The effect of left ventricular aneurysmectomy on the electrocardiogram: a study of 77 patients and review of the literature

Discordance of diagnosis of ventricular aneurysm made by the electrocardiogram and myocardial imaging: “ST-segment counterpoise” as a hypothetical mechanism

There is a discordance between ECG and imaging modalities in the diagnosis of ventricular aneurysm (VA) consequent to an old myocardial infarction. A hypothesis is being proposed that this discordance, which results in electrocardiograms (ECGs) not showing ST-segment elevations (+ST) in patients with proven by imaging modalities to have VA (false negative, low diagnostic sensitivity), may be due to "ST-segment counterpoise," rendering the ECG isoelectric. Accordingly, +ST generated by myocardial territories involved with the VA, when poised opposite each other, cancel out via vectorial summation, rendering the ECG falsely negative for VA. Also, a misalignment of the apex longitudinal axis with the left ventricular inflow axis due to myocardial remodeling from the VA (boot-shaped heart) when the apex and another myocardial region are involved with VA leads to +ST cancellation and a false-negative ECG for VA. ST-segment counterpoise as a mechanism rendering the ECG falsely negative for VA can be tested in the future if studies of patients with VA adopt in their methodologies a systematic reporting of severity and topography [corrected] of the regional left ventricular contraction abnormalities, as recommended by the American Society of Echocardiography.

ST segment elevation with ventricular aneurysm: results of encircling endocardial ventriculotomy

The ST segment elevation characteristic of ventricular aneurysm is thought to represent unmodified repolarization of the opposing wall or to arise from viable tissue at the border of the scar because of ischemia, traction or the non-uniform injury that is the architecture for ventricular tachycardia. Encircling endocardial ventriculotomy to prevent tachycardia interrupts coronary perfusion to the viable tissue bordering the scar, with noticeable loss of electrical and mechanical function. Five patients had anterior or apical aneurysms resected and encircled to treat recurrent ventricular tachycardia. ECGs were examined 49 days +/- 12 SEM post-operatively. Encircling did not eliminate their ST segment elevation. Only one patient had less ST elevation post-operatively. Thus ST elevation associated with aneurysms does not arise from viable tissue at the edge of the scar because it persists after this tissue is damaged by encircling endocardial ventriculotomy.