Survival analysis of patients with idiopathic dilated cardiomyopathy in Oman

OBJECTIVE: To study the 10-year survival of adults with idiopathic dilated cardiomyopathy (IDC) in Oman.

METHODS: Ninety-seven patients aged >13 years with IDC attending the Cardiology Unit, Sultan Qaboos University Hospital, Muscat, Oman from 1992-1995 were prospectively studied, in order to identify the outcome and factors contributing to death.

RESULTS: Among 97 patients, 2 died from acute heart failure at presentation. The remaining 95 patients were followed up for periods ranging from 1-10 years (median 7 years). Twenty-four out of 95 patients exhibited clinical deterioration with reduced left ventricular ejection fraction (LVEF), by 5-11%, and 17 of them expired due to resistant heart failure. The remaining 71 patients remained stable and did not show deterioration in LVEF; however, 7 of them died suddenly at home possibly from ventricular arrhythmia. The survival rates were 94% at one year (95% confidence interval [CI] 88% to 99%), 86% at 3 years (95% CI 79% to 93%), and 64% at 10 years (95% CI 51% to 78%). Mean survival was 6.5 years (95% CI 6 to 7 years). Multivariate regression analysis revealed that factors related to death were LVEF <30% (p<0.001) and presence of severe mitral regurgitation (p=0.01).

CONCLUSION: Outcome of dilated cardiomyopathy has improved due to greater understanding of this condition leading to better therapeutic approach. Resistant heart failure and cardiac arrhythmias remain the main causes of mortality. Poor outcome was related to low LVEF and presence of severe mitral regurgitation.