DiDi
Trial question
What is the role of diltiazem in patients with idiopathic dilated cardiomyopathy?
Study design
Multi-center
Double blinded
RCT
Population
Characteristics of study participants
24.0% female
76.0% male
N = 186
186 patients (45 female, 141 male).
Inclusion criteria: patients with idiopathic dilated cardiomyopathy diagnosed by coronary angiography, catheterization of left side of heart, and LVEF < 0.50.
Key exclusion criteria: hypertension; valvular or congenital heart disease; myocarditis; coronary artery disease; insulin-dependent diabetes mellitus.
Interventions
N=92 diltiazem (at a dose of 60-90 mg TID).
N=94 placebo (matching placebo).
Primary outcome
Transplant listing-free survival
85.2%
80.4%
85.2 %
63.9 %
42.6 %
21.3 %
0.0 %
Diltiazem
Placebo
No significant
difference ↔
No significant difference in transplant listing-free survival (85.2% vs. 80.4%; AD 4.8%, 95% CI -7.27 to 16.87).
Secondary outcomes
Significant increase in cardiac index at rest in 2 years (0.37 L/min vs. 0.33 L/min; AD 0.04 L/min, 95% CI 0.01 to 0.07).
Significant increase in cardiac index at workload in 2 years (0.57 L/min vs. 0.33 L/min; AD 0.24 L/min, 95% CI 0.09 to 0.39).
Significant decrease in HR (-7.7 L/min vs. -1.6 L/min; ARD -6.1, 95% CI -9.72 to -2.48).
Safety outcomes
No significant difference in adverse reactions.
Significant difference in PQ interval (0.015 s vs. -0.003 s).
Conclusion
In patients with idiopathic dilated cardiomyopathy diagnosed by coronary angiography, catheterization of left side of heart, and LVEF < 0.50, diltiazem was not superior to placebo with respect to transplant listing-free survival.
Reference
H R Figulla, F Gietzen, U Zeymer et al. Diltiazem improves cardiac function and exercise capacity in patients with idiopathic dilated cardiomyopathy. Results of the Diltiazem in Dilated Cardiomyopathy Trial. Circulation. 1996 Aug 1;94(3):346-52.
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