Fascicular Substrate Modification to Treat Human Ventricular Fibrillation.

BACKGROUND: Purkinje fibers play an important role in initiation and maintenance of ventricular fibrillation (VF) and polymorphic ventricular tachycardia (PMVT). Fascicular substrate modification (FSM) approaches have been suggested to treat recurrent VF in case reports and small case series. OBJECTIVES: The aim of this study was to investigate outcomes of catheter-based FSM to treat VF and PMVT. METHODS: Of 2,212 consecutive patients with ventricular arrhythmia undergoing catheter ablation, 18 (0.81%) underwent FSM of the Purkinje fibers as identified with high-density mapping during sinus rhythm. Fascicular substrate and VF initiation were mapped using a multipolar catheter. The endpoint of the ablation was noninducibility of VF and PMVT. In select patients, remapping revealed elimination of the targeted Purkinje potentials. Demographic, clinical, and follow-up characteristics were prospectively collected in our institutional database. RESULTS: A total of 18 patients (mean age 56 ± 3.8 years, 22% women) were included in the study. Of those, 11 (61.1%) had idiopathic VF, 3 (16.7%) had nonischemic cardiomyopathy, and 4 (22.2%) had mixed cardiomyopathy. The average left ventricular ejection fraction was 42.5%. At least 2 antiarrhythmic drugs had failed preablation. At baseline, all patients had inducible VF or PMVT. At the end of the procedure, no patient demonstrated new evidence of fascicular block or bundle branch block. There were no procedure-related complications. After a median follow-up period of 24 months, 16 patients (88.9%) were arrhythmia free on or off drugs: 11 of 11 patients (100%) with idiopathic VF vs 5 of 7 patients (71.4%) with underlying cardiomyopathy (P = 0.06). CONCLUSIONS: Catheter ablation of human VF and PMVT with FSM is feasible and safe and appears highly effective, with high rates of acute VF noninducibility and long-term freedom from recurrent VF.

Identifying Origin of Nonpulmonary Vein Triggers Using 2 Stationary Linear Decapolar Catheters: A Novel Algorithm.

BACKGROUND: Targeting nonpulmonary vein triggers (NPVTs) of atrial fibrillation (AF) after pulmonary vein isolation can be challenging. NPVTs are often single ectopic beats with a surface P-wave obscured by a QRS or T-wave. OBJECTIVES: The goal of this study was to construct an algorithm to regionalize the site of origin of NPVTs using only intracardiac bipolar electrograms from 2 linear decapolar catheters positioned in the posterolateral right atrium (along the crista terminalis with the distal bipole pair in the superior vena cava) and in the proximal coronary sinus (CS). METHODS: After pulmonary vein isolation in 42 patients with AF, pacing from 15 typical anatomic NPVT sites was conducted. For each pacing site, the electrogram activation sequence was analyzed from the CS catheter (simultaneous/chevron/inverse chevron/distal-proximal/proximal-distal) and activation time (ie, CSCTAT) between the earliest electrograms from the 2 decapolar catheters was measured referencing the earliest CS electrogram; a negative CSCTAT value indicates the crista terminalis catheter electrogram was earlier, and a positive CSCTAT value indicates the CS catheter electrogram was earlier. A regionalization algorithm with high predictive value was defined and tested in a validation cohort with AF NPVTs localized with electroanatomic mapping. RESULTS: In the study patient cohort (71% male; 43% with persistent AF, 52% with left atrial dilation), the algorithm grouped with high precision (positive predictive value 81%-99%, specificity 94%-100%, and sensitivity 30%-94%) the 15 distinct pacing sites into 9 clinically useful regions. Algorithm testing in a 98 patient validation cohort showed predictive accuracy of 91%. CONCLUSIONS: An algorithm defined by the activation sequence and timing of electrograms from 2 linear multipolar catheters provided accurate regionalization of AF NPVTs to guide focused detailed mapping.

Predictors of cardiovascular implantable electronic device dependence at long-term follow-up after alcohol septal ablation in hypertrophic cardiomyopathy patients.

