Bleeding and Thrombosis in Patients With Out-of-Hospital Ventricular Tachycardia/Ventricular Fibrillation Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation improves outcomes after out-of-hospital cardiac arrest. However, bleeding and thrombosis are common complications. We aimed to describe the incidence and predictors of bleeding and thrombosis and their association with in-hospital mortality. METHODS AND RESULTS: Consecutive patients presenting with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest between December 2015 and March 2022 who met the criteria for extracorporeal cardiopulmonary resuscitation initiation at our center were included. Major bleeding was defined by the Extracorporeal Life Support Organization's criteria. Adjusted analyses were done to seek out risk factors for bleeding and thrombosis and evaluate their association with mortality. Major bleeding occurred in 135 of 200 patients (67.5%), with traumatic bleeding from cardiopulmonary resuscitation in 73 (36.5%). Baseline demographics and arrest characteristics were similar between groups. In multivariable analysis, decreasing levels of fibrinogen were independently associated with bleeding (adjusted hazard ratio [aHR], 0.98 per every 10 mg/dL rise [95% CI, 0.96-0.99]). Patients who died had a higher rate of bleeds per day (0.21 versus 0.03, P<0.001) though bleeding was not significantly associated with in-hospital death (aHR, 0.81 [95% CI. 0.55-1.19]). A thrombotic event occurred in 23.5% (47/200) of patients. Venous thromboembolism occurred in 11% (22/200) and arterial thrombi in 15.5% (31/200). Clinical characteristics were comparable between groups. In adjusted analyses, no risk factors for thrombosis were identified. Thrombosis was not associated with in-hospital death (aHR, 0.65 [95% CI, 0.42-1.03]). CONCLUSIONS: Bleeding is a frequent complication of extracorporeal cardiopulmonary resuscitation that is associated with decreased fibrinogen levels on admission whereas thrombosis is less common. Neither bleeding nor thrombosis was significantly associated with in-hospital mortality.

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.

Incidental Arrhythmias During Atrial Fibrillation Screening With Repeat 7-Day Holter ECGs in a Hospital-Based Patient Population.

BACKGROUND: Screening for atrial fibrillation (AF) may reveal incidental arrhythmias of relevance. The aim of this study was to describe incidental arrhythmias detected during screening for AF in the STAR-FIB (Predicting SilenT AtRial FIBrillation in Patients at High Thrombembolic Risk) cohort study. METHODS AND RESULTS: In the STAR-FIB cohort study, we screened hospitalized patients for AF with 3 repeat 7-day Holter ECGs. We analyzed all Holter ECGs for the presence of the following incidental arrhythmias: (1) sinus node dysfunction, defined as sinus pause of ≥3 seconds' duration; (2) second-degree (including Wenckebach) or higher-degree atrioventricular block (AVB); (3) sustained supraventricular tachycardia of ≥30 seconds' duration; and (4) sustained ventricular tachycardia of ≥30 seconds' duration. We furthermore report treatment decisions because of incidental arrhythmias. A total of 2077 Holter ECGs were performed in 794 patients (mean age, 74.7 years; 49% women), resulting in a mean cumulative duration of analyzable ECG signal of 414±136 hours/patient. We found incidental arrhythmias in 94 patients (11.8%). Among these were sinus node dysfunction in 14 patients (1.8%), AVB in 41 (5.2%), supraventricular tachycardia in 42 (5.3%), and ventricular tachycardia in 2 (0.3%). Second-degree AVB was found in 23 patients (2.9%), 2:1 AVB in 10 (1.3%), and complete AVB in 8 (1%). Subsequently, 8 patients underwent pacemaker implantation, 1 for sinus node dysfunction (post-AF conversion pause of 9 seconds) and 7 for advanced AVB. One patient had an implantable cardioverter-defibrillator implanted for syncopal ventricular tachycardia. CONCLUSIONS: Incidental arrhythmias were frequently detected during screening for AF in the STAR-FIB study and resulted in device therapy in 1.1% of our cohort patients.

