Effectiveness and Reliability of Selected Site Pacing for Avoidance of Phrenic Nerve Stimulation in CRT Patients with Quadripolar LV Leads: The EffaceQ Study

Conduction system pacing on track to replace CRT? Review of current evidence and prospects of conduction system pacing

Conduction system pacing (CSP) has been emerging over the last decade as a pacing option instead of conventional right ventricular (RV) pacing and biventricular (BiV) pacing. Numerous case reports, some observational studies and a few randomized control trials have looked at optimum pacing strategies for heart failure (HF) with left bundle branch block (LBBB) or cases where left ventricular (LV) dysfunction is anticipated due to chronic RV pacing (RVP). Evolution of pacing strategies from standard RVP to septal RVP, BiV pacing and now CSP have shown improving hemodynamic responses and possible ease of implantation of CSP systems. In this review article, we review the literature on the evolution of CSP and common scenarios where it might be beneficial.

Case report: An unusual case of phrenic nerve stimulation in a patient with single chamber implantable cardioverter defibrillator

Background

Phrenic nerve stimulation is a well-recognized complication related to cardiac implantable electronic devices, in particular with left ventricular coronary sinus pacing leads for cardiac resynchronization therapy.

Case presentation

We report an unusual case of symptomatic phrenic nerve stimulation due to inadvertent placement of a right ventricular defibrillation lead in coronary sinus posterior branch in a patient with heart failure with reduced ejection fraction with a recently implanted single-chamber cardioverter defibrillator.

Discussion

Phrenic nerve stimulation is a relatively common complication of left ventricular pacing. Inadvertent placement of a right ventricular lead in a coronary sinus branch is a rare but possible cause of phrenic nerve stimulation. Careful evaluation of intraprocedural fluoroscopic and electrocardiographic appearance of pacing and defibrillation leads during implantation may prevent inadvertent placement of a right ventricular lead in the coronary sinus.

Paced or sensed conduction time to determine programming with cardiac resynchronization therapy: The PASED-CRT Trial

BACKGROUND

Cardiac resynchronization therapy (CRT) is a well-established treatment for patients with drug refractory heart failure.

OBJECTIVES

This study sought to compare the longest RV_sense to LV_sense activation time (sLAT) versus the longest RV_pace to LV_sense activation time (pLAT) as the programmed site for left ventricular (LV) pacing in CRT patients with quadripolar LV leads at 3 months.

METHODS

This single site, double-blinded, prospective trial, randomized patients 1:1 into the sLAT or pLAT group to determine response. LV pacing was programmed at implant and maintained through 3 months of follow-up. The 6-minute hall walk (6MHW) test, NYHA, Minnesota living with heart failure, and clinical composite score (CCS) at the 3 months was compared.

RESULTS

N = 92 patients (73M:19F age 66 ± 11.3 years) were randomized implanted and programmed per protocol. Baseline characteristics were comparable. N = 39 sLAT and N = 34 pLAT completed the 3-month visit for final analysis. Significant improvement from baseline to 3 months was seen in the sLAT group from 253.9 (+/-11.5) to 323.1 (+/-11.9) P = .001. Similarly, the pLAT group improved from 274.9 (+/-16.15) to 343.9 (+/-15.9) P = .003. The difference between these groups, however, did not reach significance (P = .86). The pLAT group demonstrated a higher responder rate of (71%) versus the sLAT group (64%) based on the CCS although not reaching significance (P = .56).

CONCLUSIONS

Use of both the pLAT and sLAT method of programming demonstrated significant improvement in 6MHW distance at 3 months with pLAT demonstrating a slightly higher responder rate based on CCS (P = .56). pLAT should be considered at minimum as equivalent in patients with no intrinsic conduction.

Five-year follow-up of transvenous and epicardial left ventricular leads: experience with more than 1000 leads

OBJECTIVES

Transvenous coronary sinus leads are considered to be the gold standard for cardiac resynchronization therapy (CRT). However, in patients with abnormal coronary vein anatomy, the epicardial leads can be an alternative. Data comparing durability and performance of these 2 lead types are limited. In order to provide clarity, we investigated patients receiving CRT system in our centre.

METHODS

One thousand and fifty-three consecutive patients scheduled for CRT implantation were retrospectively analysed. From these, 895 received transvenous coronary sinus and 158 epicardial left ventricular (LV) leads. Lead-specific as well as LV functional parameters have been evaluated in 60 months' follow-up.

