Polymorphous ventricular tachycardia associated with acute myocardial infarction

Area of Science:

• Cardiology
• Electrophysiology
• Internal Medicine

Background:

• Polymorphous ventricular tachycardia (PVT) can occur post-myocardial infarction (MI).
• This study investigated 11 patients who developed PVT 1-13 days after acute anterior or inferior MI.
• Patients typically had normal QT intervals and no significant electrolyte abnormalities.

Purpose of the Study:

• To determine the characteristics and effective treatments for post-myocardial infarction polymorphous ventricular tachycardia.
• To assess the relationship between PVT, QT interval, sinus node function, and electrolytes.
• To evaluate the efficacy of various antiarrhythmic drugs and revascularization strategies.

Main Methods:

• Observational study of 11 patients with post-MI PVT.
• Analysis of electrocardiographic parameters (QT, QTc), heart rate, and serum electrolytes.
• Evaluation of treatment responses to lidocaine, procainamide, bretylium, amiodarone, nitroglycerin, overdrive pacing, and coronary revascularization.

Main Results:

• Nine of 11 patients experienced recurrent myocardial ischemia before PVT onset.
• Class I antiarrhythmics (lidocaine, procainamide) and bretylium were largely ineffective.
• Intravenous amiodarone was effective in four patients; nitroglycerin in one.
• Coronary revascularization successfully treated PVT in two patients with recurrent ischemia and angina.

Conclusions:

• Post-MI PVT is not consistently associated with prolonged QT, bradycardia, or electrolyte imbalances.
• Variable response to antiarrhythmics; amiodarone shows potential.
• Recurrent myocardial ischemia is a common trigger for PVT.
• Coronary revascularization is effective for PVT associated with postinfarction angina.