left ventricular hypertrophy

When a weightlifter trains against heavy resistance, the muscles grow thicker. The left ventricle does the same: if it must pump against high pressure for years, its wall thickens. Left ventricular hypertrophy is this thickening of the main pumping chamber's muscular wall, and it is the heart's response to a chronically increased workload.

The commonest driver is long-standing high blood pressure, which forces the ventricle to work against high afterload; another is aortic stenosis, a narrowed outflow valve. At first the thicker wall helps generate the needed force, but it comes at a cost: the muscle becomes stiffer and harder to fill, its blood supply may not keep pace, and the electrical tissue becomes more prone to arrhythmias.

Left ventricular hypertrophy is a marker of long-term risk — it is linked to heart failure (especially the preserved-ejection-fraction type), atrial fibrillation, and stroke. It can be detected on an ECG or, more reliably, measured on an echocardiogram. Importantly, not all wall thickening is the same: pressure-driven hypertrophy differs from hypertrophic cardiomyopathy, an intrinsic muscle disease, and treating the underlying cause can partly reverse it.