Hypertrophic cardiomyopathy: the importance of arrhythmic events in patients at risk for sudden cardiac death.
OBJECTIVE
To evaluate, in patients with hypertrophic cardiomyopathy and risk for SCD who underwent implantable cardioverter-defibrillator (ICD) implantation: a- the occurrence of arrhythmic events; b- the occurrence of clinical events and their correlation with arrhythmic events; c- the occurrence of ICD shock therapy and clinical and functional correlations; d- clinical and functional predictors of prognosis.


METHODS
Twenty six patients with hypertrophic cardiomyopathy and risk factors for SCD undergoing ICD implantation from May, 2000 to January, 2004 (mean follow-up = 20 months) were studied. Fourteen patients (53.8%) were females and the mean age was 42.7 years. ICD was indicated for primary prevention of sudden cardiac death in 16 patients (61.5%), and for secondary prevention in 10 patients (38.5%). Twenty patients (76.9%) presented syncope prior to ICD implantation; half of them were related to ventricular fibrillation or sustained ventricular tachycardia, 15 (57.7%) had a history of familial sudden death, 12 patients (46.2%) had nonsustained ventricular tachycardia on the 24-hour Holter monitoring, and five (19.2%) had an interventricular septal thickness greater than 30 mm.


RESULTS
Four shock therapies were recorded by the ICD in potentially lethal arrhythmias (three patients with sustained ventricular tachycardia and one patient with ventricular fibrillation) during the follow-up. One death occurred, probably due to a thromboembolic stroke. Four patients had recurrence of syncope with no arrhythmic event recorded by the ICD. The statistical analysis showed a significant difference in early ICD shock therapy in patients whose interventricular septal thickness was greater than 30 mm.


CONCLUSIONS
1- occurrence of arrhythmic events in 50% of the patients; most of them (62%) were ventricular tachycardia, whether sustained (31%) or nonsustained (31%); in the remaining patients paroxysmal supraventricular tachycardia was observed. 2- recurrent syncope in the minority of the patients (16%), however not associated with the presence of arrhythmic events. 3- the presence of an interventricular septal thickness greater than 30 mm in the echocardiogram was associated with early shock therapy (p = 0.003). 4- absence of clinical or functional predictors.
Medeiros
Paulo de Tarso Jorge
Pde T
Instituto do Coração do Hospital das Clínicas--FMUSP, Instituto Dante Pazzanese de Cardiologia, São Paulo, SP, Brazil. paulotjm@cardiol.br
Martinelli Filho
Martino
M
Arteaga
Edmundo
E
Costa
Roberto
R
Siqueira
Sérgio
S
Mady
Charles
C
Piegas
Leopoldo Soares
LS
Ramires
José Antonio Franchini
JA
D000293:Adolescent; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology*; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control; D017147:Defibrillators, Implantable; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012307:Risk Factors