Left ventricular hypertrophy (LVH) is a common finding in patients with fixed or borderline hypertension and can be diagnosed either by ECG or by echocardiography [1,2]. Echocardiography is the procedure of choice, since the sensitivity of the different ECG criteria may be as low as 7 to 35 percent with mild LVH and only 10 to 50 percent with moderate to severe disease . In a report from the Treatment of Mild Hypertension Study, for example, almost none of 844 patients had ECG criteria for LVH, while echocardiographic LVH (indexed by body surface area, see below) was present in 13 percent of men and 20 percent of women . Nevertheless, if echocardiography is unavailable or too expensive, appropriate ECG criteria can be used to detect increased LV mass [5,6]. (See "Electrocardiographic diagnosis of left ventricular hypertrophy".)
The definition and pathogenesis of LVH in hypertension will be reviewed here. The clinical implications of and effects of therapy on this complication and the indications for echocardiography in hypertensive patients are discussed separately. (See "Clinical implications and treatment of left ventricular hypertrophy in hypertension".)
Left ventricular hypertrophy is defined as an increase in the mass of the left ventricle, which can be secondary to an increase in wall thickness, an increase in cavity size, or both. LVH as a consequence of hypertension usually presents with an increase in wall thickness, with or without an increase in cavity size. This increase in mass predominantly results from a chronic increase in afterload of the LV caused by the hypertension, although there is also a genetic component. A significant increase in the number and /or size of sarcomeres within each myocardial cell is the pathologic mechanism.
The estimation of LV mass is commonly derived from LV measurements obtained by 2D echocardiography. The American Society of Echocardiography with the European Association of Echocardiography has issued the following criteria for LVH using modified Simpson's rule :
- Estimated LV mass of 201 to 227 g (103 to 116 g/m2) for men and 151 to 171 g (89 to 100 g/m2) for women is mildly abnormal
- Estimated LV mass of 228 to 254 g (117 to 130 g/m2) for men and 172 to 182 g (101 to 112 g/m2) for women is moderately abnormal
- Estimated LV mass >255 g (>131 g/m2) for men and >193 g (>113 g/m2) for women is severely abnormal