Comparison between catheter ablation versus permanent pacemaker implantation as an initial treatment for tachycardia-bradycardia syndrome patients: a prospective, randomized trial.

BACKGROUND: Clinical outcomes after catheter ablation (CA) or pacemaker (PM) implantation for the tachycardia-bradycardia syndrome (TBS) has not been evaluated adequately. We tried to compare the efficacy and safety outcomes of CA and PM implantation as an initial treatment option for TBS in paroxysmal atrial fibrillation (AF) patients. METHODS: Sixty-eight patients with paroxysmal AF and TBS (mean 63.7 years, 63.2% male) were randomized, and received CA (n = 35) or PM (n = 33) as initial treatments. The primary outcomes were unexpected emergency room visits or hospitalizations attributed to cardiovascular causes. RESULTS: In the intention-to-treatment analysis, the rates of primary outcomes were not significantly different between the two groups at the 2-year follow-up (19.8% vs. 25.9%; hazard ratio (HR) 0.73, 95% confidence interval (CI) 0.25-2.20, P = 0.584), irrespective of whether the results were adjusted for age (HR 1.12, 95% CI 0.34-3.64, P = 0.852). The 2-year rate of recurrent AF was significantly lower in the CA group compared to the PM group (33.9% vs. 56.8%, P = 0.038). Four patients (11.4%) in the CA group finally received PMs after CA owing to recurrent syncope episodes. The rate of major or minor procedure related complications was not significantly different between the two groups. CONCLUSION: CA had a similar efficacy and safety profile with that of PM and a higher sinus rhythm maintenance rate. CA could be considered as a preferable initial treatment option over PM implantation in patients with paroxysmal AF and TBS. TRIAL REGISTRATION: KCT0000155.

External electrical and pharmacological cardioversion for atrial fibrillation, atrial flutter or atrial tachycardias: a network meta-analysis.

