By Ken Grauer, MD

Professor Emeritus in Family Medicine, College of Medicine, University of Florida

The ECG in the figure below was obtained from a middle-aged woman who presented with a febrile illness and shortness of breath. She reported no chest pain. In addition to the rhythm, what else is going on?

The obvious finding in this 12-lead ECG and long lead II rhythm strip is ventricular bigeminy as every other beat is a premature ventricular contraction (PVC). Especially because of the large size of the PVCs, our attention is easily diverted from an even more important finding on this tracing.

Each even numbered beat on this ECG is sinus-conducted. Focusing attention on the ST-segment and T waves for each sinus-conducted beat, note the ST-segment is coved with a straight “take-off” in each inferior lead. There is subtle-but-definite ST elevation in lead III and a lesser degree of ST elevation for the tiny QRS complex in lead aVF. There is reciprocal ST depression in both high-lateral leads (leads I and aVL). There is early transition, with abrupt development of a predominant R wave already by lead V2. The ST-segment is abnormally straightened in each of the six chest leads. Each chest lead manifests some degree of ST depression, which is maximal for sinus-conducted beats 8 and 10 in lead V3.

The rhythm in the figure is ventricular bigeminy. Despite the lack of chest pain, the ECG in the figure suggests this patient has experienced a recent (if not acute) inferior-posterior myocardial infarction. It is estimated that at least one-quarter of all myocardial infarctions are “silent” (i.e., occur in the absence of chest pain). This case provides an example of this that might not have been noticed had it not been for the abnormal cardiac rhythm.

For more information about and further discussion of this case, please click here.