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Effect of digoxin on contractility and symptoms in infants with a large ventricular septal defect
T R Kimball1, S R Daniels, R A Meyer
1Division of Cardiology, Children's Hospital Medical Center, Cincinnati, Ohio 45229.
Insights
Digoxin did not improve symptoms in infants with large ventricular septal defects (VSD). While digoxin increased contractility when added to diuretics, this effect was not sustained, and symptoms remained unchanged.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Pharmacology
Background:
- Ventricular septal defects (VSD) can cause congestive heart failure in infants.
- The efficacy of digoxin in improving contractility and symptoms in VSD patients is debated.
- Current treatment guidelines for VSD-related heart failure often involve diuretics and potentially digoxin.
Purpose of the Study:
- To evaluate the effect of digoxin on cardiac contractility in infants with large VSDs receiving diuretics.
- To determine if digoxin improves clinical symptoms and signs of heart failure in this population.
- To assess the impact of adding digoxin to diuretic therapy versus diuretics alone.
Main Methods:
- Nineteen infants with symptomatic large VSDs were studied over four periods: baseline, diuretics, diuretics + digoxin, and diuretics alone.
- Load-independent indexes of contractility were measured, alongside clinical symptoms and signs.
- Contractility was assessed using the difference between measured and predicted velocities of circumferential fiber shortening relative to afterload.
Main Results:
- Adding digoxin to diuretic therapy significantly increased the contractility index compared to baseline (p=0.04).
- This improvement in contractility was not observed when patients were on diuretics alone after digoxin withdrawal.
- Neither diuretics alone nor the combination of diuretics and digoxin led to significant improvements in clinical symptoms or signs of heart failure.
Conclusions:
- Digoxin can transiently enhance contractility in infants with large VSDs on diuretic therapy.
- However, digoxin does not appear to provide significant clinical benefit in terms of symptom improvement for these patients.
- The use of digoxin in infants with large VSDs warrants careful consideration of its limited symptomatic impact.
Abstract:
The effect of digoxin on contractility and symptoms in infants with a large ventricular septal defect (VSD) is controversial. Nineteen infants with symptoms of congestive heart failure due to a VSD were studied with load-independent indexes during 4 study periods: (1) before any medication; (2) while on chronic diuretics; (3) while on both diuretics and digoxin; and (4) while on diuretics alone, to determine if digoxin: (a) increases "contractility" when added to diuretic therapy; and (b) improves symptoms. Symptoms, signs (heart and respiratory rates, and weight gain), shortening fraction, preload (left ventricular end-diastolic dimension), afterload (left ventricular end-systolic wall stress) and contractility were measured at each period. The difference between the measured and predicted velocities of circumferential fiber shortening for the measured left ventricular end-systolic wall stress served as an index of contractility. Eighteen infants also underwent catheterization. Mean pulmonary-to-systemic blood flow ratio was 3:1. When digoxin was added to diuretics, contractility index was significantly greater than in control subjects (0.13 +/- 0.15 vs 0.0 +/- 0.12 circ/s, p = 0.04). When patients were again on diuretics alone (after discontinuation of digoxin), contractility index was no longer different. Symptoms and signs were not significantly improved by either diuretics or digoxin. It is concluded that in infants with a large left-to-right VSD shunt and receiving digoxin and diuretics, contractility index was significantly greater than in control subjects. However, neither diuretics alone nor in combination with digoxin improved symptoms significantly.