By: Jamie McClure
A cardiac pacemaker is a battery-powered apparatus implanted under the skin with leads placed on the heart or in the chamber of the heart. It is used to treat an abnormal heart rhythm, usually one that is too slow, secondary to an abnormal sinus node.
Almost all pacemakers are implanted to treat slow heart beating, which is called “bradycardia.” At rest, the heart usually beats about 50 to 70 times each minute, and the heart rate may increase 2- to 3-fold during stress or exercise. If the heart beats too slowly, the brain and body do not get enough blood flow and a variety of symptoms may result.
REASONS FOR PACEMAKER
Lack of energy
Shortness of breath
(Note: Although most people who receive pacemakers are aged
60 years or older, people of any age, even children, may need pacemakers.) (Ellenbogen, MD & Wood, MD, 2002)
SYMPTOMS ASSOCIATED WITH
NEED FOR A PACEMAKER
Ventricular demand pacemaker helps a patient who has slow ventricular rate caused by blockage of the electrical impulses to the ventricles, employing the most basic pacing mode - a pacemaker with a single lead to the right ventricle. "Demand" signifies that the device will provide impulses only when needed. The pacemaker is individually programmed to maintain the patient's natural, intrinsic ventricular rate which usually falls between 50 and 70 beats per minute.
Dual-chamber pacemakers have been developed for patients whose heart disease or lifestyle requires a more adaptable device. These respond with different heart rates to the varying demands of the heart. They stimulate the ventricles at the rate sensed in the atria and can enable even a patient with complete heart block-that is, a condition in which no impulses are getting through from the upper to the lower heart chamber-to enjoy exercising again.
TYPES OF PACEMAKERS
Most modern pulse generators have an expected longevity of
5-9 years and unexpected pulse generator (electrical) failure is rare. Lead-related problems (increased thresholds, decreased impedance) resulting in increased current drain are…