Cardiovascular imaging in conduction system pacing: What does the clinician need?

Permanent pacemakers are used for symptomatic bradycardia and biventricular pacing (BVP)-cardiac resynchronization therapy (BVP-CRT) is established for heart failure (HF) patients traditionally. According to guidelines, patients' selection for CRT is based on QRS duration (QRSd) and morphology by surface electrocardiogram (ECG). Cardiovascular imaging techniques evaluate cardiac structure and function as well as identify pathophysiological substrate changes including the presence of scar. Cardiovascular imaging helps by improving the selection of candidates, guiding left ventricular (LV) lead placement, and optimization devices during the follow-up. Conduction system pacing (CSP) includes His bundle pacing (HBP) and left bundle branch pacing (LBBP) which is screwed into the interventricular septum. CSP maintains and restores ventricular synchrony in patients with native narrow QRSd and left bundle branch block (LBBB), respectively. LBBP is more feasible than HBP due to a wider target area. This review highlights the role of multimodality cardiovascular imaging including fluoroscopy, echocardiography, cardiac magnetic resonance (CMR), myocardial scintigraphy, and computed tomography (CT) in the pre-procedure assessment for CSP, better selection for CSP candidates, the guidance of CSP lead implantation, and the optimization of devices programming after the procedure. We also compare the different characteristics of multimodality imaging and discuss their potential roles in future CSP implantation.

Chinese expert consensus on the construction of the fluoroless cardiac electrophysiology laboratory and related techniques.

Transcatheter radiofrequency ablation has been widely introduced for the treatment of tachyarrhythmias. The demand for catheter ablation continues to grow rapidly as the level of recommendation for catheter ablation. Traditional catheter ablation is performed under the guidance of X-rays. X-rays can help display the heart contour and catheter position, but the radiobiological effects caused by ionizing radiation and the occupational injuries worn caused by medical staff wearing heavy protective equipment cannot be ignored. Three-dimensional mapping system and intracardiac echocardiography can provide detailed anatomical and electrical information during cardiac electrophysiological study and ablation procedure, and can also greatly reduce or avoid the use of X-rays. In recent years, fluoroless catheter ablation technique has been well demonstrated for most arrhythmic diseases. Several centers have reported performing procedures in a purposefully designed fluoroless electrophysiology catheterization laboratory (EP Lab) without fixed digital subtraction angiography equipment. In view of the lack of relevant standardized configurations and operating procedures, this expert task force has written this consensus statement in combination with relevant research and experience from China and abroad, with the aim of providing guidance for hospitals (institutions) and physicians intending to build a fluoroless cardiac EP Lab, implement relevant technologies, promote the standardized construction of the fluoroless cardiac EP Lab.

Efficacy of ablation index-guided pulmonary vein isolation in patients with paroxysmal atrial fibrillation.

BACKGROUND: Ablation index (AI) is a novel technology of ablation lesion quality to help improve homogeneity of lesion size and continuity. In this study, we aim to evaluate whether AI-guided PVI improves clinical outcomes compared to CF-guided PVI in patients with paroxysmal AF (PAF). METHODS: Patients undergoing first-time radiofrequency ablation for PAF were randomized in a 2:1 ratio to two groups: AI-guided PVI and CF-guided PVI. In the AI group, AI ≥500 was recommended at the anterior/superior/inferior walls, 350-400 at the posterior wall, and inter-lesion distance ≤4 mm. The primary endpoint is the freedom from atrial arrhythmia recurrence during 12 months follow-up, without antiarrhythmic drug therapy (ADT). The key secondary endpoints include intra-procedural efficiency and peri-procedural complications. RESULTS: Two hundred twenty five patients were randomized (AI group [n = 149] and CF group [n = 76]). First-pass isolation rate in AI group was significantly higher than that in CF group (58.3% vs. 43.4%, p = .035). After a median follow-up of 12.2 months, 154/225 (68.4%) of patients were free from atrial arrhythmia recurrence without ADT, which was higher in AI group compared with CF group, but without significant difference (71.1% vs. 63.2%, p = .253). The incidence of peri-procedural complications is low and without difference between two groups. CONCLUSIONS: AI-guided ablation provided higher acute efficacy than CF-guided ablation in PV isolation for patients with paroxysmal AF. The long-term success rate in AI group was higher than CF group, but did not reach statistical significance.

Intraprocedural endpoints to predict durable pulmonary vein isolation: a randomized trial of four post-ablation techniques.