BACKGROUND: The most common complication of alcohol septal ablation (ASA) is transient periprocedural high-grade AV block (HGAVB). To date, no long-term follow-up of cardiovascular implantable electronic device (CIED) utilization after ASA has been reported. We hypothesized that CIED dependence on long-term follow-up can be predicted by ECG or procedural characteristics. METHODS: We analyzed all patients with HCM who underwent ASA from December 1998 to December 2019 and received their first CIED within 30 days after ASA for HGAVB. All follow-up interrogations were reviewed. CIED dependence was defined as ventricular pacing of ≥ 5%. RESULTS: A total of 138 patients with HCM underwent ASA. Of these, 35 had a prior device and were excluded. Of the remaining 103 patients, 25 patients received a CIED for HGAVB within 30 days after ASA. Average follow-up duration was 10.1 years. On long-term follow-up, 16 patients (64%) were found to be CIED-dependent. Baseline characteristics, including pre- and post-ASA ECG, were not significantly different between dependent and non-dependent patients. The only predictor for CIED dependence was > 1 ml of alcohol injected (OR 6.0, p = 0.031). CONCLUSIONS: CIED implantation after ASA is common. Almost two thirds of patients who received a CIED for post-procedural HGAVB were CIED-dependent on long-term follow-up. CIED dependence can be predicted by the amount of injected alcohol > 1 ml.

Catheter ablation of intramural outflow tract premature ventricular complexes: a multicentre study.

AIMS: Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs). METHODS AND RESULTS: This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation. CONCLUSION: Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.

Focal Atrial Tachycardia Arising From the Posterior Wall of the Left Atrium.

Potential foci for atrial tachycardia have been previously described in various locations including crista terminalis, tricuspid annulus, coronary sinus ostium, pulmonary vein ostia. In this report, we present a case of a focal atrial tachycardia arising from the posterior wall of the left atrium which has not been described before. (Level of Difficulty: Advanced.).

Outcome of high-power short-duration radiofrequency ablation in combination with half-normal saline irrigation for the treatment of atrial fibrillation.

BACKGROUND: Data regarding the use of high-power short-duration (HPSD) radiofrequency (RF) in combination with half-normal saline irrigation for catheter irrigation are limited. OBJECTIVES: This study investigated the safety and efficacy of using HPSD RF ablation in combination with half-normal saline irrigation for the treatment of AF. METHODS: One hundred consecutive patients with AF underwent RF ablation using HPSD combined with half-normal saline for catheter irrigation. In addition, the following ablation strategies were used: 1 mm tags for the display of ablation lesions on the mapping system, high-frequency jet ventilation (HFJV), low contact force, pacing after ablation to verify areas of noncapture, atrial/ventricular pacing at 500 to 700 ms to aid in catheter stability, use of two skin electrodes to reduce impedance, and postablation adenosine infusion. Power was started at 40 to 45 W and was modulated manually based on impedance changes. RESULTS: The average age of patients was 65.2 years and 70% were male. Forty seven percent had paroxysmal AF and the average CHA2 DS2 -VASc score was 2.1 ± 1.6. The average power and lesion duration were 38.1 ± 3.3 W and 8.1 ± 2.3 s, respectively. During a median follow-up period of 321 ± 139 days, 89% of the patients remained free from any atrial arrhythmias after a single RF ablation procedure. No procedure-related death, stroke, pericardial effusion, or atrioesophageal fistula occurred during follow-up. CONCLUSIONS: Catheter ablation using HPSD RF lesions in combination with half-normal saline irrigation and is safe and effective, and results in high rate of freedom from AF.

Management of Atrial Fibrillation in the Emergency Department.

PURPOSE OF REVIEW: Atrial fibrillation (AF) is the most common arrhythmia in adults and is responsible for 600,000 emergency department (ED) visits each year in the USA. Over 60% of these patients are admitted to inpatient units. The prevalence of AF is increasing, resulting in higher numbers of AF-related ED visits and inpatient admissions. These trends underscore the need for improvements in the efficiency of AF management in the ED. RECENT FINDINGS: Several treatment protocols have been developed to address challenges associated with AF management in the ED, including: initiation of oral anticoagulant (OAC) therapy, cardioversion, and arranging for outpatient follow-up. Studies of these protocols have demonstrated that they can be utilized safely and effectively. Published treatment protocols for AF in the ED have been shown to reduce unnecessary hospital admissions and improve adherence to guideline-directed OAC therapy. Widespread adoption of AF treatment protocols could improve patient outcomes and reduce the costs associated with inpatient AF treatment.

Comparative Effectiveness of Implantable Defibrillators for Asymptomatic Brugada Syndrome: A Decision-Analytic Model.

