Pacemaker Malfunction

Excerpt

The human heart is a pivotal organ in the circulatory system, and it beats more than 2 billion times during normal life. This functioning of the heart depends on the cardiac conduction system, which includes impulse generators (e.g., sino-atrial node) and the impulse propagating (His-Purkinje) system. The sinoatrial node acts as the natural pacemaker of the heart. The cells present in the sinus node have innate automaticity, which starts the electrical activity in the heart. This innate electrical potential moves from the sinoatrial node to the atrioventricular node and finally into the His-Purkinje system. This movement of electric potential in an orderly manner controls the rhythmic contraction of the heart's chambers. The failure of this intrinsic electrical conduction in the heart can result in different arrhythmic problems. Several diseases and conditions affect the conduction system by involving impulse generation, impulse propagation, or both. Acquired conditions such as myocardial infarction, age-related degeneration, procedural complications, and drug toxicity are the major causes of the native conduction system malfunction.

The current standard of care for symptomatic bradyarrhythmias due to conduction system diseases is the implantation of a cardiac implantable electronic device. These pacing devices provide an external electrical stimulus that leads to depolarization of myocytes and helps maintain the electrical excitability of the heart tissue. This process leads to excitation-contraction coupling resulting in the contraction of myocardial tissue.

Despite their success, electronic pacemakers have limitations, including complications related to implantation, limited battery life, the potential for infection, lack of physiologic autonomic responsiveness, and size restriction in younger patients. The periodic evaluation of an implanted pacemaker is necessary to optimize programming and to identify correctable problems. This review will discuss the common pacing system problems of a cardiac implantable electronic device (pacemaker).