AIMS: The optimal procedural endpoint to achieve permanent pulmonary vein isolation (PVI) during ablation of atrial fibrillation (AF) remains unknown. We aimed to compare the impact of prolonged waiting periods and adenosine triphosphate (ATP) testing after PVI on long-term freedom from AF. METHODS AND RESULTS: In total, 538 patients (median age 61 years, 62% male) undergoing first-time radiofrequency ablation for paroxysmal AF were randomized into four groups: Group 1 [PVI (no testing), n = 121], Group 2 (PVI + 30min waiting phase, n = 151), Group 3 (PVI+ATP, n = 131), and Group 4 (PVI + 30min+ATP, n = 135). The primary endpoint was freedom from AF. Repeat mapping to assess for late pulmonary vein (PV) reconnection was performed in patients who remained AF-free for >3 years (n = 46) and in those who had repeat ablation for AF recurrence (n = 82). During initial procedure, acute PV reconnection was observed in 33%, 26%, and 42% of patients in Groups 2, 3, and 4, respectively. At 36 months, no significant differences in freedom from AF recurrence were observed among all four groups (55%, 61%, 50%, and 62% for Groups 1, 2, 3, and 4, respectively; P = 0.258). Late PV reconnection was commonly observed, with a similar incidence between patients with and without AF recurrence (74% vs. 83%; P = 0.224). CONCLUSION: Although PVI remains the cornerstone for AF ablation, intraprocedural techniques to assess for PV reconnection did not improve long-term success. Patients without AF recurrence after 3 years exhibited similarly high rates of PV reconnection as those that underwent repeat ablation for AF recurrence. The therapeutic mechanisms of AF ablation may not be solely predicated upon durable PVI.

Spontaneous dissection in the left main coronary artery.

We present two cases of spontaneous left main stem coronary artery dissection. One was underdiagnosed with suboptimal percutaneous coronary artery intervention followed by acute vessel occlusion again during the hospitalization. The other one was identified and confirmed by intravascular ultrasound, followed by conservative medical treatment, with completed healing of SCAD during two-month follow up.

Impact of Anatomically Guided Ganglionated Plexus Ablation on Electrical Firing from Isolated Pulmonary Veins.

BACKGROUND: The mechanisms underlying atrial fibrillation (AF) initiation and pulmonary vein isolation (PVI) effectiveness remain unclear. Ganglionated plexus (GPs) have been implicated in AF initiation and maintenance. In this study, we evaluated the impact of GP ablation in patients with pulmonary vein (PV) firing after PVI. METHODS: Patients with drug-refractory paroxysmal AF undergoing radiofrequency catheter ablation therapy with PVI were screened. Among 840 cases over a 3.75-year period, 12 cases were identified with persistent PV firing (left = 4 and right = 8) after PVI was achieved and left atrial sinus rhythm restored. Adjacent GP ablation was performed anatomically and followed if necessary by additional PV ablation. RESULTS: In eight patients, PV firing was terminated during GP ablation outside of the circumferential ablation line. In one patient, additional PV ablation resulted in cessation of PV firing and in the remaining three patients, firing could not be terminated by GP ablation or additional PVI. CONCLUSION: GP ablation outside of wide antral circumferential line frequently results in the cessation of rapid firing from electrically isolated PVs. These observations suggest that interactions between left atrium and PV beyond electrical conduction warrant consideration in AF mechanisms.

Left bundle branch pacing better preserves ventricular mechanical synchrony than right ventricular pacing: a two-centre study.

