The usefulness of microvolt T-wave alternans in the risk stratification of patients with hypertrophic cardiomyopathy.
BACKGROUND
Patients with hypertrophic cardiomyopathy are prone to ventricular arrhythmias and sudden death. Identifying patients at risk of sudden death is difficult.


OBJECTIVE
To determine whether microvolt T-wave alternans detected during exercise or rapid atrial pacing can identify patients with HCM who are at risk of ventricular arrhythmias and sudden death.


METHODS
This prospective observational study included 21 patients with HCM: the disease was abstructive in 11, nonobstructive in 9 and apical in 1. TWA was measured while the patients were on anti-arrhythmic medication.


RESULTS
TWA was positive in 9 patients (43%) and negative in 12 (57%). Three patients were resuscitated after sudden death before their enrollment in the study and two patients developed ventricular tachycardia and fibrillation respectively during the study period. After combining the endpoint of sudden death from a ventricular arrhythmia and the presence of ventricular arrhythmias on a Holter monitor, there was no significant correlation between the presence of a positive TWA and the presence of ventricular arrhythmias on the Holter monitor or a history of sudden death.


CONCLUSIONS
TWA cannot be used as a non-invasive test for detecting patients with HCM and electrical instability. TWA is not useful for predicting sudden death in patients with HCM.
Fuchs
Therese
T
Arrhythmia Service, Assaf Harofeh Medical Center, Zerifin, Israel. therese@fuchs.org
Torjman
Amram
A
D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage; D002304:Cardiac Pacing, Artificial; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003645:Death, Sudden / Q000209:etiology; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000209:etiology
D000889:Anti-Arrhythmia Agents