Impact on clinical outcome of ventricular arrhythmias in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has become a largely used treatment for severe aortic stenosis. There are limited data, however, about predictors of long-term prognosis in this population. In this study, we assessed whether ventricular arrhythmias may predict clinical outcomes in patients undergoing TAVI. METHODS AND RESULTS: We performed a 24 h ECG Holter monitoring in 267 patients who underwent TAVI for severe aortic stenosis within 30 days from a successful procedure. The occurrence of frequent premature ventricular complexes (PVCs; ≥30/h), polymorphic PVCs and nonsustained ventricular tachycardia (NSVT) was obtained for each patient. Clinical outcome was obtained for 228 patients (85%), for an average follow-up of 3.5 years (range 1.0-8.6). Cardiovascular events (CVEs; cardiovascular death or resuscitated cardiac arrest) occurred in 26 patients (11.4%) and 63 patients died (27.6%). Frequent PVCs but not polymorphic PVCs and NSVT were found to be associated with CVEs at univariate analysis. Frequent PVCs were indeed found in 12 patients with (46.2%) and 35 without (17.3%) CVEs [hazard ratio 2.30; 95% confidence interval (CI) 1.03-5.09; P  = 0.04], whereas polymorphic PVCs were found in 11 (42.3%) and 54 (26.7%) patients of the two groups, respectively (hazard ratio 1.44; 95% CI 0.64-3.25; P  = 0.38), and NSVT in 9 (34.6%) and 43 patients of the two groups, respectively (hazard ratio 1.18; 95% CI 0.48-2.87; P  = 0.72). Frequent PVCs, however, were not significantly associated with CVEs at multivariate Cox regression analysis (hazard ratio 1.53; 95% CI 0.37-6.30; P  = 0.56). Both frequent PVCs, polymorphic PVCs and NSVT showed no significant association with mortality. CONCLUSION: In our study, the detection of frequent PVCs at Holter monitoring after TAVI was a predictor of CVEs (cardiovascular death/cardiac arrest), but this association was lost in multivariable analysis.

Insights into adherence to medication and lifestyle recommendations in an international cohort of patients with catecholaminergic polymorphic ventricular tachycardia.

AIMS: In patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), a rare inherited arrhythmia syndrome, arrhythmic events can be prevented by medication and lifestyle recommendations. In patients who experience breakthrough arrhythmic events, non-adherence plays an essential role. We aimed to investigate the incidence and potential reasons for non-adherence to medication and lifestyle recommendations in a large, international cohort of patients with CPVT. METHODS AND RESULTS: An online multilingual survey was shared with CPVT patients worldwide by their cardiologists, through peer-recruitment, and on social media from November 2022 until July 2023. Self-reported non-adherence was measured using the validated Medication Adherence Rating Scale (MARS) and a newly developed questionnaire about lifestyle. Additionally, validated questionnaires were used to assess potential reasons for medication non-adherence. Two-hundred-and-eighteen patients completed the survey, of whom 200 (92%) were prescribed medication [122 (61%) female; median age 33.5 years (interquartile range: 22-50)]. One-hundred-and-three (52%) were prescribed beta-blocker and flecainide, 85 (43%) beta-blocker, and 11 (6%) flecainide. Thirty-four (17%) patients experienced a syncope, aborted cardiac arrest or appropriate implantable cardioverter defibrillator shock after diagnosis. Nineteen (13.4%) patients were exercising more than recommended. Thirty (15%) patients were non-adherent to medication. Female sex [odds ratio (OR) 3.7, 95% confidence interval (CI) 1.3-12.0, P = 0.019], flecainide monotherapy compared to combination therapy (OR 6.8, 95% CI 1.6-31.0, P = 0.010), and a higher agreement with statements regarding concerns about CPVT medication (OR 1.2, 95% CI 1.1-1.3, P < 0.001) were independently associated with non-adherence. CONCLUSION: The significant rate of non-adherence associated with concerns regarding CPVT-related medication, emphasizes the potential for improving therapy adherence by targeted patient education.

Implantable cardioverter defibrillator and cardiac resynchronization treatment in people with type 2 diabetes: a comparison with age- and sex matched controls from the general population.

BACKGROUND: Increased risk of severe tachyarrhythmias is reported in patients with type 2 diabetes mellitus (T2DM). The aim of this study was to explore if treatment with cardiac implantable electronic device (CIED) such as implantable cardioverter defibrillator (ICD), cardiac resynchronization therapy- pacemaker and -defibrillator (CRT-P/CRT-D) differed in patients with vs. without T2DM. A secondary aim was to identify patient characteristics indicating an increased CIED treatment. METHOD: 416 162 adult patients with T2DM from the Swedish National Diabetes Registry and 2 081 087 controls from the Swedish population, matched for age, sex and living area, were included between 1/1/1998 and 31/12/2012 and followed until 31/12/2013. They were compared regarding prevalence of ventricular tachycardia (VT) at baseline and the risk of receiving a CIED during follow-up. Multivariable Cox regression analysis was performed to estimate the risk of CIED-treatment and factors identifying patients with such risk. RESULTS: Ventricular fibrillation (VF) (0.1% vs 0.0004%) and (VT) (0.2% vs. 0.1%) were more frequent among patients with T2DM compared to controls. CIED-treatment was significantly increased in patients with T2DM both in unadjusted and adjusted analyses. HR and 95% CI, after adjustment for sex, age, marital status, income, education, country of birth, coronary artery disease and congestive heart failure, were 1.32 [1.21-1.45] for ICD, 1.74 [1.55-1.95] for CRT-P and 1.69 [1.43-1.99] for CRT-D. Blood-pressure and lipid lowering therapies were independent risk factors associated to receiving CIED, while female sex was protective. CONCLUSIONS: Although the proportion of VT/VF was low, patients with T2DM had a higher prevalence of these conditions and increased risk for treatment with CIED compared to controls. This underlines the importance of recognizing that T2DM patients have an increased need of CIED.

