Left bundle branch pacing lead for sensing ventricular arrhythmias in implantable cardioverter-defibrillator: A pilot study (LBBP-ICD study)

BACKGROUND

Left bundle branch pacing (LBBP) has been suggested as an alternative modality for biventricular pacing in cardiac resynchronization therapy (CRT)-eligible patients. As it provides stable R-wave sensing, LBBP has been recently used to provide sensing of ventricular arrhythmia in patients receiving implantable cardioverter-defibrillator (ICD) with CRT.

OBJECTIVE

The aim of this study was to analyze the long-term safety and efficacy of the LBBP lead for appropriate detection of ventricular arrhythmia and delivery of antitachycardia pacing (ATP) in patients requiring defibrillator therapy with CRT.

METHODS

CRT-eligible patients who underwent successful LBBP-optimized ICD and LBBP-optimized CRT with defibrillator were enrolled. The LBBP lead was connected to the right ventricular-P/S port after capping the IS-1 connector plug of the DF-1-ICD lead. LBBP-optimized ICD or LBBP-optimized CRT with defibrillator was decided on the basis of correction of conduction system disease. Documented arrhythmic episodes and therapy delivered were analyzed.

RESULTS

Thirty patients were enrolled. The mean age was 59.7 ± 10.5 years. LBBP resulted in an increase in left ventricular ejection fraction from 29.9% ± 4.6% to 43.9% ± 11.2% (P < .0001). During a mean follow-up of 22.9 ± 12.5 months, 254 ventricular arrhythmic events were documented. Appropriate events (n = 225 [89%]) included nonsustained ventricular tachycardia (VT) (n = 212 episodes [94%]), VT (n = 8 [3.5%]), and ventricular fibrillation (n = 5 [2.5%]). ATP efficacy in terminating VT was 75%. Eleven percent of episodes (n = 29) were inappropriately detected because of T-wave oversensing. Inappropriate therapy (ATP) was delivered for 14 episodes (5.5%). Three patients (10%) had worsening of tricuspid regurgitation.

CONCLUSION

Sensing from the LBBP lead for arrhythmia detection is safe as ∼90% of the episodes were detected appropriately. Future studies with a dedicated LBBP-defibrillator lead along with algorithms to avoid oversensing can help in combining defibrillation with conduction system pacing.

Pacing induced cardiomyopathy: recognition and management

Right ventricle (RV) apex continues to remain as the standard pacing site in the ventricle due to ease of implantation, procedural safety and lack of convincing evidence of better clinical outcomes from non-apical pacing sites. Electrical dyssynchrony resulting in abnormal ventricular activation and mechanical dyssynchrony resulting in abnormal ventricular contraction during RV pacing can result in adverse LV remodelling predisposing some patients for recurrent heart failure (HF) hospitalisation, atrial arrhythmias and increased mortality. While there are significant variations in the definition of pacing induced cardiomyopathy (PIC), combining both echocardiographic and clinical features, the most acceptable definition for PIC would be left ventricular ejection fraction (LVEF) of <50%, absolute decline of LVEF by ≥10% and/or new-onset HF symptoms or atrial fibrillation (AF) after pacemaker implantation. Based on the definitions used, the prevalence of PIC varies between 6% and 25% with overall pooled prevalence of 12%. While most patients undergoing RV pacing do not develop PIC, male sex, chronic kidney disease, previous myocardial infarction, pre-existing AF, baseline LVEF, native QRS duration, RV pacing burden, and paced QRS duration are the factors associated with increased risk for PIC. While conduction system pacing (CSP) using His bundle pacing and left bundle branch pacing appear to reduce the risk for PIC compared with RV pacing, both biventricular pacing and CSP may be used to effectively reverse PIC.

