Effect of electrode location in great cardiac vein on the ventricular defibrillation threshold

This study tested the hypothesis that the DFT could be lowered by delivering a weak auxiliary shock in conjunction with a stronger primary shock with the auxiliary shock electrode near the cardiac region where the primary shock electric field is weakest. This hypothesis was tested by determining the DFTs with the auxiliary shock delivered from different locations within the great cardiac vein (GCV). In 15 dogs, catheters with defibrillation electrodes were placed transvenously in the RV apex, the SVC, and the GCV. An active can electrode and the SVC electrodes were electrically coupled to serve as a return electrode for the RV and GCV electrodes. DFTs were determined for a primary shock through the RV electrode with and without a subsequent auxiliary shock of lower amplitude through the GCV electrode. The leading edge voltage and current at DFT were significantly lowered by addition of the auxiliary shock (17% and 19% decreased, respectively), but energy was not changed. The animals were divided into three groups according to the location of the GCV electrode. The leading edge voltage, current, and total delivered energy at the DFT were significantly lower in animals with the GCV electrode near the apex (22%, 24%, and 13% reduction, respectively) compared with those where the GCV electrode was positioned away from apex (8%, 10% reduction and 18% increase, respectively, P < 0.001). Application of an auxiliary shock to the apical region, near the region where previous studies have indicated that the RV primary shock has its weakest effects, caused the greatest decrease in DFT.     

Successful implantation of a coronary sinus lead after stenting of a coronary vein stenosis

Dislodgment of the coronary sinus lead was observed in a 79-year-old patient 8 months after implantation of a biventricular pacing system. A severe stenosis in the posterolateral branch, in which the lead was previously positioned, prohibited reinsertion of the lead. Because no other branches with adequate anatomy for lead insertion were available in the targeted area, the stenosis was dilated and stented. Subsequently, the left ventricular lead could be reimplanted in the same vessel.     

Cardiac resynchronization after left ventricular lead extraction: usefulness of angioplasty in coronary sinus stenosis

A 68-year-old man, 54 months after having been implanted with a biventricular device, underwent successful extraction of the malfunctioning left ventricular (LV) lead using mechanical dilation. During LV lead reimplantation, venography documented stenosis of the coronary sinus (CS). To overcome the obstacle, balloon angioplasty was performed and a LV lead was then inserted into a lateral tributary of the CS. The procedure was complicated by local infection and, after 2 months, removal of the entire unit became necessary. During controlateral device implantation, a second angioplasty was carried before insertion of the new LV lead because, in the meantime, restenosis had developed in the CS.     

Coronary sinus lead extraction in the era of cardiac resynchronization therapy: single center experience

As the number of coronary sinus (CS) lead implantations for cardiac resynchronization therapy increases so will the need for extraction of these leads. The safety of extraction of leads from the branches of the CS has not been reported. We reviewed our database of patients undergoing pacemaker lead extraction from January 2002 through February 2004 at our institution. Of 149 patients referred for lead extraction, 14 (9%) had a biventricular device. The indications for lead extraction were infection, lead malfunction, and exit block. The duration of CS lead implants ranged between 2 and 43 months (mean 17 months). All 14 CS leads were removed successfully using nonsurgical lead extraction techniques. Three leads that were in place the longest (≥27 months) were removed via the femoral vein approach due to fibrous attachment of the CS lead body to the other pacemaker leads. The leads were structurally intact and without any significant fibrosis of their tips upon visual inspection. There were no major complications of CS laceration, hypotension, pericardial effusion, or excessive blood loss associated with any of the extraction procedures. CS leads were removed safely, successfully and with relative ease based on our experience in this small cohort of patients.     

Examination of a middle cardiac vein defibrillation coil as stand-alone anode, auxiliary anode, and bystander electrode in a transvenous defibrillation circuit

