Atrial Fibrillation Complicating Congestive Heart Failure: Electrophysiological Aspects And Its Deleterious Effect On Cardiac Resynchronization Therapy

Abstract

More successful recognition and treatment of cardiovascular risk factors and diseases continues to decrease mortality and increase the proportion of elderly population. Therefore, there are more people with increased risk of developing heart failure and atrial fibrillation in the course of their lives. Atrial fibrillation (AF) can complicate the course of congestive heart failure (HF) leading to acute pulmonary edema. The prevalence of AF, in patients with heart failure, increases with the severity of the disease, reaching up to 40% in advanced cases. In these HF patients, AF is an independent predictor of morbidity and mortality increasing the risk of death and hospitalization. Despite the excellent results obtained with different drugs, the optimal medical treatment can fail in the intention to improve symptoms and quality of life of patients with severe HF. Thus, the necessity to use cardiac devices emerges facing the failure of optimal medical treatment in order to achieve hemodynamic improvement and correction of the physiopathological alterations. Cardiac resynchronization therapy (CRT) can reduce the interventricular and intraventricular mechanical dissynchrony in HF patients. It has been shown that CRT increases the left ventricular filling time, decreases septal dissynchrony, mitral regurgitation, and left ventricular volumes allowing a hemodynamic improvement. However, the development of AF in this setting can avoid the beneficial effects of CRT. Therefore, this manuscript will review the available data on this topic, the electrophysiological aspects of AF, to determine what can be done in the event of an AF complicating congestive HF in CRT patients.

Figure 1.. Catheter electrodes position during CRT. By placing pacing electrodes in the coronary sinus, the right ven- tricular apex, and in the right atrial appendage, CRT can deliver simultaneous electrical stimulation of both ventricles which results in a significant hemodynamic improvement restoring a more homogeneous contraction pattern

Figure 2.. Transmitral Pulse Wave Doppler Echocardiography. With the CRT device on, there is an increase and improvement in the left ventricular filling time

Figure 3.. Transmitral Color Doppler Echocardiography. With the CRT device on, there is a decrease in mitral regur- gitation