolic pressure and provide symptomatic relief. Vasodilators also reduce afterload and can improve forward cardiac output. Their use may be limited by systemic hypotension, and it may be necessary to commence inotropes first to achieve a satisfactory blood pressure.
Nitroprusside (see phase IV) is the vasodilator of choice in both acute MR and AR, although it is used in fewer than 1% of patients with AHF in Europe and the United States. In acute MR, nitroprusside may reduce MR by up to 50%. Because the determinants of the regurgitant volume in acute AR include the duration of diastole and the diastolic transvalvular gradient, it is important to avoid bradycardia and arterial hypertension where possible.
Acute presentation of chronic disease
These patients often have advanced RHD, and it is important to consider and correct/treat the etiologies or triggers summarized in Box 16.2 . Otherwise, the mainstay of treatment is diuretics and vasodilators for the AHF episode, commencing/optimizing disease-modifying therapies for chronic HF once the patient is stable (discussed in Chapter 6) , and, importantly, mechanical or surgical intervention of the valve lesion(s) (discussed in Chapter 7, Chapter 8 , respectively).
Prosthetic valve dysfunction (mechanical and bioprosthetic valves)
The 2014 American Heart Association/American College of Cardiology (AHA/ACC) guidelines, the 2017 AHA/ACC focused update, and the 2017 European Society of Cardiology/European Association for Cardio-Thoracic Surgery (ESC/EACTS) valvular heart disease guidelines provide detailed recommendations for assessment and management of prosthetic valves.
Mechanical valve dysfunction may be due to (1) valve thrombosis, (2) pannus formation, or (3) infective endocarditis. The presentation can vary from mild dyspnea to severe acute pulmonary edema. Urgent diagnosis, evaluation, and therapy are indicated because rapid deterioration can occur if there is thrombus causing malfunction of leaflet opening. The 2017 AHA/ACC focused update recommends multimodality imaging with transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), fluoroscopy, and/or computed tomography (CT). Combined imaging may be more effective than one imaging modality alone to diagnose and characterize valve thrombosis. TTE allows correct alignment of the Doppler beam with transvalvular flow for measurement of velocity, gradient, and valve area.
Gradients should be compared to the baseline postoperative echocardiogram. Increasing valve gradients may indicate prosthetic valve dysfunction. However, the left atrial side of a prosthetic mitral valve is obscured by acoustic shadowing using TTE, so it is difficult to diagnose prosthetic mitral valve thrombus, pannus, or vegetation. TEE allows better images of the left atrial side of the mitral prosthesis. Fluoroscopy or CT imaging is very helpful to image aortic prosthetic leaflet motion. Differentiation of valve dysfunction due to thrombus versus fibrous tissue ingrowth (pannus) is challenging as the clinical presentations are similar. Thrombus is more likely when there is a history of inadequate anticoagulation and with more acute onset of symptoms. Auscultation may reveal diminished or abolished mechanical prosthetic clicks together with a new systolic or diastolic murmur.
Prosthetic valve thrombosis management
Mechanical left-sided prosthetic valve obstruction is a serious complication and if left untreated has high mortality and morbidity. Urgent therapy with either fibrinolytic agents or surgical intervention is indicated. As of 2014, the weight of the evidence favored surgical intervention for left-sided prosthetic valve thrombosis unless the patient was asymptomatic and the thrombus burden was small.
The 2017 ESC/EACTS guidelines favor urgent or emergency mechanical valve replacement in critically ill patients without serious comorbidity (class I recommendation) over fibrinolysis (class IIa). Fibrinolysis regimens include recombinant tissue plasminogen activator 10 mg bolus plus 90 mg over 90 min with unfractionated heparin or streptokinase 1,500,000 units over 60 min without unfractionated heparin. For bioprosthetic valve thrombosis, ESC/EACTS guidelines recommend anticoagulation using a vitamin K antagonist or unfractionated heparin before considering reintervention.
However, new data were presented in the 2017 AHA/ACC guidelines. The evidence indicates a 30-day surgical mortality rate of 10%–15%, with a lower mortality rate of <5% in patients with NYHA class I or II symptoms. Recent reports using an echocardiogram-guided slow-infusion low-dose fibrinolytic protocol has shown success rates >90%, with embolic event rates <2% and major bleeding rates <2%. Moreover, fibrinolytic therapy regimens can be successful even in patients with advanced NYHA class and larger-sized thrombi. The 2017 AHA/ACC guidelines recommend urgent initial therapy for symptomatic prosthetic mechanical valve thrombosis. However, the decision for surgery versus fibrinolysis is dependent on individual patient characteristics and experience and capabilities of the institution.
These improved outcomes with fibrinolytic therapy are of great importance to those with RHD who may have had their surgery remote from where they live, or surgery undertaken by a fly-in fly-out team to the region. Fibrinolytic therapy may be the only realistic option for RHD patients who develop mechanical valve thrombosis.
