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An 80-year-old woman is described with two different causes (pericardial effusion and cardiac amyloidosis) for low QRS voltage on the electrocardiogram. Total 12-lead QRS voltage (from the peak of the R wave to the nadir of either the Q or the S wave, whichever is deeper) was only 34 mm (10 mm standard in all leads), the lowest we have encountered among 331 previously reported patients with 10 different cardiac conditions.
Among the causes of extremely low voltage on the electrocardiogram are large pericardial effusions and cardiac amyloidosis. The occurrence of both conditions in the same patient can lead to extremely low voltage on the electrocardiogram. The occurrence of such a situation prompted this report.
An 80-year-old woman with dementia was hospitalized because of worsening confusion and lower leg edema. She was known to have systemic hypertension and diabetes mellitus. She was in no acute distress. Her blood pressure was 85/60 mm Hg. Her body mass index was 18 kg/m2. No abdominal organs or subcutaneous lymph nodes were palpated. The electrocardiogram showed total 12-lead QRS voltage of 17 mm (standard ≈ 20 mm; double standard) (Figure 1). An echocardiogram disclosed pericardial effusion, thickened right and left ventricular walls, and low (≈20%) ejection fraction (Figure 2). Both ventricular cavities were of normal size.
Total 12-lead QRS voltage was introduced in 1982 as a means to predict the presence of left ventricular hypertrophy (1) (Figure 3). Subsequently, total 12-lead QRS voltage has been described in 10 different disease states involving 331 patients and compared in all to heart weight (2). It has been found to be a better predictor of left ventricular hypertrophy than any previous criteria.
The concept of low QRS voltage was described initially when only three electrocardiographic leads were available. The 12-lead total QRS voltage has rarely been employed as an indicator of low QRS voltage. Among the 10 conditions in which total QRS voltage was measured and reported, those with the lowest voltage included cardiac amyloidosis, 58–199 mm (mean 104); cardiac adiposity, 73–210 mm (mean 120); and the carcinoid syndrome, 48–227 mm (mean 117). The lowest total 12-lead QRS voltage among the previously described 331 patients was 58 mm. Thus, to have an electrocardiographic total 12-lead QRS voltage of only 34 mm, as in the present patient, is indeed unusual.
A limitation of the present report is the lack of anatomic confirmation of cardiac amyloidosis. The echocardiogram, however, is virtually diagnostic of extensive cardiac amyloidosis.