AIMS: Left bundle branch pacing (LBBP) has been shown to better maintain electrical synchrony compared with right ventricular pacing (RVP), but little is known about its impact on mechanical synchrony. This study investigates whether LBBP better preserves left ventricular (LV) mechanical synchronicity and function compared with RVP. METHODS AND RESULTS: Sixty patients with pacing indication for bradycardia were included: LBBP (n = 31) and RVP (n = 29). Echocardiography was performed before and shortly after pacemaker implantation and at 1-year follow-up. The lateral wall-septal wall (LW-SW) work difference was used as a measure of mechanical dyssynchrony. Septal flash, apical rocking, and septal strain patterns were also assessed. At baseline, LW-SW work difference was small and similar in two groups. SW was markedly decreased, while LW work remained mostly unchanged in RVP, resulting in a larger LW-SW work difference compared with LBBP (1253 ± 687 mmHg·% vs. 439 ± 408 mmHg·%, P < 0.01) at last follow-up. In addition, RVP more often induced septal flash or apical rocking and resulted in more advanced strain patterns compared with LBBP. At 1 year follow-up, LV ejection fraction (EF) and global longitudinal strain (GLS) were more decreased in RVP compared with LBBP (ΔLVEF: -7.4 ± 7.0% vs. 0.3 ± 4.1%; ΔLVGLS: -4.8 ± 4.0% vs. -1.4 ± 2.5%, both P < 0.01). In addition, ΔLW-SW work difference was independently correlated with LV adverse remodelling (r = 0.42, P < 0.01) and LV dysfunction (ΔLVEF: r = -0.61, P < 0.01 and ΔLVGLS: r = -0.38, P = 0.02). CONCLUSION: LBBP causes less LV mechanical dyssynchrony than RVP as it preserves a more physiologic electrical conduction. As a consequence, LBBP appears to preserve LV function better than RVP.

Electrical Synchrony Optimization for Left Bundle Branch Area Pacing in Patients With Bradycardia and Heart Failure.

Left bundle branch area pacing (LBBAP) has emerged as a promising physiological pacing modality. This study was designed to investigate the acute impact of the atrioventricular delay (AVD) on cardiac electrical characteristics and identify an optimal range of AVDs for LBBAP to achieve electrical atrioventricular and interventricular synchrony. Patients indicated for ventricular or biventricular pacing were studied during routine follow-ups at least 3 months after LBBAP implantation. Patients were excluded if they had a complete AV block or persistent atrial fibrillation. AVD was programed from 40 to 240 ms or until intrinsic conduction occurred. Optimal AVD was determined by the electrocardiography criteria, including QRS duration, reduced R-wave in lead V1, reduced notching or slurring in lateral leads, and more desirable precordial QRS transition. A total of 38 patients (age 68.7 ± 10.3 years; 16 male (42%); 18 dual-chamber pacemakers and 20 cardiac resynchronization therapy devices; average follow-up period 15.1 ± 10.2 months) were included. The fusion of LBBAP and intrinsic right ventricular conduction occurred in 21 patients with corresponding optimal AVD determined. A great proportion (∼85%) of the optimal AVDs ranged from 50% to 80% of the observed atrium-to-left bundle branch-sensing (A-LBBS) intervals. The linear correlation between the optimal AVD and corresponding A-LBBS interval (optimal AVD = 0.84 × [A-LBSs interval] - 36 ms) produced R = 0.86 and p <0.0001. In conclusion, AVD selection during LBBAP greatly impacted the ventricular electrical characteristics and the optimal AVD was linearly correlated with the corresponding A-LBBS interval.

Left Bundle Branch Pacing for Heart Failure and Left Bundle Branch Block Patients With Mildly Reduced and Preserved Left Ventricular Ejection Fraction.

BACKGROUND: Left bundle branch block (LBBB) may induce or aggravate heart failure (HF). Few data are available on patients with HF and LBBB with mildly reduced ejection fraction (HFmrEF; left ventricular ejection fraction [LVEF] 40%-50%) and those with preserved EF (HFpEF. LVEF ≥ 50%). We aimed to assess the long-term outcomes of left bundle branch pacing (LBBP) on cardiac function and remodelling in patients with LBBB and symptomatic HFmrEF and HFpEF. METHODS: Nonischemic cardiomyopathy (NICM) patients with HFmrEF and HFpEF (LVEF from 40% to 60% as defined with the use of echocardiography) with LBBB who successfully underwent LBBP (n = 50) were prospectively included from 4 centres. Patient characteristics and echocardiographic and lead parameters were recorded at implantation and during follow-ups of 1, 3, 6, and 12 months. RESULTS: All patients completed 1-year follow up. The LVEF was significantly improved from 46.5 ± 5.2% at baseline to 60.0 ± 6.1% (n = 50; P < 0.001) after 1-year follow up. Higher ΔLVEF and super-response rate were observed in the HFmrEF group (n = 30) than in the HFpEF group (n = 20). CONCLUSIONS: LBBP improved symptoms and reversed remodelling in patients with LBBB and symptomatic HF at 1-year follow-up. Improvement occurred even in HFpEF patients, and the resynchronisation effect was better in HFmrEF group.

Coronary Intervention Guided by Quantitative Flow Ratio vs Angiography in Patients With or Without Diabetes.