In porcine studies anodes in the middle cardiac vein compare favorably with those in the RV. It has not been demonstrated whether the RV and middle cardiac vein or the middle cardiac vein alone anodes are superior when shocking to a conventional SVC and active housing cathode nor whether a bystander middle cardiac vein electrode exerts a passive electrode affect. Twelve pigs were anesthetized and had an active housing implanted in the left pectoral region and defibrillation coils placed at the RV apex and in the SVC. A custom-made defibrillation coil (Ela Medical) was advanced into the middle cardiac vein through a 9 Fr transvenous catheter. The DFT for three anodes (RV; RV and middle cardiac vein; middle cardiac vein) to the SVC and active housing was then assessed by a three reversal binary search, the order of testing was randomized. In seven animals DFT was assessed in the same way for the configuration of RV to SVC and active housing twice more, with and without a bystander middle cardiac vein coil electrode in place. The results were middle cardiac vein 7.5 +/- 1.7 J, RV and middle cardiac vein 7.3 +/- 1.7 J reduced DFT significantly compared to RV 13.8 +/- 4.2 J (both P < 0.000). There was no significant difference between the middle cardiac vein and the middle cardiac vein and RV (P = 0.67, 95% CI for difference -0.64-0.96). The DFT of RV to SVC and the active housing was the same with (13.2 +/- 4.0) and without (13.7 +/- 4.2) the middle cardiac vein bystander coil in place (P = 0.177, 95% CI for difference -0.33-1.33 J). Shocking to a SVC and active housing cathode, middle cardiac vein, and RV and middle cardiac vein anodes are equally effective in lowering DFT compared to the RV. The middle cardiac vein coil electrode does not exert a passive electrode affect on the RV to the SVC and active housing defibrillation.     

Double wire technique to catheterize sharply angulated coronary sinus branches in cardiac resynchronization therapy

Placing a pacing lead for left ventricular pacing through the coronary sinus can be hampered by anatomic obstacles. In this case report we describe a technique that can overcome the problem of sharply angulated coronary sinus branches by using simultaneously two guidewires in the target vessel.     

Sheathless implantation of permanent coronary sinus-LV pacing leads

BACKGROUND: Implantation of CS-LV pacing leads is usually accomplished through specialized sheaths with additional use of contrast venography and other steps. Direct implantation at a target pacing site could provide a simplified procedure with appropriate leads. METHODS: A progressive CS-LV lead implant protocol was used, with initial attempts made to place the lead directly using only fluoroscopy and lead stylet or wire manipulation. Coronary sinus (CS) sheaths were only used later if direct lead placement failed. RESULTS: There were 105 attempted implants with 96% (101/105) success. Leads were implanted sheathlessly in 69% (70/101) cases. Pacing parameters and final lead position did not differ significantly between implants that did or did not require sheaths for implants. Three peri-procedural complications occurred in implants where sheaths were used. In 33% (33/101) of implants, the leads were placed without the use of sheaths or contrast venography in 20 minutes or less. CONCLUSIONS: Direct placement of the CS-LV pacing lead without sheaths can be accomplished successfully in a majority of implants and in < or =20 minutes in a third, without inferior pacing parameters. This may provide for shorter or less technically difficult or expensive procedures with low risk.     

Postmortem anatomy of the coronary sinus pacing lead

Biventricular pacing nowadays represents a recognized method of nonpharmacological treatment of severe congestive heart failure refractory to medication. A growing number of biventricular implants is likely to bring an increasing demand for the extraction of specially designed coronary sinus (CS) leads for left ventricular pacing. There is a lot of data regarding conventional pacing or defibrillation lead extractions, but only very limited experience with the CS lead extractions. We describe the pathological-anatomical findings of a woman who died after 26 months postimplantation due to refractory ventricular fibrillation with focus on the left ventricular pacing lead course and feasibility of extraction.     

Successful epicardial ablation of idiopathic mitral annular ventricular tachycardia from the great cardiac vein

This case report describes idiopathic ventricular tachycardia (VT) originating from the anterolateral site of mitral annulus. Radiofrequency (RF) energy application at an endocardial site of mitral annulus could not eliminate the tachycardia. The earliest epicardial activation preceding the onset of the QRS complex by 34 ms was found at the great anterior cardiac vein just opposite to the endocardial ablation catheter, pace mapping provided an identical (12/12) match with the VT morphology at the site, and RF ablation effectively eliminated the VT from the great cardiac vein within the coronary venous system.     

Role of the nitric oxide on diazoxide-induced relaxation of the calf cardiac vein and coronary artery during cooling

The effects of cooling (to 28 °C) on the vasodilation induced by diazoxide (10⁻⁹–3 × 10⁻⁴  m ) on carbachol-pre-contracted calf cardiac vein and coronary artery and the role of nitric oxide in these effects were analyzed. Diazoxide produced concentration-dependent relaxation of calf cardiac vein and coronary artery rings pre-contracted with carbachol (10⁻⁶  m ). During cooling, the pIC₅₀ values, but not the maximal responses, to diazoxide were significantly lower than at 37 °C in both preparations. Cooling to 28 °C in the presence of N^G-nitro-L-arginine methyl ester (10⁻⁴  m ) did not modify the effect of temperature both in cardiac vein and coronary artery. These results suggest that cooling-induced changes of diazoxide in calf cardiac vein and coronary artery are independent of nitric oxide.     