Ventricular fibrillation/ventricular tachycardia within 72 h of VA-ECMO: incidence, outcomes, risk factors, and management.

AIMS: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an important technique for the treatment of refractory cardiogenic shock and cardiac arrest; however, the early management of ventricular fibrillation/ventricular tachycardia (VF/VT), within 72 h of VA-ECMO, and its effects on patient prognosis remain unclear. METHODS AND RESULTS: We retrospectively analysed patients at the First Affiliated Hospital of Nanjing Medical University who underwent VA-ECMO between January 2017 and March 2022. The patients were divided into two groups, VF/VT and nVF/VT, based on whether or not VF/VT occurred within 72 h after the initiation of VA-ECMO. We utilized logistic regression analysis to evaluate the independent risk factors for VF/VT in patients undergoing VA-ECMO and to ascertain whether the onset of VF/VT affected 28 day survival rate, length of intensive care unit stay, and/or other clinical prognostic factors. Subgroup analysis was performed for the VF/VT group to determine whether defibrillation affected prognosis. In the present study, 126 patients were included, 65.87% of whom were males (83/126), with a mean age of 46.89 ± 16.23, a 28 day survival rate of 57.14% (72/126), an incidence rate of VF/VT within 72 h of VA-ECMO initiation of 27.78% (35/126), and 80% of whom (28/35) received extracorporeal cardiopulmonary resuscitation. The incidence of VF/VT resulting from cardiac arrest at an early stage was significantly higher than that of refractory cardiogenic shock (80% vs. 20%; P = 0.022). The restricted cubic spline model revealed a U-shaped relationship between VF/VT incidence and initial heart rate (iHR), and multivariate logistic regression analysis showed that an iHR > 120 b.p.m. [odds ratio (OR) 6.117; 95% confidence interval (CI) 1.672-22.376; P = 0.006] and hyperlactataemia (OR 1.125; 95% CI 1.016-1.246; P = 0.023) within 1 h of VA-ECMO initiation were independent risk factors for the occurrence of VF/VT. VF/VT was not found to be associated with the 28 day survival of patients undergoing VA-ECMO support, nor did it affect other secondary endpoints. Defibrillation did not alter the overall prognosis in patients with VF/VT during VA-ECMO. CONCLUSIONS: An iHR > 120 b.p.m. and hyperlactataemia were independent risk factors for the occurrence of VF/VT within 72 h of VA-ECMO initiation. The occurrence of VF/VT does not affect, nor does defibrillation in these patients improve the overall patient prognosis. TRIAL REGISTRATION: ChiCTR1900026105.

Risk of atrial arrhythmias in patients with ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: In arrhythmogenic right ventricular cardiomyopathy (ARVC), risk of atrial arrhythmias (AAs) persists after ventricular tachycardia (VT) ablation. OBJECTIVE: The purpose of this study was to determine the type, prevalence, outcome, and risk correlates of AA in ARVC in patients undergoing VT ablation. METHODS: Prospectively collected procedural and clinical data on ARVC patients undergoing VT ablation were analyzed. Risk score for typical atrial flutter was determined from univariate logistic regression analysis. RESULTS: Of 119 consecutive patients with ARVC and VT ablation, 40 (34%) had AA: atrial fibrillation (AF) in 31, typical isthmus-dependent atrial flutter (AFL) in 27, and atrial tachycardia/atypical flutter (AT) in 10. Seventeen patients (43%) with AA experienced inappropriate defibrillator therapy, with 15 patients experiencing shocks. Ablation was performed for typical AFL in 21 (53%), AT in 5 (13%), and pulmonary vein isolation for AF in 4 (10%) patients and prevented AA in 78% and all AFL during additional mean follow-up of 65 months. Risk score for typical flutter included age >40 years (1 point), ≥moderate right ventricular dysfunction (2 points), ≥moderate tricuspid regurgitation (2 points), ≥moderate right atrial dilation (2 points), and right ventricular volume >250 cc (3points), with score >4 identifying 50% prevalence of typical flutter. CONCLUSION: AAs are common in patients with ARVC and VT, can result in inappropriate implantable cardioverter-defibrillator shocks, and typically are controlled with atrial ablation. A risk score can be used to identify patients at high risk for typical AFL who may be considered for isthmus ablation at the time of VT ablation.

