Persistent left superior vena cava: is it an incidental pathology detected during pacemaker implantation or one of the causes of sick sinus syndrome?

We read with interest the article by Archontakis et al.1 in which they implanted a pacemaker via an optimal technique in a patient with isolated persistent left superior vena cava (PLSVC) anomaly, syncope attacks, and sick sinus syndrome (SSS). In this article, we were more interested in the comorbidity of PLSVC and SSS. In our previous experimental study, using the chronic coronary venous insufficiency model, we showed that the exposure of the coronary veins to high pressure and volume load leads to haemosiderin deposition in the myocardial tissue.2 It is known that chronic iron overload selectively reduces CaV1.3-mediated L-type Ca2+ channels and causes bradycardia, heart block, and atrial fibrillation (AF).3 In some patients with PLSVC (especially those with underdeveloped coronary venous collaterals, thebesian vein, and sinusoidal vein network), chronic iron overload in the myocardial tissue may lead to SSS development due to chronic volume and pressure load on the coronary sinus and coronary veins over the years.