Ventricular Arrhythmias and Left Ventricular Hypertrophy in Hypertrophic Cardiomyopathy

Background: In hypertrophic cardiomyopathy (HCM), the degree of left ventricular hypertrophy (LVH) could influence the development of ventricular arrhythmias. Objective: In HCM, analyze the association between the occurrence of ventricular arrhythmias on Holter electrocardiogram (Holter ECG) and the degree of LVH determined by maximum wall thickness (MWT) and mass index (MI) on echocardiography. Methods: Fifty-four consecutive patients with HCM underwent 24-hour Holter ECG and echocardiography for assessment of degree of LVH through MWT and MI. Two levels were established for the occurrence of ventricular arrhythmias: I - isolated or paired extrasystoles and II - non-sustained ventricular tachycardia (NSVT). Results: In 13 patients (24%) with NSVT (level II), there was a higher frequency of left ventricular (LV) MWT >= 21 mm (n = 10, 77%, 25 +/- 4 mm) and LVMI >= 144g/m(2) (n = 10, 77%, 200 +/- 30 g/m(2)), in comparison with those presenting with only extrasystoles (level I) (n = 41, 76%), in which these measures were identified in, respectively, 37% (n = 15, 23 +/- 1 mm), p = 0.023, and 39% (n = 16, 192 +/- 53 g/m(2)) of the cases p = 0.026. The cut-off values mentioned were determined by the ROC curve with a 95% interval confidence. NSVT was more common in patients with LVMWT >= 21 mm and LVMI = 144 g/m(2) (8 of 13, 62%) than in those with one (4 of 13, 31%) or none (1 of 13; 8%) echocardiographic variables above cut-off values (p = 0.04). Conclusion: In HCM, the occurrence of ventricular arrhythmias on Holter-ECG was associated with the degree of LVH assessed by echocardiography through MWT and MI