Arrhythmic Risk in Biventricular Pacing Compared With Left Bundle Branch Area Pacing: Results From the I-CLAS Study.

BACKGROUND: Left bundle branch area pacing (LBBAP) may be associated with greater improvement in left ventricular ejection fraction and reduction in death or heart failure hospitalization compared with biventricular pacing (BVP) in patients requiring cardiac resynchronization therapy. We sought to compare the occurrence of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and new-onset atrial fibrillation (AF) in patients undergoing BVP and LBBAP. METHODS: The I-CLAS study (International Collaborative LBBAP Study) included patients with left ventricular ejection fraction ≤35% who underwent BVP or LBBAP for cardiac resynchronization therapy between January 2018 and June 2022 at 15 centers. We performed propensity score-matched analysis of LBBAP and BVP in a 1:1 ratio. We assessed the incidence of VT/VF and new-onset AF among patients with no history of AF. Time to sustained VT/VF and time to new-onset AF was analyzed using the Cox proportional hazards survival model. RESULTS: Among 1778 patients undergoing cardiac resynchronization therapy (BVP, 981; LBBAP, 797), there were 1414 propensity score-matched patients (propensity score-matched BVP, 707; propensity score-matched LBBAP, 707). The occurrence of VT/VF was significantly lower with LBBAP compared with BVP (4.2% versus 9.3%; hazard ratio, 0.46 [95% CI, 0.29-0.74]; P<0.001). The incidence of VT storm (>3 episodes in 24 hours) was also significantly lower with LBBAP compared with BVP (0.8% versus 2.5%; P=0.013). Among 299 patients with cardiac resynchronization therapy pacemakers (BVP, 111; LBBAP, 188), VT/VF occurred in 8 patients in the BVP group versus none in the LBBAP group (7.2% versus 0%; P<0.001). In 1194 patients with no history of VT/VF or antiarrhythmic therapy (BVP, 591; LBBAP, 603), the occurrence of VT/VF was significantly lower with LBBAP than with BVP (3.2% versus 7.3%; hazard ratio, 0.46 [95% CI, 0.26-0.81]; P=0.007). Among patients with no history of AF (n=890), the occurrence of new-onset AF >30 s was significantly lower with LBBAP than with BVP (2.8% versus 6.6%; hazard ratio, 0.34 [95% CI, 0.16-0.73]; P=0.008). The incidence of AF lasting >24 hours was also significantly lower with LBBAP than with BVP (0.7% versus 2.9%; P=0.015). CONCLUSIONS: LBBAP was associated with a lower incidence of sustained VT/VF and new-onset AF compared with BVP. This difference remained significant after adjustment for differences in baseline characteristics between patients with BVP and LBBAP. Physiological resynchronization by LBBAP may be associated with lower risk of arrhythmias compared with BVP.

Epidemiology of arrhythmogenic ventricular cardiomyopathy in China.

BACKGROUND: Arrhythmogenic ventricular cardiomyopathy (AVC) is a common cause of ventricular arrhythmias and mortality, but limited data are available from large Asian cohorts. Our aim was to explore the current status of AVC and second, we examined the prevalence of ventricular tachycardia (VT), heart failure (HF) and mortality in patients with AVC in the Chinese population. HYPOTHESIS: At present, some studies have reported that the incidence of AVC is on the rise, which may be due to the increasing number of diagnostic methods for AVC. However, there is no epidemiological data on AVC in the Chinese population, so we speculate that the incidence of AVC in the Chinese population is increasing. METHODS AND RESULTS: We studied 15 888 adults from the Beijing Municipal Health Commission Information Center (BMHCIC) registry database in China from January 2010 to December 2020, and calculated the average annual percentage change (AAPC). Second, we determined the incidence of VT, HF and mortality in patients with AVC. Of the 10 318 men and 5570 women who were screened by cardiac magnetic resonance or examined by myocardial biopsy, there were a total of 256 newly diagnosed AVC patients (mean [SD]: 37.54[17.10]; 39.45% female). The incidence of AVC increased from 7.60 (3.12-12.06) in 2010 to 19.62 (11.51-27.75) per 1000 person-years in 2020. Males had higher incidence of AVC than females. The AAPC for the rising incidence of AVC was 8.9 %. Males had similar VT prevalence (70.32% vs. 62.38%, p = 0.19) and mortality (1.94% vs. 1.98%, p = 0.98) but lower HF prevalence (42.58% vs. 60.40%, p = 0.006), when compared to females. Radiofrequency ablation (RFA) was more likely to be performed in males (p = 0.006). CONCLUSIONS: The rising trend in AVC incidence was evident, with two-fold increase by 2020. Males with AVC had similar VT prevalence and mortality rate, but HF prevalence were lower than females, perhaps impacted by RFA use.

