Improving Pharmacotherapy for Heart Failure in Infants with Monitoring of Heart Rate Variability

Abstract

Heart failure is one of the main causes of death in infants with and without congenital heart disease and has long term consequences in surviving infants, such as impaired linear growth, worse neurodevelopmental outcomes and an enhanced cardiovascular mortality. Current pharmacotherapy is not proven by prospective randomized trials. We use online monitoring of heart rate variability (HRV) to measure the effect of pharmacotherapy on the autonomic nervous system. Methods: The infants are routinely monitored with Drager Infinity Monitors™ (Drager; Germany) on our pediatric intensive care unit. For analysis of heart rate variability, we export the monitor data to the Pathfinder™ ECG Software using a network connection. 7 clinical cases are discussed. Results: Infants with a high frequency power in the spectral analysis of heart rate variability below 20ms had a high risk to die from heart failure ± inflammation. Propranolol but not metoprolol improves HRV, NT-Pro BNP and troponin T values. We anticipate a further improvement of HRV in 2 cases with an additional digoxin treatment. Conclusion: Reduced HRV seems to be an important risk factor for life threatening complications in infants with severe heart failure and should be monitored in infants with severe heart failure. Propranolol but not metoprolol improves HRV. Additional digoxin further improves HRV in two cases treated with propranolol. These preliminary results have to be proven by prospective trials using HRV analysis for risk stratification.