Left Bundle Branch Area Pacing Versus Conventional Pacing in Patients with Advanced Atrioventricular Conduction Abnormalities: a Prospective Cohort Study

BACKGROUND

Left bundle branch area pacing (LBBAP) is an emerging pacing method, which may prevent the deleterious effects of right ventricular pacing. The aim of this study is to compare the effects of LBBAP with right ventricular septal pacing (RVSP) in patients with advanced atrioventricular conduction abnormalities and preserved left ventricular ejection fraction.

METHODS

The effect of pacing was evaluated by echocardiographic indices of dyssynchrony, including global myocardial work efficiency (GWE) and peak systolic dispersion (PSD). The primary endpoint was GWE postprocedural, at 3, 6 and 12 months after the procedure.

RESULTS

Twenty patients received LBBAP and 18 RVSP. Complete follow-up was accomplished in 37 patients (97.4%), due to the death of a patient (RVSP arm), from non-related cause. GWE was significantly increased in the group of LBBAP compared to RVSP at all timepoints (90.8% in LBBAP vs 85.8% in RVSP group at 12 months, p=0.01). PSD was numerically lower in the LBBAP arm at all timepoints, yet not statistically significant (56.4 msec in LBBP vs 65.1 msec in RVSP arm at 12 months, p=0.178). The implantation time was increased (median 93 min in LBBAP vs 45 min in RVSP group, p<0.01), along with fluoroscopy time and dose area product (DAP), in the arm of LBBAP. There were no severe perioperative acute complications in either group.

CONCLUSIONS

LBBAP is an emerging and safe technique for patients with a pacing indication. Despite the longer procedural and fluoroscopy time, as well as higher DAP, LBBAP seems to offer better left ventricular synchrony compared to RVSP, according to GWE measurements.

Efficacy and Safety of Thirty-Day Dual-Antiplatelet Therapy Following Complex Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

The optimal duration of DAPT after complex PCI remains under investigation. The purpose of this systematic review and meta-analysis was to explore the safety and efficacy of a one-month therapy period versus a longer duration of DAPT after complex PCI. We systematically screened three major databases, searching for randomized controlled trials or sub-analyses of them, which compared shortened DAPT (S-DAPT), namely, one month, and longer DAPT (L-DAPT), namely, more than three months. The primary endpoint was any Net Adverse Clinical Event (NACE), and the secondary was any MACE (Major Adverse Cardiac Event), its components (mortality, myocardial infarction, stroke, and stent thrombosis), and major bleeding events. Three studies were included in the analysis, with a total of 6275 patients. Shortening DAPT to 30 days after complex PCI did not increase the risk of NACEs (OR: 0.77, 95% CI: 0.52-1.14), MACEs, mortality, myocardial infractions, stroke, or stent thrombosis. Pooled major bleeding incidence was reduced, but this finding was not statistically significant. This systematic review and meta-analysis showed that one-month DAPT did not differ compared to a longer duration of DAPT after complex PCI in terms of safety and efficacy endpoints. Further studies are still required to confirm these findings.

Safety and efficacy of left bundle branch area pacing compared with right ventricular pacing in patients with bradyarrhythmia and conduction system disorders: Systematic review and meta-analysis

BACKGROUND

Right Ventricular Pacing (RVP) may have detrimental effects in ventricular function. Left Bundle Branch Area Pacing (LBBAP) is a new pacing strategy that appears to have better results. The aim of this systematic review and meta-analysis is to compare the safety and efficacy of LBBAP vs RVP in patients with bradyarrhythmia and conduction system disorders.

METHODS

MEDLINE, EMBASE and Pubmed databases were searched for studies comparing LBBAP with RVP. Outcomes were all-cause mortality, atrial fibrillation (AF) occurrence, heart failure hospitalizations (HFH) and complications. QRS duration, mechanical synchrony and LVEF changes were also assessed. Pairwise meta-analysis was conducted using random and fixed effects models.

