Right-Ventricular-Pacing-via-Left-Superior-Vena-Cava
Santosh Kumar Dora, Jagan Mohan Tharakan, Ajith Kumar
Sri Chitra Tirunal Institute of Medical Science and Technology, Thiruvananthapuram
Negotiating the pacing lead into the right ventricle via left superior vena cava, at times, can be difficult. We report two such cases in which pacing leads were introduced into the right ventricle via left superior vena cava, with the help of stylet tip shaped into a large pigtail loop.
(Indian Heart J 2004; 56: 150–151)Key Words:
Pacing, Left superior vena cava, ArrhythmiaP
acing lead insertion into the right ventricular (RV) apex via left superior vena cava (SVC) has been rarely reported. We describe two cases of RV pacing lead insertion via left SVC-coronary sinus-right atrium route. In the first case a tined bipolar ventricular lead was introduced and in the second case, a bipolar active fixation screw-in lead was placed. The pacing leads could be easily introduced into right ventricle with the help of a stylet tip shaped into a large pigtail loop.Case Reports
Case 1: An 81-year-old male presented with recurrent giddiness and presyncope and was found to be in atrial fibrillation with ventricular rate of 40 beats per min. A diagnosis of atrial fibrillation with complete heart block was made and single chamber ventricular permanent pacemaker implantation was planned. An extrathoracic left subclavian venipuncture was performed. The course of guide wire suggested presence of left SVC draining into coronary sinus that was subsequently confirmed by contrast injection under fluoroscopy. A bipolar tined steroid eluting lead (St Judes Medical E 1450 T) was inserted via left SVC into the right atrium. With a stylet shaped to a large pigtail loop, the lead could be negotiated into the RV apex with little difficulty. The optimum lead parameters obtained were : R wave 19.8 mV, threshold 0.5 V, and resistance 519 ohms. An interrogation at 3 months and 1 year showed normal functioning of the pacemaker.
Case 2: A 50-year-old female had undergone prior surgical closure of sinus venosus type atrial septal defect with rerouting of right upper pulmonary vein into left atrium in 1984. Few days after surgery, she was detected to have infarction of upper lobe of the right lung due to right upper pulmonary vein obstruction for which she underwent lobectomy. Recently, she presented with history of presyncope, and electrocardiogram revealed intermittent atrial flutter with fast ventricular rate. During sinus rhythm she was having slow heart rate of less than 40 beats per min. Atrial flutter was thought to be scar-related; a radiofrequency ablation was attempted, which was unsuccessful. A diagnosis of brady-tachy syndrome was made and single chamber ventricular permanent pacemaker implantation was planned. Contrast injection in the upper limb veins showed blocked right SVC and presence of left SVC draining into the right atrium via coronary sinus (Fig.1). Extrathoracic subclavian venipuncture was performed in the left side and a bipolar steroid eluting active fixation screw-in ventricular lead (Medtronic Capsure 4068) was introduced into the right atrium via left SVC and coronary sinus (Fig. 2). A stylet was shaped to a large pigtail loop with an additional curve anteriorly to facilitate lead entry into the right ventricle. With this pre-shaping of the stylet, the lead could be easily introduced into the right ventricle. The lead was screwed at right ventricular apex and optimum lead parameters were obtained: R wave 13.8 mV, threshold 0.8 V and resistance 624 ohms.
Discussion
Due to its rarity, there is no large series on RV pacing lead insertion via left SVC, reported in the literature. However, several case reports of the pacing lead insertion via left SVC into the right atrium and right ventricle have been published in the literature.1-4 There is also a case report of insertion of defibrillator lead into the right ventricle via left SVC.5 There is no standard procedure for easy and effective negotiation of the pacing lead into the right ventricle via left SVC - coronary sinus route. Negotiating the pacing lead via left SVC into the right ventricle is challenging and at times difficult due to its anatomical location and relationship of coronary sinus ostium and right ventricular inflow. By shaping the stylet into a large pigtail loop with an additional curve anteriorly at the distal end, we found it easier to introduce the lead into right ventricle. However, in case RV lead cannot be placed, the left ventricle can be paced via a left ventricular vein draining into the coronary sinus.6
We recommend a detailed echocardiographic study to exclude left SVC and if doubt exists, a left forearm vein contrast injection under fluoroscopy may be done. In the presence of left SVC it is advisable to do a right-sided approach for better stability of the pacing lead. In cases, where the right-sided SVC is absent like in our second patient, it may be worth preshaping the stylet, as we did, to negotiate the lead into the right ventricle. A large loop may be left in the right atrium for greater stability so as to support the lead by the right atrial free wall to decrease the tension over the lead. An active screw-in fixation lead may prevent lead tip displacement.
Correspondence:
References
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