By: Mahmoud Negm, Assistant lecturer ECG cases By: Mahmoud Negm, Assistant lecturer

Case No. 1

A 74-year-old woman with a distant history of rheumatic fever presents with dyspnea, hemoptysis, palpitations, and a murmur

1. Interpret this ECG. 2. What is the likely diagnosis?

1. The heart rate is 72 beats/min 1. The heart rate is 72 beats/min. There is no organized atrial activity, and the rhythm is “irregularly irregular” most consistent with coarse atrial fibrillation. Although one may be tempted to diagnose atrial flutter on the basis of “flutter waves” in lead V1, the inferior leads do not demonstrate the classic sawtooth pattern of atrial flutter.

Further supporting the diagnosis of coarse atrial fibrillation, the rhythm is highly irregular with each R–R interval different from the next. The axis is rightward. Coupled with a tall R wave in V1, this finding suggests right ventricular hypertrophy.

Finally, there are diffuse downsloping ST segments with inverted T waves. The morphology of these ST-T waves can be characterized as “sagging” or “scooped” and looks quite distinct from myocardial ischemia. The ST-segment and T-wave abnormality seen here is consistent with digoxin effect.

2. The findings of atrial fibrillation and right ventricular hypertrophy in the setting of prior rheumatic fever suggest mitral stenosis.

Case No. 2

22-year-old young woman with profound weight loss and poor oral intake.

1. What are the findings? 2. What do you expect the laboratory studies to demonstrate?

1. The heart rate is 66 beats/min and sinus rhythm is present as evidenced by low amplitude, otherwise normal-appearing P waves in lead I. The axis is rightward. There is no evidence of chamber enlargement. There are diffuse ST-segment depressions with inverted T waves. Best seen in lead V2 is a large U wave merging with the T wave (positive deflection at the terminal portion of the T wave).

2. The presence of U waves and the diffusely abnormal ST segments coupled with the clinical history suggest hypokalemia. In fact, this patient presented with lethargy, malnutrition, and multiple electrolyte abnormalities including a potassium of 1.8.

Case No. 3

An 83-year-old female presents to the emergency department after 2 syncopal episodes at home.

1. What rhythm is present on this ECG. 2 1. What rhythm is present on this ECG? 2. What treatment (if any) is indicated for this patient based on the ECG findings?

The atrial rhythm is sinus at a rate of 100 beats/min The atrial rhythm is sinus at a rate of 100 beats/min. The P waves and QRS complexes do not bear any obvious relationship to each other and atrioventricular dissociation is present. The ventricular rate is approximately 42 beats/min. The presence of AV dissociation with an atrial rate faster than ventricular rate is diagnostic of complete heart block. The QRS complex has left bundle branch block morphology and a normal axis.

P waves, denoted with asterisks, march out independently of the QRS complexes, denoted with arrows. The atrial rate is faster than the ventricular rate. This is diagnostic of complete heart block.

The patient has symptomatic bradycardia secondary to complete heart block. She should be referred for placement of a permanent pacemaker. Whether a temporary pacemaker is indicated in the interim would depend on the patient’s blood pressure, clinical status, and symptoms; if needed, transcutaneous or transvenous pacing could be instituted while awaiting permanent device placement.

Thank you