Editor's Note: View video accompanying this article at "Left Ventricular Delivery Tool to Access the Right Ventricle in Persistent Superior Vena Cava."
A 67-year-old male with an underlying hypertrophic cardiomyopathy and documented symptomatic sustained monomorphic ventricular tachycardia was referred for implantation of an implantable cardioverter-defibrillator (ICD). His prior ischemic work-up with coronary angiography was unremarkable. His echocardiogram revealed asymmetric left ventricular hypertrophy with provoked left outflow tract gradient and bi-atrial enlargement. A dual-lead system was considered as the patient also has a history of paroxysmal atrial fibrillation.
We proceeded with our usual approach using a lateral left subclavian venous entry using a micropuncture needle along with immediate creation of a subcutaneous left infra-clavicular pocket. The vein was easily accessed, but the guidewire immediately traversed inferiorly and the subsequent venography identified a very large persistent left superior vena cava (SVC) emptying onto the low right atrium (Figure 1). Further anatomical delineation confirmed the absence of right-sided SVC (Figure 2).
This scenario has been associated with increased difficulty in the placement of a right ventricular lead, especially when a right ventricular apical position is desired (such as for an ICD system). The additional challenge lies in the need for lead advancement through the counter angulations, and the need for a ‘back support’ for forward advancement after entry into the right ventricle. In the presence of a right atrial enlargement, this ‘back support’ looping can be further challenging. Hence, previous case reports have suggested changing to a right-sided approach or placement of the ventricular lead toward the outflow tract.
As a right-sided approach was not feasible, we proceeded with the left-sided entry and use of a left ventricular (coronary vein) lead delivery system to facilitate entry into the right ventricle as suggested by the manufacturer’s field representative. Guidewires were advanced and placed in the right atrium. Over one of the guidewires, an extended curve (135º) outer sheath was advanced and positioned facing the tricuspid valve with anterior (counterclockwise) rotation. The guidewire was then advanced into the right ventricular outflow tract. The softer inner sheath with an obtuse angle tip (pointed downward) was then advanced over the guidewire and the guidewire was withdrawn until it could be re-directed toward the right ventricular apex. Both the outer and inner sheaths were then advanced over the wire through the valve and directed toward the right ventricular apex (Figure 3). The inner sheath was then removed, and a 7 French ICD lead (Durata, St. Jude Medical) was advanced and positioned near the apex. Advancement of the lead was somewhat tight, especially when the distal coil traversed through the curve. The use of a firm stylet was found to be helpful in the advancement of the lead within the sheath. Confirmation of lead tip contact with the endocardial tissue was guided by the usual criteria of good sensing and pacing parameters and the presence of injury current. After confirmation of sufficient electrical parameters (18 mV sensed R wave and 0.6 volts at 0.5 ms pulse width capture threshold), the lead was secured by extending the helix in the usual fashion and the sheath was removed using a standard slitter. The atrial lead was placed at the lateral wall of the right atrium using a manually shaped stylet. Figure 4 shows the final positions of the leads. The defibrillation threshold using the upper limit vulnerability method was estimated at 10 joules.
Although persistent left SVC is the most common thoracic vein anomaly, its presence in the general population is low, estimated at only 0.3-0.5%.1-3 The anomaly typically causes no hemodynamic sequelae; therefore, it is usually undetected and is typically only found incidentally during (venous) catheterization. The presence of persistent left SVC is caused by the failure of regression of the left cardinal vein caudal to the innominate vein. The right SVC is also commonly present with or without the presence of the innominate vein. In a minority of cases (10-18%), the right SVC is absent. In such cases, implantation of endovascular leads can pose quite a challenge, as in our case presented here.
There have been many case reports of the placement of pacing leads in patients with persistent left SVC. Placement of an atrial lead is typically straightforward, as the persistent left SVC typically empties into the right atrium. Placement of the ventricular lead poses more of a challenge for the reasons described above. One choice is to place a lead in a coronary vein tributary.4
Others have placed the lead at the outflow tract or customized a stylet to assist in aiming the lead toward the apex.5-7 We report here the utility of an LV lead delivery system to facilitate the aim of the lead toward the right ventricular apex, taking advantage of the J curve of the sheath. As the delivery system was designed for an LV lead, which is typically of a small caliber (4.7-5.2 F), the passage of an ICD lead is somewhat tight even when using the smallest ICD lead available on the market. But by avoiding extra bulk (by using a single-coil lead) and utilizing a firm stylet, the lead could be successfully advanced to the desired location, achieving satisfactory sensing, pacing and defibrillation parameters. This method had been described8 and the authors also believed that the use of a delivery sheath system is useful in such anatomical anomaly. In that case, a coronary sinus delivery sheath (SafeSheath, Pressure Products) facilitated the delivery of an active fixation lead (Riata, St. Jude Medical) on to the right ventricular outflow tract.
Placement of the ICD lead took 25 minutes and the total procedure took 55 minutes, not considerably longer than a ‘routine’ dual-lead ICD implant procedure. Therefore, we believe that the utility of such a delivery system offers a practical solution to a challenging situation. Suitable delivery sheath(s) and small-caliber ICD lead(s) are key in the success of utilizing this technique. n
Disclosure: The authors report no conflicts of interest regarding the content herein. Outside the submitted work, Mr. Umlauf reports employment with St. Jude Medical, and Dr. Liem reports grants/grants pending to his institution from St. Jude Medical.
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- Gaba D, Kitussamy P, Ho R, et al. Permanent pacing from a left ventricular vein in a patient with a persistent left superior vena cava and absent right superior vena cava: use of an over-the-wire system. J Interv Card Electrophysiol. 2003;9:357-360.
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