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Conventional right ventricular (RV) pacing, particularly RV apical pacing, can have deleterious effects on cardiac function. Long-term RV apical pacing has been associated with increased risk of atrial fibrillation, hospitalization for heart failure, pacing-induced cardiomyopathy and associated death. His bundle pacing (HBP) results in physiological ventricular activation and has generated tremendous research interest and enthusiasm. By stimulating the His–Purkinje network directly, HBP results in synchronized ventricular activation, which might translate into improved clinical outcomes compared with dyssynchronous ventricular activation with RV apical pacing. HBP can also overcome bundle branch block patterns, and data are accumulating on the benefit of HBP for cardiac resynchronization therapy. In this Review, we summarize the anatomy of the His bundle and early clinical observations, implantation techniques and available outcome data associated with permanent HBP. We also highlight the challenges with HBP and the need for additional tools and more randomized data before widespread application of permanent HBP.

In this comparative-effectiveness trial, biventricular pacing prevented the reduction in left ventricular ejection fraction that is seen with right ventricular pacing. The deleterious effect of nonphysiologic right ventricular apical pacing on left ventricular systolic function has been recognized since the 1920s. 1 In the Dual Chamber and VVI Implantable Defibrillator (DAVID) trial, the unexpected increased rates of death and hospital admission for heart failure among patients who were randomly assigned to the dual-chamber, rate-adaptive (DDDR) mode were purportedly due to the adverse effect of right ventricular apical pacing on left ventricular structural remodeling. 2 Results of subsequent trials have supported the notion that right ventricular apical pacing might lead to adverse clinical outcomes in patients with standard pacing indications. 3 – 7 Nevertheless, right ventricular . . .

A cohort of 2580 patients with pacemakers or defibrillators were monitored for 3 months to detect subclinical atrial tachyarrhythmias. Patients with subclinical atrial tachyarrhythmias had a significantly increased risk of subsequent ischemic stroke. Atrial fibrillation may be asymptomatic and consequently subclinical. 1 , 2 Epidemiologic studies indicate that many patients with atrial fibrillation on screening electrocardiograms had not previously received a diagnosis of atrial fibrillation. 3 About 15% of strokes are attributable to documented atrial fibrillation, and 50 to 60% to documented cerebrovascular disease, 4 – 7 but in about 25% of patients who have ischemic strokes, no etiologic factor is identified. 4 , 8 , 9 Subclinical atrial fibrillation is often suspected to be the cause of stroke in these patients. 10 However, the prevalence and prognostic value of subclinical atrial fibrillation has been difficult to assess. 8 , 9 , 11 , 12 An . . .

Patients with high-grade atrioventricular block usually require the implantation of a permanent pacemaker. Retrospective studies have suggested that dual-chamber pacemakers reduce the risk of atrial fibrillation, stroke, heart failure, and death in this setting, as compared with single-chamber ventricular pacemakers. In a randomized trial comparing these two pacing methods, however, no significant advantage of dual-chamber pacing was demonstrated. In a randomized trial comparing these two pacing methods, no significant advantage of dual-chamber pacing was demonstrated. Cardiac pacing is the established treatment for high-grade atrioventricular block, but the appropriate pacing mode remains the subject of debate. 1 Single-chamber ventricular pacing prevents bradycardia and death from ventricular standstill, but dual-chamber pacing better emulates normal cardiac physiology by restoring atrioventricular synchrony and matching the ventricular pacing rate to the sinus rate. As a result, dual-chamber pacing, as compared with single-chamber ventricular pacing, improves hemodynamic function, 2 – 4 but the clinical benefit is uncertain. Nonrandomized studies suggest that dual-chamber pacing is associated with a lower incidence of atrial fibrillation, stroke, and heart failure than is single-chamber pacing. 5 There is also evidence . . .

