Severity of diastolic dysfunction as a determinant of left atrial size

Abstract

Background: Left ventricular diastolic dysfunction (LV DD) increases cardiac morbidity. High left atrial (LA) pressure results from LV DD, leading to LA enlargement. We conducted a study to determine if LV DD severity is correlated to increased LA size. Methods: We reviewed 367 patients with echocardiographic evaluations over 36 months. Severity of LV DD and LA diameter were determined in apical views. The onset of AF following the initial echo was recorded. LA diameter was calculated for normal patients (NP) and those with LV DD. The odds ratio (OR) of developing AF and time to event for each class of LV DD was determined. The OR for AF was calculated for congestive heart failure (CHF), LV hypertrophy (LVH), coronary disease (CAD), diabetes (DM), and hypertension (HTN). Results: LA diameter in NP=43.6±8.28 mm (95% C.I.=42.4–44.8 mm). LA diameter for grade I LV DD=43.5±6.26 mm (95% C.I.=41.6–45.3 mm); grades II+III LV DD= 47.5±7.34 mm (95% C.I.=45.5–49.5 mm). LA diameter in grades II and III LV DD was increased (P<0.05) compared to NP and grade I. There was no difference in LA size between NP and grade I LV DD, nor was there between grade II and III LV DD. Overall, the risk of AF was not increased in patients with LV DD as compared to NP (OR=1.03, 95% C.I.=0.61–1.73, P=NS). Patients with grades II+III LV DD trended toward a shorter time to onset of AF (763.8±586.6 days vs. 1090.9±758.3 and 1085.4±711.8 days, respectively, P=NS) compared to NP and grade I LV DD. CHF was associated with a risk for AF (OR 2.39, 95% C.I.=1.41–4.07, P<0.005). LVH, CAD, DM, and HTN had no increased risk for AF. Conclusions: Our study demonstrates an association between abnormal LV DD and increased LA diameter. LV DD did not increase the risk of AF, however, the presence of heart failure was a strong predictor for AF development.