ACR Appropriateness Criteria® Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation.

This document summarizes the relevant literature for the selection of preprocedural imaging in three clinical scenarios in patients needing endovascular treatment or cardioversion of atrial fibrillation. These clinical scenarios include preprocedural imaging prior to radiofrequency ablation; prior to left atrial appendage occlusion; and prior to cardioversion. The appropriateness of imaging modalities as they apply to each clinical scenario is rated as usually appropriate, may be appropriate, and usually not appropriate to assist the selection of the most appropriate imaging modality in the corresponding clinical scenarios. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

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.

Thromboembolic and bleeding complications after elective cardioversion of atrial fibrillation: a nationwide cohort study.

AIMS: Elective cardioversion (ECV) is routinely used in atrial fibrillation (AF) to restore sinus rhythm. However, it includes a risk of thromboembolism even during adequate oral anticoagulation treatment. The aim of this study was to evaluate the risk of thromboembolic and bleeding complications after ECV in a real-life setting utilizing data from a large AF population. METHODS AND RESULTS: This nationwide register-based study included all (n = 9625) Finnish AF patients undergoing their first-ever ECV between 2012 and 2018. The thromboembolic and bleeding complications within 30 days after ECV were analysed. The mean age of the patients was 67.7 ± 9.9 years, 61.2% were men, and the mean CHA2DS2-VASc score was 2.6 ± 1.6. Warfarin was used in 6245 (64.9%) and non-vitamin K oral anticoagulants (NOACs) in 3380 (35.1%) cardioversions. Fifty-two (0.5%) thromboembolic complications occurred, of which 62% were ischaemic strokes, 25% transient ischaemic attacks, and 13% other systemic embolisms. Thromboembolic events occurred in 14 (0.4%) NOAC-treated patients and in 38 (0.6%) warfarin-treated patients (odds ratio 0.77; confidence interval: 0.42-1.39). The median time from ECV to the thromboembolic event was 2 days, and 78% of the events occurred within 10 days. Age and alcohol abuse were significant predictors of thromboembolic events. Among warfarin users, thromboembolic complications were more common with international normalized ratio (INR) <2.5 than INR ≥2.5 (0.9% vs. 0.4%, P = 0.026). Overall, 27 (0.3%) bleeding events occurred. CONCLUSION: The rate of thromboembolic and bleeding complications related to ECV was low without significant difference between NOAC- and warfarin-treated patients. With warfarin, INR ≥2.5 at the time of cardioversion reduced the risk of thromboembolic complications.

Sex differences among subcutaneous implantable cardioverter-defibrillator recipients: a propensity-matched, multicentre, international analysis from the i-SUSI project.

AIMS: Women have been historically underrepresented in implantable cardioverter-defibrillator (ICD) trials. No data on sex differences regarding subcutaneous ICDs (S-ICD) carriers have been described. Aim of our study was to investigate sex-related differences among unselected S-ICD recipients. METHODS AND RESULTS: Consecutive patients enrolled in the multicentre, international i-SUSI registry were analysed. Comparisons between sexes were performed using a 1:1 propensity matching adjusted analysis for age, body mass index (BMI), left ventricular function, and substrate. The primary outcome was the rate of appropriate shocks during follow-up. Inappropriate shocks and other device-related complications were deemed secondary outcomes. A total of 1698 patients were extracted from the i-SUSI registry; 399 (23.5%) were females. After propensity matching, two cohorts of 374 patients presenting similar baseline characteristics were analysed. Despite similar periprocedural characteristics and a matched BMI, women resulted at lower risk of conversion failure as per PRAETORIAN score (73.4% vs. 81.3%, P = 0.049). Over a median follow-up time of 26.5 [12.7-42.5] months, appropriate shocks were more common in the male cohort (rate/year 3.4% vs. 1.7%; log-rank P = 0.049), while no significant differences in device-related complications (rate/year: 6.3% vs. 5.8%; log-rank P = 0.595) and inappropriate shocks (rate/year: 4.3% vs. 3.1%; log-rank P = 0.375) were observed. After controlling for confounders, sex remained significantly associated with the primary outcome (aHR 1.648; CI 0.999-2.655, P = 0.048), while not resulting predictor of inappropriate shocks and device-related complications. CONCLUSION: In a propensity-matched cohort of S-ICD recipients, women are less likely to experience appropriate ICD therapy, while not showing higher risk of device-related complications. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT0473876.