BACKGROUND: Atrial fibrillation (AF) is the most frequent sustained arrhythmia. Cardioversion is a rhythm control strategy to restore normal/sinus rhythm, and can be achieved through drugs (pharmacological) or a synchronised electric shock (electrical cardioversion). OBJECTIVES: To assess the efficacy and safety of pharmacological and electrical cardioversion for atrial fibrillation (AF), atrial flutter and atrial tachycardias. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, Conference Proceedings Citation Index-Science (CPCI-S) and three trials registers (ClinicalTrials.gov, WHO ICTRP and ISRCTN) on 14 February 2023. SELECTION CRITERIA: We included randomised controlled trials (RCTs) at the individual patient level. Patient populations were aged ≥ 18 years with AF of any type and duration, atrial flutter or other sustained related atrial arrhythmias, not occurring as a result of reversible causes. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology to collect data and performed a network meta-analysis using the standard frequentist graph-theoretical approach using the netmeta package in R. We used GRADE to assess the quality of the evidence which we presented in our summary of findings with a judgement on certainty. We calculated differences using risk ratios (RR) and 95% confidence intervals (CI) as well as ranking treatments using a P value. We assessed clinical and statistical heterogeneity and split the networks for the primary outcome and acute procedural success, due to concerns about violating the transitivity assumption. MAIN RESULTS: We included 112 RCTs (139 records), from which we pooled data from 15,968 patients. The average age ranged from 47 to 72 years and the proportion of male patients ranged from 38% to 92%. Seventy-nine trials were considered to be at high risk of bias for at least one domain, 32 had no high risk of bias domains, but had at least one domain classified as uncertain risk, and one study was considered at low risk for all domains. For paroxysmal AF (35 trials), when compared to placebo, anteroapical (AA)/anteroposterior (AP) biphasic truncated exponential waveform (BTE) cardioversion (RR: 2.42; 95% CI 1.65 to 3.56), quinidine (RR: 2.23; 95% CI 1.49 to 3.34), ibutilide (RR: 2.00; 95% CI 1.28 to 3.12), propafenone (RR: 1.98; 95% CI 1.67 to 2.34), amiodarone (RR: 1.69; 95% CI 1.42 to 2.02), sotalol (RR: 1.58; 95% CI 1.08 to 2.31) and procainamide (RR: 1.49; 95% CI 1.13 to 1.97) likely result in a large increase in maintenance of sinus rhythm until hospital discharge or end of study follow-up (certainty of evidence: moderate). The effect size was larger for AA/AP incremental and was progressively smaller for the subsequent interventions. Despite low certainty of evidence, antazoline may result in a large increase (RR: 28.60; 95% CI 1.77 to 461.30) in this outcome. Similarly, low-certainty evidence suggests a large increase in this outcome for flecainide (RR: 2.17; 95% CI 1.68 to 2.79), vernakalant (RR: 2.13; 95% CI 1.52 to 2.99), and magnesium (RR: 1.73; 95% CI 0.79 to 3.79). For persistent AF (26 trials), one network was created for electrical cardioversion and showed that, when compared to AP BTE incremental energy with patches, AP BTE maximum energy with patches (RR 1.35, 95% CI 1.17 to 1.55) likely results in a large increase, and active compression AP BTE incremental energy with patches (RR: 1.14, 95% CI 1.00 to 1.131) likely results in an increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: high). Use of AP BTE incremental with paddles (RR: 1.03, 95% CI 0.98 to 1.09; certainty of evidence: low) may lead to a slight increase, and AP MDS Incremental paddles (RR: 0.95, 95% CI 0.86 to 1.05; certainty of evidence: low) may lead to a slight decrease in efficacy. On the other hand, AP MDS incremental energy using patches (RR: 0.78, 95% CI 0.70 to 0.87), AA RBW incremental energy with patches (RR: 0.76, 95% CI 0.66 to 0.88), AP RBW incremental energy with patches (RR: 0.76, 95% CI 0.68 to 0.86), AA MDS incremental energy with patches (RR: 0.76, 95% CI 0.67 to 0.86) and AA MDS incremental energy with paddles (RR: 0.68, 95% CI 0.53 to 0.83) probably result in a decrease in this outcome when compared to AP BTE incremental energy with patches (certainty of evidence: moderate). The network for pharmacological cardioversion showed that bepridil (RR: 2.29, 95% CI 1.26 to 4.17) and quindine (RR: 1.53, (95% CI 1.01 to 2.32) probably result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up when compared to amiodarone (certainty of evidence: moderate). Dofetilide (RR: 0.79, 95% CI 0.56 to 1.44), sotalol (RR: 0.89, 95% CI 0.67 to 1.18), propafenone (RR: 0.79, 95% CI 0.50 to 1.25) and pilsicainide (RR: 0.39, 95% CI 0.02 to 7.01) may result in a reduction in this outcome when compared to amiodarone, but the certainty of evidence is low. For atrial flutter (14 trials), a network could be created only for antiarrhythmic drugs. Using placebo as the common comparator, ibutilide (RR: 21.45, 95% CI 4.41 to 104.37), propafenone (RR: 7.15, 95% CI 1.27 to 40.10), dofetilide (RR: 6.43, 95% CI 1.38 to 29.91), and sotalol (RR: 6.39, 95% CI 1.03 to 39.78) probably result in a large increase in the maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: moderate), and procainamide (RR: 4.29, 95% CI 0.63 to 29.03), flecainide (RR 3.57, 95% CI 0.24 to 52.30) and vernakalant (RR: 1.18, 95% CI 0.05 to 27.37) may result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: low). All tested electrical cardioversion strategies for atrial flutter had very high efficacy (97.9% to 100%). The rate of mortality (14 deaths) and stroke or systemic embolism (3 events) at 30 days was extremely low. Data on quality of life were scarce and of uncertain clinical significance. No information was available regarding heart failure readmissions. Data on duration of hospitalisation was scarce, of low quality, and could not be pooled. AUTHORS' CONCLUSIONS: Despite the low quality of evidence, this systematic review provides important information on electrical and pharmacological strategies to help patients and physicians deal with AF and atrial flutter. In the assessment of the patient comorbidity profile, antiarrhythmic drug onset of action and side effect profile versus the need for a physician with experience in sedation, or anaesthetics support for electrical cardioversion are key aspects when choosing the cardioversion method.

Atrial tachyarrhythmias after lung transplantation in children: A common occurrence.

