Left bundle branch pacing as an alternative to biventricular pacing for cardiac resynchronisation therapy.

BACKGROUND: Left bundle branch pacing (LBBP) is a novel physiological pacing technique which may serve as an alternative to biventricular pacing (BVP) for the delivery of cardiac resynchronisation therapy (CRT). This study assessed the feasibility and outcomes of LBBP in comparison to BVP. METHODS: LBBP was attempted in 40 consecutive patients as the first-line method for delivering CRT. To evaluate LBBP versus BVP, 40 patients with identical inclusion criteria who received BVP were compared with the LBBP group. Acute success rate, complications, functional and echocardiographic outcomes as well as hospitalisation for heart failure and all-cause mortality 6 months after implantation were evaluated. RESULTS: LBBP was successfully performed in 31 (78%) patients and resulted in significant QRS narrowing (from 166 ± 16 to 123 ± 18 ms, p < 0.001), improvement in left ventricular ejection fraction (LVEF; from 28 ± 8 to 43 ± 12%, p < 0.001) and New York Heart Association functional class (from 2.8 ± 0.5 to 1.6 ± 0.6, p < 0.001) at 6 months. No LBBP-related complications occurred. Compared to BVP, LBBP resulted in a greater reduction in QRS duration (44 ± 17 vs 15 ± 26 ms, p < 0.001) with comparable absolute improvement in LVEF (15.2 ± 11.7 vs 9.6 ± 12.1%, p = 0.088). Hospitalisation for heart failure and all-cause mortality were similar in the two groups. CONCLUSIONS: LBBP is feasible and was safe in 78% of patients with favourable electrical resynchronisation and functional improvement and may serve as an alternative to BVP.

Initial experience, feasibility and safety of permanent left bundle branch pacing: results from a prospective single-centre study.

BACKGROUND: Left bundle branch (LBB) pacing is a novel pacing technique which may serve as an alternative to both right ventricular pacing for symptomatic bradycardia and cardiac resynchronisation therapy (CRT). A substantial amount of data is reported by relatively few, highly experienced centres. This study describes the first experience of LBB pacing in a high-volume device centre. METHODS: Success rates (i.e. the ability to achieve LBB pacing), electrophysiological parameters and complications at implant and up to 6 months of follow-up were prospectively assessed in 100 consecutive patients referred for various pacing indications. RESULTS: The mean age was 71 ± 11 years and 65% were male. Primary pacing indication was atrioventricular (AV) block in 40%, CRT in 42%, and sinus node dysfunction or refractory atrial fibrillation prior to AV node ablation in 9% each. Baseline left ventricular ejection fraction was < 50% in 57% of patients, mean baseline QRS duration 145 ± 34 ms. Overall LBB pacing was successful in 83 of 100 (83%) patients but tended to be lower in patients with CRT pacing indication (69%, p = ns). Mean left ventricular activation time (LVAT) during LBB pacing was 81 ms and paced QRS duration was 120 ± 19 ms. LBB capture threshold and R­wave sense at implant was 0.74 ± 0.4 mV at 0.4 ms and 11.9 ± 5.9 V and remained stable at 6­month follow-up. No complications occurred during implant or follow-up. CONCLUSION: LBB pacing for bradycardia pacing and resynchronisation therapy can be easily adopted by experienced implanters, with favourable success rates and safety profile.

Comparison between laser sheaths, femoral approach and rotating mechanical sheaths for lead extraction.

INTRODUCTION: Efficiency and safety are important features in the selection of lead extraction tools. We report our experience with different endovascular techniques to extract individual pacing and defibrillator leads. METHODS: This is a single-centre study of consecutive lead extraction procedures from 1997 until 2019. A total of 1725 leads were extracted in 775 patients. Direct traction sufficed for 588 leads, and 22 leads were primarily removed by surgery. The endovascular techniques used in the remainder were a laser sheath (190 leads), the femoral approach (717 leads) and rotating mechanical sheaths (208 leads). RESULTS: The three approaches were comparably effective in completely removing the leads (p = 0.088). However, there were more major complications with the laser sheath than with the femoral approach or rotating mechanical sheaths (8.4%, 0.5% and 1.2%, respectively). Therefore, the procedural result-extraction without major complications-was significantly better with both the femoral approach and rotating mechanical sheaths than with the laser sheath (p < 0.001). This result was confirmed after propensity score matching to compensate for differences between lead cohorts (p = 0.007). Cross-over to another endovascular tool was necessary in 7.9%, 7.1% and 8.2% of laser, femoral and rotating mechanical attempts, respectively. CONCLUSION: All three endovascular lead extraction techniques showed comparable efficacy. However, there were significantly more major complications using the laser sheath compared to the femoral approach or rotating mechanical sheaths, leading us to abandon the laser technique. Importantly, no single endovascular technique sufficed to successfully extract all leads.

The Hemodynamic Effects of Different Pacing Modalities After Cardiopulmonary Bypass in Patients With Reduced Left Ventricular Function.