Prosthetic valve stenosis
Bioprosthetic valve degeneration causes increasing stenosis, is not altered by medical treatment, and is treated by cardiac surgery. Chronic thrombus or pannus formation impinging on the leaflet motion of the valve can cause increasing stenosis of mechanical valves reflected by increased gradients detected by TTE.
Other prosthetic valve complications
Severe intravascular hemolysis may be due to paravalvular leak. This can be treated with surgery or complex catheter techniques. The latter have success rates of 80%–85% in specialized centers. Patient-prosthesis mismatch may require reoperation.
Indications for surgery in bioprosthetic valve regurgitation are the same as for native valve regurgitation. The technology of valve-in-valve transcatheter techniques is a rapidly evolving field. Outcomes are comparable or better for bioprosthetic aortic valve regurgitation/stenosis compared to revisional surgery.
Pericardial tamponade
The signs and symptoms of pericarditis are a pericardial friction rub, positional chest pain, and sometimes reduced heart sounds (see also Chapter 3 ). Pericarditis is common in ARF with or without a small identifiable pericardial effusion but pericardial tamponade is rare. Patients with HF and a pericardial effusion usually have severe valve regurgitation. In this setting, the relative contribution of a moderate effusion to the signs and symptoms of HF may be hard to judge. In particular, tachycardia is common to both. However, an adult patient with unequivocal signs of tamponade, that is, tachycardia greater than that would be expected for the degree of valve regurgitation, hypotension (SBP <100 mmHg), pulsus paradoxus (an abnormally large decrease in SBP (>10 mmHg) with inspiration), jugular venous distension, Kussmaul’s sign (a paradoxical rise in jugular venous pressure with inspiration), muffled heart sounds, and echocardiographic signs of pericardial tamponade ( Box 16.7 ) may benefit from pericardial drainage. The pericardial fluid will usually be hemorrhagic with potential for blockage of pigtail catheters left to drain. The reduction of symptoms and signs of tamponade (e.g., tachycardia) may be less dramatic than seen in pericardial tamponade due to viral pericarditis or postpericardiotomy syndrome. Rheumatic pericarditis only very rarely leads to constrictive pericarditis.
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Collapse of the free wall of the right ventricle during diastole
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Reduction in the left ventricular cavity size on inspiration
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A decease in mitral inflow velocity or aortic velocity by >25% on inspiration
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Enlarged inferior vena cava diameter with no inspiratory variation
Tachyarrhythmia in chronic mitral stenosis
Patients with moderate or severe MS may deteriorate acutely, presenting with dyspnea and pulmonary edema or even cardiogenic shock. Some presentations may mimic acute respiratory distress syndrome, presenting with poor gas exchange and bilateral pulmonary infiltrates. Acute deterioration commonly occurs following an abrupt increase in heart rate or change in cardiac output, commonly seen with the onset of atrial fibrillation or immediately after delivery during labor. Subacute presentations due to increased cardiac output are more commonly seen with pregnancy, in the peripartum period or anemia. A thorough search for potential triggers is therefore important as it will often help guide the most appropriate therapy.
The management of unwell patients with MS who develop an acute tachyarrhythmia is broadly the same as patients who do not have MS, i.e. determining whether the patient is stable or unstable. Hemodynamically unstable tachycardia is usually defined as a heart rate ≥150 beats/min plus any of the following: hypotension (SBP <90 mmHg), acutely altered mental status, signs of shock, ischemic chest discomfort, or evidence of AHF. If any of these signs are present, an anesthetist should be called in preparation for synchronized DC cardioversion (the initial recommended doses varies depending on the guideline used). Conversely, in patients with hemodynamically stable tachycardias, cardioversion is usually not the first-line therapeutic option. Instead, a 12-lead ECG should be recorded to help guide targeted pharmacological management based on the type of tachyarrhythmia ( Table 16.5 ).
