# Teaching Visual: How to Interpret an Electrocardiogram

Chapter 12
Teaching Visual: How to Interpret an Electrocardiogram

Jessica L. Israel MD

#### Objectives

Develop a systematic approach to ECG interpretation.

Create a narrative description of ECG findings.

Apply this systematic approach and narrative description techniques to the interpretation of three commonly encountered ECGs and two rhythm strips.

### INTRODUCTION: WHO SHOULD HAVE AN ECG?

In general, ECGs should be done for patients with cardiac complaints or in those who present with related complaints secondary to other cardiovascular or pulmonary disease. Outpatient ECGs are helpful to document a known ECG abnormality, which may serve as a useful comparison in the future, and for preoperative screening in the appropriate patient.

### DEVELOPING A SYSTEMATIC APPROACH

Figure 12-1 (From Goldberger AL. Clinical electrocardiography: a simplified approach. 7th ed. Philadelphia: Mosby; 2006, p. 44, question 1.)

A systematic stepwise approach includes examination in five major areas of the ECG tracing in the following order:

#### Step 1: Determining the Rate

To calculate the rate, find an R wave that is lined up with a heavy border of a background grid box. After this, you simply count down until your next R wave appears. The counting is specific: the distance to the next grid line is 300 bpm, to the second grid line is 150 bpm, the third is 100 bpm, the fourth is 75 bpm, the fifth is 60 bpm, and the sixth is 50 bpm. Often the next R wave will appear between two major grid lines, and in these cases you simply estimate the rate. For example, if your rate determination falls exactly between the 75 and the 60 line, you can perhaps estimate the heart rate at 68 bpm. Note: to be precise the distance between two heavy grid lines is 1/300 of a minute. Therefore, the distance between two heavy grid lines is 2/300, and three grid lines is 3/300, which can be simplified to 1/150 and 1/100, respectively. That’s where these numbers come from, so committing them to memory can be helpful.

Oct 3, 2016 | Posted by in MANUAL THERAPIST | Comments Off on Teaching Visual: How to Interpret an Electrocardiogram
Premium Wordpress Themes by UFO Themes