In this trial, patients with mild-to-moderate heart failure were randomly assigned to receive an implantable cardioverter–defibrillator (ICD) alone or an ICD plus cardiac-resynchronization therapy. Patients in the latter group had lower rates of death and hospitalization for heart failure. The use of implantable cardioverter–defibrillators (ICDs) improves survival among patients who have New York Heart Association (NYHA) class II or III heart failure with left ventricular systolic dysfunction despite optimal medical therapy. 1 Cardiac-resynchronization therapy (CRT) improves symptoms of heart failure, quality of life, exercise capacity, 2 – 6 and left ventricular function 7 when used in patients with NYHA functional class III or ambulatory class IV heart failure with a wide QRS complex. CRT has also been shown to reduce mortality among patients not receiving an ICD. 8 However, studies have not shown a survival benefit of CRT in patients with NYHA class II . . .

The clinical value of interventricular (V-V) delay optimization in patients with chronic congestive heart failure (CHF) undergoing implantation of a device for cardiac resynchronization therapy (CRT) has not been clearly demonstrated. RHYTHM II was a single-blind randomized trial including 121 recipients of a device for CRT with cardioverter/defibrillator capabilities (CRT-D) randomly assigned in a 1:3 ratio to simultaneous (n = 30) versus optimized (OPT) (n = 91) biventricular pacing. V-V delay was optimized by echocardiography. The study end points were (1) freedom from CRT-D system-related complications and (2) changes between preimplant and 6 months of follow-up in (a) New York Heart Association CHF functional class, (b) distance covered during a 6-minute hall walk, and (c) quality of life (QOL). In the OPT group, the V-V delay ranged from 0 to 80 milliseconds, with 28.4% of patients stimulated at an OPT V-V delay of 0 milliseconds. The overall 6-month survival free of adverse events requiring invasive interventions was 81.8%. In the whole cohort, 6 months of CRT-D was associated with a significant decrease in New York Heart Association class, increase in the distance covered during the 6-minute hall walk, and improvement in QOL (each P < .0001). The effects of CRT-D on these end points were similar in both study groups. Cardioverter-defibrillator capabilities was associated with a significant alleviation of CHF symptoms, increase in functional capacity, and improvement in QOL. The optimization of the V-V delay conferred no additional benefit compared with simultaneous biventricular stimulation.

About a third of patients with chronic heart failure have an intraventricular conduction delay, which may lead to dyssynchrony of cardiac contraction and further clinical impairment. The patients in this clinical trial were randomly assigned to a group receiving resynchronization therapy with an atrial–biventricular pacemaker or to a control group. As compared with the control group, the resynchronization group had improved functional capacity, quality of life, and ejection fraction over a six-month period. Patients were randomly assigned to receive an atrial–biventricular pacemaker or to a control group. The resynchronization group had improved functional capacity and ejection fraction. In approximately 30 percent of patients with chronic heart failure, the disease process not only depresses cardiac contractility but also affects the conduction pathways by causing a delay in the onset of right or left ventricular systole. 1 , 2 Such dyssynchrony is apparent on the electrocardiogram as a QRS interval lasting more than 120 msec. Some have proposed that this intraventricular conduction delay may further impair the ability of the failing heart to eject blood and may thus enhance the severity of regurgitant flow through the mitral valve. 3 – 6 The finding of an intraventricular conduction delay has been associated with clinical . . .

•Conduction system pacing, also termed physiologic pacing, is a novel alternative to biventricular resynchronization that may improve left ventricular remodeling while minimizing costs.•PhysioSync-HF is an investigator-led, randomized, multicenter clinical trial comparing conduction system pacing and biventricular resynchronization on heart failure-related outcomes in 179 patients with heart failure with reduced ejection fraction and left bundle branch block.•Half of trial participants are women, and most are non-White, ensuring patient representativeness and generalizability. Cardiac resynchronization therapy reduces heart failure hospitalizations and mortality in patients with heart failure with reduced ejection fraction (HFrEF) and left bundle branch block (LBBB). Conduction system pacing, which directly activates the His-Purkinje system, has emerged as a safe alternative to traditional biventricular resynchronization that may offer clinical benefits at lower costs. The PhysioSync-HF trial is an investigator-led, randomized, multicenter clinical trial designed to assess whether conduction system pacing is noninferior to biventricular resynchronization on heart failure-related outcomes in patients with HFrEF and LBBB. The study population consists of 179 adults with symptomatic heart failure (New York Heart Association [NYHA] class II-III), left ventricular ejection fraction (LVEF) ≤35%, and LBBB (QRS ≥130 ms). Patients were randomized 1:1 to receive conduction system pacing or biventricular resynchronization and followed for 12 months postprocedure. The primary endpoint is a hierarchy of all-cause death, any hospitalization for heart failure, any urgent visit for heart failure, and change in LVEF from baseline. The key secondary endpoint is the mean total direct medical cost per patient. Additional endpoints include assessments of health-related quality of life, functional capacity, and safety. Enrollment began in November 2022 and concluded in December 2023. PhysioSync-HF will determine whether conduction system pacing is noninferior to biventricular resynchronization on heart failure-related outcomes in patients with HFrEF with LBBB. NCT05572736. *In selected sites. 6MWT indicates 6-minute walk test; CPET, cardiopulmonary exercise test; ECG, electrocardiogram; EQ-5D, EuroQol Group 5-Dimensions questionnaire; HF, heart failure; KCCQ, Kansas City Cardiomyopathy Questionnaire; LVEF, left ventricular ejection fraction. [Display omitted]