Background Optimal management of asymptomatic Brugada syndrome (BrS) with spontaneous type I electrocardiographic pattern is uncertain. Methods and Results We developed an individual-level simulation comprising 2 000 000 average-risk individuals with asymptomatic BrS and spontaneous type I electrocardiographic pattern. We compared (1) observation, (2) electrophysiologic study (EPS)-guided implantable cardioverter-defibrillator (ICD), and (3) upfront ICD, each using either subcutaneous or transvenous ICD, resulting in 6 strategies tested. The primary outcome was quality-adjusted life years (QALYs), with cardiac deaths (arrest or procedural-related) as a secondary outcome. We varied BrS diagnosis age and underlying arrest rate. We assessed cost-effectiveness at $100 000/QALY. Compared with observation, EPS-guided subcutaneous ICD resulted in 0.35 QALY gain/individual and 4130 cardiac deaths avoided/100 000 individuals, and EPS-guided transvenous ICD resulted in 0.26 QALY gain and 3390 cardiac deaths avoided. Compared with observation, upfront ICD reduced cardiac deaths by a greater margin (subcutaneous ICD, 8950; transvenous ICD, 6050), but only subcutaneous ICD improved QALYs (subcutaneous ICD, 0.25 QALY gain; transvenous ICD, 0.01 QALY loss), and complications were higher. ICD-based strategies were more effective at younger ages and higher arrest rates (eg, using subcutaneous devices, upfront ICD was the most effective strategy at ages 20-39.4 years and arrest rates >1.37%/year; EPS-guided ICD was the most effective strategy at ages 39.5-51.3 years and arrest rates 0.47%-1.37%/year, and observation was the most effective strategy at ages >51.3 years and arrest rates <0.47%/year). EPS-guided subcutaneous ICD was cost-effective ($80 508/QALY). Conclusions Device-based approaches (with or without EPS risk stratification) can be more effective than observation among selected patients with asymptomatic BrS. BrS management should be tailored to patient characteristics.

Catheter Ablation for Brugada Syndrome.

We report a case of catheter ablation of Brugada syndrome in a patient with refractory ventricular fibrillation despite quinidine therapy. We performed epicardial substrate mapping, which identified an area of abnormal fractionated, prolonged electrogram in the anterior right ventricular outflow tract. Warm saline infusion into the pericardial space induced further delay of the local electrogram, consistent with Brugada syndrome physiology. Coronary angiography confirmed that the area was distant from major coronary arteries. Ablation was performed in this area, which eliminated local abnormal electrograms and led to the disappearance of coved-type ST elevation in V1-V2. No ventricular fibrillation had recurred by five months of follow-up.

Comparison between TightRail rotating dilator sheath and GlideLight laser sheath for transvenous lead extraction.

BACKGROUND: There are limited data on the comparative analyses of TightRail rotating dilator sheath (Philips) and laser sheath for lead extraction. OBJECTIVE: To evaluate the effectiveness and safety of the TightRail sheath as a primary or secondary tool for transvenous lead extraction (TLE). METHODS: Retrospective cohort analysis of 202 consecutive patients who underwent TLE using either TightRail sheath and/or GlideLight laser sheath (Philips) in our hospital. The study population was divided into three groups: Group A underwent TLE with laser sheath only (N = 157), Group B with TightRail sheath only (N = 22), and Group C with both sheaths (N = 23). RESULTS: During this period, 375 leads in 202 patients were extracted, including 297 leads extracted by laser sheath alone, 45 leads by TightRail sheath alone, and 33 by both TightRail sheath and laser sheaths. The most common indications included device infection (44.6%) and lead-related complications (44.1%). The median age of leads was 8.9 years. TightRail sheath (Group B) achieved similar efficacy as a primary extraction tool compared with laser sheath (Group A), with complete procedure success rate of 93.3% (vs. 96.6%, P = .263) and clinical success rate of 100.0% (vs. 98.1%, P = .513). Among 32 leads in which Tightrail was used after laser had failed (Group C), the complete procedure success rate was 75.8%. No significant difference in procedural adverse events was observed. CONCLUSION: Our single-center experience confirms that the TightRail system is an effective first-line and second-line method for TLE. Further investigation is required to guide the selection of mechanical and laser sheaths in lead extraction cases.

Management of patients with interrupted inferior vena cava requiring electrophysiology procedures.

BACKGROUND: Interrupted inferior vena cava (IVC) is a rare venous anomaly that complicates the treatment of patients who require electrophysiology (EP) procedures. METHODS: We describe five consecutive cases of patients with interrupted IVC who presented to the EP laboratory requiring interventional procedures including catheter ablation for atrial fibrillation and supraventricular tachycardia and left atrial appendage closure. All cases were successfully completed utilizing a variety of approaches to vascular access including transseptal puncture via transhepatic and internal jugular approaches. CONCLUSION: Procedures in the EP lab can be performed successfully in patients with interrupted IVC.

The factor Xa inhibitor rivaroxaban reduces cardiac dysfunction in a mouse model of myocardial infarction.

