Dyspnea Confines Woman to Wheelchair

ANSWER

The ECG shows normal sinus rhythm, right atrial enlargement, a left anterior fascicular block, and evidence of an old anterolateral MI. Normal sinus rhythm is evidenced by the presence of a P wave for each QRS complex at a rate of 60 to 100 beats/min. Right atrial enlargement is diagnosed by the presence of tall, peaked P waves ≥ 2.5 mm in leads II, III, and aVF, and is a result of the patient’s pulmonary hypertension (P pulmonale).

A left anterior fascicular block is evidenced by the presence of left-axis deviation (typically between –45° and –90°), small R and large S complexes in leads II, III, and aVF, small Q waves in leads I and aVL, a QRS duration < 120 ms, and poor R-wave progression in leads V₁ to V₃ and deep S waves in V₅ to V₆.

The usual criteria for an anterolateral MI include Q, QS, or QRS complexes in leads V4 to V6 with ST-T wave changes. Poor R-wave progression in the absence of Q, QS, or QRS complexes in the anterolateral precordial leads (seen in this ECG) is also consistent with an old anterolateral MI.