Left ventricular hypertrophy (LVH) refers to an increase in the size of myocardial fibers in the main cardiac pumping chamber. Such hypertrophy is usually the response to a chronic volume or pressure load.
- The two most important pressure overload states are systemic hypertension and aortic stenosis.
- The major conditions associated with left ventricular volume overload are aortic or mitral valve regurgitation and dilated cardiomyopathy.
Ventricular septal defects cause both right and left ventricular volume overload, while hypertrophic cardiomyopathy is an example of an inherited condition in which LVH (usually with asymmetric septal hypertrophy) occurs in the absence of any apparent hemodynamic pressure or volume overload. A physiologic type of hypertrophy with increase in wall thickness and left ventricular and diastolic volume may occur in trained athletes. The "athletic heart" is often associated with ECG voltage criteria for LVH.
LVH is not an acute condition. It takes weeks and usually months to years to develop. Patients with LVH from any cause are at increased risk for major cardiovascular complications including congestive heart failure and cardiac arrhythmias . These pathophysiologies may be fostered by the development of myocardial fibrosis in concert with LVH.
The electrocardiogram is a useful but imperfect tool for detecting LVH. The utility of the ECG relates to its being relatively inexpensive and widely available. The limitations of the ECG relate to its moderate sensitivity or specificity depending upon which of the many proposed sets of criteria are applied [2,3].