RESULTS

Twenty-five trials with 4250 patients (2127 LBBAP) were included in the analysis. LBBAP was associated with lower risk for HFH (RR:0.33, CI 95%:0.21 to 0.50; p < 0.001), all-cause mortality (RR:0.52 CI 95%:0.34 to 0.80; p = 0.003), and AF occurrence (RR:0.43 CI 95%:0.27 to 0.68; p < 0.001) than RVP. Lead related complications were not different between the two groups (p = 0.780). QRSd was shorter in the LBBAP group at follow-up (WMD: -32.20 msec, CI 95%: -40.70 to -23.71; p < 0.001) and LBBAP achieved better intraventricular mechanical synchrony than RVP (SMD: -1.77, CI 95%: -2.45 to -1.09; p < 0.001). LBBAP had similar pacing thresholds (p = 0.860) and higher R wave amplitudes (p = 0.009) than RVP.

CONCLUSIONS

LBBAP has better clinical outcomes, preserves ventricular electrical and mechanical synchrony and has excellent pacing parameters, with no difference in complications compared to RVP.

Mechanisms of Atrial Fibrillation: How Our Knowledge Affects Clinical Practice

Atrial fibrillation (AF) is a very common arrhythmia that mainly affects older individuals. The mechanism of atrial fibrillation is complex and is related to the pathogenesis of trigger activation and the perpetuation of arrhythmia. The pulmonary veins in the left atrium arei confirm that onfirm the most common triggers due to their distinct anatomical and electrophysiological properties. As a result, their electrical isolation by ablation is the cornerstone of invasive AF treatment. Multiple factors and comorbidities affect the atrial tissue and lead to myocardial stretch. Several neurohormonal and structural changes occur, leading to inflammation and oxidative stress and, consequently, a fibrotic substrate created by myofibroblasts, which encourages AF perpetuation. Several mechanisms are implemented into daily clinical practice in both interventions in and the medical treatment of atrial fibrillation.

A worldwide survey on incidence, management and prognosis of oesophageal fistula formation following atrial fibrillation catheter ablation: The POTTER-AF study

AIMS

Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management and outcome are sparse.

METHODS AND RESULTS

This international multicenter registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553,729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed at 214 centers in 35 countries. In 78 centers 138 patients (0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (p<0.0001)) were diagnosed with an oesophageal fistula. Periprocedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8%, and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) (odds ratio 7.463 (2.414, 23.072) p<0.001).

CONCLUSIONS

Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

Global left ventricular myocardial work efficiency in left bundle branch pacing versus right ventricular septal pacing: preliminary results of a randomized trial

Background

Recently, the concept of left bundle branch pacing (LBBP) has emerged in clinical practice, in an attempt to prevent the deteriorating effects of right ventricular pacing (Vp).

Purpose

The aim of this study is to compare the effect of Vp on left ventricular (LV) dyssynchrony in patients with atrioventricular block (AVB) and preserved ejection fraction (EF), subjected to either LBBP or right ventricular septal pacing (RVSP).

Methods

Patients with AVB are randomized 1:1 to LBBP or RVSP. The effect of Vp is evaluated by echocardiographic indices of dyssynchrony, such as global myocardial work efficiency (GWE) and peak systolic dispersion (PSD). GWE represents the ratio of constructive work divided by the sum of constructive and wasted work [1]. Successful LBBP is defined by the presence of right bundle branch block paced QRS morphology in lead V1 and stim to LV activation time &lt;75 msec [2]. No back-up right Vp lead was used in LBBP group.

Results

We conducted a preliminary analysis of the first 20 patients. Enrollment is still ongoing and total follow-up period is one year. We sought to investigate the acute effect of Vp on LV dyssynchrony 24 hours post procedure. Patients' baseline characteristics were similar in both groups and are presented in Table 1.

One crossover was noted from LBBP to RVSP group, due to high ventricular capture threshold during implant. Implantation time was increased in LBBP arm (130±17.4 min in LBBP versus 47.7±4.5 min in RVSP group, p=0.004). Left bundle branch potential was recorded in 3 out of 10 LBBP patients. No statistically significant difference was demonstrated in GWE between the two groups (91.3% in LBBP versus 87.4% in RVSP group, p=0.052). PSD was numerically shorter in LBBP (53.3 msec) versus in RVSP (63.6 msec), p=0.114. There were no complications during both the acute perioperative phase and the running period of the follow-up. Moreover, no acute ventricular threshold capture rise, or lead dislodgement has been observed in neither group.

