Cardiac Electrical and Mechanical Synchrony Analysis of LBBP and RVP Utilizing Tissue Doppler Imaging Technology.

Background: Right ventricular pacing (RVP) therapy is the conventional approach for atrioventricular block despite its propensity to cause electrical and mechanical dyssynchrony. This dyssynchrony increases the risk of atrial fibrillation and heart failure, eventually leading to left ventricular dysfunction. Left bundle branch pacing (LBBP) has recently emerged as a novel physiological pacing method. This study utilizes conventional ultrasound cardiography (UCG), two-dimensional speckle tracking imaging (2D-STI), and tissue Doppler imaging (TDI) to investigate the disparities in electrical and mechanical cardiac synchrony between LBBP and RVP patients. Methods: The retrospective analysis includes data from patients who underwent LBBP (n=50) and RVP (n=50) in Zhangjiagang First People's Hospital between January 2019 and June 2020, meeting the stipulated inclusion criteria. The study compares pacing parameters, UCG metrics, cardiac electrical and mechanical synchrony, pacing success rates, and safety events both pre-operation and at 3, 6, 12, and 24 months post-operation. Results: Implantation success rates for both RVP and LBBP groups were 100%, with 92% and 100% pacing success rates, respectively [P = .001 RR (95% CI) : 2.5 (1.5, 3.5)]. The LBBP group exhibited significant advantages over the RVP group throughout the follow-up period. LBBP patients displayed shortened QRS duration, reduced pacing thresholds and impedance, improved sensory function, lower serum NT-proBNP levels, and an increased proportion of NYHA class I patients [P = .003 RR (95% CI) : 1.6 (1.1, 2.3)]. Furthermore, left ventricular ejection fraction increased significantly, while left ventricular diastolic and end-systolic diameters decreased in the LBBP group compared to the RVP group [P = .004 RR (95% CI) : 1.7 (1.3, 2.2)]. The LBBP group also demonstrated shorter ventricular systolic synchrony parameters, including Tls-Dif, PSD, Trs-SD, Tas-SD, Tas-post, Ts-SD, and Ts-DIf, compared to the RVP group [P = .005 RR (95% CI) : 1.5 (1.2, 2.0)]. Notably, no postoperative complications occurred in either group, such as electrode displacement, lead thrombus attachment, incision bleeding, pocket hemorrhage, or infection. However, the readmission rates for heart failure were 16% in the RVP group and 2% in the LBBP group. Conclusion: LBBP achieves physiological cardiac pacing, leading to significant improvements in serum NT-proBNP levels and cardiac function and enhanced ventricular contraction synchrony. Utilizing UCG, 2D-STI, and TDI for quantitative evaluation of cardiac electrical and mechanical synchrony proves to be a valuable clinical approach.

A novel 9-partition method using fluoroscopic images for guiding left bundle branch pacing.

BACKGROUND: Left bundle branch (LBB) pacing is a novel pacing modality, but there is no standard fluoroscopic methodology. OBJECTIVES: This study aimed to analyze the characteristics of His bundle (HB) and LBB pacing lead locations and establish a method to guide LBB pacing using fluoroscopic images. METHODS: Seventy patients who underwent HB or LBB pacing were enrolled. The fluoroscopic image was recorded, and ventricular contraction ring in the right anterior oblique 30° projection was determined. The region between the apex and the ventricular contraction ring was divided into 9 partitions. All patients underwent postoperative computed tomography to confirm components of the ventricular contraction ring and to measure the distance from the lead tip to the junction of the noncoronary aortic cusp and right coronary cusp. RESULTS: HB and LBB pacing leads were successfully implanted in 11 and 35 patients, respectively. All HB pacing leads were distributed in the second partition, and 94.3% (33/35) of LBB pacing leads were in the junctional area of second and fifth partitions. The computed tomography image confirmed that the ventricular contraction ring was composed of cardiac valves. The distance from the lead tip to the junction of the noncoronary cusp and right coronary cusp of LBB and HB pacing leads was 3.8 ± 0.6 and 1.9 ± 0.2 cm, respectively. Under the guidance of the 9-partition method, the success rate of LBB pacing in 30 prospective patients increased from 58.3% (35/60) to 83.3% (25/30) (P = .03). The fluoroscopy time and the number of screwing sites also significantly decreased. CONCLUSION: The distributions of HB and LBB pacing leads exhibited unique imaging characteristics. A new 9-partition method is useful to guide successful LBB pacing.

Cardiac electrical and mechanical synchrony of super-responders to cardiac resynchronization therapy.

