PROGNOSTIC VALUE OF NONSUSTAINED VENTRICULAR-TACHYCARDIA AND THE POTENTIAL ROLE OF AMIODARONE TREATMENT IN HYPERTROPHIC CARDIOMYOPATHY - ASSESSMENT IN AN UNSELECTED NON-REFERRAL BASED PATIENT POPULATION

Background-Amiodarone has been reported to reduce the likelihood of su dden death in patients with hypertrophic cardiomyopathy (HCM). However , data regarding the clinical course in HCM have traditionally come fr om selected referral populations biased toward assessment of high risk patients. Aims-To evaluate antiarrhythmic treatment for sudden death in an HCM population not subject to tertiary referral bias, closely re sembling the true disease state present in the community. Methods-Card iovascular mortality was assessed in relation to the occurrence of non -sustained ventricular tachycardia (NSVT) on 24 or 48 hour ambulatory Holter recording, a finding previously regarded as a marker for sudden death, particularly when the arrhythmia was frequent, repetitive or p rolonged. 167 consecutive patients were analysed by multiple Holter EC G recordings (mean (SD) 157 (129) hours) and followed for a mean of 10 (5) years. Only patients with multiple repetitive NSVT were treated w ith amiodarone, and in relatively low doses (220 (44) mg/day). Results -Nine HCM related deaths occurred: 8 were the consequence of congestiv e heart failure, but only 1 was sudden and unexpected. Three groups of patients were segregated based on their NSVT profile: group 1 (n = 39 ), multiple (greater than or equal to 2 runs) and repetitive bursts (o n greater than or equal to 2 Holters) of NSVT, or prolonged runs of ve ntricular tachycardia, included 4 deaths due to heart failure; group 2 (n = 38), isolated infrequent bursts of NSVT, included 1 sudden death ; group 3 (n = 90), without NSVT, included 4 heart failure deaths. Kap lan-Meier survival analysis showed no significant differences in survi val between the three groups throughout follow up. Conclusions-In an u nselected patient population with HCM, isolated, nonrepetitive bursts of NSVT were not associated with adverse prognosis and so this arrhyth mia does not appear to justify chronic antiarrhythmic treatment. Amiod arone, administered in relatively low doses, did not carry an independ ent and additive risk for cardiac mortality. Amiodarone may have contr ibuted to the absence of sudden cardiac death in patients believed to be at higher risk because of multiple repetitive NSVT.