Effective long-term left atrial pacing using regular screw-in leads implanted within the coronary sinus

Passive-fixation leads positioned inside the coronary sinus (CS) have been found to be effective in LA pacing and sensing, but their use is limited by a high incidence of early and late dislodgment. Since anatomic studies have shown that the proximal part of the CS is surrounded by a relatively thick musculature, the feasibility, safety, and efficacy of acute and chronic coronary sinus pacing via regular screw-in leads positioned within the first centimeters of the CS were evaluated as compared to passive-fixation leads. Thirty-three patients (21 men, age 62 +/- 10 years) underwent dual chamber pacemaker implantation with LA pacing obtained via passive-fixation leads (7 patients) or regular screw-in leads (26 patients). The former approach was prematurely abandoned because of a high rate of acute and late lead dislodgment (42%). The chronic pacing threshold was 1.7 +/- 1.0 V at 0.67-ms pulse width and 1.47 +/- 1.3 V at 0.5-ms pulse width for passive- and active-fixation leads, respectively. In the CS active-fixation lead group, no postoperative pericardial effusion, CS lead dislodgment, nor diaphragmatic stimulation were observed. In this last group, steroid eluting leads (14 patients) have a statistically lower pacing threshold than noneluting steroid leads (12 patients) (0.88 +/- 0.23 vs 2.29 +/- 1.68 V, P = 0.011) at long-term follow-up. The use of regular screw-in leads implanted within the CS allows effective and safe long-term LA pacing without risk of dislodgment.     

Large, single-center experience in transvenous coronary sinus lead extraction: procedural outcomes and predictors for mechanical dilatation

Background: The aim of this study was to evaluate procedural outcomes of coronary sinus (CS) lead extraction, focusing on predictors and need for mechanical dilatation (MD) in the event that manual traction (MT) is ineffective. Methods: The study assessed results in 145 consecutive patients (age 69 ± 10 years; 121 men)—a total of 147 CS pacing leads—who underwent transvenous CS lead removal between January 2000 and March 2010. Results: All leads but one (99%) (implantation time 29 ± 25 months) were successfully removed. MT was effective in 103 (70%), and MD was necessary in the remaining 44 (30%) procedures. In multivariate analyses, unipolar design (odds ratio [OR] 3.22, 95% confidence interval [CI] 1.43–7.7; P = 0.005) and noninfective indication (OR 4.8, 95% CI 1.8–13, P = 0.002) were independent predictors for MD (P < 0.0001), with a predictive trend for prior cardiac surgery (OR 2.2, 95% CI 0.98–5.26; P = 0.06). Five (3.4%) complex procedures required a transfemoral vein approach (TFA) or repeat procedure. No deaths occurred, and there was one major complication (0.7%), cardiac tamponade, after MT. No complication predictors were identified. Conclusions: CS leads were safely and effectively removed in nearly all patients, and 70% were removed with MT alone; 30% required MD. Preoperative predictors suggesting the need for MD or TFA were noninfective indication and unipolar lead design. Complications were rare, and there was no predictable pattern among MT or MD removal techniques. (PACE 2012; 35:215–222)     

Mapping the Coronary Sinus and Great Cardiac Vein

GIUDICI, M., et al. : Mapping the Coronary Sinus and Great Cardiac Vein. The purpose of this study was to develop a better understanding of the pacing and sensing characteristics of electrodes placed in the proximal cardiac veins. A detailed mapping of the coronary sinus (CS) and great cardiac vein (GCV) was done on 25 patients with normal sinus rhythm using a deflectable electrophysiological catheter. Intrinsic bipolar electrograms and atrial and ventricular pacing voltage thresholds were measured. For measurement purposes, the GCV and the CS were each subdivided into distal (D), middle (M), and proximal (P) regions, for a total of six test locations. Within the CS and GCV, the average atrial pacing threshold was always lower (  P < 0.05  ) than the ventricle with an average ventricular to atrial ratio > 5, except for the GCV-D. The average atrial threshold in the CS and GCV ranged from 0.2– to 1.0-V higher than in the atrial appendage. Diaphragmatic pacing was observed in three patients. Atrial signal amplitude was greatest in the CS-M, CS-D, and GCV-P and smaller in the CS-P, GCV-M, and GCV-D. Electrode spacing did not significantly affect P wave amplitude, while narrower electrode spacing attenuated R wave amplitude. The average P:R ratio was highest with 5-mm-spaced electrodes compared to wider spaced pairs. The P:R ratio in the CS was higher (P < 0.05) than in all positions of the GVC. It is possible to pace the atrium independent of the ventricle at reasonably low thresholds and to detect atrial depolarization without undue cross-talk or noise using closely spaced bipolar electrode pairs. The areas of the proximal, middle, and distal CS produced the best combination of pacing and sensing parameters.     

