Abstract 2920: Dobutamine-induced Mechanical Alternans Predicts Poor Prognosis In Mildly To Moderately Symptomatic Patients With Idiopathic Dilated Cardiomyopathy In Sinus Rhythm
Introduction: Mechanical alternans (MA) occurs in some patients with severe heart failure, but the relation between dobutamine-induced MA and prognosis in mildly to moderately symptomatic patients (NYHA functional class I or II) with idiopathic dilated cardiomyopathy (IDCM) has remained unknown.
Hypothesis: We assessed the hypothesis that dobutamine-induced MA can predict poor prognosis in mildly to moderately symptomatic patients with IDCM in sinus rhythm.
Methods: The relation between the occurrence of dobutamine-induced MA and prognosis in patients with IDCM in sinus rhythm was investigated prospectively. Left ventricular pressure was measured during atrial pacing (increased in increments of 10 bpm up to 140 bpm) and during infusion of dobutamine (10 μg kg-1 min-1) in 80 mildly to moderately symptomatic patients with IDCM. MA was diagnosed if the pressure difference between the strong and weak beats was ≥4 mmHg. The patients were followed up for a mean of 28 months.
Results: Patients were classified into three groups consisting of 8 subjects who developed both pacing-induced MA and dobutamine-induced MA (group D), 22 subjects who manifested only pacing-induced MA (group P), and 50 subjects who exhibited neither pacing-nor dobutamine-induced MA (group C). Left ventricular ejection fraction and plasma BNP level did not differ signficantly among the three groups. Cardiac event-free survival in group D was significantly lower than that in groups P or C (P = 0.002).
Conclusions: The occurrence of dobutamine-induced MA is a potentially useful indicator of poor prognosis in mildly to moderately symptomatic patients with IDCM in sinus rhythm.