BACKGROUND: Super-responders (SRs) to cardiac resynchronization therapy (CRT) regain near-normal or normal cardiac function. The extent of cardiac synchrony of SRs and whether continuous biventricular (BIV) pacing is needed remain unknown. The aim of this study was to evaluate the cardiac electrical and mechanical synchrony of SRs. METHODS: We retrospectively analyzed CRT recipients between 2008 and 2016 in 2 centers to identify SRs, whose left ventricular (LV) ejection fraction was increased to ≥50% at follow-up. Cardiac synchrony was evaluated in intrinsic and BIV-paced rhythms. Electrical synchrony was estimated by QRS duration and LV mechanical synchrony by single-photon emission computed tomography myocardial perfusion imaging. RESULTS: Seventeen SRs were included with LV ejection fraction increased from 33.0 ±â€Š4.6% to 59.3 ±â€Š6.3%. The intrinsic QRS duration after super-response was 148.8 ±â€Š30.0 ms, significantly shorter than baseline (174.8 ±â€Š11.9 ms, P = 0.004, t = -3.379) but longer than BIV-paced level (135.5 ±â€Š16.7 ms, P = 0.042, t = 2.211). Intrinsic LV mechanical synchrony significantly improved after super-response (phase standard deviation [PSD], 51.1 ±â€Š16.5° vs. 19.8 ±â€Š8.1°, P < 0.001, t = 5.726; phase histogram bandwidth (PHB), 171.7 ±â€Š64.2° vs. 60.5 ±â€Š22.9°, P < 0.001, t = 5.376) but was inferior to BIV-paced synchrony (PSD, 19.8 ±â€Š8.1° vs. 15.2 ±â€Š6.4°, P = 0.005, t = 3.414; PHB, 60.5 ±â€Š22.9° vs. 46.0 ±â€Š16.3°, P = 0.009, t = 3.136). CONCLUSIONS: SRs had significant improvements in cardiac electrical and LV mechanical synchrony. Since intrinsic synchrony of SRs was still inferior to BIV-paced rhythm, continued BIV pacing is needed to maintain longstanding and synchronized contraction.

Machine learning for prediction of sudden cardiac death in heart failure patients with low left ventricular ejection fraction: study protocol for a retroprospective multicentre registry in China.

INTRODUCTION: Left ventricular ejection fraction (LVEF) ≤35%, as current significant implantable cardioverter-defibrillator (ICD) indication for primary prevention of sudden cardiac death (SCD) in heart failure (HF) patients, has been widely recognised to be inefficient. Improvement of patient selection for low LVEF (≤35%) is needed to optimise deployment of ICD. Most of the existing prediction models are not appropriate to identify ICD candidates at high risk of SCD in HF patients with low LVEF. Compared with traditional statistical analysis, machine learning (ML) can employ computer algorithms to identify patterns in large datasets, analyse rules automatically and build both linear and non-linear models in order to make data-driven predictions. This study is aimed to develop and validate new models using ML to improve the prediction of SCD in HF patients with low LVEF. METHODS AND ANALYSIS: We will conduct a retroprospective, multicentre, observational registry of Chinese HF patients with low LVEF. The HF patients with LVEF ≤35% after optimised medication at least 3 months will be enrolled in this study. The primary endpoints are all-cause death and SCD. The secondary endpoints are malignant arrhythmia, sudden cardiac arrest, cardiopulmonary resuscitation and rehospitalisation due to HF. The baseline demographic, clinical, biological, electrophysiological, social and psychological variables will be collected. Both ML and traditional multivariable Cox proportional hazards regression models will be developed and compared in the prediction of SCD. Moreover, the ML model will be validated in a prospective study. ETHICS AND DISSEMINATION: The study protocol has been approved by the Ethics Committee of the First Affiliated Hospital of Nanjing Medical University (2017-SR-06). All results of this study will be published in international peer-reviewed journals and presented at relevant conferences. TRIAL REGISTRATION NUMBER: ChiCTR-POC-17011842; Pre-results.

[Ablation of paroxysmal supraventricular tachycardia guided by Carto Univu electroanatomic mapping system].