BACKGROUND: Atrial arrhythmia's (AA) following lung transplant in adults are a well-described clinical finding. In pediatrics, however, there are limited data with some reports suggesting that arrhythmias are rare. METHODS: We performed a single-center retrospective review of lung transplant recipients from January 2013 to June 2020. A detailed evaluation of clinical characteristics, presence of arrhythmias, and outcomes was completed. Arrhythmias were documented based on inpatient telemetry or remote Holter monitoring. Analyses assessing risk factors for arrhythmias and associations with clinical outcomes were performed. RESULTS: Ninety-one lung transplants were performed in 90 patients. Post-operative AA occurred following 19% transplants. Ectopic atrial tachycardia was seen in 14%, atrial flutter in 2%, and a combination in 2%. The majority of these arrhythmias occurred within the first 45 days post-operatively. Antiarrhythmic treatment was required in 59%, but none required ablation or electrical cardioversion. In patients followed for a year or more, 88% had resolution of their arrhythmia. Arrhythmias were not associated with mortality. In further analysis, however, the presence of arrhythmia was associated with an increased length of ICU stay (median of 12 days (IQR 6, 23) versus 5 days (IQR 4, 9); p = .019) and overall length of hospital stay (median of 26 days (IQR 19, 36) versus 17 days (IQR 19, 36); p = .043). CONCLUSIONS: Atrial tachyarrhythmias after lung transplantation are common in the pediatric population and usually occur early. Although they frequently require medical therapy and are associated with longer stays, there is no associated increased mortality. In addition, the arrhythmias typically self-resolve.

Transition mechanisms from atrial flutter to atrial fibrillation during anti-tachycardia pacing therapy.

BACKGROUND: Atrial anti-tachycardia pacing (aATP) has been shown to be effective for the termination of atrial tachyarrhythmias, but its success rate is still not high enough. OBJECTIVE: The main objective of this study was to investigate the mechanisms of atrial flutter (AFL) termination by aATP and the transition from AFL to atrial fibrillation (AF) during aATP. METHODS: We developed a multi-scale model of the human atrium based on magnetic resonance images and examined the atrial electrophysiology of AFL during aATP with a ramp protocol. RESULTS: In successful cases of aATP, paced excitation entered the excitable gap and collided with the leading edge of the reentrant wave front. Furthermore, the excitation propagating in the opposite direction collided with the trailing edge of the reentrant wave to terminate AFL. The second collision was made possible by the distribution of the wave propagation velocity in the atria. The detailed analysis revealed that the slowing of propagation velocity occurred at the exit of the sub-Eustachian isthmus, probably due to source-sink mismatch. During the transition from AFL to AF, the excitation collided with the refractory zone of the preceding wave and broke into multiple wave fronts to induce AF. A similar observation was made for the transition from AF to sinus rhythm. In both cases, the complex anatomy of the atria played an essential role. CONCLUSION: The complex anatomy of atria plays an essential role in the maintenance of stable AFL and its termination by aATP, which were revealed by the realistic three-dimensional simulation model.

Progression from paroxysmal to persistent atrial fibrillation in pacemaker patients with tachycardia-bradycardia syndrome: a multicenter study.

Progression from paroxysmal to persistent atrial fibrillation (AF) is occasionally encountered in patients with previous pacemaker implantation (PMI) for the treatment of tachycardia-bradycardia syndrome (TBS). We aimed to determine the rate of its incidence occurring within the early years after PMI and the predictors. We studied TBS patients who received PMI at 5 core cardiovascular centers. The end point was a conversion from paroxysmal to persistent AF. We extracted 342 TBS patients out of 2579 undergoing PMI. During 5 ± 3.1 years of follow-up, 114 (33.3%) reached the end point. The time to the end point was 2.9 ± 2.7 years. The event rates within a year and 3 years after the PMI were 8.8% and 19.6%, respectively. In the multivariate hazard analyses, hypertension (hazard ratio [HR] 3.2, P = 0.03) and congestive heart failure (HR 2.1, P = 0.04) were found to be independent predictors of the end point occurring within a year after the PMI. Congestive heart failure (HR 1.82, P = 0.04), left atrial diameter of ≥ 40 mm (HR 4.55, P < 0.001), and the use of antiarrhythmic agents (HR 0.58, P = 0.04) were independently associated with the 3-year end point. Prediction models including combinations of those 4 parameters for the 1- and 3-year incidence both exhibited a modest risk discrimination (both c-statistics 0.71). In conclusion, early progression from paroxysmal to persistent AF was less frequent than expected in the TBS patients with PMI. Factors related to atrial remodeling and no use of antiarrhythmic drugs may facilitate the progression.

