Left atrial enlargement provides early evidence of left ventricular dysfunction in hypertensive heart disease, preceding the decline in cardiac index associated with left ventricular hypertrophy.
In order to understand more precisely the progression of ventricular dysfunction in hypertension prior to development of ventricular failure, 25 normal volunteer subjects and 97 untreated essential hypertensive patients (21 of whom had coronary arteriography and failed to show significant atherosclerosis) were classified into three groups: (I) normal-sized hearts, 54 patients; (II) left atrial enlargement (ECG criteria), 20 patients; and (III) left ventricular enlargement (ECG and chest X-ray criteria), 23 patients. Heart rate was elevated ( P < 0.001) in all three groups; total peripheral resistance and arterial pressure increased progressively from group I to II to III ( P < 0.001); cardiac index was reduced only in group III ( P < 0.001). However, despite normal cardiac index in group II, left ventricular ejection rate was impaired ( P < 0.01), and tension-time index and pressure-time per beat were greater than in patients with normal-sized hearts ( P < 0.001). Thus, left atrial enlargement provided the initial evidence of left ventricular dysfunction. Later, when left ventricular hypertrophy became clinically apparent (always associated with left atrial abnormality) further impairment of left ventricular function was evident. Since these hemodynamic changes were observed in patients with normal coronary arteries, presence of left atrial and ventricular enlargement should provide useful criteria for classifying functional impairment in hypertensive heart disease.
Fröhlich et al. (1971) studied this question.