OBJECTIVES: Patients with decreased left ventricular function undergoing cardiac surgery have a greater chance of difficult weaning from cardiopulmonary bypass and a poorer clinical outcome. Directly after weaning, interventricular dyssynchrony, paradoxical septal motion, and even temporary bundle-branch block might be observed. In this study, the authors measured arterial dP/dtmax, mean arterial pressure (MAP), and cardiac index using transpulmonary thermodilution, pulse contour analysis, and femoral artery catheter and compared the effects between right ventricular (A-RV) and biventricular (A-BiV) pacing on these parameters. DESIGN: Prospective study. SETTING: Single-center study. PARTICIPANTS: The study comprised 17 patients with a normal or prolonged QRS duration and a left ventricular ejection fraction ≤35% who underwent coronary artery bypass grafting with or without valve replacement. INTERVENTIONS: Temporary pacing wires were placed on the right atrium and both ventricles. Different pacing modalities were used in a standardized order. MEASUREMENTS AND MAIN RESULTS: A-BiV pacing compared with A-RV pacing demonstrated higher arterial dP/dtmax values (846 ± 646 mmHg/s v 800 ± 587 mmHg/s, p = 0.023) and higher MAP values (77 ± 19 mmHg v 71 ± 18 mmHg, p = 0.036). CONCLUSION: In patients with preoperative decreased left ventricular function undergoing coronary artery bypass grafting, A-BiV pacing improve the arterial dP/dtmax and MAP in patients with both normal and prolonged QRS duration compared with standard A-RV pacing. In addition, arterial dP/dtmax and MAP can be used to evaluate the effect of intraoperative pacing. In contrast to previous studies using more invasive techniques, transpulmonary thermodilution is easy to apply in the perioperative clinical setting.

Haemodynamic evaluation of alternative left ventricular endocardial pacing sites in clinical non-responders to cardiac resynchronisation therapy.

INTRODUCTION: Non response to cardiac resynchronisation therapy (CRT) may be related to the position of the coronary sinus lead. METHODS: We studied the acute haemodynamic response (AHR) from alternative left ventricular (LV) endocardial pacing sites in clinical non-responders to CRT. AHR and the interval from QRS onset to LV sensing (Q-LV interval) from four different endocardial pacing sites were evaluated in 24 clinical non-responders. A rise in LVdP/dtmax ≥ 15 % from baseline was considered a positive AHR. We also compared the AHR from endocardial with the corresponding epicardial lead position. RESULTS: The implanted system showed an AHR ≥ 15 % in 5 patients. In 9 of the 19 remaining patients, AHR could be elevated to ≥ 15 % by endocardial LV pacing. The optimal endocardial pacing site was posterolateral. There was no significant difference in AHR between the epicardial and the corresponding endocardial position. The longest Q-LV interval corresponded with the best AHR in 12 out of the 14 patients with a positive AHR, with an average Q-LV/QRS width ratio of 90 %. CONCLUSIONS: Acute haemodynamic testing may indicate an alternative endocardial pacing site with a positive AHR in clinical non-responders. The Q-LV interval is a strongly correlated with the optimal endocardial pacing site. Endocardial pacing opposite epicardial sites does not result in a better AHR.

Managing patients with advisory defibrillator leads: what can we learn from published data?

Defibrillator lead advisories stir a lot of emotions, both with patients and physicians, and this may influence lead management. We reviewed the literature for a more evidence-based approach to this issue.From the complications of two of the current advisory leads, the Medtronic Sprint Fidelis and St. Jude Riata leads, and the consequences of possible interventions, we can conclude that a restrained approach to premature replacement is appropriate. It may be opportune to replace the leads during a scheduled generator replacement in case of a higher electrical failure rate, in order to prevent future premature interventions.We found no support to extract non-functional advisory leads. In contrast, extraction is often more demanding than anticipated, and the risk substantially exceeds that of simply abandoning the leads.

Torsade de pointes during sevoflurane anesthesia and fluconazole infusion in a patient with long QT syndrome. A case report.

We present the occurrence of 'torsade de pointes' induced by the combination of peroperative fluconazole administration and sevoflurane anesthesia in a patient with 'long QT syndrome' (LQTS) scheduled for resection of a sacral abscess. Eight minutes following uneventful induction of anesthesia 'torsade de pointes' occurred, terminated by a counter shock. At this time the end-tidal concentration of sevoflurane was 2%. The fluconazole infusion was disconnected and the operation was continued. Post-operatively the patient awakened uneventfully. The direct postoperative ECG showed a QTc of 531 ms (preoperative QTc of 442 ms.) and remained prolonged afterwards. A long QT syndrome was the most likely diagnosis. LQTS is classified as either congenital or acquired. Patients with acquired LQTS may have an underlying predisposition for QT prolongation. Many drugs have shown to be associated with a prolonged QT interval (1). The syndrome in this particular patient was unmasked by sevoflurane. Concomitant administration of fluconazole might have further predisposed the patient to the development of 'torsade des pointes'. Although LQTS is relatively rare, it is important for the anesthesiologist to be familiar with the disease because of the associated morbidity and mortality and the potential for anesthesia to induce malignant arrhythmias in asymptomatic carriers.

