Effect of coronary artery recanalization on right ventricular function in patients with acute myocardial infarction.

The effects of coronary artery recanalization by intracoronary administration of streptokinase on left ventricular function during acute myocardial infarction have received increasing attention in recent years. Although myocardial dysfunction is often more pronounced in the right ventricle than in the left ventricle in patients with acute inferior wall myocardial infarction, the effect of coronary artery recanalization on right ventricular dysfunction has not been previously addressed. Accordingly, in this investigation, 54 patients who participated in a prospective, controlled, randomized trial of recanalization during acute myocardial infarction were studied. Among 30 patients with inferior wall infarction, 19 had right ventricular dysfunction on admission; 11 of these 19 had positive uptake of technetium-99m pyrophosphate in the right ventricle, indicative of right ventricular infarction. Patients with successful recanalization (n = 6) exhibited improved right ventricular ejection fraction from admission to day 10 (26 +/- 7 to 39 +/- 14%, p less than 0.03). However, control patients (n = 6) and patients who did not undergo recanalization (n = 7) also exhibited improvement (20 +/- 7 to 29 +/- 11% [p less than 0.02] and 30 +/- 8 to 40 +/- 6% [p less than 0.03], respectively). Improvement in several other variables of right ventricular dysfunction evolved at an equal rate with the ejection fraction changes. Patients with or without right ventricular infarction improved similarly. These data indicate that the right ventricular dysfunction commonly associated with inferior wall infarction is often transient, and improvement is the rule, irrespective of early recanalization of the "infarct vessel."

Transluminal coronary angioplasty in the elderly.

The safety and clinical efficacy of percutaneous transluminal coronary angioplasty (PTCA) in elderly patients has not been established. Of 639 PTCAs performed between March 1980 and May 1984, 119 patients were 65 years or older (mean 70 years). On angiography, elderly patients differed only in the more frequent occurrence of visible calcific deposits (26% vs 8% in younger patients, p less than 0.01). Primary success was achieved in 81%, vs 80% in patients younger than 65 years. Major complication rates were comparable to those of younger patients: emergency coronary artery bypass surgery, 4.1% vs 4.7%; acute myocardial infarction, 2.5% vs 2.9%; and death, 0.8% vs 0. Late clinical follow-up ranging from 5 to 50 months (mean 18) showed that symptomatic improvement was achieved in 91% of patients in whom PTCA was successful, with 55% being asymptomatic. Seventy percent of patients were as active or more active (30%) than before PTCA and 47% were taking fewer medications. Four late deaths occurred, none from cardiac causes. These data support the safety and clinical effectiveness of PTCA in elderly patients and justify the extension of indications for PTCA to selected patients with multivessel disease in this age group.

Serial electrophysiologic testing with a permanent pacemaker after acute myocardial infarction.

Electrophysiologic testing in patients after acute myocardial infarction may predict subsequent sudden death. We used a permanent pacemaker for repetitive electrophysiologic testing in a patient after acute infarction. Programmed, twice-threshold ventricular extrastimulation at two weeks after anteroseptal infarction failed to induce ventricular tachycardia. Subsequent programmed extrastimulation induced sustained ventricular tachycardia on four occasions (6, 16, 29 and 65 weeks) after infarction. As yet (20 months), spontaneous ventricular tachycardia has not occurred. Firm conclusions cannot be drawn from a single case. However, our patient developed a stable ventricular tachycardia circuit which was not apparent at two weeks. Thus, a single electrophysiologic study performed acutely after infarction may not accurately describe the potential for ventricular tachycardia or fibrillation. Serial electrophysiologic testing with an implantable externally triggered pacemaker may more accurately describe the potential for sudden death post-infarction in a few high-risk patients. This report shows that induction of ventricular tachycardia after acute infarction may not predict outcome.