RESULTS

Technical characteristics (pacing threshold, impedance and sensing) of both lead types remained stable during the whole observation period. Whereas an early revision (<6 month) was noted in 5.4% of transvenous leads, no reintervention has been necessary for epicardial leads. During the 5-year observation period, a lead revisions rate of 10.2% for transvenous leads and 1.9% for epicardial leads were detected. Regarding CRT efficacy, excellent results were achieved for both electrode types. In both groups, a statistically significant reduction of New York Heart Association class (2.85-2.13 and 2.96-2.09), increase in left ventricular ejection fraction (24.6-32.6% and 27.2-34.6%), reduction of left ventricular end-systolic diameter/left ventricular end-diastolic diameter and reduction in degree of mitral valve insufficiency could be observed over the time.

CONCLUSIONS

Our data demonstrate safety and functional efficacy of both transvenous and epicardial leads. Moreover, in long-term follow-up, a commendable durability and performance were found for both lead types. Thus, epicardial leads represent a good alternative when transvenous implantation fails.

Outcomes of cardiac resynchronization therapy using left ventricular quadripolar leads

BACKGROUND

Quadripolar left ventricular (LV) leads provide a more optimal pacing configuration for cardiac resynchronization therapy (CRT) than conventional bipolar leads. The objective of this study is to determine the clinical outcomes of CRT using quadripolar leads.

METHODS

This study included 516 CRT patients who received bipolar LV leads (n = 278) or quadripolar LV leads (n = 238) from January 2013 to June 2016. Data were retrospectively collected from a prospective CRT database and electronic health records. CRT response to CRT was defined as >5% improvement in the LV ejection fraction (LVEF) from baseline. Baseline characteristics and outcomes were compared between groups.

RESULTS

New York Heart Association Functional Classification and LVEF significantly improved in the quadripolar and bipolar groups after CRT. There was no difference in the all-cause mortality rate. The implant success rate was significantly higher in the quadripolar group (100% vs 97.8%; P = 0.02). Quadripolar lead placement was an independent predictor of CRT response at 12 months (hazard ratio, 0.76; 95% confidence interval, 0.58-0.98; P = 0.04). The rate of LV lead-related complications requiring invasive lead revision or abandonment was significantly higher in the bipolar group (11.2% vs 4.6%; P = 0.007).

CONCLUSIONS

Quadripolar leads achieve similar CRT outcomes as bipolar LV leads but with a higher implant success rate and fewer procedure-related complications.

Impact of intraoperative mechanical ventilation on left ventricular lead function in cardiac resynchronization therapy

BACKGROUND

Intraoperative controlled mechanical ventilation (CMV) changes the intrathoracic geometry and may impact postoperative left ventricular (LV) lead function after CRT implantation. This multicenter study investigates the effect of intraoperative ventilation setting (spontaneous breathing [SB] vs CMV) on postoperative LV lead function taking into account patients' body mass index (BMI).

METHODS

CRT implantation was performed at two centers during SB in 92 and during CMV in 73 patients. Follow-up was carried out after 3 ± 5 and 36 ± 53 days. Functional lead parameters (FLP; pacing threshold and impedance), postoperative adverse events (A;  phrenic nerve stimulation [PNS] and lead malfunction), and patients' BMI were assessed. Delta values of FLP between baseline and follow-up visits were analyzed applying an analysis of covariance model to detect subclinical alterations in LV lead function.

RESULTS

AE occurred in a total of 36 (21%) patients. PNS was observed in 26 (15%) patients and LV lead repositioning due to malfunction was necessary in 10 (6%) patients. Both AE and FLP delta values between baseline and follow-up were not associated with intraoperative ventilation settings nor the patients' BMI.

CONCLUSIONS

This study demonstrates that there is no impact of the intraoperative ventilation setting (SB vs CMV) on postoperative FLP or the occurrence of AE. This is also the case taking into account the BMI. With respect to these findings both approaches-sedation only or general anaesthesia including CMV-can be safely implemented during CRT implantation.

Multi-site multi-polar left ventricular pacing through persistent left superior vena cava in tricuspid valve disease

Multi-site multi-polar left ventricular pacing through the coronary sinus (CS) may be preferred over endocardial right ventricular or surgical epicardial pacing in the presence of tricuspid valve disease. However, the required lead placement can be difficult through a persistent left superior vena cava (PLSVC), as the CS tends to be hugely dilated and side branches tend to have sharp angulations (>90°) when approached from the PLSVC. Pre-shaped angiography catheters and techniques used for finding venous grafts from the ascending aorta post coronary bypass surgery may help with lead placement in such a situation.

Electrophysiology Catheter-Facilitated coronary sinus cannulation and implantation of cardiac resynchronization therapy systems

BACKGROUND

Cardiac resynchronization therapy (CRT) device implantation is hampered by difficult placement of the left ventricular (LV) lead. We have routinely used a steerable electrophysiology catheter to guide coronary sinus (CS) cannulation and facilitate LV lead positioning. The aim of this prospective study is to present our results with this approach in 138 consecutive patients receiving a CRT device over 10 years.