Primary prevention with the ICD in clinical practice: not as straightforward as the guidelines suggest?

At first sight, guidelines for implantation of an implantable cardioverter defibrillator (ICD) for primary prevention of sudden cardiac death in patients with left ventricular systolic dysfunction seem unambiguous. There are clear cut-off values for ejection fraction, and functional class. However, determination of the ejection fraction itself is not unambiguous, and other risk factors for sudden death that may have a profound effect on risk are not used for decision-making. Furthermore, to obtain a clinically significant impact on survival, expected longevity is important as it can greatly compromise the benefit in elderly patients but underestimate the long-term potential of ICD therapy in younger patients. (Neth Heart J 2009;17:107-10.).

Endovascular extraction techniques for pacemaker and ICD lead extraction: Part 1.

In the last few years, comprehensive endovascular techniques have been developed to extract chronically implanted pacemaker and defibrillator leads. It is important that referring physician have knowledge of the advantages and limitations of the different techniques. In this paper we discuss the techniques and results of the currently used endovascular extraction techniques.

Endovascular extraction techniques: Part 2: Complications and indications.

The use of lead extraction is expanding with the introduction of new endovascular extraction techniques. Indications for extraction of chronically implanted pacemaker leads have been classified as mandatory, necessary or discretionary, but their rationale is often based on clinical judgement without corresponding support from the literature. We reviewed the literature of pacemaker lead-related complications as a starting point for discussing the indications for lead extraction.

Endovascular extraction techniques: Part 3: Results and indications in patients with an ICD.

INTRODUCTION: We report our experience with lead extraction in patients with an implantable cardioverter defibrillator (ICD) and discuss the indications for extraction in these patients. PATIENTS: Eighteen patients with an ICD (mean age 58±12 years) were referred for lead extraction: two patients with infection and 16 with lead dysfunction. METHODS: Lead extraction was performed with a laser sheath (Excimer) if traction with a locking device was insufficient. New leads were implanted during the same procedure, if applicable. RESULTS: Shock leads were successfully extracted in 16 patients and additional pace-sense leads in seven patients. In two patients, the shock conductor was considered unaffected and only a pace-sense lead was exchanged or an additional pace-sense lead inserted. After extraction, new shock leads were implanted in 14 patients. Major complications occurred in one patient: a pericardial tamponade after perforation of the superior caval vein necessitating acute surgery. CONCLUSION: Lead extraction with a laser sheath is effective in ICD patients, but major complications can occur. Our current policy with malfunctioning leads is to extract all leads in which insulation defects cannot be ruled out to avoid interference, but to abandon leads that are without insulation defects and properly insulated. In case of infection, extraction remains the primary treatment of choice.

Reflections of six years of lead extraction: influence on indications and technique.

BACKGROUND: Endovascular techniques have become the standard approach for extraction of pacemaker and ICD leads. However, with experience, the indications and technical approach have evolved. INDICATIONS: In a population referred for lead extraction, we could not found a relation between the number of leads implanted and the incidence of occlusion of the access vein. Moreover, there is evidence that the lead extraction itself is accompanied with an increased risk of post-procedural venous occlusion. Electrical interference can be avoided in most cases, even in ICD patients. As complications of extraction have to be taken into account as well, it is therefore not in the patient's interest to extract chronically implanted non-functional superfluous leads. In contrast, lead extraction is a most effective way to cure pacemaker or ICD related infections, even if previous conservative therapy has failed. However, in patients at high risk, extraction might be deferred to attempt device saving therapy first. TECHNIQUE: Although leads can be removed with traction for almost all implant times, after six months additional tools are increasingly necessary to safely and completely extract them. No single technique suffices for all procedures: powered sheaths - as the laser sheath - and a femoral workstation with retrievers should be available when extraction is attempted. COMPLICATIONS: Venous or myocardial perforation is a life-threatening complication of lead extraction. In these circumstances, time lacks to safely transfer a patient for emergency surgery and therefore the only safe environment to perform lead extraction is the operating theatre with cardiosurgical standby.

Left ventricular endocardial pacing in cardiac resynchronisation therapy: Moving from bench to bedside.

In cardiac resynchronisation therapy, failure to implant a left ventricular lead in a coronary sinus branch has been reported in up to 10% of cases. Although surgical insertion of epicardial leads is considered the standard alternative, this is not without morbidity and technical limitations. Endocardial left ventricular pacing can be an alternative as it has been associated with a favourable acute haemodynamic response compared with epicardial pacing in both animal and human studies. In this paper, we discuss left ventricular endocardial pacing and compare it with epicardial surgical implantation. Ease of application and procedural complications and morbidity compare favourably with epicardial surgical techniques. However, with limited experience, the most important concern is the still unknown long-term risk of thromboembolic complications. Therefore, for now endovascular implants should remain reserved for severely symptomatic heart failure patients and patients at high surgical risk of failed coronary sinus implantation.