Underlying reasons for sex difference in survival following out-of-hospital cardiac arrest: a mediation analysis.

AIMS: Previous studies have indicated a poorer survival among women following out-of-hospital cardiac arrest (OHCA), but the mechanisms explaining this difference remain largely uncertain.This study aimed to assess the survival after OHCA among women and men and explore the role of potential mediators, such as resuscitation characteristics, prior comorbidity, and socioeconomic factors. METHODS AND RESULTS: This was a population-based cohort study including emergency medical service-treated OHCA reported to the Swedish Registry for Cardiopulmonary Resuscitation in 2010-2020, linked to nationwide Swedish healthcare registries. The relative risks (RR) of 30-day survival were compared among women and men, and a mediation analysis was performed to investigate the importance of potential mediators. Total of 43 226 OHCAs were included, of which 14 249 (33.0%) were women. Women were older and had a lower proportion of shockable initial rhythm. The crude 30-day survival among women was 6.2% compared to 10.7% for men [RR 0.58, 95% confidence interval (CI) = 0.54-0.62]. Stepwise adjustment for shockable initial rhythm attenuated the association to RR 0.85 (95% CI = 0.79-0.91). Further adjustments for age and resuscitation factors attenuated the survival difference to null (RR 0.98; 95% CI = 0.92-1.05). Mediation analysis showed that shockable initial rhythm explained ∼50% of the negative association of female sex on survival. Older age and lower disposable income were the second and third most important variables, respectively. CONCLUSION: Women have a lower crude 30-day survival following OHCA compared to men. The poor prognosis is largely explained by a lower proportion of shockable initial rhythm, older age at presentation, and lower income.

Atrial Fibrillation: Common Questions and Answers About Diagnosis and Treatment.

Atrial fibrillation is a supraventricular arrhythmia that increases the risk of stroke and all-cause mortality. It is the most common cardiac dysrhythmia in adults in the primary care setting, and its prevalence increases with age. The U.S. Preventive Services Task Force concluded that there is insufficient evidence to assess the benefits and harms of screening asymptomatic adults older than 50 years for atrial fibrillation. Many patients with atrial fibrillation are asymptomatic, but symptoms can include palpitations, exertional dyspnea, fatigue, and chest pain. Diagnosis is based on history and physical examination findings and should be confirmed with 12-lead electrocardiography or other recording device. The initial evaluation should include transthoracic echocardiography; serum electrolyte levels; complete blood count; and thyroid, kidney, and liver function tests. Stroke risk should be assessed in patients with atrial fibrillation using the CHA2DS2-VASc score. Warfarin and direct oral anticoagulants reduce the risk of stroke by preventing atrial thrombus formation and subsequent cerebral or systemic emboli. Hemodynamically unstable patients, including those with decompensated heart failure, should be evaluated and treated emergently. Most hemodynamically stable patients should be treated initially with rate control and anticoagulation. Rhythm control, using medications or procedures, should be considered in patients with hemodynamic instability or in some patients based on risk factors and shared decision-making. Electrical cardioversion may be appropriate as first-line rhythm control. Conversion to sinus rhythm with catheter ablation may be considered in patients who are unable or unwilling to take rate or rhythm control medications long-term or if medications have been ineffective.

Lack of Prognostic Value of T-Wave Alternans for Implantable Cardioverter-Defibrillator Benefit in Primary Prevention.

BACKGROUND: New methods to identify patients who benefit from a primary prophylactic implantable cardioverter-defibrillator (ICD) are needed. T-wave alternans (TWA) has been shown to associate with arrhythmogenesis of the heart and sudden cardiac death. We hypothesized that TWA might be associated with benefit from ICD implantation in primary prevention. METHODS AND RESULTS: In the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter-Defibrillators) study, we prospectively enrolled 2327 candidates for primary prophylactic ICD. A 24-hour Holter monitor reading was taken from all recruited patients at enrollment. TWA was assessed from Holter monitoring using the modified moving average method. Study outcomes were all-cause death, appropriate shock, and survival benefit. TWA was assessed both as a contiguous variable and as a dichotomized variable with cutoff points <47 µV and <60 µV. The final cohort included 1734 valid T-wave alternans samples, 1211 patients with ICD, and 523 control patients with conservative treatment, with a mean follow-up time of 2.3 years. TWA ≥60 µV was a predicter for a higher all-cause death in patients with an ICD on the basis of a univariate Cox regression model (hazard ratio, 1.484 [95% CI, 1.024-2.151]; P=0.0374; concordance statistic, 0.51). In multivariable models, TWA was not prognostic of death or appropriate shocks in patients with an ICD. In addition, TWA was not prognostic of death in control patients. In a propensity score-adjusted Cox regression model, TWA was not a predictor of ICD benefit. CONCLUSIONS: T-wave alternans is poorly prognostic in patients with a primary prophylactic ICD. Although it may be prognostic of life-threatening arrhythmias and sudden cardiac death in several patient populations, it does not seem to be useful in assessing benefit from ICD therapy in primary prevention among patients with an ejection fraction of ≤35%.