METHODS

The study included 120 men and 18 women, aged 64.8±11.4 years, with coronary disease (n=63), cardiomyopathy (n=72), or other disease (n=3), and mean ejection fraction of 24.5±4.5%. Devices were implanted for refractory heart failure and dyssynchrony, all but 2 in the presence of left bundle branch block. Implanted devices included biventricular pacemakers (CRT-P) (n=33) and cardioverter defibrillators (CRT-D) (n=105).

RESULTS

Using the electrophysiology catheter, the CS could be engaged in 134 (97.1%) patients. In 4 patients failing CS cannulation, a dual-chamber device was implanted in 2, and bifocal right ventricular pacing was effected in 2. Bifocal (n=2) or conventional (n=1) systems were implanted in another 3 patients, in whom the LV lead got dislodged (n=2) or removed because of local dissection (n=1). Thus, finally, a CRT system was successfully established in 131 (94.9%) patients. There were 3 patients with CS dissection, of whom 1 was complicated by cardiac tamponade managed with pericardiocentesis. There were no perioperative deaths. During follow-up (31.0±21.2 months), clinical improvement was reported by 108 (82.4%) patients.

CONCLUSION

Routine use of an electrophysiology catheter greatly facilitated CS cannulation and successful LV lead placement in ∼95% of patients undergoing CRT system implantation.

Minimal Invasive Left Ventricular Lead Repositioning is Safe and Effective in Distal Left Ventricular Lead Positions

BACKGROUND

Treatment of left ventricular electrode dislocation and phrenic nerve stimulation remains an issue in the era of new electrode designs.

METHODS

Safety and efficacy of minimal invasive lead repositioning and pocket opening reposition procedures were evaluated between December 2005 and December 2012 at our center. Minimal invasive method was developed and widely utilized at our center to treat phrenic nerve stimulation. The distally positioned left ventricular lead is looped around by a deflectable catheter in the right atrium introduced from the femoral vein access and then pulled back. Coronary stent implantation was used afterwards for lead stabilization in some patients.

RESULTS

42 minimal invasive and 48 electrode repositions with pacemaker pocket opening were performed at 77 patients for left ventricular lead problems. Minimal invasive reposition could be carried out successfully in 69% of (29 patients) cases. Note that in 14.3% of the cases (six patients) minimal invasive procedures were acutely unsuccessful and crossover was necessary. In 16.6% of the cases (seven patients) lead issues were noted later during follow-up. Opening of the pocket could be carried out successfully in 81.2% (39 patients) and was unsuccessful acutely in 6.25% (three patients). Repeated dislocation was noticed, 12.5%, in this group (six patients). Complication during minimal invasive procedures was electrode injury in one case. Pocket openings were associated with several complications: atrial fibrillation, pericardial effusion, fever, hematoma, and right ventricular electrode dislodgement.

CONCLUSION

Minimal invasive procedure-as the first line approach-is safe and feasible for left ventricular electrode repositioning in selected cases.

Short-Term Availability of Viable Left Ventricular Pacing Sites with Quartet™ Quadripolar Leads

BACKGROUND Whether quadripolar leads can provide sufficient viable left ventricular pacing sites (LVPSs) for device optimization and multipoint pacing remains unclear. This study aimed to evaluate the acute and 3-month availability of viable LVPSs provided by a quadripolar LV pacing lead. MATERIAL AND METHODS A single-center cohort study evaluated consecutive patients who underwent a CRT implant with the QuartetTM LV lead under local guidelines. The availability of viable LVPSs was assessed at the pre-discharge and 3-month follow-up visit. Bipolar lead configurations, which served as the control group, were modeled by eliminating the 2 proximal electrodes on the Quartet™ LV lead. RESULTS A total of 24 patients were enrolled and finished 3-month follow-up. The mean follow-up period was 93±3 days. At pre-discharge, the Quartet™ LV lead provided more viable LVPSs compared with the bipolar equivalents (median 3 [IQR 2-4] vs. median 2 [IQR 1-2], P<0.001). The percentage of patients with at least 1, 2, 3, and 4 viable LVPSs were 100% (24/24), 91.7% (22/24), 58.3% (14/24), and 33.3% (8/24) for Quartet™ leads and 91.7% (22/24), 70.8% (17/24), 0% (0/24), and 0% (0/24) for bipolar lead configurations, respectively. The median and IQR values of viable LVPSs provided by the Quartet™ LV lead remained the same (3 [IQR 2-4]) between pre-discharge and 3-month follow-up (P=0.45). CONCLUSIONS Compared with the bipolar equivalent, QuartetTM LV lead provides more viable LVPSs and opportunities for CRT optimization and multipoint LV pacing. The number of LVPSs provided by Quartet™ leads remained unchanged between pre-discharge and 3-month follow-up.