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.