Abnormal Rhythms Associated with Persistent Left Superior Vena Cava

Abstract

ExtractT h e electrocardiograms of 2 6 patients with persistent left superior vena cava ( S V C ) draining into t h e coronary sinus were reviewed. Left axis of P waves between + 15 a n d -29 degrees was observcd in nine cases, including t w o of three cases of persistent left SVC with absent right SI'C. Isorhythmic A-V dissociation with interference was observed in o n e subject.T h e study of t h e P wave i n five groups of patients with presumably normal caval drainage revealed t h a t frontal P wave axis fell usually between +20 a n d +70 degrees. SpeculationLeft axis of the P waves, if present i n patients with congenital h e a r t defects, m a y suggest persistent left superior vena cava draining to t h e coronary sinus. F u r t h e r pathologic a n d histologic study is needed to clarify t h e pathogenesis of these a b n o r m a l cardiac rhythms a n d t h e possible embryologic relation between persistent left superior v e n a cava a n d a n ectopic pacemaker.

Electrogram-guided isolation of the left superior vena cava for treatment of atrial fibrillation

“…Developmental abnormalities leading to a persistent LSVC may therefore be associated with abnormalities of cardiac conduction and ectopic pacemaker cells. 19 It was interesting that AF in two of four of our patients suffered AF, which was largely exercise-induced and one may speculate that initiating ectopics from the LSVC arise from ectopic pacemaker cells.…”

Primary fibroma in the right atrium of a dog

“…The abnormal negative P-waves in the electrocardiogram (ECG) of this dog suggested an atypical atrial depolarization vector. Persistent left cranial vena cava has been reported with negative P-waves in man (Momma & Linde, 1969), in the dog (Buchanan, 1974) and in the cat (Lombard & Twitchell, 1978). The abnormal P vector of the present case may have been caused by displacement of atrial tissue by the tumour, an abnormal pacemaker site or altered conduction pathways.…”

Absent right superior caval vein (vena cava) with normal atrial arrangement.

“…Dilatation of the coronary sinus, which has to transmit all blood from the upper half of the body, may alter the geometry of the atrium and displace the left atrium upwards. 12 Besides the leftward deviation of the P wave axis, there have been reports of various arrhythmias in this anomaly.9 '3 James and colleagues made a detailed pathological study in two teenage boys with absent right superior caval vein. One died suddenly and the other died of arrhythmia 16 days after repair of ventricular septal defect.…”