Nonvalvular atrial fibrillation associated with cardioembolic stroke: the role of hypertensive heart disease.

Epidemiologists have not identified high risk groups nor the entire spectrum of heart disease, especially the subclinical forms underlying nonvalvular atrial fibrillation (NVAF) predisposing to cardioembolic (CE) stroke. We analysed 36 cases of 'isolated' NVAF among 106 consecutive cases of CE stroke after excluding cases of AF associated with valvular disease, myocardial infarcts, ischaemic and other cardio-myopathies (34 cases). This revealed echocardiographic left ventricular hypertrophy (LV mass index 136 +/- 25 g, vs normal 68 +/- 12 g p less than 0.001), enlarged left atria (left atrial area 27.4 +/- 3.6 cm2 vs normal 14.3+/- 1.6 cm2 p less than 0.001), normal systolic function and formed the largest group associated with CE stroke (34%), mean age 72.6 years--Study Group D. Eighty nine per cent had known or undetected hypertension compared to 60% in matched controls (x2 = 8.3 df = 1 p less than 0.01), and hypertension remained the predominant risk factor for left ventricular hypertrophy (LVH). Although all had echocardiographic LVH, 60% had neither electrocardiographic LVH nor cardiomegaly on chest X-ray. Hence usual epidemiologic methods may fail to detect these cases. Hypertensive heart disease is known to predispose to left atrial enlargement and AF. Progressive atrial enlargement is associated with increasing risk of embolic stroke. We conclude that NVAF associated with hypertensive heart disease forms a major component of the spectrum of heart disease associated with NVAF predisposing to CE stroke. Detection and treatment of hypertension to prevent or reverse LVH and atrial enlargement should be an important preventive measure.