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 ventricle’s 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.