Mode and Characteristics of Arrhythmia Initiation in Idiopathic Ventricular Fibrillation: A THESIS Substudy.

BACKGROUND: There is limited information on the mode of arrhythmia initiation in idiopathic ventricular fibrillation (IVF). A non-pause-dependent mechanism has been suggested to be the rule. OBJECTIVES: The aim of this study was to assess the mode and characteristics of initiation of polymorphic ventricular tachycardia (PVT) in patients with short or long-coupled PVT/IVF included in THESIS (THerapy Efficacy in Short or long-coupled idiopathic ventricular fibrillation: an International Survey), a multicenter study involving 287 IVF patients treated with drugs or radiofrequency ablation. METHODS: We reviewed the initiation of 410 episodes of ≥1 PVT triplet in 180 patients (58.3% females; age 39.6 ± 13.6 years) with IVF. The incidence of pause-dependency arrhythmia initiation (prolongation by >20 ms of the preceding cycle length) was assessed. RESULTS: Most arrhythmias (n = 295; 72%) occurred during baseline supraventricular rhythm without ambient premature ventricular complexes (PVCs), whereas 106 (25.9%) occurred during baseline rhythm including PVCs. Nine (2.2%) arrhythmias occurred during atrial/ventricular pacing and were excluded from further analysis. Mode of PVT initiation was pause-dependent in 45 (15.6%) and 64 (60.4%) of instances in the first and second settings, respectively, for a total of 109 of 401 (27.2%). More than one type of pause-dependent and/or non-pause-dependent initiation (mean: 2.6) occurred in 94.4% of patients with ≥4 events. Coupling intervals of initiating PVCs were <350 ms, 350-500 ms, and >500 ms in 76.6%, 20.72%, and 2.7% of arrhythmia initiations, respectively. CONCLUSIONS: Pause-dependent initiation occurred in more than a quarter of arrhythmic episodes in IVF patients. PVCs having long (between 350 and 500 ms) and very long (>500 ms) coupling intervals were observed at the initiation of nearly a quarter of PVT episodes.

Impact of single versus double transseptal puncture on outcome and complications in pulmonary vein isolation procedures.

BACKGROUND: The aim of the current study was to analyze the impact of single versus double transseptal puncture (TSP) for atrial fibrillation (AF) ablation. METHODS: Consecutive patients undergoing AF ablation were prospectively included in the AF ablation registry and were analyzed according to single versus double TSP. RESULTS: A total of 478 patients (female 35%, persistent AF 67%) undergoing AF ablation between 01/2014 and 09/2014 were included. Single TSP was performed in 202 (42%) patients, double TSP in 276 (58%) patients. Age, gender, body mass index, CHA2DS2-VASc score, left ventricular ejection fraction and operator experience (experienced operator defined as ≥ 5 years of experience in invasive electrophysiology) were equally distributed between the two groups. Repeat procedures (re-dos) were more frequently performed using single TSP access (p < 0.001). Left atrial (LA) diameter was larger in patients with double TSP (p = 0.001). Procedure duration in single TSP was identical to double TSP procedures (p = 0.823). Radiation duration was similar between the two groups (p = 0.217). There were 49 (10%) patients with complications after catheter ablation. There were no differences between complication rates and TSP type (p = 0.555). Similarly, recurrence rates were comparable between both TSP groups (p = 0.788). CONCLUSIONS: There was no clear benefit of single or double TSP in AF ablation.

Atrial Fibrillation and Cognitive Impairment: New Insights and Future Directions.

