Premium
T Wave Alternans Threshold Late After Repair of Tetralogy of Fallot
Author(s) -
CHEUNG MICHAEL M.H.,
WEINTRAUB ROBERT G.,
COHEN RICHARD J.,
KARL TOM R.,
WILKINSON JAMES L.,
DAVIS ANDREW M.
Publication year - 2002
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2002.00657.x
Subject(s) - medicine , tetralogy of fallot , t wave alternans , asymptomatic , cardiology , qrs complex , heart disease , sudden cardiac death
TWA Threshold After TOF Repair.Introduction: Sustained microvolt‐level T wave alternans (TWA) is a marker of increased risk for malignant ventricular arrhythmia. There is a significant risk of arrhythmia and sudden death after repair of congenital heart disease. The aim of this study was to determine the prevalence and characteristics of TWA after repair of tetralogy of Fallot (TOF). Methods and Results: TWA was evaluated during bicycle exercise in 49 subjects who had consecutively undergone transatrial‐transpulmonary repair. Median values for age, age at repair, and follow‐up duration were 14.9 years (11.5–20.8), 1.6 years (0.2–4.9), and 11.6 years (9.4–17.2), respectively. All patients were in New York Heart Association functional class I and were asymptomatic. Median QRS duration was 120 msec (80–150). Sustained TWA was detected in 7 (23%) of 31 subjects with adequate tests. In these 7 subjects, median onset heart rate (HR) was 120 (98–155). Median HR threshold as a percentage of predicted maximum HR (220 – age) was 58%(48–77). Sustained TWA prevalence was not significantly different compared with normal subjects (7/31 vs 9/83; P = 0.1 ). Onset HR in the TOF group was significantly lower [mean (SD) of 122 (20) vs 139 (12), P < 0.05]. In the TOF group with sustained TWA, the TWA occurred in 4 of 7 at < 60% predicted maximum HR versus 1 of 9 normal subjects ( P < 0.05 ); 3 of 7 had onset HR < 120 versus 0 of 9 normal subjects ( P < 0.03 ). There was no significant difference in age, gender, transannular patch use, restrictive right ventricular physiology, QRS duration, QTc, QT/QRS dispersion, or nonsustained ventricular tachycardia in subjects with or those without sustained TWA. Conclusion: The onset HR for sustained TWA is significantly lower after repair of TOF. Further study is required to determine whether this represents an increased risk for arrhythmia in this patient group.