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.

A new quantitative mapping criterion to localize the ablation target of right ventricular outflow tract arrhythmias.

PURPOSE: (1) To explore the electrophysiological characteristics of the bipolar and unipolar electrogram (UEGM) of ablation targets for RVOT arrhythmias. (2) To optimize the diagnostic criteria of RVOT arrhythmia ablation targets. METHODS AND RESULTS: A consecutive series of 111 patients with RVOT arrhythmias who underwent radiofrequency catheter ablation (RFCA) were studied. The voltage of bipolar potential for ablation targets were evaluated by three-dimensional voltage mapping procedure. The max slope of the descending limb (MSDL)、local activation preceding time (LAPT), the interval of the descending limb (IDL) and the interval of MSDL (IMSDL) of the unipolar potential were then calculated and analyzed for successful targets(ST) and failed targets(FT)groups. Successful ablation was achieved in 102 patients and 9 patients failed. LAPT was higher in the ST group than that in FT group (30.0 ± 4.3 ms vs 22.8 ± 6.3 ms, P < 0.001). IMSDL was lower in the ST group than that in FT group (9.93 ± 6.32 ms vs 21.7 ± 16.1 ms, P < 0.001). IMSDL and LAPT have a predictive value for a ST (AUC 75% and 83.7%). The optimal cut off value for LAPT and IMSDL were 24.5 ms and 20 ms respectively. A better predictive value can be acquired when IMSDL and LAPT were used in combination (AUC 93.9%, Sensibility/Specificity 92.3%/84.2%). CONCLUSION: A combined use of LAPT and IMSDL may be helpful as an additional criterion for ST judgement.

Circumferential Pulmonary Vein Isolation Plus Low-Voltage Area Modification in Persistent Atrial Fibrillation: The STABLE-SR-II Trial.

BACKGROUND: Benefits of adjunctive ablation strategies beyond circumferential pulmonary vein isolation (CPVI) are uncertain in patients with persistent atrial fibrillation (PeAF). OBJECTIVES: This study sought to compare clinical outcomes of CPVI plus low-voltage area (LVA) modification during STABLE-SR (SubsTrate ABlation in the LEft Atrium during Sinus Rhythm) vs circumferential pulmonary vein isolation (CPVI) alone in patients with PeAF. METHODS: From March 2018 to August 2019, 300 patients with PeAF who underwent de novo ablation were recruited and prospectively randomized to either STABLE-SR group (n = 150) or CPVI alone (n = 150) group. In the STABLE-SR group, after CPVI, high-density voltage mapping of left atrium (LA) was performed during sinus rhythm, and additive ablation targeted LVA and complex electrograms, if any were present. All the ablations were titrated by ablation index. The primary endpoint was freedom from documented atrial arrhythmias lasting for ≥30 s without the use of antiarrhythmic drugs, after a single ablation procedure and blanking period of 3 months. RESULTS: After 18 months, atrial-arrhythmia-free survival did not differ significantly between STABLE-SR group and CPVI alone group (67.2% vs 67.4%; HR: 0.89; 95% CI: 0.55-1.36; P = 0.52). Only around one-half of the patients (50.2%) had abnormal LA substrate with a medium LVA burden of 4.6% (2.1%-9.5%). However, the success rate differs dramatically between patients with normal vs abnormal LA substrate (84.8% vs 60.9%; P < 0.001). CONCLUSIONS: Additional LVA ablation did not improve successful rates of CPVI in this PeAF cohort, of whom one-half had normal LA substrate. Voltage map could identify patients with PeAF with normal LA substrate who can achieve excellent rhythm control with CPVI alone. (CPVI Alone Versus CPVI Plus Electrophysiological Substrate Ablation in the LA During SR for the Treatment of Non-PAF [STABLE-SR_II]; NCT03448562).