INTRODUCTION: Atrial fibrillation (AF) has been recognised as the most prevalent sustained arrhythmia. Recently, a growing body of evidence has suggested that AF might be involved in the progression of cognitive impairment (CIM), potentially extending into types of dementia. Accordingly, the purpose of the present study was to summarise the findings of investigations examining association between AF and cognitive function as well as highlighting the possible causes of discrepancy between the findings and reviewing the probable mechanisms of CIM in patients affected with AF. METHODS: A systematic search in the literature was conducted in the databases of PubMed, Scopus, Cochrane Library, and Google Scholar with no language restrictions, using specified search terms to identify studies published between 1 January 1990 and 1 April 2018. Then, study designs, participant information, diagnostic approaches used for cognitive assessments, and incidence/prevalence rates of CIM and/or dementia were assessed. RESULTS: Out of the initial 2,364 articles retrieved, a total number of 40 studies were selected for data collection. Most studies had suggested a significant relationship between AF and CIM. In this regard, cerebral hypo-perfusion, altered cerebral blood flow, cerebral micro-bleeds, micro-emboli, vascular inflammation, cerebral small vessel diseases, vascular inflammation, and genetic factors were considered as the possible mechanisms of CIM in patients suffering from AF. It seemed that differences in study settings and designs, variations of diagnostic tools for CIM and AF, as well as underlying conditions such as age groups, concurrent chronic diseases, and therapeutic interventions for AF might be amongst probable factors justifying the diversity of findings across the selected articles. CONCLUSION: Although evidence is much more directed towards an association between AF and CIM, the role of AF in CIM needs to be confirmed in-depth via longer prospective and cohort studies at larger scales using accurate neuropsychological and cognitive function assessments. Moreover, the mechanisms involved in the relationship between AF and Alzheimer's disease (AD) require further studies. To conclude, the effect of different therapeutic strategies of AF on CIM should be investigated in more clinical trials.

Epicardial adipose tissue thickness as an independent predictor of ventricular tachycardia recurrence following ablation.

BACKGROUND: Although several investigations have shown a relationship between increased epicardial adipose tissue (EAT) and atrial fibrillation (AF), the association between EAT and ventricular tachycardia (VT) has not been evaluated. OBJECTIVE: We investigated the association between EAT and postablation VT recurrence. METHODS: Sixty-one consecutive patients (mean age = 62.0 ± 13.9 years) undergoing VT ablation with preprocedural cardiovascular magnetic resonance imaging (CMR) were recruited. EAT thickness was measured using CMR in the right and left atrioventricular grooves (AVGs), right ventricular free wall, and anterior, inferior, and superior interventricular grooves. RESULTS: During a mean follow-up period of 392.9 ± 180.2 days, postablation VT recurrence occurred in 15 (24.6%) patients. EAT thickness was significantly higher in the VT recurrence group than in the nonrecurrent VT group at the right (18.7 ± 5.7 mm vs 14.1 ± 4.4 mm; P = .012) and left (13.3 ± 3.9 mm vs 10.4 ± 4.1 mm; P = .020) AVGs. The best cut-off points for predicting VT recurrence were calculated as 15.5 mm for the right AVG (area under receiver operating characteristic [ROC] curve = 0.74) and 11.5 mm for the left AVG (area under ROC curve = 0.72). Multivariate Cox regression analysis showed that preprocedural right AVG-EAT (hazard ratio: 1.2; 95% confidence interval: [1.06-1.39], P = .004) was the only independent predictor of VT recurrence after adjustment for covariates. Kaplan-Meier analysis showed a difference for postablation VT recurrence between the 2 groups, with right AVG-EAT thickness cut-off value of <15.5 mm vs ≥15.5 mm (log-rank, P = .003). CONCLUSIONS: We suggested a new possible imaging marker for risk stratification of postablation VT recurrence. A higher EAT may be associated with VT recurrence after catheter ablation of VTs.

Value of Cardiogoniometry in Diagnosis of Coronary Artery Disease in Patients with Suspected Stable Ischemic Heart Disease: A Systematic Review and Meta-Analysis.

