A study on the morphology of pulmonary vein ostia and left atrium in the cadaveric heart

Abstract

Background: Classically, pulmonary veins (PV) open to the left atrium (LA) through four ostia on its posterior wall. Variations from this pattern in the form of a common venous ostium or additional ostia are not uncommon. The myocardium of the LA extends into the PVs as myocardial sleeves (MS) which are often the site of focal electrical activity that initiates atrial fibrillation. The aim is to study the morphology of pulmonary venous ostia and posterior wall of LA and to find their correlation. Materials and Methods: Forty formalin preserved specimens of the heart were included in this study. The number and position of PV ostia were noted and categorized into six types. The dimensions of ostia and posterior wall of LA were measured. Data were statistically analyzed. The pulmonary venous wall was examined microscopically for the presence of myocardial tissue. Results: Classical pattern was the commonest (62.5%) followed by additional middle PV (MPV) on the right (12.5%) and common ostium on the left (10%). The mean diameter was maximum for the common right PV ostium (14.7 mm ± 0.5) and minimum for the right MPV ostium (8 mm ± 1.4). The mean sagittal and coronal dimensions of LA were 56.4 mm ± 11.4 and 47.9 mm ± 8.7, respectively. R Square value of 43% and Pearson's correlation of 0.58 showed a strong association between ostial and atrial area. MS was found microscopically in the venous wall. Conclusion: The morphometry of PV ostia and LA can provide useful information for cardiothoracic surgery.