BACKGROUND: The clinical utility of the quantitative flow ratio (QFR), a novel angiography-based index for the functional assessment of coronary stenoses, has recently been demonstrated in patients undergoing percutaneous coronary intervention (PCI). OBJECTIVES: This study aimed to ascertain whether the beneficial outcomes of QFR guidance for lesion selection during PCI is affected by diabetes status. METHODS: This substudy from the FAVOR III China trial, in which diabetes was one of the prespecified factors for stratified randomization, compared clinical outcomes of QFR-guided vs angiography-guided PCI lesion selection according to the presence of diabetes. The primary endpoint was the 1-year risk of major adverse cardiac events (MACE) (a composite of all-cause death, myocardial infarction, or ischemia-driven revascularization). RESULTS: Among 3,825 patients enrolled, 1,295 (33.9%) had diabetes, 347 (26.8%) of whom were treated with insulin. Baseline characteristics were well balanced between treatment arms in both diabetic and nondiabetic patients. Compared with standard angiography-based lesion selection, the QFR-guided strategy consistently reduced the risk of 1-year MACE in both diabetic patients (6.2% vs 9.6%; HR: 0.64; 95% CI: 0.43-0.95) and nondiabetic patients (5.6% vs 8.3%; HR: 0.66; 95% CI: 0.49-0.89) (Pinteraction = 0.88). Among patients in whom PCI was deferred after QFR, the risk of 1-year MACE was similar in patients with and without diabetes (4.5% vs 6.2%; P = 0.51). CONCLUSIONS: A QFR-guided lesion selection strategy improves PCI outcomes compared with standard angiography guidance in patients both with and without diabetes. (The Comparison of Quantitative Flow Ratio Guided and Angiography Guided Percutaneous Intervention in Patients with Coronary Artery Disease [FAVOR III China Study]; NCT03656848).

Lipid goal attainment in post-acute coronary syndrome patients in China: Results from the 6-month real-world dyslipidemia international study II.

BACKGROUND: Dyslipidemia International Study II (DYSIS II)-China was conducted to determine the low-density lipoprotein cholesterol (LDL-C) goal (<1.8 mmol/L) attainment rate in patients with post-acute coronary syndrome (ACS). HYPOTHESIS: Compliance with treatment guideline recommendations improves the LDL-C goal attainment rate in post-ACS patients. METHODS: This multicenter prospective observational study conducted at 28 tertiary hospitals determined the LDL-C goal attainment rates at admission and 6-month follow-up in patients on lipid-lowering treatment (LLT) for ≥3 months and those not on LLT (LLT-naive or off LLT for ≥3 months) at admission. Predictors of goal attainment at 6 months were identified using multivariate logistic regression. RESULTS: The LDL-C goal attainment rate at admission in 1102/1103 enrolled patients was 17.1%; it was 41.2% among 752 patients with available lipid results at 6 months. The distance to goal was 0.7 mmol/L at 6 months. Statin monotherapy was the most prescribed LLT. Only 7.7% of patients were receiving statin + ezetimibe and 8.4% of patients were receiving an atorvastatin-equivalent dose of ≥40 mg/day at 6 months. Being male (odds ratio [OR] 1.7, 95% confidence interval [CI] 1.1-2.6) and undergoing percutaneous coronary intervention during index hospitalization (OR 1.5, 95% CI 1.1 to 2.1) were the independent predictors for LDL-C goal attainment. CONCLUSIONS: This real-world DYSIS II study in China reports a low LDL-C goal attainment rate in post-ACS patients even after 6 months of LLT. Lack of intensification of statin therapy and underutilization of combinations suggest gaps between real-world treatment practices and guideline recommendations.

PV isolation guided by esophageal visualization with a tailored ablation strategy for the avoidance of esophageal thermal injury: a randomized trial.