Patient-activated anti-tachycardia pacing in adult congenital heart disease.

INTRODUCTION: In adults with congenital heart disease, intra-atrial reentrant tachycardia (IART) is a common arrhythmia that causes significant morbidity and mortality. One treatment option for IART is antitachycardia pacing. Atrial antitachycardia pacing algorithms deliver therapy for IART with ≥2:1 conduction, but most algorithms will not recognize IART with 1:1 conduction. Temporary Patient Activated Rx (TPARx) is Medtronic software that can be installed in antitachycardia pacemakers allowing patients to deliver therapies on demand for IART with 1:1 conduction. METHODS: Retrospective chart review at a single institution of all patients who had TPARx installed into their pacemaker. RESULTS: Four adults with single ventricle congenital heart disease and IART underwent Fontan conversion, arrhythmia surgery, and placement of an epicardial dual-chamber antitachycardia pacemaker. They had recurrent IART with a long cycle length and 1:1 conduction that failed to trigger antitachycardia pacing therapies. TPARx software was programmed into their pacemakers to allow recognition and treatment of IART with 1:1 conduction. Mean follow-up duration after TPARx programming was 4.9 years. Each patient received at least one successful antitachycardia pacing therapy via TPARx - range 0.4-26 treated IART episodes per year. There were no atrial or ventricular arrhythmias induced with antitachycardia pacing. Two patients were able to discontinue anticoagulation after TPARx installation. CONCLUSION: This series demonstrates the use of TPARx software as part of a long-term IART management strategy in select patients with IART who have failed more conventional therapies.

Bidirectional ventricular tachycardia induced by respiratory alkalosis mediated hypokalemia in a patient with acute ischemic heart failure.

Bidirectional ventricular tachycardia (BVT) is a rare arrhythmia that is generally observed in patients with catecholaminergic ventricular tachycardia or digoxin overdose. Herein, we present a case of BVT and electrical storm (ES) in an acute ischemic heart failure patient that is typically induced by hypokalemia. The patient was in invasive mechanical ventilator (MV) support and hypokalemia was related to acute respiratory alkalosis and that caused refractory hypokalemia despite intravenous (IV) potassium replacement. We also discuss our approach to solve refractory hypokalemia caused by respiratory alkalosis.

Rate Versus Rhythm Control in Tachycardia-Induced Cardiomyopathy Patients with Persistent Atrial Flutter.

Tachycardia-induced cardiomyopathy (TIC) is a potentially reversible cardiomyopathy caused by tachyarrhythmia. For atrial flutter (AFL) -induced TIC, a rhythm control strategy, such as catheter ablation, has been recommended. However, the efficacy of rate control has remained unclear due to the difficulty of achieving control using arrhythmic medications.We prospectively assessed 47 symptomatic heart failure (HF) patients with left ventricular ejection fraction (LVEF) < 50% and suspected persistent AFL-induced TIC. Patients were divided into the rhythm control strategy (n = 22; treatment with catheter ablation or electrical cardioversion) and rate control strategy (n = 25; treatment with bisoprolol) groups. The latter was further divided into the strict rate control strategy (average heart rate < 80 bpm) and lenient rate control strategy (average heart rate < 110 bpm) subgroups. The primary outcome was left ventricular (LV) function recovery, which was defined as an increase in LVEF ≥ 20% or to a value of ≥ 55% after 6 months.In the rhythm control strategy group, more patients achieved LV function recovery after 6 months (95.2% versus 60.9%, P = 0.010). The cumulative incidence of worsening HF events was significantly higher in the rate control strategy group than in the rhythm control strategy group (hazard ratio, 4.66; 95% confidence interval, 1.01-21.57). The subgroup study revealed the advantage of the strict rate control strategy for achieving LV function recovery (83.3% versus 36.4%, P = 0.036).The rate control strategy was significantly inferior to the rhythm control strategy for the LV function recovery in TIC patients with persistent AFL. Our findings suggest that the strict rate control strategy should be aimed if the rhythm control strategy cannot be performed.

The effect of intrapartum oxygen supplementation on category II fetal monitoring.

