Exercise-induced STV1 elevation: a sign of right ventricular dysfunction in recent inferior myocardial infarction

Little is known about exercise-induced electrocardiographic ST segment shift in right-sided precordial leads, especially elevated ST in patients with subacute inferior myocardial infarction.

To test the clinical significance of exercise-induced STV1 deviation with special regard to right ventricular function and right ventricular involvement.

Sixty-eight patients with recent inferior myocardial infarction (without having a left descending arterial lesion) aged 30 to 73 years (mean +/- SD, 59.1 +/- 10.0) were investigated with respect to biventricular function observed in radionuclide ventriculography and treadmill stress electrocardiographic findings.

STV1 shift during exercise (delta STV1) had a negative linear logarithmic relationship only with the right ventricular ejection fraction (RVEF) and no correlation with the left ventricular ejection fraction (delta STV1 = 6.7604-1.7528xlnRVEF, r = 0.709, P = 0.0001). Significant STV1 elevation (delta STV1 of 0.5 mm or more) predicted right ventricular dysfunction (RVEF of 40% or less) and right ventricular infarction with sensitivities of 76% and 77%, specificities of 88% and 92%, and accuracies of 84% and 77%, respectively. Twenty patients with STV1 elevation (0.5 mm or more) showed nearly identical rest and exercise electrocardiographic findings, exercise capacities and similar stenotic lesions on coronary angiography, to 43 patients without significant STV1 elevation. Elective balloon angioplasty reduced the delta STV1 during exercise in only three of six patients (50%) with right ventricular infarction.

Exercise-induced STV1 elevation may be a useful indicator of global right ventricular dysfunction and/or right ventricular infarction in the subacute phase of myocardial inferior infarction.