Cardiogoniometry (CGM) has been proposed as a new diagnostic tool for coronary artery disease (CAD) in recent years. Although different studies have evaluated the diagnostic value of CGM in CAD diagnosis, no pooled analysis of its diagnostic accuracy has been performed so far. This study aimed to assess the value of CGM in diagnosing CAD in patients with suspected stable ischemic heart disease (SIHD).This was a systematic review and meta-analysis conducted on available literature until May 2018. Studies considered coronary angiography as the reference standard for CAD diagnosis and reported CGM diagnostic value parameters were included. No language and time restrictions for enrolling the studies were considered. Statistical analysis was performed using Meta-DiSc software.The findings of the 10 studies published in 9 articles were enrolled in the meta-analysis. Overall pooled sensitivity was 71.7% (69.1 to 74.1; Cochrane Q = 39.5; P < 0.00001; I2 = 77.3%), and pooled specificity was 78.8% (76.3 to 81.1; Cochrane Q = 37.39; P < 0.00001; I2 = 75.9%). Regarding Egger's regression test (P = 0.32), there was no published bias in the studies.It seems that CGM, as an easy-to-use and non-invasive modality, should be considered as a part of risk stratifying strategies for CAD in patients with SIHD, mainly in patients with contraindications for stress tests. However, further studies with a high quality of methodology are still needed to assess the diagnostic value of CGM for CAD in patients with suspected SIHD.

Is epicardial fat tissue associated with atrial fibrillation recurrence after ablation? A systematic review and meta-analysis.

INTRODUCTION: Although an undoubted association between epicardial fat tissue (EFT) and atrial fibrillation (AF) has been recently approved, the association between EFT and post-ablation AF recurrence is not evident yet. This study aimed to assess the association between EFT and AF recurrence after ablation. METHODS: The present study was a systematic review and meta-analysis using related literature available in electronic databases until July 2018 via "atrial fibrillation" and "epicardial fat" as the main keywords. Considering the different methods of EFT measurement, three different pooled meta-analyses were conducted in this study including: 1) comparison of total EFT volume, 2) left atrium (LA)-EFT volume, and 3) EFT thickness between two groups with and without AF recurrence estimating standardized mean difference (SMD) through a random and non-random effect meta-analysis. Statistical analysis was also performed using Comprehensive Meta-analysis (CMA) Software. RESULTS: Following a search into a total number of 518 articles, the findings of 12 studies published in 10 articles were enrolled in this meta-analysis. Accordingly, the results of meta-analysis showed that LA-EFT and total EFT volumes were higher in recurrent subjects (LA-EFT: SMD = 0.862 ml; I2 = 0.00, 95% confidence interval (CI) = 0.567-1.156; total EFT: SMD = 1.017 ml, I2 = 0.00, 95% CI = 0.748-1.286). Besides, a significant higher EFT thickness in patients with AF recurrence compared to those with no AF recurrence was observed (SMD = 0.808 mm, I2 = 91.07, 95% CI = 0.215-1401). CONCLUSION: The total EFT and LA-EFT volumes, as well as EFT thickness, seemed to be associated with AF recurrence in patients undergoing AF ablation.

Treatment of hypercholesterolaemia with PCSK9 inhibitors in patients after cardiac transplantation.

BACKGROUND: Hypercholesterolaemia is common in patients after cardiac transplantation. Monoclonal antibodies that inhibit proprotein convertase subtilisin-kexin type 9 (PCSK9) reduce low-density lipoprotein (LDL) cholesterol levels and subsequently the risk of cardiovascular events in patients with dyslipidaemia. There are no published data on the effect of this medication class on cholesterol levels in patients after cardiac transplantation. METHODS: In this retrospective study we investigated patients who were treated with PCSK9 inhibitors either because of intolerance of statins or residual hypercholesterolaemia with evidence of cardiac allograft vasculopathy. We compared the data of patients prior to the start with these medications with their most recent dataset. RESULTS: Ten patients (nine men; mean age 58±6 years) underwent cardiac transplantation 8.3±4.5 (range 3-15) years ago. The treatment duration of Evolocumab or Alirocumab was on average 296±125 days and lead to a reduction of total Cholesterol (281±52 mg/dl to 197±36 mg/dl; p = 0.002) and LDL Cholesterol (170±22 mg/dl to 101±39 mg/dl; p = 0.001). No significant effects on HDL Cholesterol, BNP, Creatin Kinase or hepatic enzymes were noticed. There were no unplanned hospitalisations, episodes of rejections, change of ejection fraction or opportunistic infections. Both patients on Alirocumab developed liver pathologies: One patient died of hepatocellular carcinoma and the other developed hepatitis E. CONCLUSIONS: Our study demonstrates that the PCSK9 inhibitors Evolocumab and Alirocumab lead to a significant reduction of LDL Cholesterol in heart transplantation recipients. No effect on cardiac function or episodes of rejections were noticed. Larger and long-term studies are needed to establish safety and efficacy of PCSK9 inhibitors after cardiac transplantation.