INTRODUCTION: Rivaroxaban selectively inhibits factor Xa (FXa), which plays a central role in blood coagulation. In addition, FXa activates protease-activated receptor-2 (PAR-2). We have shown that PAR-2-/- mice exhibit less cardiac dysfunction after cardiac injury. MATERIAL AND METHODS: Wild-type (WT) and PAR-2-/- mice were subjected to left anterior descending artery (LAD) ligation to induce cardiac injury and heart failure. Mice received either placebo or rivaroxaban chow either starting at the time of surgery or 3 days after surgery and continued up to 28 days. Cardiac function was measured by echocardiography pre-surgery and 3, 7 and 28 days after LAD ligation. We also measured anticoagulation, intravascular thrombi, infarct size, cardiac hypertrophy and inflammation at various times. RESULTS: Rivaroxaban increased the prothrombin time and inhibited the formation of intravascular thrombi in mice subjected to LAD ligation. WT mice receiving rivaroxaban immediately after surgery had similar infarct sizes at day 1 as controls but exhibited significantly less impairment of cardiac function at day 3 and beyond compared to the placebo group. Rivaroxaban also inhibited the expansion of the infarct at day 28. Rivaroxaban did not significantly affect the expression of inflammatory mediators or a neutrophil marker at day 2 after LAD ligation. Delaying the start of rivaroxaban administration until 3 days after surgery failed to preserve cardiac function. In addition, rivaroxaban did not reduce cardiac dysfunction in PAR-2-/- mice. CONCLUSIONS: Early administration of rivaroxaban preserves cardiac function in mice after LAD ligation.

Prominent R wave in ECG lead V1 predicts improvement of left ventricular ejection fraction after cardiac resynchronization therapy in patients with or without left bundle branch block.

BACKGROUND: QRS morphology on postprocedural ECG indicating posterolateral left ventricular pacing may be predictive of response to cardiac resynchronization therapy (CRT). OBJECTIVE: The purpose of this study was to assess whether a positive vector in V1 and/or negative vector in lead I on the first postprocedural ECG, suggesting posterolateral capture from CRT, correlates with improvement in left ventricular ejection fraction (LVEF). METHODS: A retrospective chart review was conducted on all patients who underwent CRT implantation at our institution between April 2008 and December 2011. Biventricular (BiV) paced QRS morphology was defined as R/S ≥1 in V1 and/or R/S ≤ 1 in lead I. The primary outcome was improvement of LVEF ≥7.5%. The χ(2) and t tests were used for analysis. RESULTS: Of 68 patients, 49 (72%) met our BiV paced QRS morphology criteria. Thirty-four of these 49 patients (69%) had improvement in LVEF. Of the 19 patients who did not meet our criteria, 17 (89%) did not have an improvement in LVEF (sensitivity 94%, specificity 53%, χ(2) = 19.04, P < .0001). The average LVEF improvement in patients who met our BiV paced QRS morphology criteria was significantly greater than in those who did not (14.27% vs 2.63%, P = .0001). Preprocedural left bundle branch block was not a predictor of echocardiographic response. CONCLUSION: Our results highlight the importance of periprocedural ECG analysis to optimize response to CRT. Moreover, patients without left bundle branch block still benefited from CRT if they met our BiV paced morphology criteria. This suggests that postprocedural left ventricular activation as reflected on the ECG may supersede the baseline conduction delay.

Left atrial appendage occlusion for prevention of stroke in nonvalvular atrial fibrillation: a meta-analysis.

PURPOSE: When anticoagulation for stroke prevention is contraindicated, left atrial appendage occlusion (LAAO) may be performed. Studies of LAAO have been limited by their small size, disparate patient populations, and lack of control group. Our purpose was to perform a meta-analysis of the safety and efficacy of LAAO in comparison with standard therapy for stroke prevention in nonvalvular AF. METHODS: Due to the lack of a control group in studies of LAAO, data on stroke prevention from multiple large outcomes studies were used to produce a hypothetical control group based on clinical variables in the individual studies. Results were stratified according to LAAO device type. RESULTS: We identified 16 studies with a total of 1759 patients receiving LAAO. Summary estimates demonstrate LAAO reduced risk of stroke in comparison with no therapy or aspirin therapy [relative risk (RR), 0.34; 95 % CI, 0.25-0.46] and in comparison with warfarin therapy (RR, 0.65; 95 % CI, 0.46-0.91). Summary estimates differed based on the study used to derive the hypothetical control group. Device deployment was unsuccessful in 6.1 % of patients, and overall complication rate was 7.1 %. Efficacy and safety were similar across LAAO device type although a majority of patients in the meta-analysis received a Watchman device. CONCLUSION: Our data suggest that LAAO is a reasonable option for stroke prophylaxis in AF when anticoagulation is not an option, and the risk for stroke outweighs the risk of procedural complications. Data were limited with the use of most available devices. To better establish the risk and benefit of LAAO in comparison with standard therapy, more randomized controlled trials are necessary.