Atrial fibrillation: real-life experience of a rhythm control with electrical cardioversion in a community hospital.

BACKGROUND: Atrial fibrillation is the most prevalent sustained cardiac arrhythmia. Electrical cardioversion, a well-established part of the rhythm control strategy, is probably underused in community settings. Here, we describe its use, safety, and effectiveness in a cohort of patients with atrial fibrillation treated in rural settings. METHODS: It is a retrospective cohort study. Data on all procedures from January 1, 2016, till December 1, 2022, in Tarusa Hospital, serving mostly a rural population of 15,000 people, were extracted from electronic health records. Data on the procedure's success, age, gender, body mass index, comorbidities, previous procedures, echocardiographic parameters, type and duration of arrhythmia, anticoagulation, antiarrhythmic drugs, transesophageal echocardiography, and settings were available. RESULTS: Altogether, 1,272 procedures in 435 patients were performed during the study period. The overall effectiveness of the procedure was 92%. Effectiveness was similar across all prespecified subgroups. Electrical cardioversion was less effective in patients undergoing the procedure for the first time (86%, 95% CI: 82-90) compared to repeated procedures (95%, 95% CI: 93-96), OR 0.39 (95% CI: 0.26-0.59). Complications were encountered in 13 (1.02%) procedures but were not serious. CONCLUSIONS: Electrical cardioversion is an immediately effective procedure that can be safely performed in community hospitals, both in inpatient and outpatient settings. Further studies with longer follow-up are needed to investigate the rate of sinus rhythm maintenance in these patients.

Impact of pandemic-related movement restriction on public access defibrillation in Japan: a retrospective cohort study.

OBJECTIVES: To analyse monthly changes in public access defibrillation (PAD) incidence and outcomes of out-of-hospital cardiac arrest (OHCA) during the 2020-2021 COVID-19 pandemic compared with those during the 2016-2019 prepandemic period with consideration of pandemic-related movement restriction. DESIGN: Retrospective cohort study. SETTING: An extended database was created by combining and reconciling the nationwide Utstein-style OHCA and the emergency medical service (EMS) transportation databases in Japan. PARTICIPANTS: We analysed 226 182 EMS-witnessed, non-newborn and out-of-home OHCA cases in Japan. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcomes were the PAD incidence and neurologically favourable 1-month survival rate. The secondary outcomes were bystander cardiopulmonary resuscitation (CPR) provision and dispatcher-assisted CPR attempts. RESULTS: The proportion of out-of-home OHCA cases slightly decreased during the pandemic (from 33.7% to 31.9%). Although the pandemic was associated with a decreased PAD incidence, 2-year trend analyses by an interaction test showed that the PAD incidence was lower during the first nationwide declaration of a state of emergency (p<0.001) and in the pandemic's second year (p<0.01). Regardless of location, delays in basic life support (BLS) actions and EMS contact with patients were more common and the rate of PAD-induced return of spontaneous circulation was lower during the pandemic. PAD incidence reduction was significant only in locations with a recommendation of automated external defibrillator placement (p<0.001). In other locations, a pronounced delay in BLS was found during the pandemic. The neurologically favourable survival rate was reduced in parallel with the reduced PAD incidence during the pandemic (r=0.612, p=0.002). CONCLUSIONS: Prolonged and repeated movement restrictions during the COVID-19 pandemic worsened the OHCA outcomes concurrently with disturbed BLS actions, including the reduced PAD incidence in out-of-home settings. Maintaining BLS training, re-arranging automated external defibrillator placement and establishing a local alert system for recruiting well-trained citizens to the scene are essential.

The link between initial cardiac rhythm and survival outcomes in in-hospital cardiac arrest using propensity score matching, adjustment, and weighting.