MAgnetic resonance imaging based DUal lead cardiac Resynchronization therapy: A prospectIve Left Bundle Branch Pacing Study (MADURAI LBBP study)

BACKGROUND

Cardiac resynchronization therapy(CRT) is a class-I indication for LVEF≤35%, and heart failure(HF). LBBB associated nonischemic-cardiomyopathy (LB-NICM) with minimal or no scar by cardiac-magnetic-resonance(CMR) imaging may be associated with excellent prognosis following CRT. Left-bundle-branch-pacing(LBBP) can achieve excellent resynchronization in LBBB patients.

OBJECTIVES

Aim of our study was to prospectively assess feasibility and efficacy of LBBP with or without a defibrillator in patients with LB-NICM and LVEF ≤35%, risk stratified by CMR.

METHODS

Pts with LB-NICM, LVEF≤35% and HF were prospectively enrolled from 2019 to 2022. If the scar burden<10% by CMR, LBBP only (Group-I) and if ≥10%, LBBP+ICD(Group-II) was performed. Primary endpoints-1.Echocardiographic-response(ER)- ΔLVEF ≥15% at 6 months; 2.Composite of time to death, HFH or sustained VT/VF. Secondary endpoints-1.Echocardiographic-hyper-response(EHR-LVEF≥50%orΔLVEF ≥20%) at 6 and 12 months; 2.Indication for ICD-upgradation(persistent LVEF<35% at 12 months or sustained VT/VF) RESULTS: 120 patients were enrolled. CMR showed <10% scar-burden in 109 patients(90.8%). 4 patients opted for LBBP+ICD and withdrew. LBBP optimized-dual-chamber-pacemaker(LOT-DDD-P) was done in 101 patients and LOT-CRT-P in 4 patients(Group-I,n=105). Scar-burden ≥10% in 11 pts who underwent LBBP+ICD(Group-II). During mean-follow-up 21±12 months, primary endpoint of ER observed in 80%(68/85 pts) in Group-I vs 27%(3/11 pts) in Group-II(p-0.0001). Primary composite-endpoint of death,HFH or VT/VF occurred in 3.8% in group-I vs 33.3% in Group-II(p<0.0001). Secondary endpoint of EHR(LVEF≥50%) observed in 39.5%vs0%, 61.2%vs9.1% and 80%vs33.3% at 3, 6 and 12 months in group-I and group-II respectively.

CONCLUSION

CMR guided CRT using LOT-DDD-P appears to be a safe and feasible approach in LB-NICM and has the potential to reduce healthcare cost.

Left bundle branch pacing-optimized implantable cardioverter-defibrillator (LOT-ICD) for cardiac resynchronization therapy: A pilot study

Left bundle branch pacing (LBBP) involves direct capture of left bundle fibers by placing the lead deep inside the interventricular septum. Several studies have shown the feasibility and efficacy of LBBP as an alternative modality for cardiac resynchronization therapy (CRT). This paper describes approach for providing cost effective CRT with defibrillator (CRT-D) by LBBP and dual chamber implantable cardioverter defibrillator (ICD) which we label as LBBP optimized ICD (LOT-ICD). LBBP was performed using C315 sheath and 3830 Selectsecure lead in all patients by premature ventricular complex guided approach. In patients with complete correction of conduction system disease, IS-1 connector plug of the IS-1/DF-1 lead was capped and 3830 lead connected to the dual chamber ICD pulse-generator at RV-P/S port. LOT-ICD provided stable R-wave sensing for arrhythmia monitoring and resulted in cost-effective resynchronization therapy at reduced fluoroscopy duration and radiation dose.

Left Posterior Fascicular Pacing

Left bundle branch pacing (LBBP) is emerging as an alternative to His bundle pacing that overcomes the latter’s limitations. Several studies have reported on the safety, efficacy, and electrophysiological properties of LBBP, while postoperative success rates range from 80.5% to 94%. The left posterior fascicle is composed of broad bands of fibers coursing inferiorly and posteriorly toward the papillary muscle, while the anterior fascicle is a thin, tendon-like structure. We report a case of a 70-year-old man in whom left posterior fascicular pacing was done after LBBP failed. We were able to demonstrate all the features of left posterior fascicular capture, including fascicular potential and a left anterior hemiblock pattern, using surface 12-lead electrocardiography. Left posterior fascicular pacing could be an alternative technique when attempts to deploy LBBP fail.

