Doppler-derived indexes and B-type natriuretic peptide in prediction of paroxysmal atrial fibrillation in essential hypertension: a prospective study

BACKGROUND: Onset of atrial fibrillation in hypertensive patients is usually associated with a high occurrence of cardiovascular complications. Despite its leading importance as a highly prevalent and modifiable risk factor, only a few data are available regarding the predictors of paroxysmal atrial fibrillation (PAF) in hypertensive patients. OBJECTIVES: This study was undertaken to determine if PAF could be predicted in hypertensive patients while in sinus rhythm using Doppler-derived indexes and the plasma B-type natriuretic peptide (BNP) concentration. METHODS: We prospectively evaluated 165 consecutive patients with hypertension and no known history of PAF or cardiovascular events who attended the cardiology outpatient clinic. Their mean age was 62 +/- 12, 94 male, 71 female. The conventional echocardiographic parameters were measured including: left atrial (LA) volume, mitral regurgitation (MR), left ventricular (LV) function, LV mass. The ratio of transmitral peak E-wave velocity to flow propagation velocity (E/V(p)), ratio of E-wave to mitral annular early diastolic velocity (E/E(a)) obtained by Doppler tissue at the lateral and septal corners of the mitral annulus were calculated. The plasma BNP was measured at the study entry. RESULTS: After a mean follow-up of 15 +/- 3 months, PAF (symptomatic attacks or documented on the ECG) occurred in 36 (21.8%) of 165 patients. The patients with PAF had significant higher BNP levels than those with sinus rhythm (160 +/- 109.8 vs. 87.9 +/- 57.7 pg/ml, P < 0.001) Also, E/E(a) and E/V(p) ratios were significantly higher in hypertensives with PAF (15.1 +/- 2.8 vs. 8.39 +/- 1.33, P < 0.001), and (1.65 +/- 1.29 vs. 1.19 +/- 1.06, P < 0.001) respectively. In univariate analysis, E/V(p), E/E(a), and BNP and LV hypertrophy were significant predictors of PAF. Barely E/V(p) and E/E(a) remained independently significant after adjustment of clinical and other echocardiographic variables by multivariate logistic regression analysis (odd ratio: 3.36, P < 0.001 and 4.93, P < 0.001 respectively). A cutoff value of > or =1.7 for E/V(p) predicted PAF with 91% sensitivity and 88% specificity; E/E(a) >12 has sensitivity 98%, specificity 89%, while BNP>170 pg/ml has 83% and 72% specificity, respectively, for prediction of PAF in hypertensive patients. CONCLUSION: Paroxysmal atrial fibrillation could be predicted in hypertensive patients while in sinus rhythm using Doppler-derived indexes. Increased E/V(p), E/E(a) ratios and elevated BNP appear to be useful parameters to identify patients at heightened risk. They may reflect early left ventricular dysfunction and atrial hypertension in this population.