What is the clinical evidence from this study?

Study design: Observational. Population: Hypertrophic Cardiomyopathy (n=53). Intervention: T-wave alternans (TWA) positivity vs. T-wave alternans (TWA) negativity. Primary outcome: Incidence of nonsustained ventricular tachycardia (NSVT) (p=<0.01).

January 1, 2002Open Access

Clinical Significance of T-Wave Alternans in Hypertrophic Cardiomyopathy.

Q: What are the key findings of this study?

T-wave alternans positivity in patients with hypertrophic cardiomyopathy was significantly associated with a higher incidence of nonsustained ventricular tachycardia (37% vs 0%) and greater myocardial disarray.

Key Result

T-wave alternans positivity in patients with hypertrophic cardiomyopathy was significantly associated with a higher incidence of nonsustained ventricular tachycardia (37% vs 0%) and greater myocardial disarray.

Study Design

Type

Observational (n=53)

Multicenter

Structured PICO

Does T-wave alternans correlate with histopathological changes and ventricular tachyarrhythmias in patients with hypertrophic cardiomyopathy?

Population

53 patients with idiopathic hypertrophic cardiomyopathy who underwent T-wave alternans assessment to evaluate its correlation with ventricular tachyarrhythmias and histopathological changes.

Exposure

Measurement of T-wave alternans (TWA) at rest and during controlled bicycle exercise

Comparator

TWA negative patients

Outcome

Correlation of TWA with histopathological changes (hypertrophy, disarray, fibrosis) and ventricular tachyarrhythmia (max VE, NSVT)surrogate

Main Result

Absolute Event Rate: 37% vs 0%

p-value: p=<0.01

Limitations

Malignant and high-risk patients may not have been included because HCM patients with the severe obstructive type were excluded.
The relationship between a high risk of sudden death and genetic abnormalities remains unclear and requires follow-up.
A significant proportion of patients (23%) had indeterminate TWA results due to noise or inadequate heart rate increase.

Abstract

The clinical significance of T-wave alternans (TWA) in hypertrophic cardiomyopathy (HCM) is unclear, so SV1+RV5 and QT dispersion on 12-lead electrocardiograms (ECG), the parameters of the left ventricle on echocardiography and the family history of HCM and sudden death were investigated in 53 patients with HCM who experienced TWA. The maximal numbers of successive ventricular ectopic beats (max VE) and nonsustained ventricular tachycardia (NSVT) were measured by Holter monitoring. In 13 patients, genetic abnormalities were examined. In 22 patients, the hypertrophy of myocytes, disarray and fibrosis were histopathologically examined using a scoring method. TWA was positive in 27 patients (TWA+ group), negative in 14 (TWA- group) and indeterminate in 12. The ECG and echocardiographic parameters, family history and genetic abnormalities did not significantly differ between the TWA+ and TWA- groups. Max VE, the percentage of patients with NSVT and disarray score in the TWA+ group were significantly higher than those in the TWA- group (3.6+/-3.6 vs 1.3+/-0.7, 37% vs 0%, 1.9+/-1.1 vs 0.7+/-0.5; p<0.05). TWA in HCM correlates with histopathological changes, especially disarray and ventricular tachyarrhythmia, and measuring it may be a noninvasive means of detecting high-risk patients with HCM.

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