The association between the initial cardiac rhythm and short-term survival in patients with in-hospital cardiac arrest (IHCA) has not been extensively studied despite the fact that it is thought to be a prognostic factor in patients with out-of-hospital cardiac arrest. This study aimed to look at the relationship between initial shockable rhythm and survival to hospital discharge in individuals with IHCA. 1516 adults with IHCA who received chest compressions lasting at least two minutes at the National Taiwan University Hospital between 2006 and 2014 made up the study population. Propensity scores were estimated using a fitted multivariate logistic regression model. Various statistical methodologies were employed to investigate the association between shockable rhythm and the probability of survival to discharge in patients experiencing IHCA, including multivariate adjustment, propensity score adjustment, propensity score matching, and logistic regression based on propensity score weighting. In the original cohort, the multivariate-adjusted odds ratio (OR) was 2.312 (95% confidence interval [CI]: 1.515-3.531, P < 0.001). In additional propensity score adjustment, the OR between shockable rhythm and the probability of survival to hospital discharge in IHCA patients was 2.282 (95% CI: 1.486, 3.504, P < 0.001). The multivariate-adjusted logistic regression model analysis revealed that patients with shockable rhythm had a 1.761-fold higher likelihood of surviving to hospital release in the propensity score-matched cohort (OR = 2.761, 95% CI: 1.084-7.028, P = 0.033). The multivariate-adjusted OR of the inverse probability for the treatment-weighted cohort was 1.901 (95% CI: 1.507-2.397, P < 0.001), and the standardized mortality ratio-weighted cohort was 2.692 (95% CI: 1.511-4.795, P < 0.001). In patients with in-hospital cardiac arrest, Initial cardiac rhythm is an independent predictor of survival to hospital discharge. Depending on various statistical methods, patients with IHCA who have a shockable rhythm have a one to two fold higher probability of survival to discharge than those who have a non-shockable rhythm. This provides a reference for optimizing resuscitation decisions for IHCA patients and facilitating clinical communication.

Management of incessant ventricular arrhythmias in a patient with left ventricular assist device: a case report.

BACKGROUND: The implantation of left ventricular assist devices (LVADs) as a bridge to transplantation or as destination therapy in end-stage heart failure patients is frequently complicated by the emergence of ventricular arrhythmias (VAs). These arrhythmias have been implicated in precipitating deleterious clinical outcomes, increased mortality rates and augmented healthcare expenditures. CASE PRESENTATION: We present a challenging case of a 49-year-old male with a history of dilated cardiomyopathy who received an LVAD. Post-implantation, the patient suffered from intractable VAs, leading to multiple rehospitalizations and hemodynamic deterioration. Despite exhaustive medical management and electrical cardioversion attempts, the patient's VAs persisted, ultimately necessitating prioritization for cardiac transplantation. DISCUSSION: This case highlights the challenges in managing VAs in LVAD patients and the importance of multidisciplinary collaboration. While pharmacological intervention is the initial strategy, catheter ablation may be considered in selected cases when medication is insufficient. In instances of intractable VAs, expeditious listing for heart transplantation as a high-priority candidate is advisable when feasible.

A Quantitative Assessment of Cerebral Hemodynamic Perturbations Associated with Long R-R Intervals in Atrial Fibrillation: A Pilot-Case-Based Experience.

Background and Objectives: Atrial fibrillation (AF) results in systemic hemodynamic perturbations which impact cerebral circulation, possibly contributing to the development of dementia. However, evidence documenting effects in cerebral perfusion is scarce. The aim of this study is to provide a quantitative characterization of the magnitude and time course of the cerebral hemodynamic response to the short hypotensive events associated with long R-R intervals, as detected by near-infrared spectroscopy (NIRS). Materials and Methods: Cerebral NIRS signals and arterial blood pressure were continuously recorded along with an electrocardiogram in twelve patients with AF undergoing elective electrical cardioversion (ECV). The top 0.5-2.5% longest R-R intervals during AF were identified in each patient and used as triggers to carry out the triggered averaging of hemodynamic signals. The average curves were then characterized in terms of the latency, magnitude, and duration of the observed effects, and the possible occurrence of an overshoot was also investigated. Results: The triggered averages revealed that long R-R intervals produced a significant drop in diastolic blood pressure (-13.7 ± 6.1 mmHg) associated with an immediate drop in cerebral blood volume (THI: -0.92 ± 0.46%, lasting 1.9 ± 0.8 s), followed by a longer-lasting decrease in cerebral oxygenation (TOI: -0.79 ± 0.37%, lasting 5.2 ± 0.9 s, p < 0.01). The recovery of the TOI was generally followed by an overshoot (+1.06 ± 0.12%). These effects were progressively attenuated in response to R-R intervals of a shorter duration. Conclusions: Long R-R intervals cause a detectable and consistent cerebral hemodynamic response which concerns both cerebral blood volume and oxygenation and outlasts the duration of the systemic perturbation. These effects are compatible with the activation of dynamic autoregulatory mechanisms in response to the hypotensive stimulus.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project.

