We have investigated the prognostic value of echocardiographic parameters that assess mechanical and electrical remodelling of the left atrium, to predict recurrence of atrial fibrillation after radiofrequent isolation of pulmonary vein (PVI), and to evaluate the significance of this noninvasive marker of slow impulse propagation for the identification of persons with slightly elevated blood pressure and hypertension in adults. We also studied the left atrium's (LA) reservoir function, the LA's total emptying volume (TEV), and the LA's total emptying fraction (TEF). Atrial conduction time was evaluated using the pulsed tissue Doppler and expressed as interatrial and intraatrial conduction time (ACT).

The principal finding of this study is that interatrial conduction time predicts early hypertensive disease in adults. A cutoff of 19.5 msec for inter-ACT had a sensitivity of 85% and a specificity of 89% in identifying early hypertensive disease in adults. According to available sources, this new finding has not been previously reported. Our study demonstrated that impairment in the propagation of sinus impulses is present in hypertension. However, adults with slightly elevated blood pressure had a slowing of sinus impulse propagation. It was demonstrated that ACT on the lateral, septal mitral, tricuspid annulus, and inter and intra ACT were prolonged in hypertension compared to normotension. Atrial electromechanical delay is more extended in hypertensives with elevated pulse pressure and without significant structural remodelling. Inter and intra ACT are prolonged in hypertension, and in early stages without significant prolongation of maximum P wave duration on 12-channel ECG. This explains an earlier period of atrial electrical impairment, before the appearance of P wave prolongation on a 12-lead ECG.  Slowing atrial conduction velocity and atrial conduction delay can occur due to atrial fibrosis and remodelling, and can trigger atrial fibrillation. Atrial conduction delay can be easily discovered with tissue Doppler, which may indicate the presence of arrhythmogenic substrate. 

In our study, we demonstrated significantly prolonged intra- and inter-ACT with hypertension, even when it is medically regulated. Our findings suggest that inter-ACT conduction time measured by tissue Doppler is the first sign of impaired conduction of sinus impulses in the early stage of hypertension, even in persons with slightly elevated blood pressure. In addition to morphologic remodelling known to be present in hypertensive patients, even slightly elevated blood pressure also causes electrical remodelling of atria, which are responsible for slowing conduction of sinus impulses. LA enlargement causes slowing of sinus impulse conduction because of structural and electrophysiological changes in the atrial myocardium. 

Our study also showed impairment of the LA's mechanical function in hypertension and adults with slightly elevated blood pressure. Analyzing the LA volume in various phases of the heart cycle showed a deterioration of the LA's mechanical function. There was a continuous trend in the progression of reduction in the atrial reservoir function from slightly elevated blood pressure to hypertension. 

During follow-up of patients after radiofrequency catheter ablation, only the interatrial conduction time was found to be an independent predictor of late recurrence of atrial fibrillation. Successful PVI-based atrial fibrillation significantly improved the total emptying fraction of the left atrium, intraleft, and interatrial conduction time in patients without recurrence of AF.

Prolonged atrial conduction time estimated with a tissue Doppler may be useful for distinguishing normotensive persons from those with slightly elevated blood pressure and those with hypertension, stage 1. Interatrial conduction time can predict late recurrence of AF after successful PVI.

Dr. Dijana Djikic (born August 1970) is a clinical doctor at the University Clinic Center of Serbia – Belgrade, Clinic of Cardiology, Department of Arrhythmology and Clinical Cardiology. The prevailing interest of her research and clinical practice is arrhythmology and echocardiography, which were the topics of her PhD degree, which she obtained in 2018. She completed her PhD in 2018. Previously, she received her specialized degree in internal medicine (2004) and subspecialization in cardiology (2015). She has published about 35 scientific review papers. She participated in several international scientific studies (LIBREXIA, ENGAGE AF-TIMI 48, etc). Dr Djikic is a member of several scientific societies, such as the Cardiology Society of Serbia (2004), ECHOS Serbia (2026), the European Society of Cardiology (2016), and the ESC Fellowship (2025).