BACKGROUND: Maternal oxygen administration is a widely used intrauterine resuscitation technique for fetuses with category II electronic fetal monitoring patterns, despite a paucity of evidence on its ability to improve electronic fetal monitoring patterns. OBJECTIVE: This study investigated the effect of intrapartum oxygen administration on Category II electronic fetal monitoring patterns. STUDY DESIGN: This is a secondary analysis of a randomized trial conducted in 2016-2017, in which patients with fetuses at ≥37 weeks' gestation in active labor with category II electronic fetal monitoring patterns were assigned to 10 L/min of oxygen by face mask or room air until delivery. Trained obstetrical research nurses blinded to allocation extracted electronic fetal monitoring data. The primary outcome was a composite of high-risk category II features including recurrent variable decelerations, recurrent late decelerations, prolonged decelerations, tachycardia, or minimal variability 60 minutes after randomization to room air or oxygen. Secondary outcomes included individual components of the composite high-risk category II features, resolution of recurrent decelerations within 60 minutes of randomization, and total deceleration area. The outcomes between the room air and oxygen groups were compared using univariable statistics. Time-to-event analysis was used to compare time to resolution of recurrent decelerations between the groups. Paired analysis was used to compare the pre- and postrandomization outcomes within each group. RESULTS: All 114 randomized patients (57 room air and 57 oxygen) were included in this analysis. There was no difference in resolution of recurrent decelerations within 60 minutes between the oxygen and room air groups (75.4% vs 86.0%; P=.15). The room air and oxygen groups had similar rates of composite high-risk category II features including recurrent variable decelerations, recurrent late decelerations, prolonged decelerations, tachycardia, and minimal variability 60 minutes after randomization. Time to resolution of recurrent decelerations and total deceleration area were similar between the room air and oxygen groups. Among patients who received oxygen, there was no difference in the electronic fetal monitoring patterns pre- and postrandomization. Similar findings were observed in the electronic fetal monitoring patterns pre- and postrandomization in room air patients. CONCLUSION: Intrapartum maternal oxygen administration for category II electronic fetal monitoring patterns did not resolve high-risk category II features or hasten the resolution of recurrent decelerations. These results suggest that oxygen administration has no impact on improving category II electronic fetal monitoring patterns.

Severe chronic kidney disease is associated with poor survival after initial CRT-defibrillator tachyarrhythmia therapy.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) recipients who receive appropriate device therapies have limited survival, and survival benefit in chronic kidney disease (CKD) has been questioned. We examined the association between CKD and survival after cardiac resynchronization therapy (CRT)-defibrillator tachyarrhythmia therapies. METHODS: We compared overall survival after appropriate shocks or anti-tachycardia pacing in 439 CRT-defibrillator recipients with left ventricular ejection fraction (LVEF) ≤35%, non-right bundle-branch block QRS pattern, and QRS duration >130 ms according to glomerular filtration rate (GFR) at implant, including 31 patients with GFR ≤30, 164 patients with GFR 31-60, and 244 patients with GFR >60. At least one shock occurred in 302 patients (24 with GFR ≤30, 102 with GFR 31-60, and 176 with GFR >60). Serial echocardiograms were also compared. RESULTS: Patients were followed 64 months (interquartile range [IQR]: 29-94) after implant, including 32 months (IQR: 12-61) after first therapy. Time to first therapy or shock was similar across GFR groups. However, survival after first therapy declined directly with declining GFR (P < .001), with median postshock survival of 90 days for GFR ≤30 (95% confidence of interval [CI]: 0-233), 612 days (95% CI: 365-859) for GFR 31-60, and 1672 days (95% CI: 1396-1948) for GFR >60. Declining GFR category, ischemic heart disease, diabetes, and increasing age were independently associated with increased postshock mortality. Echocardiographic response was similar across GFR groups and was not associated with post-therapy survival. CONCLUSIONS: Survival after appropriate tachyarrhythmia therapies, particularly shocks, is attenuated in patients with GFR ≤30. This raises concern over potential lack of survival benefit conferred by CRT-defibrillators versus CRT-pacemakers in this population.

Atrial tachycardia from an unusual site-Left atrial appendage tachycardia: Challenges in ablation.

Left atrial appendage (LAA) tachycardia are rarely encountered in clinical practice (2.1% of focal atrial tachycardia). Out of these, the ones arising from the distal part of LAA are difficult to ablate due to higher risk of LAA perforation and thromboembolism. We hereby present a patient with LAA tachycardia mapped to the tip of LAA with the help of the CARTO system and ablated. This case highlights the inherent challenges faced in such a scenario.

