We present a case of near-normalization of the QRS by septal pacing in a patient with dual-chamber pacemaker and underlying complete right bundle branch block and first degree atrioventricular block. The right ventricular mechanical synchronization suggested by the ECG was validated as such by strain echo. To the best of our knowledge, this is the first time it has been shown that the narrowing of the QRS corresponds to mechanical synchronization in a case of this seldom-recognized phenomenon.
Persistent left superior vena cava (PLSVC) is the most common variant of abnormal venous return to the heart. While usually asymptomatic, it is known to complicate transvenous cardiac procedures, such as implantation of cardiac electronic devices and ablations. PLSVC can present with or without the concomitant absence of right superior vena cava (RSVC). Depending on the operator's preference, implantation of permanent cardiac pacemakers (PPMs) may be performed from the left or right side. As most often the PLSVC is only identified at the time of intervention, it follows that the variant with the absence of RSVC can be diagnosed in practice only when implanting from the right side. For this reason, the true prevalence of this variant is largely unknown because most published cases of cardiac device implantations in patients with PLSVC have been performed from the left side. We present a short 3-case series of PPM implantations in a tertiary center from the right side in patients with PLSVC and absent RSVC. We found that the use of a standard curve for ventricular lead septal placement and a wide C-curve for right atrial lead placement in these patients was a feasible technique with good outcomes.
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