Reversed Septal Curvature Is Associated With Nonsustained Ventricular Tachycardia in Hypertrophic Cardiomyopathy.

Sudden cardiac death (SCD) is associated with nonsustained ventricular tachycardia (NSVT) in patients with hypertrophic cardiomyopathy (HCM). Recently, differences regarding septal morphology have been reported, with an increased probability of sudden death in patients with HCM who had reverse septal curvature (RSC). This study aimed to examine the relation between RSC and NSVT in HCM. A total of 138 patients with HCM were enrolled. Of 138 patients, 47 (34.1%) were diagnosed with RSC and 42 patients (30.4%) had NSVT. Compared with the non-RSC group, those with RSC were much younger and had an increased incidence of NSVT, thicker septal thickness, larger mass, and a higher proportion of HCM or SCD family history. Furthermore, patients with RSC had a higher risk of SCD according to the European Society of Cardiology calculator (2.5 [1.6 to 4.6] vs 1.6 [1.1 to 2.3] [%/5 years], p <0.001). The multivariate analysis showed that RSC was a strong and independent risk factor for NSVT (odds ratio 2.756, 95% confidence interval 1.164 to 6.525, p = 0.021). In conclusion, the presence of RSC in patients with HCM is independently associated with NSVT. Further studies are needed to evaluate the role of RSC as a risk factor for SCD in this population.

Major in-hospital complications after catheter ablation of cardiac arrhythmias: individual case analysis of 43 031 procedures.

AIMS: In-hospital complications of catheter ablation for atrial fibrillation (AF), atrial flutter (AFL), and ventricular tachycardia (VT) may be overestimated by analyses of administrative data. METHODS AND RESULTS: We determined the incidences of in-hospital mortality, major bleeding, and stroke around AF, AFL, and VT ablations in four German tertiary centres between 2005 and 2020. All cases were coded by the G-DRG- and OPS-systems. Uniform code search terms were applied defining both the types of ablations for AF, AFL, and VT and the occurrence of major adverse events including femoral vascular complications, iatrogenic tamponade, stroke, and in-hospital death. Importantly, all complications were individually reviewed based on patient-level source records. Overall, 43 031 ablations were analysed (30 361 AF; 9364 AFL; 3306 VT). The number of ablations/year more than doubled from 2005 (n = 1569) to 2020 (n = 3317) with 3 times and 2.5 times more AF and VT ablations in 2020 (n = 2404 and n = 301, respectively) as compared to 2005 (n = 817 and n = 120, respectively), but a rather stable number of AFL ablations (n = 554 vs. n = 612). Major peri-procedural complications occurred in 594 (1.4%) patients. Complication rates were 1.1% (n = 325) for AF, 1.0% (n = 95) for AFL, and 5.3% (n = 175) for VT. With an increase in complex AF/VT procedures, the overall complication rate significantly increased (0.76% in 2005 vs. 1.81% in 2020; P = 0.004); but remained low over time. Following patient-adjudication, all in-hospital cardiac tamponades (0.7%) and strokes (0.2%) were related to ablation. Major femoral vascular complications requiring surgical intervention occurred in 0.4% of all patients. The in-hospital mortality rate adjudicated to be ablation-related was lower than the coded mortality rate: AF: 0.03% vs. 0.04%; AFL: 0.04% vs. 0.14%; VT: 0.42% vs. 1.48%. CONCLUSION: Major adverse events are low and comparable after catheter ablation for AFL and AF (∼1.0%), whereas they are five times higher for VT ablations. In the presence of an increase in complex ablation procedures, a moderate but significant increase in overall complications from 2005-20 was observed. Individual case analysis demonstrated a lower than coded ablation-related in-hospital mortality. This highlights the importance of individual case adjudication when analysing administrative data.

Flecainide Is Associated With a Lower Incidence of Arrhythmic Events in a Large Cohort of Patients With Catecholaminergic Polymorphic Ventricular Tachycardia.

