Adrenoceptor and cholinoceptor modulation of rat pulmonary vein cardiac muscle contractility

Mechanical function of left atrium and pulmonary vein sleeves before and after their antrum isolation

BACKGROUND AND OBJECTIVE

Pulmonary vein (PV) sleeves are established as the main substrate taking part in the mechanisms of atrial fibrillation (AF) initiation. However, we have extremely few data concerning their physiological role in the heart contractility. The aim of the study was to estimate the mechanical function of the left atrium (LA) and PV sleeves before and early after their isolation.

MATERIALS AND METHODS

A total of 17 patients with a mean age of 57.4±8.3 years who underwent PVs isolation due to AF were enrolled in the study. A day before the procedure a computed tomography (CT) of the LA and PVs and dopplerography of transmitral flow were performed. During the procedure the mechanical function of the LA and PV sleeves were estimated by transesophageal echocardiography and manometry in the left heart chambers.

RESULTS

During the invasive study the patterns of the heart chambers and PV sleeves pressure were identified. These patterns confirmed the active role of the PV sleeves in LA filling and active LA relaxation during left ventricular systole. After PV isolation an alteration of transmitral blood flow and increase of LA pressure were registered. However, diastolic dysfunction was ruled out by LV manometry, thereby testifying LA mechanical function disturbance. The change in PV hemodynamics also occurred as a result of the decrease in PV sleeves contractility, revealed by manometry and paired CT scans.

CONCLUSIONS

The PVs take an active part in left atrial filling by contraction of their sleeves. Antrum isolation of the PVs leads to the deterioration of their contractility and LA reservoir function.