The increased implantation time may be attributed to the more demanding technique, or the learning curve period required in the arm of LBBP. In the present analysis, a remarkable difference regarding GWE in favor of the LBBP group was demonstrated, although statistically not significant. However, even in this initial phase of the study, there is a trend of better LV synchrony and less wasted myocardial work in the LBBP group. The final difference of these indices will be assessed at the end of the one-year follow-up, when comparative results will be available.

Conclusion

LBBP is a novel, safe pacing method. Despite the longer procedural time and the risk of crossover, LBBP seems to offer better – without however statistical significance – LV synchrony even in the acute postoperative phase compared to RVSP. Longer follow-up studies are required to test whether LBBP compared to RVSP confers substantial clinical benefit.

Funding Acknowledgement

Type of funding sources: None.

Paradoxical pacing spikes during a wide complex tachycardia in biventricular defibrillator. What is the mechanism? Is it undersensing due to troubleshooting?

We present the case of a 68‐year‐old man with a cardiac resynchronization therapy‐defibrillator Medtronic device implanted 3 years ago, admitted to our hospital due to a wide complex tachycardia with unexpected pacing spikes inside QRS complexes. Although that could be easily attributed to ventricular undersensing, more complicated mechanisms are involved, including the origin of the tachycardia, the parameters of the device, and the position of the device and the leads.

Heart failure and atrial fibrillation: new concepts in pathophysiology, management, and future directions

A bidirectional pathophysiological link connects heart failure and atrial fibrillation, creating a frequent and challenging comorbidity, which includes neurohormonal hyperactivation, fibrosis development, and electrophysiologic remodeling, while they share mutual risk factors. Management for these devastating comorbidities includes most of the established treatment measures for heart failure as well as rhythm or rate control and anticoagulation mostly for atrial fibrillation, which can be achieved with either pharmaceutical or non-pharmaceutical approaches. The current manuscript aims to review the existing literature regarding the underlying pathophysiology, to present the novel trends of treatment, and to predict the future perspective of these two linked diseases with the numerous unanswered questions.

You cannot ablate the Lernaean Hydra: SCN5A mutation in a patient with multifocal ectopic Purkinje-related premature contractions syndrome treated with Flecainide and an implant of a subcutaneous defibrillator—a case report

Background

SCN5A mutations may present with different clinical phenotypes such as Brugada syndrome, long QT3 syndrome, sick sinus syndrome, atrial fibrillation, dilated cardiomyopathy, and the least known multifocal ectopic Purkinje-related premature contractions syndrome.

Case summary

We report a case of a 29-year-old woman with palpitations due to multifocal premature ventricular complexes (PVCs) and a family history of sudden death. The previous electrophysiological study had shown that PVCs arose from Purkinje fibres but catheter ablation was unsuccessful. Cardiac magnetic resonance (CMR) imaging demonstrated non-ischaemic areas of subendocardial fibrosis at multiple left ventricular (LV) segments with concomitant dilatation and mild systolic impairment. Amiodarone suppressed the ectopy but caused hyperthyroidism. Due to recent pregnancy, she received no antiarrhythmics which resulted in PVC burden increase and further deterioration of the ejection fraction (EF). After gestation, amiodarone was reinitiated and switched to flecainide after implantation of a subcutaneous defibrillator as a safety net. At follow-up, LV function had almost normalized. Genetic analysis confirmed an SCN5A mutation.

Discussion

Multifocal ectopic Purkinje-related premature contractions syndrome is associated with SCN5A mutation which in our case (R222Q) is the most common described. Flecainide can be an appropriate treatment option when ablation is ineffective. Defibrillator—even a subcutaneous type—could be implanted in cases of LV dysfunction or scar. PVCs suppression by flecainide and restoration of EF implies an arrhythmia—induced mechanism of LV impairment.