Background In recent years, lead-induced tricuspid regurgitation (LITR) has attracted increasing attention. At present, there are two commonly used transvalvular methods for pacing lead wires to enter the right ventricle. The first transvalvular approach involves placing the tip of the pacing lead directly through the tricuspid valve into the right ventricle, including “direct-crossing” and “drop-down.” The second transvalvular approach is to bend the pacing lead so that the reflexed lead body crosses the tricuspid valve and then enters the right ventricle, which is “prolapsing.” However, there are no clinical trials to evaluate or compare the effects of the above two different pacing lead transvalvular approaches on tricuspid regurgitation. In this study, we will perform a randomized clinical trial to understand the effect of different transvalvular lead wire transversal techniques on the incidence of tricuspid regurgitation. Methods Three hundred seventy-six subjects with right ventricular single-chamber pacemaker implantation or dual-chamber pacemaker implantation were recruited in the First Affiliated Hospital of Shantou University Medical College. Participants will be randomized into the direct group (“direct-crossing” and “drop-down”) or the bending group (“prolapsing”). The primary objective will be new tricuspid regurgitation or exacerbation of existing tricuspid regurgitation within 1 year of follow-up. Discussion This study aims to verify whether different transvalvular approaches influence the incidence of LITR, and is expected to provide an optimized method for routine pacemaker surgery and improve the long-term prognosis and quality of life of patients. Trial registration Chinese Clinical Trials Registry ChiCTR2100045558. Registered on April 19, 2021.

Background Left bundle branch area pacing (LBBaP) is a new physiological pacing strategy that produces comparable clinical effects to His bundle pacing (HBP). Objective The purpose of this study was to investigate the immediate clinical outcomes of LBBaP vs RVP. Methods and Results From April 2018 to September 2018, we included 44 patients under continuous pacemaker implantation. Patients were randomly divided into the LBBaP group and conventional RVP group. Compared to the RVP group, the LBBaP group displayed significantly increased operative (90.10 ± 19.68 minutes vs 61.57 ± 6.62 minutes, P < .001) and X‐ray exposure times (15.55 ± 5.62 minutes vs 4.67 ± 2.06 minutes, P < .001). The lead threshold of the LBBaP group was increased (0.68 ± 0.20 mV vs 0.51 ± 0.0 mV, P = .001), while the R‐wave amplitude and ventricular impedance did not significantly differ between the two groups. The conventional RVP procedure significantly widened the QRS complex (93.62 ± 8.28 ms vs 135.19 ± 12.21 ms, P = .001), whereas the LBBaP had no effect on QRS complex (130.13 ± 43.30 ms vs 112.63 ± 12.14 ms, P = .904). Furthermore, the LBBaP procedure significantly narrowed the QRS complex in patients with left bundle branch block (LBBB) (168.43 ± 38.870 ms vs 119.86 ± 6.69 ms, P = .019). Conclusion LBBaP is a new physiological, safe and effective pacing procedure with a high overall success rate. Compared to conventional RVP, LBBaP can correct LBBB, thereby improving cardiac electrical dyssynchrony.