Aim: To assess the extent of hyperenhancement in hypertrophic cardiomyopathy (HCM) patients with nonsustained ventricular tachycardia (NSVT) in comparison to patients without NSVT.
Design: In HCM patients, NSVT in Holter monitoring is a risk factor for sudden cardiac death; however, its positive predictive value is low. Varying risk of sudden death related to NSVT may be dependent on the heterogeneous extent of the arrhythmogenic substrate, which seems to be visible as hyperenhancement in gadolinium-enhanced magnetic resonance imaging (MRI).
Methods: Hyperenhancement was assessed in 47 HCM patients (30 males and 17 females, mean age 42 +/- 12 years): 32 patients had NSVT, 15 patients had no NSVT. The extent of hyperenhancement was calculated by software and expressed as a mass.
Results: In HCM patients with NSVT 97% had some extent of hyperenhancement on MRI, ranging from 1 to 76 g. The mean mass of hyperenhanced myocardium was 19 +/- 18 g (8.1 +/- 7.6% of total left ventricular mass). In HCM patients without NSVT, a significantly lower percentage of patients (60%) had hyperenhancement (P < 0.05). However, the amount of hyperenhanced myocardium was not significantly different (13 +/- 19 g, 6.3 +/- 9.1% of total left ventricular mass; P < 0.05).
Conclusions: Hyperenhancement was visible in almost all HCM patients with NSVT (97%) and in a significantly lower percentage of patients without NSVT (60%). Whether this finding explains the increased risk of sudden death in case of NSVT is not clear, since the extent of hyperenhancement was not significantly different between the two groups.