BACKGROUND: In severely affected patients with catecholaminergic polymorphic ventricular tachycardia, beta-blockers are often insufficiently protective. The purpose of this study was to evaluate whether flecainide is associated with a lower incidence of arrhythmic events (AEs) when added to beta-blockers in a large cohort of patients with catecholaminergic polymorphic ventricular tachycardia. METHODS: From 2 international registries, this multicenter case cross-over study included patients with a clinical or genetic diagnosis of catecholaminergic polymorphic ventricular tachycardia in whom flecainide was added to beta-blocker therapy. The study period was defined as the period in which background therapy (ie, beta-blocker type [beta1-selective or nonselective]), left cardiac sympathetic denervation, and implantable cardioverter defibrillator treatment status, remained unchanged within individual patients and was divided into pre-flecainide and on-flecainide periods. The primary end point was AEs, defined as sudden cardiac death, sudden cardiac arrest, appropriate implantable cardioverter defibrillator shock, and arrhythmic syncope. The association of flecainide with AE rates was assessed using a generalized linear mixed model assuming negative binomial distribution and random effects for patients. RESULTS: A total of 247 patients (123 [50%] females; median age at start of flecainide, 18 years [interquartile range, 14-29]; median flecainide dose, 2.2 mg/kg per day [interquartile range, 1.7-3.1]) were included. At baseline, all patients used a beta-blocker, 70 (28%) had an implantable cardioverter defibrillator, and 21 (9%) had a left cardiac sympathetic denervation. During a median pre-flecainide follow-up of 2.1 years (interquartile range, 0.4-7.2), 41 patients (17%) experienced 58 AEs (annual event rate, 5.6%). During a median on-flecainide follow-up of 2.9 years (interquartile range, 1.0-6.0), 23 patients (9%) experienced 38 AEs (annual event rate, 4.0%). There were significantly fewer AEs after initiation of flecainide (incidence rate ratio, 0.55 [95% CI, 0.38-0.83]; P=0.007). Among patients who were symptomatic before diagnosis or during the pre-flecainide period (n=167), flecainide was associated with significantly fewer AEs (incidence rate ratio, 0.49 [95% CI, 0.31-0.77]; P=0.002). Among patients with ≥1 AE on beta-blocker therapy (n=41), adding flecainide was also associated with significantly fewer AEs (incidence rate ratio, 0.25 [95% CI, 0.14-0.45]; P<0.001). CONCLUSIONS: For patients with catecholaminergic polymorphic ventricular tachycardia, adding flecainide to beta-blocker therapy was associated with a lower incidence of AEs in the overall cohort, in symptomatic patients, and particularly in patients with breakthrough AEs while on beta-blocker therapy.

Incidence, management, and prognostic impact of arrhythmias in patients with Takotsubo syndrome: a nationwide retrospective cohort study.

AIMS: Arrhythmia is a major complication of Takotsubo syndrome (TTS). However, its incidence, management, and prognostic impact remain to be elucidated in a large cohort. METHODS AND RESULTS: We retrospectively identified 16 713 patients hospitalized for TTS between July 2010 and March 2021 from the Japanese Diagnosis Procedure Combination database. Serious arrhythmias were defined as ventricular tachycardia/fibrillation (VT/VF), 2nd-/3rd-degree atrioventricular block (AVB), sick sinus syndrome (SSS), or unspecified arrhythmias requiring device treatment. Patient characteristics and outcomes were compared based on the occurrence of serious arrhythmias. The overall incidence proportion of serious arrhythmias was 6.2% (n = 1036; 449 VT/VF, 283 2nd-/3rd-degree AVB, 133 SSS, 55 multiple arrhythmias, 116 others), which remained stable over 11 years. The arrhythmia group was younger, more often male, and exhibited greater impairment in activities of daily living (ADLs) and consciousness than the non-arrhythmia group. Although crude in-hospital mortality was higher in the arrhythmia group (9.6% vs. 5.0%, P < 0.001), the significant association between arrhythmias and mortality disappeared after adjustment for confounders (odds ratio = 1.15, 95% confidence interval = 0.90-1.49). Meanwhile, age, sex, ADLs, consciousness level, and Charlson comorbidity index were significantly associated with mortality. In the arrhythmia group, 254 (24.5%) patients received pacemakers (18.4%) or defibrillators (6.1%), which were implanted at a median of 8 and 19 days after admission, respectively. CONCLUSION: Arrhythmias are not uncommon in TTS. Patients' background characteristics, rather than arrhythmia itself, may be associated with in-hospital mortality. Given the reversibility of cardiac dysfunction in TTS, there may be unnecessary device implantations for arrhythmias occurring as sequelae to TTS, warranting further investigations.

Ventricular Arrhythmias in Adults With Congenital Heart Disease, Part II: JACC State-of-the-Art Review.