Increasing age does not affect time to appropriate therapy in primary prevention ICD/CRT-D: a competing risks analysis

Aims

To evaluate the impact of age on the clinical outcomes in a primary prevention implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) population.

Methods and Results

A retrospective, multicentre analysis of patients aged 60 years and over with primary prevention ICD/CRT-D devices implanted between 1 January 2006 and 1 November 2014 was performed. Survival to follow-up with no therapy (T1), death prior to follow-up with no therapy (T2), delivery of appropriate therapy with survival to follow-up (T3), and delivery of appropriate therapy with death prior to follow-up (T4) were measured. In total, 424 patients were eligible for inclusion in the analysis, mean follow-up of 32.6 months during which time 44 patients (10.1%) received appropriate therapy. The sub-hazard ratio (SHR) for the cumulative incidence of appropriate therapy (T3) according to age at implant was 1.00 (P = 0.851; 95% CI 0.96–1.04). The SHR for cumulative incidence of death (T2) according to age at implant was 1.06 (P < 0.001; 95% CI 1.03–1.01). Age at implant, ischaemic aetiology, baseline haemoglobin, and the presence of diabetes mellitus were predictors of all-cause mortality.

Conclusion

Age has no impact on the time to appropriate therapy, but risk of death prior to therapy increases by 6% for every year increment. As the ICD population ages, the proportion who die without receiving appropriate therapy increases due to competing risks. Characterizing competing risks predictive of death independent of ICD indication would focus therapy on those with potential to benefit and reduce unnecessary exposure to ICD-related morbidity.

Myocardial deformation imaging unmasks subtle left ventricular systolic dysfunction in asymptomatic and treatment-naïve HIV patients

BACKGROUND

Patients infected by the human immunodeficiency virus (HIV) and receiving highly active antiretroviral therapy have a higher incidence of cardiovascular disease than healthy subjects, but little is known about cardiac function in asymptomatic and treatment-naïve patients. We sought to study cardiac function in asymptomatic HIV-infected, treatment-naïve patients.

METHODS

We studied 41 HIV-infected and treatment-naïve patients and 20 age- and sex-matched healthy controls. Patients with cardiac symptoms, history of cardiac disease or NT-proBNP >100 pg/mL were excluded. We addressed cardiac function using standard echocardiography along with tissue Doppler (TDI) measurements, including strain/strain rate assessment.

RESULTS

Standard echocardiographic parameters did not differ between groups, except for transmitral E wave velocity (64.8 ± 14 cm/s in HIV vs 76.1 ± 10 cm/s in controls, p = 0.002). In contrast, TDI mitral and tricuspid annulus s velocity and all strain/strain rate measurements were significantly lower in HIV patients: s lateral, 10.2 ± 2.4/11.3 ± 0.7, p = 0.011; s septal, 8.1 ± 1.6/8.7 ± 0.8, p = 0.045; s tricuspid, 13.4 ± 2.3/14.9 ± 1.3, p = 0.002; strain/strain rate, septal (strain/strain rate, 15.1 ± 5.7/-0.9 ± 0.3, 25.3 ± 1.7/-1.9 ± 0.2, p < 0.001), anterior (16.7 ± 3/-1.0 ± 0.1, 26.7 ± 1.7/-1.9 ± 0.2, p < 0.001), lateral (16.0 ± 6/-1.0 ± 0.1, 27.5 ± 1.8/-2.2 ± 0.3, p < 0.001) and posterior (15.2 ± 5.8/-1.0 ± 0.2, 26.2 ± 1.8/-2.2 ± 0.3, p < 0.001) left ventricular wall.

CONCLUSIONS

HIV infection itself is accompanied by subclinical systolic dysfunction, not apparent to standard echocardiography that can be unmasked though using sensitive echocardiographic techniques.

Noonan syndrome and systemic lupus erythematosus in a patient with a novel KRAS mutation

Noonan syndrome is characterised by distinct facial stigmata, short stature and congenital cardiopathy. It has a high genetic heterogeneity and mutations in six different genes can be involved. We report a patient with Noonan syndrome and a novel KRAS mutation who presents systemic lupus erythematosus.