IntrOductIOnIn the past decade, pulmonary veins have been known to play an important role as the triggering focus of the electrical activity in atrial fibrillation [1]. Earlier, it was considered that the variations in the number and course of pulmonary veins were rare and they were confined only to few case reports [2]. Recently, however, it has been found that variations in pulmonary venous anatomy were seen in 36% of patients [3] and that they were one of the aetiologies for ectopic heart beats [4]. This greater than expected variability in pulmonary venous anatomy could substantially alter success rates of radiofrequency ablation, as ectopic foci could go untreated in variant veins. Increasingly, selective radiofrequency ablations of these arrythmogenic foci are being performed, to treat patients with refractory atrial fibrillation [5]. The successful treatment of atrial fibrillation by radiofrequency ablation of the ectopic foci can be made possible only by having accurate knowledge on the normal pulmonary venous anatomy and its measurement. Thus, the present study was done to find out the variations in the number of right and left pulmonary veins which drained into the left atrium.
MAterIAls And MethOdsThe present study was done on 50 formalin fixed hearts which were obtained from the Department of Anatomy. Left atria of these hearts were studied from external aspect, for the variations in the number of pulmonary veins which drained into it. Left atrium were opened by making a midline incision along the whole length of its posterior wall and the number of pulmonary ostia which opened into the left atrium were identified and documented.
resultsThirty-four heart specimens (68%) had normal four pulmonary veins, two from each lung which extended to the left atrium and opened into it via two separate pulmonary ostia, on either side. In 16 (32%) out of 50 specimens, variations in the number of pulmonary veins and the pulmonary ostia were observed either on one side or on both sides of the left atrium.Following variations were recorded in our study: Seven specimens (14%) had a single pulmonary vein with a single ostium on the right side and two pulmonary veins on left side of the left atrium. Six specimens (12%) had three pulmonary veins with three ostia on the right side and two veins on the left side. Two specimens (4%) showed a single pulmonary vein and an ostium on the left side of the left atrium. The remaining 2% of the hearts presented with four separate pulmonary veins with four ostia, along with single left side pulmonary veins opening into the left atrium.Overall, in our study, the most common variation which was observed in the number of pulmonary veins on right side was a single pulmonary vein (14%), followed by three veins in 12% specimens, a normal pattern of two veins in 4% specimens, and four pulmonary veins in 2% of specimens. In contrast to the right side, left side showed no such variants, except a single left pulmonary vein which drained into the left atrium in 50% of specimens and rest of th...