Cardiac rhythm disorders, also called arrhythmias or dysrhythmias, encompass a variety of relatively common acute and chronic conditions characterized by recurrent distortions in the electrical and contractile activity of the heart, which may cause clinically significant and progressive hemodynamic deficits and cardiopulmonary impairment.
According to the available statistics from the American Heart Association (AHA) and Heart Rhythm Society, symptomatic cardiac arrhythmias effect over 10 million Americans and account for approximately 20% of all chronic conditions treated by cardiologists in the United States.
The rate and rhythm of the heart are determined by the intrinsic rhythmicity of special tissues and structures within the heart wall muscle generated by the heart’s natural electrophysiological mechanism. Normal cardiac rate and rhythm ensure continued uninterrupted blood flow an associated supply of oxygen and nutrients to the brain and other vital organs. Irregularities in the rate, rhythm, or origin of a stimulus leading to myocardial contraction can potentially interrupt normal blood circulation, causing inadequate function of important body systems, stroke or sudden cardiac arrest and death. Heart pacing disorders usually degenerate and worsen over time.
Although cardiac arrhythmias may be triggered by congenital heart defects, in which the electrical system of the heart does not develop properly, non-congenital heart disorders are believed to be the most common causes of chronic arrhythmias. The latter is particularly true for ischemic heart disease, which results in reduced blood flow and oxygen delivery to heart tissue, and heart tissue scarring typically caused by myocardial infarction. Other causes of arrhythmia include abnormal blood and tissue concentrations of certain minerals; abnormalities of the autonomic nervous system, which is involved in cardiovascular regulation; stress; and use of alcohol, caffeine, illicit drugs, and tobacco, as well as diet pills and some other medications.
Cardiac arrhythmias are generally categorized according to their impact on heart rates. Bradycardia is an abnormally slow resting heart rate, whereas tachycardia is an abnormally high resting heart rate. Bradycardias are most commonly associated with SA node disease and/or various forms of heart block.
Tachycardias are usually classified by their origination site and may be subdivided into two broad categories, specifically, supraventricular tachycardias (SVTs) and ventricular tachycardias (VTs).
Below are shown the projected implantable pump generator placements by region from 2015 to 2022. These include pacemaker placements, implantable cardioverter defibrillator placements, and cardiac resynchronization therapy placements.
Source: MedMarket Diligence LLC (Report #C500).