Transcatheter ablation using near-zero fluoroscopy in children with focal atrial tachycardia: a single-centre experience.

OBJECTIVE: Focal atrial tachycardia accounts for up to 10-15% of supraventricular tachycardiasubstrates in patients < 30 years. In this study, we aimed to demonstrate the outcome of transcatheter ablation procedures performed through three-dimensional electroanatomic mapping systems using minimal fluoroscopy in a paediatric cohort with focal atrial tachycardia. METHODS: Forty-nine consecutive patients with focal atrial tachycardia who underwent an electrophysiologic study and a transcatheter ablation procedure in our hospital from September 2014 to February 2020 were included into the study. RESULTS: The mean weight of the patients was 48.63 ± 15.4 kg, and the mean age was 14.56 ± 3.5 (5.5-18.4) years. The tachycardia was defined as incessant in 26 patients. Thirteen patients had left ventricular systolic dysfunction with a mean left ventricular ejection fraction of 38.47 ± 12.4% on echocardiography. The mean procedure time was 148.7 ± 94.5 minutes. Transseptal puncture and thus fluoroscopy were required in nine patients. The mean fluoroscopy time was 4.51 ± 5.9 minutes. No fluoroscopy was needed in ablations performed in the right atrium. The acute success rate of the ablation procedures was 97.9%. The mean follow-up period was 50.71 ± 23.5 months. Recurrence was noted in two patients (4.2%). CONCLUSION: The outcomes of three-dimensional electroanatomic mapping-guided transcatheter ablation procedures are promising with high acute success, low recurrence and complication rates in children with focal atrial tachycardia. The use of fluoroscopy can be significantly decreased with three-dimensional mapping systems in this group of patients.

Effect of Catheter Ablation With Vein of Marshall Ethanol Infusion vs Catheter Ablation Alone on Persistent Atrial Fibrillation: The VENUS Randomized Clinical Trial.

Importance: Catheter ablation of persistent atrial fibrillation (AF) has limited success. Procedural strategies beyond pulmonary vein isolation have failed to consistently improve results. The vein of Marshall contains innervation and AF triggers that can be ablated by retrograde ethanol infusion. Objective: To determine whether vein of Marshall ethanol infusion could improve ablation results in persistent AF when added to catheter ablation. Design, Setting, and Participants: The Vein of Marshall Ethanol for Untreated Persistent AF (VENUS) trial was an investigator-initiated, National Institutes of Health-funded, randomized, single-blinded trial conducted in 12 centers in the United States. Patients (N = 350) with persistent AF referred for first ablation were enrolled from October 2013 through June 2018. Follow-up concluded in June 2019. Interventions: Patients were randomly assigned to catheter ablation alone (n = 158) or catheter ablation combined with vein of Marshall ethanol infusion (n = 185) in a 1:1.15 ratio to accommodate for 15% technical vein of Marshall ethanol infusion failures. Main Outcomes and Measures: The primary outcome was freedom from AF or atrial tachycardia for longer than 30 seconds after a single procedure, without antiarrhythmic drugs, at both 6 and 12 months. Outcome assessment was blinded to randomization treatment. There were 12 secondary outcomes, including AF burden, freedom from AF after multiple procedures, perimitral block, and others. Results: Of the 343 randomized patients (mean [SD] age, 66.5 [9.7] years; 261 men), 316 (92.1%) completed the trial. Vein of Marshall ethanol was successfully delivered in 155 of 185 patients. At 6 and 12 months, the proportion of patients with freedom from AF/atrial tachycardia after a single procedure was 49.2% (91/185) in the catheter ablation combined with vein of Marshall ethanol infusion group compared with 38% (60/158) in the catheter ablation alone group (difference, 11.2% [95% CI, 0.8%-21.7%]; P = .04). Of the 12 secondary outcomes, 9 were not significantly different, but AF burden (zero burden in 78.3% vs 67.9%; difference, 10.4% [95% CI, 2.9%-17.9%]; P = .01), freedom from AF after multiple procedures (65.2% vs 53.8%; difference, 11.4% [95% CI, 0.6%-22.2%]; P = .04), and success achieving perimitral block (80.6% vs 51.3%; difference, 29.3% [95% CI, 19.3%-39.3%]; P < .001) were significantly improved in vein of Marshall-treated patients. Adverse events were similar between groups. Conclusions and Relevance: Among patients with persistent AF, addition of vein of Marshall ethanol infusion to catheter ablation, compared with catheter ablation alone, increased the likelihood of remaining free of AF or atrial tachycardia at 6 and 12 months. Further research is needed to assess longer-term efficacy. Trial Registration: ClinicalTrials.gov Identifier: NCT01898221.

