Left Ventricular Hypertrophy (LVH)
Except for blood to the lungs (from the right ventricle), the left ventricle is the rest of the body’s major pump. Over time, long-term pressure, such as from hypertension, or volume overloading, such as happens with valve disease, can cause its muscle fibers to enlarge, which increases the mass of the entire ventricle. Typically, its walls become thickened, its cavity size increases, or both.
Hypertension (long term pressure) and volume overloading (e.g., from valve disease such as aortic stenosis or regurgitation) are the two most common causes.
Causes of LVH
Besides chronic hypertension, even the temporary blood pressure spikes that occur in exercise or with stress, if frequent enough in high percentages of pressures >135/85, can predispose an individual to LVH; at night, when blood pressure should fall–the 10% “dip,” sustained pressures increase the risk of LVH; this probably explains the increased risk of LVH with obstructive sleep apnea.
The valvular diseases either obstruct flow out or allow blood already pumped out to flow back in.
LVH can cause congestive heart failure and cardiac arrhythmias as life-threatening cardiovascular complications.
How Is Enlarged Heart Diagnosed?
Left ventricular hypertrophy (LVH) is the result of other pathology such as chronic high blood pressure, chronic overload of the chamber, or both. Therefore, the signs and symptoms of LVH itself are those of its causes.
Diagnosis is based on elevated blood pressure, the abnormal heart sounds heard on auscultation of the heart (murmurs, etc.) due to valve dysfunction, incidental findings on chest X-ray, or electrocardiogram.
Auscultation of the Heart
Listening to the sounds of the heart is diagnostic of valvular disease when extra sounds result from turbulence and flow abnormalities through them, or from their ineffective closing.
The heart presents on chest X-ray as a structure that eclipses the lungs, a silhouette in contrast to the air-filled lungs around and behind it. As such, it stands out easily and when enlarged, can easily be identified as enlarged.
Because the ECG is a recording of the wave of electrical signals signifying contractions and relaxations of the heart chambers (“depolarizations” and “repolarizations”), a larger bulk of muscle, like what occurs in LVH, will give higher spikes on the recording. More mass means more electrical discharge. Besides the increased amplitude of the contraction spike (the “R” wave in the ventricles QRS complex), the whole complex widens. Since the ECG uses several electrodes around the heart to catch the “wave” of impulse in three dimensions, the “axis” (direction of the ventricular vector force) will shift to the left as an exaggeration of its own direction of force outward. The rest of the familiar ECG wave pattern can be affected, too, with alterations attributed to the repolarizations (relaxation and priming for the next contraction). These are recognizable to those skilled in ECG interpretation.
LVH is one of the “cardiomyopathies,” or disease of heart muscle. The ECG can be helpful in determining the severity of disease and predict who may be at most risk for serious cardiac problems, such as myocardial ischemia or infarction.
How to Manage Enlarged Heart?
Left ventricular hypertrophy (LVH) is the heart’s response to hypertension, increased filling loads, or both. Therefore, management is designed to treat the underlying causes of these predisposing factors. Their successful treatment, consequently, will also treat LVH.
Hypertension is often associated with obesity and the metabolic syndrome, lipid (cholesterol and triglyceride) abnormalities, smoking, stress, family history, age, and a sedentary lifestyle. Although age and genetics are not treatable, the others are. When the other factors are addressed, the impact of the unalterable age and genetic factors become less.
- Obesity is addressed with weight management, diet, nutritional counseling, and exercise
- Lipid abnormalities can be treated with statin drugs, which decrease the amount of cholesterol made in the liver and interfere with its absorption from the gastrointestinal tract
- Sedentary lifestyle can be altered with only minimal–but routine–activity and exercise each day
- Smoking must stop, but the addiction is very strong, sometimes needing medication to help (e.g., verenicline–Chantix)
- Stress can be managed via identifying stressors and learning strategies for reducing them. Professional psychological therapy can be very useful
- Hypertension itself, when the above conservative measures fail, can be treated with antihypertensive medications
The heart valves are designed to assure a one-way flow through the heart chambers. They ensure that once blood is forced into the next chamber from the atria, or to the pulmonary artery or aorta from the ventricles, that it won’t flow back. When these valves fail, retrograde flow-back is what occurs, and this leaves extra volumes of blood for the muscle fibers to deal with. As a result, they hypertrophy, i.e., they increase in size in compensation for the extra demand of this load for effective pumping.
To stop this process, heart valve disease can be treated with valve repair or replacement. Repair can be done percutaneously (i.e., by threading catheters to render balloon dilation at target sites of stenosis) or via surgical “commissurotomy,” to open the calcified leaflets of the valve; replacement can be with a biological prosthesis of donor tissue or a mechanical valve implant. Valve replacement often requires anticoagulation (blood clotting) therapy as part of the treatment.
Prevention of Enlarged Heart
Since prevention as it relates to left ventricular hypertrophy (LVH) is in preventing the conditions which cause it or reducing the risk of those conditions, management and treatment of hypertension and/or valvular disease is the best way to prevent LVH. Another aspect of prevention is in preventing the complications of LVH–heart failure and arrhythmias. With management and treatment of its causes, LVH can actually regress.
Regression of LVH is the best way to prevent serious cardiac events, and regression is via treating LVH’s causes, above:
- Hypertension risk is increased with obesity, the metabolic syndrome, hyperglycemia, smoking, stress, age, and genetics. Age and genetics are not possible to change, but how they mix with the other risk factors is.
- Weight management, caloric restriction, strict control of blood sugar, exercise, refusal to abuse drugs that increase blood pressure (cocaine, methamphetamines), medication exchange away from those with hypertension as a side effect, stress management, a good circadian rhythm (normal sleep/wake cycles), all reduce the risks of hypertension.
- Valve disease is best prevented by addressing the problems that cause it, such as treating rheumatic fever in a timely fashion with antibiotics, possibly continuing antibiotics indefinitely for those with recurrences, avoidance of intravenous drug abuse, antibiotic prophylaxis for procedures that might risk seeding of the blood stream with bacteria that could colonize on the valves, and treatment of hypertension all help to prevent valvular disease.