Dysrhythmic profile and clinical aspects in a population of 23 patients with hypertrophic cardiomyopathy

OBJECTIVES: To evaluate: 1. The incidence and characteristics of ventricular arrhythmias on Holter monitoring and their relation to the clinical, functional and morphological aspects. 2. The survival and therapeutical efficiency of amiodarone in a subgroup of patients with ventricular tachycardia. SETTING: Department of Cardiology in a General Hospital. METHODS: 23 patients (pts) aged 19 to 74 years with an echocardiographic diagnosis of cardiomyopathy were studied during a four year period by 24 hours Holter monitoring. Ventricular arrhythmias were defined according the Lown classification. Patients were classified according to: obstructive or nonobstructive hypertrophy (funtional groups, 11 and 12 pts respectively), asymmetric hypertrophy of the septum or ventricular concentric hypertrophy or apical hypertrophy (morphological groups, 18, 3 and 2 pts respectively). They were also classified according medical therapy (pharmacological with B-blockers or calcium antagonists and nonpharmacological groups, 7 and 16 pts respectively). RESULTS: the incidence of severe ventricular arrhythmias was 57.1% and 62.5% in the pharmacological and nonpharmacological groups respectively. In both obstructive and nonobstructive forms, severe ventricular arrhythmias were also found (7/8 pts in each group). 12 pts with asymmetric hypertrophy of the septum and 2 pts with the concentric hypertrophic form also had severe ventricular arrhythmias. Five pts with nonsustained ventricular tachycardia have been submitted to oral amiodarone therapy in a dosage of 200 mg daily. All these pts are alive (follow-up ranged from 15 to 54 months) and in five no significant ventricular arrhythmias have been detected on serial Holter records. CONCLUSIONS: the incidence of ventricular arrhythmias was high in this patients population and no definitive relation could be found between the severity of ventricular arrhythmias and the previous described groups. Meanwhile, classic medical therapy seems not to alter the incidence and the characteristics of ventricular arrhythmias. On other hand, amiodarone therapy seems to abolish ventricular tachycardia in a large percentage of cases and no death occurred during a significant period of time (maximal 54 months).