Hemodynamic Optimization of Pacing Configuration in Bradyarrhythmias

Abstract

The electric treatment of cardiac bradyarrhythmias by an implanted pacemaker is mandatory whenever the reduction in ventricular rate results in a functional impairment affecting health, safety, and quality of life [1]. Nevertheless, it is well-known that electrical stimulation of the heart may have disadvantages and drawbacks, which have been progressively identified and brought to attention as a consequence of increasing clinical experience and medical knowledge. Parallel improvements in pacing technology have allowed many essential issues to be addressed and solved, such as the prevention of competitive pacing and synchronization of atrial and ventricular stimulation to maintain physiological sequential activation. In the last decade, the increasing use of biventricular pacing in the therapy of heart failure has underlined the relevance of interventricular and intraventricular synchronization for effective pump function. However, conventional singlesite pacing in the right ventricular apex (RVA) necessarily implies myocardial conduction of the evoked action potential, resulting in deep modification of the ventricular activation pattern and delayed contraction of the left ventricle (LV), as indicated by the altered axis and increased duration of the QRS complex and confirmed by echocardiographic observation. The shortand long-term impacts of RVA pacing on cardiac hemodynamics have therefore become major concerns in the care of patients presenting with bradycardia [2].