Methamphetamine Use and Cardiomyopathy
Cardiomyopathy is a general term that doctors use to describe a range of diseases that damage the heart muscle and reduce its ability to perform its job. Minor forms of these diseases cause no health problems and require no treatment; however, in their severe forms, these diseases can produce major, potentially life-threatening health problems. Methamphetamine use can trigger the onset of cardiomyopathy. Compared to people who don’t use meth or other drugs, meth users develop the condition far more frequently, and also tend to develop particularly severe health complications.
According to the National Heart Lung and Blood Institute, there are four main types of cardiomyopathy, called hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, and arrhythmogenic right ventricular dysplasia. People with hypertrophic cardiomyopathy develop abnormal thickening in the walls of the heart’s major pumping chambers, called the ventricles. People with dilated cardiomyopathy develop unusual heart chamber enlargement and overall heart muscle weakness. People with restrictive cardiomyopathy develop one of several different conditions that produce unusual stiffness in the heart muscle. Arrhythmogenic right ventricular dysplasia is a rare condition that destroys healthy tissue and leads to scar tissue formation in the lower right heart chamber (right ventricle). Other types of cardiomyopathy include ischemic cardiomyopathy, which involves a thinning of the heart’s walls produced by an inadequate blood supply; and peripartum cardiomyopathy, a form of dilated cardiomyopathy that appears only during pregnancy or in the months immediately following childbirth.
Each type of cardiomyopathy has a common underlying cause, or causes. For instance, hypertrophic cardiomyopathy is usually a hereditary condition, while restrictive cardiomyopathy commonly stems from the formation of abnormal proteins, called amyloids, in the heart’s tissues. Dilated cardiomyopathy has a range of potential underlying causes, including genetic predisposition, excessive alcohol consumption, drug use, heart disease and viral infection. In their most severe forms, all types of cardiomyopathy are associated with potentially fatal problems such as heart failure, heart valve malfunction, dangerous changes in normal heart rhythm, blood clot formation inside the heart’s tissues, and an unpredictable stoppage of the heart called sudden cardiac arrest, or SCA.
Methamphetamine is a powerful stimulant. Like other stimulant drugs of abuse, such as cocaine and amphetamine, it achieves many of its effects through its ability to increase the rate of activity in the sympathetic nervous system. This system-which extends from the central nervous system to a number organs, including the heart, blood vessels, lungs, and eyes-helps maintain a stable body environment (homeostasis) during everyday circumstances, and also triggers the body’s “fight-or-flight” response in unusually dangerous or stressful circumstances. In the context of cardiomyopathy, the most important sympathetic nervous system effects of methamphetamine use are a significant elevation of blood pressure inside the blood vessels that feed the heart, an abnormal narrowing of the heart’s blood vessels known as vasospasm, and an elevation of the normal heart rate that can range in severity from notable to extreme.
Methamphetamine use is associated with the onset of dilated cardiomyopathy. Typically, the weakness and enlargement that characterize this condition occur gradually over time as repeated drug use produces the heart rate accelerations, blood pressure surges and vasospasms that damage the heart muscle. In addition, the presence of methamphetamine in the bloodstream can contribute further to the development of dilated cardiomyopathy by directly irritating the heart’s tissues. Compared to other sources of cardiomyopathy, methamphetamine use can produce markedly severe health problems, according to a study published in 2007 in the American Journal of Medicine. This is likely true because of the extent of the damage that meth use produces in the left ventricle, the lower heart chamber that pumps blood out of the heart and into the body’s main artery, called the aorta.
Methamphetamine users develop dilated cardiomyopathy almost four times as often as people who don’t use drugs. When compared to methamphetamine users over the age of 45, younger meth users have what appears to be a significantly higher chance of developing dilated cardiomyopathy, the authors of the study in the American Journal of Medicine report. However, this fact may not indicate an actual drop in risk for older meth users; instead, it may only reflect the tendency of older people in general to develop cardiomyopathy as a consequence of other, non-drug-related health issues. Some meth users can recover from the effects of cardiomyopathy if they stop taking the drug, according to a study published in 2009 in the Journal of Cardiovascular Magnetic Resonance. However, other meth users develop additional, irreversible problems with their normal heart function that effectively prevent a recovery from cardiomyopathy.