Feasibility, safety and outcomes of left bundle branch pacing in octogenarians

OBJECTIVES

Left bundle branch pacing (LBBP) provides physiological pacing at low and stable threshold. The safety and efficacy of LBBP in elderly population is unknown. Our study was designed to assess the safety, efficacy and electrophysiological parameters of LBBP in octogenarian (≥80 years) population.

RESULTS

LBBP was successful in 10 out of 11 patients. Mean age 82.1 ± 2.5 yrs. Follow up duration 7.7 months(range4-10). Indication for pacing included atrioventricular (AV) block 5 patients, Left bundle branch block (LBBB) with low ejection fraction (EF) 4 patients, sinus node dysfunction in 1. QRS duration reduced from 145.9 ± 27.7ms to 107.1 ± 9.5ms (p value0.00001) LV ejection fraction increased from 47.6% to 58.4% after LBBP (p value0.017). Pacing threshold was 0.58 ± 0.22 V and sensed R wave 17.35 ± 6.5 mV and it remained stable during follow up. LBBB with low EF patients also showed similar reduction in QRS duration along with improvement in LVEF.

CONCLUSION

LBBP is a safe and effective strategy (91% acute success) of physiological pacing in elderly patients. LBBP also provided effective resynchronization therapy in our small group of elderly patients. The pacing parameters remained stable over a period of 10 months follow up.

Memory performance is related to language dominance as determined by the intracarotid amobarbital procedure

OBJECTIVE

The goal of this study was to explore the relationship between language and memory lateralization in patients with epilepsy undergoing the intracarotid amobarbital procedure.

METHODS

In 386 patients, language lateralization and memory lateralization as determined by laterality index (LI) were correlated with each other.

RESULTS

Language lateralization and memory lateralization were positively correlated (r=0.34, P<0.01). Correlations differed depending on the presence and type of lesion (chi(2)=7.98, P<0.05). LIs correlated significantly higher (z=2.82, P<0.05) in patients with cortical dysplasia (n=41, r=0.61, P<0.01) compared with the group without lesions (n=90, r=0.16, P>0.05), with patients with hippocampal sclerosis falling between these two groups. Both memory (P<0.01) and language (P<0.01) LIs were higher in right- compared with left-sided lesions.

CONCLUSION

Correlation of language and memory is more pronounced in patients with structural lesions as compared with patients without lesions on MRI.

Management of grade III supracondylar fracture of the humerus by straight-arm lateral traction

Supracondylar fracture of the humerus is a common upper limb fracture in children for which treatment is controversial and often technically difficult, and complications are common. Cubitus varus is the most prevalent complication encountered in such fractures, with a mean incidence rate of 30%. A variety of methods for treating displaced fractures have been recommended. We reviewed 20 cases of severely displaced grade III supracondylar fractures of the humerus in children. There was marked swelling and distorted local anatomy in all these fractures, which were managed conservatively with straight-arm lateral traction. The patients were treated in skin traction for 2 weeks, following which they commenced physiotherapy. The traction was applied with the arm at 90 degrees of abduction and the forearm in supination. None of the patients developed any complication, and all had the full range of movements. None had cubitus varus deformity, and none of these patients required further surgical treatment. There was a complete patient and parent satisfaction. Open or closed reduction with internal fixation is the most common method of treating these injuries, however in some cases this can be very difficult and dangerous. If the local anatomy and swelling do not allow this treatment then non-operative measures have to be adopted. We conclude that straight-arm lateral traction is a safe and effective method of treating these fractures, especially when the local anatomy is disturbed and the swelling makes operative intervention relatively more risky and difficult. Moreover, this method is also appropriate in areas where access to specialised centres in treating these injuries is either difficult or delayed.