There are marked variations in the incidence of sudden cardiac death (SCD) and in the substrates for ventricular arrhythmias (VAs) across the gamut of congenital heart defects. In this 2-part review, patients with higher-risk forms of congenital heart disease (CHD) were conceptually categorized into those with discrete anatomic isthmuses for macro-reentrant ventricular tachycardia (VT) (Group A) and those with more diffuse or less well-defined substrates (Group B) that include patchy or extensive myocardial fibrosis. The latter category encompasses CHD lesions such as Ebstein anomaly, transposition of the great arteries with a systemic right ventricle (RV), and congenital aortic stenosis. For Group B patients, polymorphic VT and ventricular fibrillation account for a higher proportion of VA. The prognostic value of programmed ventricular stimulation is less well established, and catheter ablation plays a less prominent role. As cardiomyopathies evolve over time, pathophysiological mechanisms for VA among Groups A and B become increasingly blurred.

N-terminal pro-B-type natriuretic peptide for prediction of ventricular arrhythmias: Data from the SMASH study.

BACKGROUND: Elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations predict heart failure (HF) and mortality, but whether NT-proBNP predicts ventricular arrhythmias (VA) is not clear. HYPOTHESIS: We hypothesize that high NT-proBNP concentrations associate with the risk of incident VA, defined as adjudicated ventricular fibrillation or sustained ventricular tachycardia. METHODS: In a prospective, observational study of patients treated with implantable cardioverter defibrillator (ICD), we analyzed NT-proBNP concentrations at baseline and after mean 1.4 years in association to incident VA. RESULTS: We included 490 patients (age 66 ± 12 years, 83% men) out of whom 51% had a primary prevention ICD indication. The median NT-proBNP concentration was 567 (25-75 percentile 203-1480) ng/L and patients with higher concentrations were older with more HF and ICD for primary prevention. During mean 3.1 ± 0.7 years, 137 patients (28%) had ≥1 VA. Baseline NT-proBNP concentrations were associated with the risk of incident VA (hazard ratio [HR]: 1.39, 95% confidence interval [95% CI]: 1.22-1.58, p < .001), HF hospitalizations (HR: 3.11, 95% CI: 2.53-3.82, p < .001), and all-cause mortality (HR: 2.49, 95% CI: 2.04-3.03, p < .001), which persisted after adjusting for age, sex, body mass index, coronary artery disease, HF, renal function, and left ventricular ejection fraction. The association with VA was stronger in secondary versus primary prevention ICD indication: HR: 1.59 (95% CI: 1.34-1.88 C-statistics 0.71) versus HR: 1.24, 95% CI: 1.02-1.51, C-statistics 0.55), p-for-interaction = 0.06. Changes in NT-proBNP during the first 1.4 years did not associate with subsequent VA. CONCLUSIONS: NT-proBNP concentrations are associated with the risk of incident VA after adjustment for established risk factors, with the strongest association in patients with a secondary prevention ICD indication.

Ventricular Parasystole in Cardiomyopathy Patients: A Link Between His-Purkinje System Damage and Ventricular Fibrillation.

BACKGROUND: The clinical relevance and prognostic implications of ventricular parasystole are unknown. OBJECTIVES: This study sought to assess the prevalence of ventricular parasystole in patients with implantable cardioverter-defibrillators (ICDs) and ventricular parasystole's association with ventricular arrhythmias and conduction system abnormalities. METHODS: This study retrospectively evaluated patients who underwent ICD interrogation at a single center between June 1, 2019, and August 31, 2020, and reviewed all available ICD and electrocardiogram data. This study identified patients with ventricular parasystole and compared the prevalence of ventricular fibrillation (VF), ventricular tachycardia (VT), and new conduction system abnormalities in those with ≥5 years of intrinsic QRS-complex electrocardiograms to those without parasystole. RESULTS: This study included 374 patients (age 57 ± 21 years, 72% male, 45% nonischemic, 32% ischemic cardiomyopathy), of which, 104 (28%) had VT only, 39 (10%) VF only, and 10 (3%) both VT/VF. Ventricular parasystole was identified in 33 patients (9%); parasystolic foci were predominantly from the His-Purkinje system. Compared with those without parasystole, patients with parasystole had a significantly higher rate of VF (36% vs 11%; P < 0.01), but not VT (42% vs 29%; P = 0.12). Patients with parasystole, compared with those without parasystole, had a higher prevalence of new conduction abnormalities, particularly progressive intraventricular conduction delay (11 of 18 [61%] vs 12 of 83 [14%]; P < 0.01) and new right bundle branch block (4 of 18 [22%] vs 1 of 83 [1%]; P < 0.01). CONCLUSIONS: Ventricular parasystole was strongly associated with new conduction system abnormalities and VF in patients who have cardiomyopathy with ICDs, suggesting a potential link between VF and His-Purkinje damage in this patient population.

