Focal mechanisms underlying ventricular tachycardia during prolonged ischemic cardiomyopathy
Abstract
The present study was performed to define the mechanisms underlying spontaneously occurring ventricular arrhythmias in the failing heart. Three-dimensional cardiac mapping from as many as 232 intramural sites was performed in five dogs with ischemic cardiomyopathy induced by multiple intracoronary embolizations. After 5 to 10 weekly embolizations with 90-microns latex microspheres into the left anterior and circumflex coronary arteries, left ventricular ejection fraction decreased from 63 +/- 3% to 22 +/- 3%. Subsequent weekly Holter monitoring of dogs in the conscious state demonstrated frequent multiform premature ventricular complexes (PVCs) (< or = 2000/d), couplets, and runs of ventricular tachycardia (VT) (< or = 70 beats in duration and < or = 560 beats per minute) in all dogs. Three-dimensional mapping of spontaneous rhythm for 60 minutes was performed an average of 6.4 weeks after the last embolization, during which time each dog demonstrated multiform PVCs, couplets, and runs of nonsustained VT at rates comparable to those in the conscious state. Mapping was of sufficient density to define the mechanism for 31 PVCs, 45 beats of ventricular couplets, and 99 beats of VT. Sinus beats preceding PVCs (n = 36) initiated in ...Continue Reading
References
Electrophysiologic consequences of chronic experimentally induced left ventricular pressure overload
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