Evaluation of atrial conduction time by P wave dispersion and tissue Doppler echocardiography in prehypertensive patients

OBJECTIVES
Prehypertension is a predictor for the future development of hypertension and represents an increased risk for cardiovascular morbidity and mortality. Prolonged intra/interatrial conduction times demonstrated by P wave dispersion (PD) and tissue Doppler echocardiography (TDE) are related to the development of atrial fibrillation. The aim of this study was to evaluate atrial conduction time by PD and TDE in patients with prehypertension.

STUDY DESIGN
In 46 prehypertensive patients (22 males, 24 females; mean age 56.5±12.3 years) and 39 normotensive healthy controls (19 males, 20 females; mean age 55.8±11.7 years), we measured P wave duration and dispersion on 12-lead electrocardiography, and atrial electromechanical coupling intervals (PA) by TDE.

RESULTS
Maximum P wave duration (Pmax) and PD were prolonged in prehypertensives compared to controls (Pmax 110.1±13.8 vs. 91.4±7.7 msec, p<0.001; PD 55.7±11.1 vs. 36.8±5.7 msec, p<0.001). Atrial PAs measured at the lateral and septal mitral annuluses were significantly delayed in the prehypertensive group (lateral PA 76.5±10.1 vs. 65.4±10.4 msec, p<0.001; septal PA 59.0±6.4 vs. 53.5±7.5 msec, p=0.002). Both interatrial (lateral PA-tricuspid PA) and intra-atrial (septal PA-tricuspid PA) conduction times were delayed in the prehypertensive group (25.8±9.3 vs. 17.0±9.5 msec, p<0.001; 9.2±3.7 vs. 6.7±3.0 msec, p=0.008, respectively). Correlation analysis showed that both Pmax and PD were correlated with interatrial (r=0.38, p<0.001 and r=0.40, p<0.001, respectively) and intra-atrial (r=0.31, p=0.01 and r=0.38, p<0.001, respectively) electromechanical delays.

CONCLUSION
Our finding of significant prolongation of atrial electromechanical coupling and PD may indicate an increased risk for the development of atrial fibrillation in prehypertensive subjects.