| Drug | Dose (intravenous) | Comment |
|---|---|---|
| Atrial Fibrillation, Atrial Flutter, or Atrial Tachycardia | ||
| Esmolol | Adult : loading dose 500 mcg/kg over 1 min, followed by 50 mcg/kg over 4 min Child : loading dose 100–500 mcg/kg over 1 min, followed by 100–500 mcg/kg/min continuous infusion | Short half-life (8 min), useful if concerned about hypotension |
| Metoprolol | Adult : 5 mg over 5 min Child : not used | May cause hypotension Dose can be repeated after 5 min if required, up to maximum of 10–15 mg |
| Verapamil | Adult : 2.5–5 mg over 5 min, repeat every 15–30 min if required to max dose of 15 mg Child (1–15-year-old): 0.1–0.3 mg/kg IV –1, up to 5 mg 1st dose, 2nd dose up to 10 mg after 30 min | May cause hypotension Contraindicated if concomitant beta-blocker use or heart failure |
| Digoxin | Adult : 500–1000 mcg over 1 h Child : 15 mcg/kg stat and 5 mcg/kg after 6 h, then 3–5 mcg/kg. Rarely given as dose | Digoxin ± amiodarone are the preferred agents in patients with structural heart disease and reduced LVEF; however, both agents should be used with caution. Digoxin levels should be checked after 6 h |
| Amiodarone | Adult : loading dose 300 mg over 20 min via central line; maintenance 900–1200 mg over 24 h Child : Loading dose 25 mcg/kg/min for 4 h; maintenance 5–15 mcg/kg/min | |
| Supraventricular tachycardia (AVNRT and AVRT) | ||
| Adenosine | Adult : 1st dose 6 mg, repeat dosing after 2 min if no response; 2nd dose 12 mg, 3rd dose 18 mg Child : <50 kg 0.05–0.1 mg/kg × 1, then increase by 0.05–0.1 mg/kg to max 0.3 mg/kg, up to 12 mg/dose Child : >50 kg 1st dose 6 mg IV, 2nd dose 12 mg | Vagal maneuvers are usually performed before adenosine Contraindicated in severe bronchospastic airways disease and coronary artery disease IV bolus should be given via wide-bore cannula followed by rapid saline flush |
| Verapamil | As discussed earlier | |
| Esmolol and metoprolol | As discussed earlier | |
| Sustained Monomorphic Ventricular Tachycardia | ||
| Amiodarone | As discussed earlier | There is no consensus on which drug should be used first Lidocaine does not cause hypotension, unlike amiodarone and procainamide, and can also be given more quickly Amiodarone is slower in action than lidocaine and procainamide but has a major role in suppression of recurrent episodes |
| Lidocaine | Adult : loading dose 1.5 mg/kg over 2 min; maintenance 1–4 mg/min Child : 1 mg/kg × 1, can repeat dose after 10–15 min up to total dose of 3–5 mg/kg in 1st hour | |
| Procainamide | Adult : 20–50 mg/min until arrhythmia terminates or a max dose of 15–17 mg/kg is administered Child : 15 mg/kg ×1 or 3–6 mg/kg up to 100 mg every 5–10 min | |
The primary therapeutic aim is a reduction in heart rate. Diuretics and nitrates may also be considered as they will reduce LA pressures and provide symptomatic relief from pulmonary congestion, although should be used with caution as they can reduce LV filling and lead to a significant drop in stroke volume and cardiac output. In those with sinus tachycardia, treatment should be targeted at the underlying cause, such as pain, anxiety, sepsis, hypoxemia, anemia, and thyrotoxicosis.
In patients with significant MS presenting with decompensated AHF, the threshold for percutaneous mitral balloon commissurotomy (PMBC) is lower than that for surgery, as surgical mortality in this context is very high (ranging from 20% to 50%). PMBC is also the treatment of choice as a “bridge to surgery” in those who are too unwell for immediate surgery or during pregnancy (best undertaken in the second trimester).
Advanced heart block
Advanced atrioventricular (AV) block with second degree AV block, complete heart block, and accelerated junctional rhythm may occur in ARF, although are seldom associated with cardiac compromise and symptoms. Patients should be monitored with cardiac monitoring and frequent ECGs. Monitoring will reveal return of AV synchrony for short periods, then permanently. Pacing should be avoided in most cases as return to sinus rhythm occurs spontaneously, although permanent pacemaker implantation has been reported, probably as the natural history was not understood. If pacing is decided upon, a temporary pacing lead rather than permanent pacemaker implantation is recommended. Paradoxically, advanced AV block has been associated with milder degrees of valvulitis (see Chapter 3 ).
AV block with tachycardia is more common than bradycardia in ARF cases. The resulting accelerated junctional tachycardia results in a junctional rate faster than the sinus rate. Cardiac monitoring may reveal sinus tachycardia (with first-degree block) alternating with the accelerated junctional tachycardia (with AV block by definition) at similar or slightly faster rates. Corticosteroids appear an intuitive treatment and are often given (for AV block with bradycardia or tachycardia) but this has not been tested in an randomized control trial (RCT). In conclusion, the presence of advanced AV block in a patient with suspected ARF is useful diagnostically, requires cardiac monitoring, but is expected to resolve spontaneously.
Phase III: Diagnostic work-up to confirm acute heart failure
Once the acute therapeutic processes in phases I and II have been completed (if required) and the patient hospitalized, an important next step is to complete the diagnostic work-up. Phase III also involves excluding alternative etiologies that might explain the presentation, such as acute renal failure, pneumonia, asthma, and anemia.
ESC guidelines recommend that the diagnosis of AHF should be based on clinical history ( Box 16.3 and Table 16.6 ) and examination ( Table 16.6 ); prior cardiovascular history, including any potential cardiac and noncardiac precipitants ( Box 16.2 ); and appropriate early investigations ( Table 16.7 ).
Related posts:
Pathogenesis of Acute Rheumatic Fever
Clinical Evaluation and Diagnosis of Acute Rheumatic Fever
Surgical Management of Rheumatic Valvular Heart Disease
Rheumatic Heart Disease in Pregnancy
Primary Prevention of Acute Rheumatic Fever and Rheumatic Heart Disease
Secondary Prevention of Acute Rheumatic Fever and Rheumatic Heart Disease
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