Transcatheter mapping and ablation of arrhythmias in the coronary sinus

The coronary sinus (CS) is a complex structure of particular interest to cardiac electrophysiologists. It is exploited as an anatomical reference, a site to record left-sided atrial and ventricular signals and for cardiac resynchronization therapy. Perhaps less appreciated, it may itself serve as a substrate for arrhythmias. It is now increasingly recognized that arrhythmias may be targeted by transcatheter ablation within the CS. This review summarizes pertinent anatomic considerations, explores the relationship between the CS and various arrhythmia substrates, elaborates on current indications for intra CS ablation and addresses efficacy and safety concerns associated with transcatheter ablation.     

Permanent left atrial pacing: a 2-year follow-up of coronary sinus leads

Left atrial pacing is feasible via the coronary sinus. However, long-term characteristics of coronary sinus pacing parameters are largely undefined as yet. This study assessed the feasibility and long-term pacing parameters of coronary sinus pacing. Twenty four patients (13 men, 11 women) with a history of paroxysmal AF refractory to drug therapy underwent biatrial pacemaker implantation. Leads were sited in the high right atrium or right atrial appendage and in either proximal (PCS) or distal coronary sinus (DCS). Pacemaker parameters were measured at implant, 24 hours postimplant, 1 month, 3 months, and at 3 monthly intervals over a period of 2 years. Threshold, impedance, and energy requirements (E = Threshold2/impedance x pulse width) were measured. There was one lead displacement from the PCS within 24 hours postimplant. There were no other acute or chronic complications. The energy values at implant and at 2 years were 0.49 +/- 0.47 and 2.18 +/- 1.69 mJ for the PCS leads and 0.94 +/- 1.47 and 1.27 +/- 0.75 mJ for the DCS leads. P values were >0.05 at all points and suggested no significant difference between the two sites over the long-term. Chronic coronary sinus pacing is a safe and feasible technique. There was no significant difference in energy parameters for leads positioned in the proximal or distal coronary sites. The trends seen at both sites for chronic changes in pacing characteristics are analogous to those described for endocardial leads at other sites.     

Transvenous implantation of a coronary sinus lead for left ventricular pacing after cutting balloon angioplasty

We describe a patient in whom a localized proximal vein stenosis at the only possible target vein precluded placement of a coronary sinus lead for left ventricular (LV) pacing. After multiple attempts to perform venoplasty with both compliant and noncompliant balloons, a cutting balloon relieved the obstruction, and an LV pacing lead was successfully placed in the midportion of this lateral vein.     

Combined use of transesophageal ECHO and fluoroscopy for the placement of left ventricular pacing leads via the coronary sinus

Biventricular pacing is an emerging technology for treatment of congestive heart failure. Left ventricular leads are most commonly placed through the coronary sinus (CS) into an epicardial coronary vein. Cannulation of the CS can be difficult and standard guiding catheters have a tendency to displace during lead advancement. This study found that transesophageal echocardiography facilitated CS cannulation in complex cases requiring antecedent lead extraction.     

Characterization of human coronary sinus valves by direct visualization during biventricular pacemaker implantation

BACKGROUND: The precise reasons for failure to cannulate the coronary sinus during biventricular device implantation are unknown. Visualization of the coronary sinus ostium during electrophysiology procedures may enhance understanding of how unusual anatomy can affect successful cannulation of the coronary sinus. OBJECTIVES: The aim of this study was to describe the morphology of valves at the coronary sinus ostium (CSO) visualized directly with an illuminated fiberoptic endoscope during implantation of biventricular devices. METHODS: The coronary sinus anatomy of one hundred consecutive patients undergoing implantation of biventricular devices was investigated using a fiberoptic endocardial visualization catheter (EVC). RESULTS: The CSO was clearly visualized in 98 patients using the EVC. A Thebesian valve was seen in 54% of these. Almost all Thebesian valves were positioned at the inferior (61%) or posterior (33%) aspect of the CSO. Only six patients had Thebesian valves that covered more than 70% of the CSO, but all were successfully implanted with a transvenous left ventricular pacing lead after cannulating the coronary sinus under direct visualization. CONCLUSIONS: Over half of patients undergoing biventricular device implantation have identifiable Thebesian valves. Even valves covering the majority of the ostial area may be traversed using direct visualization and modern catheterization techniques.