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[Effectiveness of diltiazem in controlling ventricular response and improving exercise capacity in chronic atrial
Insights
Diltiazem effectively controls heart rate in chronic atrial fibrillation patients during exercise, improving their exercise capacity. This study found diltiazem superior to digoxin for managing exercise-induced heart rate increases.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Digoxin is a common treatment for chronic atrial fibrillation but inadequately controls exercise-induced heart rate.
- Exercise intolerance is a significant concern for patients with chronic atrial fibrillation.
Purpose of the Study:
- To investigate diltiazem's efficacy in controlling ventricular response during maximal exercise in patients with chronic atrial fibrillation.
- To assess diltiazem's impact on cardiovascular performance and exercise capacity.
Main Methods:
- A placebo-controlled, prospective, randomized, double-blind study.
- 13 patients with chronic atrial fibrillation, already on digoxin, participated.
- Patients underwent assessment during digoxin therapy, and then with diltiazem or placebo.
Main Results:
- Diltiazem significantly reduced mean ventricular response at rest and during maximal exercise compared to digoxin alone.
- Exercise capacity, measured by METs and maximum exercise capacity (MEC), significantly improved with diltiazem treatment.
- Heart rate reduction was observed both at rest and during submaximal (50 W) and maximal exercise.
Conclusions:
- Diltiazem is more effective than digoxin in controlling ventricular response during exercise in chronic atrial fibrillation.
- Diltiazem improves cardiovascular performance and exercise capacity in these patients.
- Diltiazem offers a valuable therapeutic option for managing chronic atrial fibrillation with exercise intolerance.
Abstract:
Although digoxin is often the drug of choice to control the ventricular response in chronic atrial fibrillation, it fails to control exercise-induced increase in heart rate. The efficacy of diltiazem to control ventricular response and to improve cardiovascular performance during maximal exercise was investigated in 13 digitalized patients with chronic atrial fibrillation. A placebo controlled prospective randomized double-blind study, was preceded by open titration phase. During the diltiazem treatment phase, mean ventricular response diminished at rest (85 +/- 12 versus 107 +/- 19 during digoxin therapy and versus 101 +/- 18 during digoxin and placebo therapy; p less than 0.001), as well as during maximal exercise (142 +/- 13 versus 159 +/- 17 during digoxin treatment and versus 160 +/- 14 during digoxin plus placebo treatment; p less than 0.001). During exercise (50 W), in a subgroup of 7 patients, mean ventricular rate dropped: 109 +/- 19 versus 142 +/- 21 during digoxin treatment and versus 143 +/- 17 during digoxin plus placebo treatment; p less than 0.001). In all patients, the mean rate at rest decreased about 19.3 +/- 6.9% and at maximal exercise about 10.3 +/- 4.9%. In the subgroup of the 7 patients ventricular mean rate at a load of 50 W decreased about 23.6 +/- 7.9%. In all the patients, maximal exercise capacity improved: the MET mean value increased from 3.59 +/- 1.3 to 4.52 +/- 1.18 (p less than 0.001); the mean value of the maximum exercise (MEC), according to the Redfords formula, increased from 65 +/- 48 to 132 +/- 70 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)