Electrophysiological significance of the interatrial conduction including cavo-tricuspid isthmus during atrial fibrillation.

KEY POINTS: The interatrial conduction, including Bachmann's bundle, the posterior septal conduction, the anterior septal conduction, and the cavo-tricuspid isthmus, contributes to the maintenance mechanisms of atrial fibrillation in a 3D biatrial model. The interatrial conduction ablation including a cavo-tricuspid isthmus ablation significantly affects the wave dynamics of atrial fibrillation (AF) and facilitates the AF termination or atrial tachycardia conversion of the AF after the circumferential pulmonary vein isolation. Additional cavo-tricuspid isthmus ablation after the circumferential pulmonary vein isolation improves long-term rhythm outcome after clinical AF catheter ablation. ABSTRACT: Although it is known that atrial fibrillation (AF) is mainly a left atrial (LA) disease, the role of the right atrium (RA) and interatrial conduction (IAC), including the cavo-tricuspid isthmus (CTI), has not been clearly defined. We tested AF wave dynamics with or without IAC in computational modelling and the rhythm outcome of AF catheter ablation (AFCA) including CTI ablation in clinical cohort data. We evaluated the dominant frequency (DF) in 3D biatrial AF simulations integrated with 3D-computed tomograms obtained from 10 patients. The IAC was implemented at Bachmann's bundle, posterior septum and the CTI. After virtual circumferential PV isolation (CPVI), we disconnected IACs one by one, and observed the wave dynamics. We compared the long-term rhythm outcome after CPVI alone and additional CTI ablation in 846 patients with AFCA. LA-DF was higher than RA-DF in AF (P < 0.001). After CPVI, the DF decreased significantly by additional IAC ablation (P = 0.003), especially in the LA (P = 0.016). The amount of DF reduction (P = 0.020) and rates of AF termination (P < 0.001) or AT conversion (P = 0.021) were significantly higher after IAC ablations including CTI than those without. In clinical AFCA, the AF recurrence rate was significantly lower in patients with additional CTI ablation than CPVI alone during 25 ± 20 months' follow-up (hazard ratio 0.60 [0.46-0.79], P < 0.001, Log rank P < 0.001). IAC contributes to the maintenance mechanism of AF, and IAC including CTI ablation affects AF wave dynamics, facilitating AF termination in 3D biatrial modelling. Additional CTI ablation after CPVI improves the long-term rhythm outcome in clinical AFCA, potentially in a paroxysmal type with accompanying atrial flutter, or atrial dimension close to normal.

Optimal Duration for Dual Antiplatelet Therapy After Left Main Coronary Artery Stenting.

BACKGROUND: Coronary interventions using drug-eluting stents (DESs) of left main coronary artery (LMCA) lesions have shown favorable clinical outcomes. However, duration of dual antiplatelet therapy (DAPT) after LMCA interventions has not yet been investigated.Methods and Results:From a multicenter Korean Multicenter Angioplasty Team (KOMATE) registry, 1,004 patients who received DES implantations for LMCA lesions and did not experience major adverse cardiovascular events (including major bleeding) for 1 year after coronary intervention were analyzed. Patients were divided into 2 groups; DAPT ≤12 (n=503) and >12 months (n=501). The primary endpoint was number of net clinical adverse events (NACEs), composite of cardiac deaths, myocardial infarctions, stent thrombosis and major bleeding events. During a 4.5-year follow-up period after LMCA interventions, the DAPT >12 months group showed a lower NACE rate than the DAPT ≤12 months group (adjusted-HR 0.53 [0.29-0.99], P=0.045). For patients who maintained DAPT >12 months, rate of cardiac deaths, myocardial infarctions, and stent thrombosis events were lower than in patients who had DAPT ≤12 months (adjusted-HR 0.35 [0.17-0.73], P=0.005) without increased major bleeding (P=0.402). CONCLUSIONS: For patients who can continue DAPT without major bleeding events, prolonged DAPT (>12 months) after LMCA stenting demonstrated better long-term efficacy outcomes than DAPT ≤12 months with comparable safety.

Dual antiplatelet therapy after percutaneous coronary intervention for left main coronary artery disease.

INTRODUCTION AND OBJECTIVES: There are scarce data on the optimal duration and prognostic impact of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) with second-generation drug-eluting stents for left main coronary artery (LMCA) disease. The aim of this study was to investigate the practice pattern and long-term prognostic effect of DAPT duration in patients undergoing PCI with second-generation drug-eluting stents for LMCA disease. METHODS: Using individual patient-level data from the IRIS-MAIN and KOMATE registries, 1827 patients undergoing PCI with second-generation drug-eluting stents for LMCA disease with valid information on DAPT duration were included. The efficacy outcome was major adverse cardiovascular events (MACE, a composite of cardiac death, myocardial infarction, and stent thrombosis) and the safety outcome was TIMI major bleeding. RESULTS: DAPT duration was <6 months (n=273), 6 to 12 months (n=477), 12 to 24 months (n=637), and ≥ 24 months (n=440). The median follow-up duration was 3.9 [interquartile range, 3.01-5.00] years. Prolonged DAPT duration was associated with lower incidences of MACE. In multigroup propensity score analysis, adjusted HR for MACE were significantly higher for DAPT <6 months and DAPT 6 to 12 months than for DAPT 12 to 24 months (HR, 4.51; 95%CI, 2.96-6.88 and HR 1.92; 95%CI, 1.23-3.00). There was no difference in HR for major bleeding among the assessed groups. CONCLUSIONS: DAPT duration following PCI for LMCA disease is highly variable. Although the duration of DAPT should be considered in the context of the clinical situation of each patient, <12 months of DAPT was associated with higher incidence of MACE. Registration identifiers: NCT01341327; NCT03908463.

Non-vitamin K antagonist oral anticoagulants have better efficacy and equivalent safety compared to warfarin in elderly patients with atrial fibrillation: A systematic review and meta-analysis.

BACKGROUND: To evaluate the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) in elderly patients (aged ≥75 years) with atrial fibrillation (AF), depending on dose and/or renal function. METHODS: After systematically searching the databases (Medline, EMBASE, CENTRAL, SCOPUS, and Web of Science), 5 phase III randomized controlled trials and reported data according to subgroups of elderly/non-elderly AF patients, comparing any NOACs and warfarin were included. The primary efficacy and safety outcomes were stroke/systemic thromboembolism and major bleeding. RESULTS: (1) NOACs showed better efficacy than warfarin in elderly patients [RR 0.83 (0.69-1.00), p=0.04, I2=55%], but equivalent efficacy in non-elderly patients. (2) NOACs reduced major bleeding compared to warfarin in non-elderly (p<0.001) and had comparable safety to warfarin in elderly patients. (3) Even in elderly patients with moderately impaired renal function, NOACs had a safety profile comparable to that of warfarin for major bleeding if dose reduction was reached appropriately [pooled RR 0.82 (0.35-1.88), p=0.63, I2=63%]. (4) All-cause mortality was lower with NOACs in non-elderly patients [RR 0.89 (0.83-0.95), p=0.001, I2=0%], and with standard-dose NOAC group of elderly patients [RR 0.93 (0.86-1.00), p=0.04, I2=0%] compared to warfarin. CONCLUSIONS: For elderly patients (aged ≥75 years), NOACs showed better efficacy and equivalent safety compared to warfarin even in those with moderately impaired renal function. All-cause mortality was lower with standard-dose NOACs compared to warfarin in the elderly patient group. SYSTEMATIC REVIEW REGISTRATION: The protocol of this meta-analysis was registered on PROSPERO under CRD42016047922 (https://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42016047922).