PURPOSE: Radiofrequency ablation along the posterior wall of the left atrium may lead to atrioesophageal fistula due to esophageal thermal injury. The purpose of our study was to prospectively investigate whether ablation guided by soluble contrast esophageal visualization (SCEV) reduces injury during atrial fibrillation (AF) ablation. METHODS: Seventy-eight patients with paroxysmal AF undergoing circumferential pulmonary vein isolation (PVI) were randomized to a SCEV group (n = 39) and control group without visualization (n = 39). Cine imaging of the esophagus was performed during soluble contrast swallowing at the beginning of ablation, after adjacent ipsilateral PVI and at the end of the procedure. The ablation lesion set was modified to avoid radiofrequency delivery within the contrast esophagram boundaries. In the control group, a single final ingestion was performed at the end of the procedure. Esophageal injury was assessed by esophagogastroscopy within 24 h in all patients. RESULTS: In the control group, the ablation lesion crossed over the esophagus in 46.2% of patients, whereas in SCEV group, the ablation line violated the boundaries of the esophagus unavoidably in 15.4% of patients (confidence interval (CI); 1.61-13.98, p = 0.003). The incidence of esophageal injury was significantly lower in patients that underwent ablation with SCEV (5.1% vs. 20.5%, CI; 0.04-1.06, p = 0.042). Regardless of randomization group, patients who received ablation which overlapped the esophagus had a higher incidence of esophageal injury compared with those without overlap (37.5 vs. 1.9%, CI; 3.73-271.37, p = 0.000). CONCLUSIONS: Esophageal contrast visualization helps to reduce the potential for esophageal injury during paroxysmal AF ablation. This simple procedural adjunct has important implications to improve safety of paroxysmal AF ablation procedures globally.

Heart rate control is associated with reduced cardiovascular events in Asian patients with coronary artery disease treated with bisoprolol (BISO-CAD): results from a multi-national, real-world experience.

OBJECTIVE: To evaluate the association between decrease in resting heart rate (RHR) and occurrence of composite cardiac clinical outcomes in coronary artery disease (CAD) patients after bisoprolol treatment. METHODS: This phase IV, multi-national, single-arm, open-label, non-randomized, observational trial was conducted between October 2011 and July 2015 across 42 hospitals from China, South Korea and Vietnam. RESULTS: Analysis of 866 patients (mean age 63.85 ± 10.35; mean RHR at baseline 75.71 ± 6.87 bpm in intent-to-treat [ITT]; 75.56 ± 6.73 in efficacy analysis [EA] sets) was performed. Patients with lower mean RHR had fewer composite cardiac events and patients with RHR of 69-74 bpm reported significantly higher outcomes than patients with RHR <65 bpm (p = .0449). A significant association with occurrence of the composite cardiac outcome and hospital admission for unstable angina or revascularization was reported in the EA set (regression estimate: 0.03, 95% CI 0.00-0.07, p = .0412) and not in the ITT set for bisoprolol treated CAD patients. Composite cardiac outcomes significantly increased in patients with mean RHR ≥70 bpm compared to patients with mean RHR <70 bpm (p = .0328). Adverse events (AEs) were reported in 206 (23.8%) patients, of whom 102 (11.8%) patients had serious adverse event (SAEs). Among the patients with SAEs, 11 (1.3%) patients died. Treatment related adverse events were only 12 (1.4%). No treatment related SAE happened. CONCLUSION: The findings showed bisoprolol to be efficacious, in terms of lowering RHR and causing a significant decrease in the occurrence of the composite cardiac outcome, as well as safe in Asian patients with CAD.

A randomised comparison of biodegradable polymer- and permanent polymer-coated platinum-chromium everolimus-eluting coronary stents in China: the EVOLVE China study.

AIMS: The EVOLVE China randomised study sought to evaluate the clinical safety and effectiveness of the SYNERGY bioabsorbable polymer-coated everolimus-eluting stent (EES) for the treatment of patients with coronary heart disease in China. METHODS AND RESULTS: Eligible patients with de novo native coronary artery lesions were randomised (1:1) to receive the SYNERGY or PROMUS Element Plus stent. The primary endpoint was in-stent late loss at nine months. Secondary endpoints included death, MI, revascularisation, and stent thrombosis up to 12 months. A total of 412 subjects were randomised (205 SYNERGY; 207 PROMUS Element Plus) at 14 sites in China from October 2013 to July 2014. SYNERGY was non-inferior to PROMUS Element Plus for the primary endpoint of nine-month in-stent late loss: SYNERGY 0.20±0.33 mm vs. PROMUS Element Plus 0.17±0.38 mm with an upper one-sided 97.5% confidence interval of the difference (0.10 mm), significantly less than the non-inferiority margin (0.15 mm; p<0.0008). Clinical adverse event rates were low and not significantly different between groups at nine and 12 months (all p>0.05). CONCLUSIONS: In the EVOLVE China trial, the SYNERGY bioabsorbable polymer-coated EES was noninferior to the PROMUS Element Plus permanent polymer-coated EES for the primary endpoint of late loss at nine months.