Early initiation of extracorporeal life support in refractory out-of-hospital cardiac arrest: Design and rationale of the INCEPTION trial.

Return of spontaneous circulation occurs in less than 10% of patients with cardiac arrest undergoing cardiopulmonary resuscitation (CPR) for more than 15 minutes. Studies suggest that extracorporeal life support during cardiopulmonary resuscitation (ECPR) improves survival rate in these patients. These studies, however, are hampered by their non-randomized, observational design and are mostly single-center. A multicenter, randomized controlled trial is urgently warranted to evaluate the effectiveness of ECPR. HYPOTHESIS: We hypothesize that early initiation of ECPR in refractory out-of-hospital cardiac arrest (OHCA) improves the survival rate with favorable neurological status. STUDY DESIGN: The INCEPTION trial is an investigator-initiated, prospective, multicenter trial that will randomly allocate 110 patients to either continued CPR or ECPR in a 1:1 ratio. Patients eligible for inclusion are adults (≤ 70 years) with witnessed OHCA presenting with an initial rhythm of ventricular fibrillation (VF) or ventricular tachycardia (VT), who received bystander basic life support and who fail to achieve sustained return of spontaneous circulation within 15 minutes of cardiopulmonary resuscitation by emergency medical services. The primary endpoint of the study is 30-day survival rate with favorable neurological status, defined as 1 or 2 on the Cerebral Performance Category score. The secondary endpoints include 3, 6 and 12-month survival rate with favorable neurological status and the cost-effectiveness of ECPR compared to CCPR. SUMMARY: The INCEPTION trial aims to determine the clinical benefit for the use of ECPR in patients with refractory OHCA presenting with VF/VT. Additionally, the feasibility and cost-effectiveness of ECPR will be evaluated.

Impact of atrial arrhythmia on survival in adults with tetralogy of Fallot.

BACKGROUND: Atrial arrhythmia is a late complication after tetralogy of Fallot (TOF) repair, but arrhythmia outcomes data are limited. OBJECTIVES: The purpose of the study was to describe atrial arrhythmia presentations, outcomes of antiarrhythmic therapy, and impact of arrhythmia on transplant-free survival. METHODS: We reviewed the MACHD (Mayo Adult Congenital Heart Disease) Registry and identified 113 patients (age 49 ±â€¯13 years) with documented arrhythmia, and 302 patients without history of arrhythmia, 1990-2017. We classified arrhythmias into atrial fibrillation and atrial flutter/tachycardia based on the rhythm on the first abnormal electrocardiogram. RESULTS: At the time of first documented arrhythmia, 58(51%) had atrial fibrillation while 55(49%) had atrial flutter/tachycardia. Of the 113 patients, 14(12%) received rhythm control with class I/III antiarrhythmic drugs (AAD), 79(70%) had direct current cardioversion, 9(8%) received rate control with class II/IV AAD, and 11(10%) received only anticoagulation. Successful cardioversion occurred in 100(89%) patients, and arrhythmia recurrence rate was 16 per 100 patient-years. The multivariate risk factors for death and/or heart transplant were atrial fibrillation (HR 1.94, CI 1.10-3.15, P = .031) and older age (HR 1.63, CI 1.12-2.43, P = .019) per 5 year increment. CONCLUSIONS: Atrial fibrillation, but not atrial flutter, was associated with reduced survival in our repaired TOF cohort. Further studies are required to determine if more aggressive antiarrhythmic therapy will improve survival in patients with atrial fibrillation.

The heat is on: A device that reduces cold stress-induced tachycardia in laboratory mice.