Catheter ablation of atrial fibrillation with nonfluoroscopic catheter visualization-a prospective randomized comparison.

PURPOSE: The application of a novel platform for nonfluoroscopic catheter sensor tracking within pre-recorded x-ray loops in the context of catheter ablation of atrial fibrillation (AF) demonstrated significant potential for reduction of fluoroscopy. We sought to provide the first prospective randomized comparison of fluoroscopy needs, procedure times, and complications in AF catheter ablation with or without additional use of nonfluoroscopic catheter visualization (NFCV). METHODS: Patients with AF were randomized into two groups before scheduled radiofrequency ablation: (1) using established mapping systems and fluoroscopy as needed (CONV group) or (2) with additional NFCV (NFCV group). All procedures were performed in the same lab using the same ablation catheter tip technology and the same mapping and ablation strategies. Primary endpoints were radiation time and dose. Secondary endpoints were procedural parameters, complications, and long-term success. RESULTS: A total of 80 patients (48 male patients, mean age 60 years, 46 patients with paroxysmal AF) were randomized into the two groups. Clinical parameters between both groups were similar. NFCV use reduced mean fluoroscopy time (1.9 vs. 13.2 min, p < 0.001) and mean dose (510 vs. 1549 Gycm2, p < 0.001) significantly. Procedural parameters were similar in the two groups. One conservatively treated groin complication occurred (1.3%). CONCLUSIONS: Radiation exposure can be significantly reduced by using the novel NFCV technology in addition to standard AF ablation technologies without negative effects on procedure durations, success rates, or complication rates. With the use of the technology, abandonment of lead protection for EP staff is possible following transseptal puncture.

Catheter ablation of atrial fibrillation supported by novel nonfluoroscopic 4D navigation technology.

BACKGROUND: The MediGuide technology (MGT) represents a novel sensor-based electromagnetic 4-dimensional (4D) navigation system allowing real-time catheter tracking in the environment of prerecorded X-ray loops. OBJECTIVE: To report on our clinical experience in atrial fibrillation (AF) ablation with recently available MGT-enabled ablation catheters. METHODS: The MGT was used in addition to a conventional 3D mapping system in 80 patients with AF (age 61 ± 10 years; 47 men; 40 with persistent AF), who underwent circumferential pulmonary vein isolation and voltage mapping with and without substrate modification. Short native right anterior oblique/left anterior oblique loops were used as background movies for the nonfluoroscopic placement of sensor-equipped diagnostic catheters into the coronary sinus and the right ventricle. After single transseptal puncture, selective angiograms of the pulmonary veins were used as background movies for near nonfluoroscopic left atrial reconstruction. Computed tomography registration as well as mapping/ablation was performed by using the new open-irrigated MGT-enabled ablation catheter. RESULTS: MGT application was not associated with a change in established workflow. Large parts of the procedure (mean entire duration 167 ± 47 minutes) could be done without additional fluoroscopy, whereas median residual fluoroscopy duration of 4.6 (interquartile range: 2.9, 7.1) minutes was mainly used for the acquisition of background loops, transseptal puncture, occasional verification of transseptal sheath position, and manipulation of the circular mapping catheter. Three (4%) minor complications occurred. CONCLUSIONS: The MGT integrates easily into the workflow of standard AF ablation and allows for high-quality nonfluoroscopic 4D catheter tracking. This results in low radiation exposure for patients and staff without complicating the workflow of the procedure.