OBJECTIVE: To explore the safety and efficacy for radiofrequency ablation of paroxysmal supraventricular tachycardia (PSVT) guided by Carto Univu three-dimensional mapping system.
 Methods: A total of 99 patients with PSVT underwent radiofrequency catheter ablation (RFCA) were assigned to a Carto Univu group (51 patients) and a two-dimensional X-ray group (48 patients) according to the mapping method. The operation time, X-ray exposure time, X-ray exposure dose, dose area product (DAP), operation success rate and complication rate were compared between the two groups.
 Results: The Carto Univu group and the two-dimensional X-ray group were not significant difference in the operation time, the X-ray exposure time of placing catheter, the X-ray DAP of placing catheter, the number of discharge, the discharge power, and the total discharge time (P>0.05). The mapping and ablation time, total exposure time, mapping and ablation DAP and total DAP in the Carto Univu group were significantly lower than those in the two-dimensional X-ray group (P<0.01). In the right accessory pathway cases, the mapping and ablation DAP and the total DAP in the Carto Univu group decreased compared with X-ray group (P<0.05), but it decreased more profound (P<0.01) in the left accessory pathway cases and the dual atrioventricular nodal pathways cases. Seven cases in the Carto Univu group achieved "zero X-ray", including 5 cases of the dual atrioventricular nodal pathways and 2 cases of the left accessory pathway. The immediate success rate for the two groups was 100%. After 3-12 months of follow-up, there was no recurrence in the Carto Univu group but 3 suspected recurrences in the two-dimensional X-ray group. In addition, no complications occurred in the two groups. 
 Conclusion: Carto Univu electroanatomic mapping system can guide PSVT safely and effectively during radiofrequency ablation and reduce radiation exposure to both doctors and patients. It is especially suitable for dual atrioventricular nodal pathways, which may even achieve "zero X-ray". Perhaps Carto Univu will be the first choice for RFCA of dual atrioventricular nodal pathways.

Comparison of the effects of selective and non-selective His bundle pacing on cardiac electrical and mechanical synchrony.

Aims: This study aimed to assess the acute effect of selective His bundle pacing (S-HBP), non-selective His bundle pacing (NS-HBP), and right ventricular septum pacing (RVSP) on electrical synchrony and left ventricular (LV) mechanical synchrony using electrocardiogram and phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Methods and results: Totally 39 patients eligible for pacemaker were enrolled. Thirty-seven patients underwent successful His bundle pacing (HBP) including S-HBP in 23 and NS-HBP in 14 patients, respectively. Thirty-one patients simultaneously underwent backup RVSP. Twenty-three patients received SPECT MPI scans under different pacing modes, including S-HBP low- and high-output, NS-HBP low- and high-output, and RVSP mode. The paced QRS duration (QRSd) in the S-HBP low- and high-output mode and in the NS-HBP high-output mode were similarly compared with the baseline intrinsic QRSd. QRS duration in the NS-HBP low-output mode was slightly longer than the baseline. QRS duration was the longest in the RVSP group. Left ventricular mechanical synchrony parameters in both the S-HBP and the NS-HBP groups were remarkably better than those in the RVSP group. Moreover, LV mechanical synchrony parameters were much better in the S-HBP groups and NS-HBP high-output group. Conclusion: Selective His bundle pacing and high-output NS-HBP could restore normal electrical and LV mechanical synchrony.

The incidence and outcomes of delayed response to cardiac resynchronization therapy.

BACKGROUND: The incidence and clinical outcomes of delayed response to cardiac resynchronization therapy (CRT) have not been well clarified. We aimed to observe the incidence and prognosis of delayed response and to identify its possible mechanisms. METHODS: A total of 115 CRT patients were retrospectively analyzed in our study. Patients who met the enrollment criteria were divided into two groups: group A, conventional responders who showed response at 1-year follow-up, and group B, delayed responders who showed response after 1-year follow-up. CRT response was defined as an absolute increase of ≥10% in left ventricular ejection fraction. RESULTS: Fifty-two patients (61 ± 12 years, 37 male) experienced conventional response to CRT and 17 patients (63 ± 11 years, 10 male) experienced delayed response. The mean follow-up time was 5.2 ± 2.4 years. The incidence of delayed response was 14.8% (17/115). All-cause mortality and hospitalization rates for heart failure were similar for delayed and conventional responders. Multivariate logistic regression analysis revealed that scar burden > 35% was an independent predictor of CRT delayed response (odds ratio 8.794, P  =  0.038). CONCLUSIONS: A significant proportion of patients demonstrated delayed response to CRT. The delayed responders had a good prognosis that was similar to that of conventional responders. More scar burden might be related to the incidence of delayed response.

Long-term efficacy of pneumatic dilation and esophageal stenting for the treatment of achalasia.

