Some children with cardiomyopathy develop abnormal heart rate or rhythms (arrhythmias) because swelling or scarring irritates the heart muscle and affects the electrical signaling that controls the heartbeat. During an arrhythmia, the heart is unable to pump enough blood to the body and symptoms such as fatigue, shortness of breath or fainting may result. Severe arrhythmias (ventricular fibrillation and ventricular tachycardia) can be life-threatening and lead to a cardiac arrest. An automatic implantable cardioverter defibrillator (AICD) or biventricular pacemaker may be recommended to relieve symptoms or protect against sudden cardiac death. These small electronic medical devices are surgically implanted and require regular monitoring by an electrophysiologist.
Pacemakers and Biventricular Pacemakers
A pacemaker is implanted to monitor the heart’s electrical activity and regulate the heart’s contractions. Low energy electrical pulses prompt the heart to beat at a normal rate. Pacemakers are often used to treat less dangerous heart rhythms such as those that occur in the upper chambers of the heart (atria). It can help relieve symptoms such as fatigue and fainting.
People who have heart failure may undergo cardiac resynchronization therapy (CRT) with a special device. The CRT device, also known as a biventricular pacemaker, regulates the contraction of both lower chambers of the heart (ventricles), which allows them to work together to pump blood out of the heart better.
Automatic Implantable Cardioverter Defibrillator
An automatic internal cardioverter defibrillator (ICD) is similar to a pacemaker but there are some differences. An ICD is used to regulate irregular heartbeats and treat life-threatening arrhythmia that occur in the lower chambers of the heart (ventricles). When an ICD detects an abnormal heart rhythm, it will emit either a low-energy or high energy electrical pulse or shock depending on the seriousness of the heart rhythm disturbance.
ICDs are prescribed to patients who are at higher risk for sudden cardiac death. Risk factors include:
Implanting a pacemaker or ICD involves placing a small, battery-operated device — composed of a generator and a computer chip — under the skin of the chest or abdomen with electrical wires (leads) placed directly on the heart or threaded through veins into the heart.
The procedure requires a short hospital stay. Once the device is inserted, it requires careful monitoring to determine when parts need to be replaced and to ensure that the electrical settings are correct. The battery and the patient's heart rhythm are checked monthly by placing a monitor over the skin above the device generator.