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Myocardial Mechanics Before and After Ablation of Chronic Tachycardia
Author(s) -
FISHBERGER STEVEN B.,
GOLAN STEVEN D.,
SAUL J. PHILIP,
MAYER JOHN E.,
WALSH EDWARD P.
Publication year - 1996
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1996.tb04789.x
Subject(s) - medicine , cardiology , tachycardia , afterload , preload , contractility , cardiomyopathy , ventricular tachycardia , dilated cardiomyopathy , heart failure , anesthesia , hemodynamics
Chronic tachycardia has been shown to cause a congestive cardiomyopathy; however, previous methods of evaluating ventricular function are highly dependent on cardiac loading conditions. Mean velocity of fiber shortening and its relation to end‐systolic wall stress (ESS) is a preload independent index of contractility that incorporates afterload. We reviewed 33 patients (aged 6 months to 20 years; mean 9.7 years) with ectopic atrial tachycardia (EAT) (n = 19), permanent functional reciprocating tachycardia (PfRT) (n = 12), or ventricular tachycardia (n = 2). who underwent nonpharniacological elimination of tachycardia; 28 by radiofrequency ablation and 5 surgically. Ventricular function was evaluated by echocardiographic measurements of shortening fraction, mean velocity of shortening corrected for heart rate (VcFc), and afterload as ESS. Contractility, expressed as the stress‐velocity index, was determined by comparing the ESS/VcFc relation to the predicted normal VcFc for the measured ESS. Myocardial dysfunction was seen in 21 patients: 13 with EAT; 7 with PJRT; and 1 with ventricular tachycardia. In patients with EAT, the mean heart rate in tachycardia was significantly faster in those with dysfunction than in those without dysfunction (176.8 ± 32.2 vs 136.7 ± 28.2; P < 0.02). Of the 21 patients with dysfunction, full recovery was seen in 17 of 18 patients restudied after intervention (mean 17.5 ± 17.6 weeks), and the remaining patient improved markedly, but did not normalize entirely. Dysfunction, seen in 64% of young patients with chronic tachycardia, was due to depressed myocardial contractility, and is generally reversible within 3 months of definitive therapy.