AIMS: To compare the efficacy and safety of pneumatic dilation with stenting for the treatment of achalasia. METHODS: Achalasia patients treated with pneumatic dilation or stenting were included in this analysis. Clinical symptoms were assessed by the Eckardt score. An esophagram and esophageal manometry were performed at the pretreatment and posttreatment follow-up visits. Data such as patient demographics and complications were collected. A drop in the Eckardt score to ≤3 was defined as treatment success. RESULTS: There were 151 patients treated with pneumatic dilation (n = 76) or stenting (n = 75). The 1-, 12- and 24-month therapeutic success rates were 100, 92 and 79%, respectively, in the dilation group and 100, 93 and 87%, respectively, in the stenting group. The decrease of Eckardt score in the stenting group was significantly notable (p < 0.05) compared to that of the dilation group at the long-term follow-up visits. The maximum esophageal diameter was comparable at baseline and became statistically significant [25 mm (22-30) vs. 22 mm (19-27), p = 0.004] at posttreatment month 24. The recurrence rate was 21% in the dilation group and 13% in the stenting group. The complications of either treatment were usually mild, transient and statistically insignificant. CONCLUSION: Esophageal stenting had a comparable short-term but better long-term efficacy in comparison with pneumatic dilation.

[Toll-like receptor gene polymorphisms and susceptibility to inflammatory bowel disease in Chinese Han and Caucasian populations].

OBJECTIVE: To explore the distribution of Toll-like receptors gene polymorphisms in inflammatory bowel disease (IBD) in Chinese Han patients and Caucasians. METHODS: The toll-like receptor 2 (TLR2) genes Arg677Trp and Arg753Glu, TLR4 genes Asp299Gly and Thr399Ile, and TLR9 gene 1237T/C polymorphisms were genotypes in 113 patients with IBD and 120 age and gender-matched healthy controls by the analyses of polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). A meta-analysis was performed to test whether TLR4 Asp299Gly and Thr399Ile polymorphisms were associated with ulcerative colitis (UC) or Crohn's disease (CD) susceptibility and whether 299Gly carriage was associated with phenotypes of CD patients in the Caucasian population. RESULTS: We found two carriers of TLR9 1237C in UC patients, one carrier in CD patients and one in healthy controls respectively (CD: P = 0.361; UC: P = 0.569). There was no statistically significant difference in both allelic and genotypic frequencies. The mutant genotypes of TLR2 gene Arg677Trp and Arg753Glu, TLR4 gene Asp299Gly and Thr399Ile were not found in either the IBD patients or the healthy controls. The TLR4 299G allele showed a significant association with CD and UC in Caucasian population (OR = 1.29, 95%CI: 1.08 - 1.54, P = 0.004 and OR = 1.28, 95%CI: 1.08 - 1.51, P = 0.004 respectively). Similar association was detected between T399I polymorphism and susceptibility to IBD (OR = 1.37, 95%CI: 1.12 - 1.68, P = 0.002 and OR = 1.46, 95%CI: 1.13 - 1.88, P = 0.003 respectively). However, no significant association was identified between CD phenotypes and 299Gly carriage. CONCLUSION: TLR2 genes Arg677Trp and Arg753Glu, TLR4 genes Asp299Gly and Thr399Ile and TLR9 gene 1237T/C polymorphisms are not associated with IBD in Chinese Han patients. In Caucasians, both TLR4 299G and 399I confer a significant risk for developing CD and UC. The contribution of genetic determinants may differ significantly between ethnicities.

The Toll-like receptor 4 D299G and T399I polymorphisms are associated with Crohn's disease and ulcerative colitis: a meta-analysis.

BACKGROUND: Some studies have reported that Toll-like receptor 4 (TLR4) D299G and T399I polymorphisms are associated with increased Crohn's disease (CD) and ulcerative colitis (UC) risk in the Caucasian population. However, the results have been inconsistent. METHODS: A systemic review of the published data (16 studies with 8,387 cases and 7,013 controls for D299G; 8 studies with 3,881 cases and 1,861 controls for T399I) was undertaken and a meta-analysis was performed to test whether TLR4 D299G and T399I polymorphisms were associated with CD or UC susceptibility and whether 299Gly carriage was associated with phenotypes of CD patients. RESULTS: The TLR4 299Gly allele showed a significant association with CD and UC in the Caucasian population (OR 1.29, 95% CI 1.08-1.54, and OR 1.28, 95% CI 1.08-1.51, respectively). Similar association was detected between the T399I polymorphism and susceptibility to CD and UC (OR 1.37, 95% CI 1.12-1.68, and OR 1.46, 95% CI 1.13-1.88, respectively). However, no significant association was identified between CD phenotypes and 299Gly carriage. CONCLUSION: The meta-analysis showed that TLR4 D299G and T399I confer a significant risk for developing CD and UC in Caucasians. Additional well-powered studies of the association between TLR4 variants and UC are needed.