Relationship of left atrial enlargement to persistence or development of ECG left ventricular hypertrophy in hypertensive patients: implications for the development of new atrial fibrillation

Abstract

Persistence and development of ECG left ventricular hypertrophy (LVH) by Cornell product criteria are associated with an increased risk of atrial fibrillation compared with regression or continued absence of LVH. We postulated that this association might be in part mediated via greater left atrial enlargement (LAE) in patients with new and persistent ECG LVH. Baseline and third year ECG LVH and left atrial systolic diameter were examined in 663 patients in the Losartan Intervention For Endpoint reduction in hypertension echocardiographic substudy who were in sinus rhythm at baseline and had no history of atrial fibrillation. Left atrial systolic diameter was measured and considered enlarged if more than 3.8 cm in women or more than 4.2 cm in men. Cornell product LVH above 2440 mm-ms was considered consistent with LVH. After 3 years follow-up, 238 patients (35.9%) had continued absence of Cornell product LVH, 156 (23.5%) had regression of LVH, 236 (35.6%) had persistent LVH and 33 patients (5.0%) developed new ECG LVH. Compared with third year mean left atrial systolic dimension and prevalence of LAE in patients with continued absence of LVH (3.62+/-0.52 cm, 12.6%), there were step-wise increases in patients with regression of LVH (3.71+/-0.49 cm, 20.5%), persistence of LVH (3.82+/-0.57 cm, 32.2%) and development of new ECG LVH (3.91+/-0.42 cm, 36.4%, both P<0.001). After controlling for differences in age, sex, baseline SBP, BMI and Sokolow-Lyon voltage, randomized treatment allocation, change in DBP and SBP between baseline and third year and for isovolumic relaxation time and presence of an abnormal mitral E/A ratio at baseline and third year, the odds of having LAE were significantly increased in patients with persistent LVH (odds ratio 1.8, 95% confidence interval 1.1-3.2, P=0.043) or new LVH (odds ratio 3.1, 95% confidence interval 1.3-7.7, P=0.016), but not in patients with regression of Cornell product LVH (odds ratio 1.1, 95% confidence interval 0.6-2.0, P=0.860). Persistence or development of new ECG LVH during antihypertensive therapy are associated with an increased risk of LAE after 3-year follow-up, whereas regression of ECG LVH is not associated with an increased risk of LAE. These findings provide insight into a possible mechanism by which changes in ECG LVH are associated with changing risk of developing atrial fibrillation.