Permanent His-bundle pacing: Long-term lead performance and clinical outcomes

Transient rise in His-lead threshold due to acute myocardial infarction

An 85-year-old male was admitted to our center with a non-ST elevation myocardial infarction. The patient had a dual-chamber pacemaker in situ with an atrial and His lead. A transient increase in His threshold and loss of nonselective capture occurred at the presentation of right coronary artery infarction, peaking during rotational atherectomy therapy causing loss of capture and complete atrioventricular block. A follow-up interrogation, 2 weeks postrevascularization, showed a return to a normal nonselective capture morphology and threshold measurements. Physicians should be aware of this complication in patients with His leads, particularly those with a history of coronary artery disease.

His Bundle (Conduction System) Pacing: A Contemporary Appraisal

The His bundle (conduction system) is an attractive target for physiologic pacing because it uses the native conduction system. Although the potential benefits of conduction system pacing were recognized in the 1970s, in the past 2 decades, it has grown in interest as a potentially preferred method of ventricular stimulation in appropriate patients. This review provides an appraisal of conduction system pacing, with focus on anatomy, physiology, tools, and techniques as well as an appraisal of current published data and thoughts on future directions.

His Bundle Pacing – Why Should You be Doing it?

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Permanent His bundle pacing in heart failure patients: A systematic review and meta-analysis

BACKGROUND

Cardiac resynchronization therapy (CRT) is the standard-of-care therapy for the patients with heart failure and left ventricular (LV) dyssynchrony. However, approximately 30% of the patients show no response. Recent studies have shown that His bundle pacing (HBP) could be an alternative for the patients with CRT indications. The purpose of this study was to evaluate the efficacy of HBP in patients with heart failure.

METHODS

We searched PubMed and Embase databases for studies evaluating HBP in patients with heart failure and LV dyssynchrony. The successful rate of implantation, QRS duration, pacing threshold, LV function at baseline and follow-up, and mortality rates were extracted and summarized.

RESULTS

Eleven studies including 494 patients were included in this analysis. The overall successful rate for implantation was 82.4%. The main indications for HBP were CRT candidates and cardiomyopathy with atrial fibrillation undergoing atrioventricular node ablation. Permanent HBP resulted in narrow QRS duration of 116.3 ± 13.9 ms after implantation. LV functions, including echocardiographic parameters and clinical outcomes, significantly improved at follow-up (P < 0.001). However, there was a trend of increased capture and bundle branch block correction thresholds at follow-up compared to baseline (P = 0.01 and 0.02, respectively). During a mean follow-up of 23.7 months, 5.9% of the patients experienced heart failure-related hospitalization and the mortality rate was 9.1%.

CONCLUSION

Permanent HBP has shown promising results for heart failure patients in small observational studies. Randomized controlled trials are needed to assess the efficacy of HBP in these patients.

Updates on His bundle pacing: The road more traveled lately

His bundle pacing (HBP) has continued to evolve over the past decade and has started to become a global phenomenon. Evidence is mounting of its clinical benefits as compared to both right ventricular and left ventricular pacing. In this paper, we review recent data in support of His bundle pacing and some of the challenges facing us as we advocate its increasing role in clinical practice.

Electrical parameters for physiological His-Purkinje pacing vary by implant location in an ex vivo canine model

BACKGROUND

Permanent His-bundle pacing (HBP) is an attractive, perhaps more physiological, alternative to traditional right ventricular pacing.

OBJECTIVE

The purpose of this study was to utilize direct visualization to more comprehensively understand the anatomy central to HBP, correlating electrical lead performance to implant locations along the His-bundle (HB) pathway.

METHODS

Canine hearts (n = 5) were isolated and reanimated using Visible Heart methodologies. Medtronic 3830 SelectSecure leads were fixated where His potentials were present. The location of each implant was mapped/binned into 4 regions approximately analogous to the proximal, penetrating, and distal HB. Locational differences in HBP capture and resultant QRS morphology were assessed.

RESULTS

Average HBP capture thresholds did not significantly vary with respect to implant location (1.0-ms pulse width; P = .48). The resulting QRS morphologies from HB-paced beats varied in relation to implant location. As leads were placed further distally along the HB, the ratio of paced to native QRS complex duration increased (ΔQRS_paced/ΔQRS_native ratios-region 2: 0.84 ± 0.16; region 3: 1.04 ± 0.42; region 4: 1.74 ± 0.86).

CONCLUSION

We demonstrated correlation between the anatomic locations of HBP lead placement and resultant QRS morphologies in a reanimated canine heart model. Proximal placement along the HB pathway resulted in more favorable QRS morphologies, suggesting improved selective HBP capture, with no significant increase in HBP capture thresholds. Pacing the HB in more proximal pathway locations improved the selectivity of HBP and may confer electrical and anatomic benefits relative to distal HBP.

Long-Term Results of His Bundle Pacing

Right ventricular pacing is associated with pacing-induced cardiomyopathy in some patients. His Bundle Pacing (HBP) is an alternative site to pace to achieve ventricular contraction with fewer adverse hemodynamic effects. HBP has been shown to be safe and feasible in the short term. The few studies that look at long-term results of HBP are promising with regard to electrophysiological, echocardiographic, and clinical outcomes. Further randomized clinical trials are needed to fully understand the long-term effects of HBP.

His Bundle Pacing: Getting on the Learning Curve

Permanent His bundle pacing prevents ventricular dyssynchrony in patients who depend on ventricular pacing and can provide an alternative means to implementing cardiac resynchronization therapy in patients with bundle branch disease and congestive heart failure. Adoption of His bundle pacing, however, has lagged in part due to perceived and real challenges in performing the procedure well and durably. This article focuses on what is required to get on the learning curve and developing technical competence.

Painful left bundle branch block syndrome treated with his bundle pacing

This is a case report of a patient with painful LBBB Syndrome that responded favorably to His Bundle Pacing. This syndrome is largely under recognized despite 50 reports in the literature over the last 60 years. Both diagnosis and treatment are not well defined and represent a major challenge in patients with this entity. Right ventricular pacing has been attempted with inconsistent efficacy outcomes. We report for the first-time complete resolution of chest pain with His bundle pacing. HBP provides a promising alternative pacing option that might provide symptom resolution to patients with a painful LBBB syndrome.

His Bundle Pacing: A New Frontier in the Treatment of Heart Failure

Biventricular pacing has revolutionised the treatment of heart failure in patients with sinus rhythm and left bundle branch block; however, left ventricular-lead placement is not always technically possible. Furthermore, biventricular pacing does not fully normalise ventricular activation and, therefore, the ventricular resynchronisation is imperfect. Right ventricular pacing for bradycardia may cause or worsen heart failure in some patients by causing dyssynchronous ventricular activation. His bundle pacing activates the ventricles via the native His-Purkinje system, resulting in true physiological pacing, and, therefore, is a promising alternate site for pacing in bradycardia and traditional CRT indications in cases where it can overcome left bundle branch block. Furthermore, it may open up new indications for pacing therapy in heart failure, such as targeting patients with PR prolongation, but a narrow QRS duration. In this article we explore the physiology, technology and potential roles of His bundle pacing in the prevention and treatment of heart failure.