QT prolongation (QTc > 480 ms) was present in 13% of patients with hypertrophic cardiomyopathy and was significantly associated with greater cardiac hypertrophy and outflow tract obstruction.
Observational (n=479)
Blinded
Yes
What is the prevalence and clinical correlates of QT prolongation in patients with hypertrophic cardiomyopathy?
QT prolongation (QTc > 480 ms) is common in HCM (13%) and correlates with disease severity, suggesting routine QTc assessment is warranted, especially when considering QT-prolonging medications.
AIMS: Congenital or acquired QT prolongation is a risk factor for life-threatening arrhythmias. In patients with hypertrophic cardiomyopathy (HCM), the QT interval may be intrinsically prolonged. However, the prevalence, cause, and significance of QT prolongation among patients with HCM are unknown. METHODS AND RESULTS: After exclusion of patients on QT-prolonging drugs, a blinded, retrospective analysis of electrocardiograms, echocardiograms, and genotype status in 479 unrelated patients with HCM 201 females, age at diagnosis 41 ± 18 years, maximal left ventricular wall thickness (MLVWT) 22 ± 6 mm from two independent centres was performed. The mean QTc was 440 ± 28 ms. The QTc exceeded 480 ms in 13% of patients. Age, gender, family history of HCM or sudden cardiac arrest, and genotype status had no association with QTc. Patients with a QTc over 480 ms were more symptomatic at diagnosis (P 480 ms) was present in 1 out of 8 patients with HCM. The QTc was partly reflective of the degree of cardiac hypertrophy and left ventricular outflow tract obstruction. Because of its pro-arrhythmic potential and its potential relevance to management and risk stratification, routine QTc assessment should be performed in patients with HCM, particularly when concomitant use of QT-prolonging medications is considered.
Johnson et al. (2011) conducted an observational in Hypertrophic cardiomyopathy (n=479). QT prolongation assessment was evaluated on Prevalence of QTc > 480 ms. QT prolongation (QTc > 480 ms) was present in 13% of patients with hypertrophic cardiomyopathy and was significantly associated with greater cardiac hypertrophy and outflow tract obstruction.