Mouse vivaria are typically maintained at an ambient temperature (Ta) of 20-26 °C which is comfortable for human researchers. However, as this Ta is well below the mouse thermoneutral zone (TNZ) of 30-32 °C, typical vivarium temperatures result in cold stress for mice. Recently, a cage has been developed that provides variable cage floor heating, allowing mice to behaviorally regulate body temperature through thermotaxis. A hand warmer provides supplemental heat, elevating cage floor surface temperature for 13 + hours up to 30 °C. This provides a heated surface for the entirety of the light phase. Here, we test the ability of these local heat sources to remove physiological signs of cold stress in mice housed at room temperature by analyzing heart rate (HR), activity, and body temperature in three experimental conditions: 23 °C, 23 °C + heated surface, or 30 °C. The location of C57Bl/6 J mice within the cage was recorded using an infrared camera. In the presence of supplemental heat at a Ta of 23 °C, mice resided atop of the area of the heated surface 85 ±â€¯3% of the 12-h light phase, as compared to 7 ±â€¯2% in the absence of supplemental heat. Further, addition of supplemental heat lowered light phase HR and activity to that seen at a Ta of 30 °C. These results indicate that provision of a local heat source is successful in reducing cold-induced tachycardia in mice housed at typical vivarium temperatures without increasing the ambient temperature of the entire laboratory and subjecting researchers to heat stress.

[Permanent Cardiostimulation Training Course - from Simple to Complex. Patient Management and Electrocardiographic Diagnosis].

The article deals with methods of treating patients with bradyarrhythmias, life-threatening tachyarrhythmias and chronic heart failure with the use of implantable antiarrhythmic devices permanent pacemakers, cardioverter defibrillators, and cardio-resynchronizing systems. Methods of instrumental and electrocardiographic diagnosis acceptable for such patients are described. The work defines management approaches to these patients in the postoperative and subsequent periods of life.

Termination of re-entrant atrial tachycardia via optogenetic stimulation with optimized spatial targeting: insights from computational models.

KEY POINTS: Optogenetics has emerged as a potential alternative to electrotherapy for treating heart rhythm disorders, but its applicability for terminating atrial arrhythmias remains largely unexplored. We used computational models reconstructed from clinical MRI scans of fibrotic patient atria to explore the feasibility of optogenetic termination of atrial tachycardia (AT), comparing two different illumination strategies: distributed vs. targeted. We show that targeted optogenetic stimulation based on automated, non-invasive flow-network analysis of patient-specific re-entry morphology may be a reliable approach for identifying the optimal illumination target in each individual (i.e. the critical AT isthmus). The above-described approach yields very high success rates (up to 100%) and requires dramatically less input power than distributed illumination We conclude that simulations in patient-specific models show that targeted light pulses lasting longer than the AT cycle length can efficiently and reliably terminate AT if the human atria can be successfully light-sensitized via gene delivery of ChR2. ABSTRACT: Optogenetics has emerged as a potential alternative to electrotherapy for treating arrhythmia, but feasibility studies have been limited to ventricular defibrillation via epicardial light application. Here, we assess the efficacy of optogenetic atrial tachycardia (AT) termination in human hearts using a strategy that targets for illumination specific regions identified in an automated manner. In three patient-specific models reconstructed from late gadolinium-enhanced MRI scans, we simulated channelrhodopsin-2 (ChR2) expression via gene delivery. In all three models, we attempted to terminate re-entrant AT (induced via rapid pacing) via optogenetic stimulation. We compared two strategies: (1) distributed illumination of the endocardium by multi-optrode grids (number of optrodes, Nopt  = 64, 128, 256) and (2) targeted illumination of the critical isthmus, which was identified via analysis of simulated activation patterns using an algorithm based on flow networks. The illuminated area and input power were smaller for the targeted approach (19-57.8 mm2 ; 0.6-1.8 W) compared to the sparsest distributed arrays (Nopt  = 64; 124.9 ± 6.3 mm2 ; 3.9 ± 0.2 W). AT termination rates for distributed illumination were low, ranging from <5% for short pulses (1/10 ms long) to ∼20% for longer stimuli (100/1000 ms). When we attempted to terminate the same AT episodes with targeted illumination, outcomes were similar for short pulses (1/10 ms long: 0% success) but improved for longer stimuli (100 ms: 54% success; 1000 ms: 90% success). We conclude that simulations in patient-specific models show that light pulses lasting longer than the AT cycle length can efficiently and reliably terminate AT in atria light-sensitized via gene delivery. We show that targeted optogenetic stimulation based on analysis of AT morphology may be a reliable approach for defibrillation and requires less power than distributed illumination.