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Nonuniform recovery of excitability in the left ventricle
J A Vassallo1, D M Cassidy, K E Kindwall
1Clinical Electrophysiology Laboratory, Hospital of the University of Pennsylvania, Philadelphia 19104.
Insights
Patients with coronary artery disease and ventricular tachycardia showed longer left ventricular activation and recovery time. Long QT syndrome patients exhibited greater dispersion of refractoriness, indicating distinct electrical abnormalities in these heart conditions.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Ventricular tachycardia (VT) and long QT syndrome (LQTS) are serious cardiac arrhythmias.
- Understanding the electrical properties of the left ventricle is crucial for managing these conditions.
Purpose of the Study:
- To compare left ventricular activation, refractoriness dispersion, and recovery time in patients with coronary artery disease (CAD) and VT, LQTS, and healthy individuals.
- To elucidate the electrophysiological differences underlying these arrhythmias.
Main Methods:
- Left ventricular endocardial catheter mapping was performed in 18 patients.
- Refractory periods were determined in three groups: healthy controls, patients with CAD and VT, and patients with LQTS and cardiac arrest.
Main Results:
- Left ventricular endocardial activation was significantly longer in CAD/VT patients (75 msec) versus controls (34 msec) and LQTS patients (42 msec).
- Dispersion of refractoriness was significantly greater in LQTS patients (87 msec) compared to controls (40 msec) and CAD/VT patients (53 msec).
- Dispersion of total recovery time was significantly greater in CAD/VT patients (90 msec) and LQTS patients (114 msec) compared to controls (52 msec).
Conclusions:
- Patients with CAD and VT have prolonged left ventricular activation and recovery time.
- Patients with LQTS exhibit increased dispersion of refractoriness.
- These findings highlight distinct electrophysiological abnormalities in VT and LQTS, aiding in understanding and managing these arrhythmias.
Abstract:
The purpose of this study was to determine left ventricular activation, dispersion of refractoriness, and total recovery time in patients with coronary artery disease and ventricular tachycardia and in patients with the long QT syndrome and to compare these patients with a group of normal patients. Left ventricular endocardial catheter mapping and left ventricular refractory period determination were performed in 18 patients. Group 1 consisted of seven patients with no heart disease and no arrhythmia; group 2 consisted of six patients with previous infarction and sustained ventricular tachycardia; and group 3 consisted of five patients with prolonged QT interval and previous cardiac arrest. Total left ventricular endocardial activation was significantly longer in group 2 (75 +/- 23 msec, mean +/- SD) compared with group 1 (34 +/- 9 msec, p less than 0.01) and group 3 (42 +/- 5 msec, p less than 0.05). Dispersion of refractoriness was significantly greater in group 3 (87 +/- 27 msec) than in group 1 (40 +/- 14 msec, p less than 0.01) and group 2 (53 +/- 14 msec, p less than 0.05). Dispersion of total recovery time was significantly greater in group 2 (90 +/- 30 msec) than in group 1 (52 +/- 14 msec, p less than 0.05) as well as group 3 (114 +/- 43 msec) compared with group 1 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)