AIMS: Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers. METHODS AND RESULTS: International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006]. CONCLUSION: In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up. CLINICALTRIALS.GOV IDENTIFIER: NCT0473876.

Association between survival and number of shocks for pulseless ventricular arrhythmias during pediatric in-hospital cardiac arrest in a national registry.

BACKGROUND: Annually 15,200 children suffer an in-hospital cardiac arrest (IHCA) in the US. Ventricular fibrillation or pulseless ventricular tachycardia (VF/pVT) is the initial rhythm in 10-15% of these arrests. We sought to evaluate the association of number of shocks and early dose escalation with survival for initial VF/pVT in pediatric IHCA. METHODS: Using 2000-2020 data from the American Heart Association's (AHA) Get with the Guidelines®-Resuscitation (GWTG-R) registry, we identified children >48 hours of life and ≤18 years who had an IHCA from initial VF/pVT and received defibrillation. RESULTS: There were 251 subjects (37.7%) who received a single shock and 415 subjects (62.3%) who received multiple shocks. Baseline and cardiac arrest characteristics did not differ between those who received a single shock versus multiple shocks except for duration of arrest and calendar year. The median first shock dose was consistent with AHA dosing recommendations and not different between those who received a single shock versus multiple shocks. Survival was improved for those who received a single shock compared to multiple shocks. However, no difference in survival was noted between those who received 2, 3, or ≥4 shocks. Of those receiving multiple shocks, no difference was observed with early dose escalation. CONCLUSIONS: In pediatric IHCA, most patients with initial VF/pVT require more than one shock. No distinctions in patient or pre-arrest characteristics were identified between those who received a single shock versus multiple shocks. Subjects who received a single shock were more likely to survive to hospital discharge even after adjusting for duration of resuscitation.

Impact of preventive substrate catheter ablation on implantable cardioverter-defibrillator interventions in patients with ischaemic cardiomyopathy and infarct-related coronary chronic total occlusion.

AIMS: Primary prevention patients with ischaemic cardiomyopathy and chronic total occlusion of an infarct-related coronary artery (CTO) are at a particularly high risk of implantable cardioverter-defibrillator (ICD) therapy occurrence. The trial was designed to evaluate the efficacy of preventive CTO-related substrate ablation strategy in ischaemic cardiomyopathy patients undergoing primary prevention ICD implantation. METHODS AND RESULTS: The PREVENTIVE VT study was a prospective, multicentre, randomized trial including ischaemic patients with ejection fraction ≤40%, no documented ventricular arrhythmias (VAs), and evidence of scar related to the coronary CTO. Patients were randomly assigned 1:1 to a preventive substrate ablation before ICD implantation or standard therapy with ICD implantation only. The primary outcome was a composite of appropriate ICD therapy or unplanned hospitalization for VAs. Secondary outcomes included the primary outcome's components, the incidence of appropriate ICD therapies, cardiac hospitalization, electrical storm, and cardiovascular (CV) mortality. Sixty patients were included in the study. During the mean follow-up of 44.7 ± 20.7 months, the primary outcome occurred in 5 (16.7%) patients undergoing preventive substrate ablation and in 13 (43.3%) patients receiving only ICD [hazard ratio (HR): 0.33; 95% confidence interval (CI): 0.12-0.94; P = 0.037]. Patients in the preventive ablation group also had fewer appropriate ICD therapies (P = 0.039) and the electrical storms (Log-rank: P = 0.01). While preventive ablation also reduced cardiac hospitalizations (P = 0.006), it had no significant impact on CV mortality (P = 0.151). CONCLUSION: Preventive ablation of the coronary CTO-related substrate in patients undergoing primary ICD implantation is associated with the reduced risk of appropriate ICD therapy or unplanned hospitalization due to VAs.