Arrhythmia and Survival Outcomes Among Black Patients and White Patients With a Primary Prevention Defibrillator.

BACKGROUND: Black Americans have a higher risk of nonischemic cardiomyopathy (NICM) than White Americans. We aimed to evaluate differences in the risk of tachyarrhythmias among patients with an implantable cardioverter-defibrillator (ICD). METHODS: The study population comprised 3895 ICD recipients in the United States enrolled in primary prevention ICD trials. Outcome measures included ventricular tachyarrhythmia (VTA), atrial tachyarrhythmia (ATA), ICD therapies, VTA burden (using Andersen-Gill recurrent event analysis), death, and the predicted benefit of the ICD. All events were adjudicated blindly. Outcomes were compared between self-reported Black patients versus White patients with cardiomyopathy (ischemic and NICM). RESULTS: Black patients were more likely to be female (35% versus 22%) and younger (57±12 versus 62±12 years) with a higher frequency of comorbidities. In NICM, Black patients had a higher rate of first VTA, fast VTA, ATA, and appropriate and inappropriate ICD therapy (VTA ≥170 bpm, 32% versus 20%; VTA ≥200 bpm, 22% versus 14%; ATA, 25% versus 12%; appropriate therapy, 30% versus 20%; and inappropriate therapy, 25% versus 11%; P<0.001 for all). Multivariable analysis showed that Black patients with NICM experienced a higher risk of all types of arrhythmia or ICD therapy (VTA ≥170 bpm, hazard ratio [HR] 1.71; VTA ≥200 bpm, HR 1.58; ATA, HR 1.87; appropriate therapy, HR 1.62; inappropriate therapy, HR 1.86; P≤0.01 for all), higher burden of tachyarrhythmias or therapies (VTA, HR 1.84; appropriate therapy, HR 1.84; P<0.001 for both), and a higher risk of death (HR 1.92; P=0.014). In contrast, in ischemic cardiomyopathy, the risk of all types of tachyarrhythmia, ICD therapy, or death was similar between Black patients and White patients. Both Black patients and White patients derived a significant and similar benefit from ICD implantation. CONCLUSIONS: Among patients with NICM with an ICD for primary prevention, Black patients compared with White patients had a high risk and burden of VTA, ATA, and ICD therapies with a lower survival rate. Nevertheless, the overall benefit of the ICD was maintained and was similar to that of White patients.

Ventricular arrhythmias in patients with hypertrophic cardiomyopathy: Prevalence, distribution, predictors, and outcome.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) carries an increased risk of sudden cardiac death. Ventricular fibrillation (VF) is thought to be the common culprit arrhythmia. OBJECTIVE: The purpose of this study was to describe the incidence and predictors of sustained ventricular arrhythmias (VTAs) in HCM patients. METHODS: We retrospectively analyzed all patients with HCM and an implantable cardioverter-defibrillator (ICD) from a prospectively derived registry in 2 tertiary medical centers. Clinical, electrocardiographic, echocardiographic, ICD interrogation, and genetic data were collected and compared, first between patients with and without VTAs and then between patients with only VF and those with ventricular tachycardia (VT) with or without VF. RESULTS: Of the 1328 HCM patients, 207 (145 [70%] male; mean age 33 ± 16 years) were implanted with ICDs. Over a mean follow-up of 10 ± 6 years, 37 patients with ICDs (18%) developed sustained VTAs. These were associated with a family history of sudden cardiac death and a personal history of VTAs (P = .036 and P = .001, respectively). Sustained monomorphic VT was the most common arrhythmia (n = 26, 70%) and was linked to decreased left ventricular (LV) ejection fraction and increased LV end-systolic and end-diastolic diameters. Antitachycardia pacing (ATP) successfully terminated 258 (79%) of the 326 VT events. Mortality rates were comparable between patients with and without VTAs (4 [11%] vs 29 [17%]; P = .42) and between those with and without ICDs (24 [16%] vs 85 [20%]; P = .367). CONCLUSION: VT rather than VF is the most common arrhythmia in patients with HCM; it is amenable to ATP and is associated with lower LV ejection fraction and higher LV diameters. Therefore, ATP-capable devices may be considered in HCM patients with these LV features.

Outcomes of Ventricular Tachycardia Catheter Ablation in Patients Who Underwent Cardiac Defibrillator Implantation Nationwide Readmission Database Analysis.

The timing of when to perform ventricular tachycardia (VT) ablation while receiving an implantable cardioverter defibrillator (ICD) during the same hospitalization has not been explored. This study aimed to investigate the use and outcomes of VT catheter ablation in patients with sustained VT receiving ICD in the same hospital stay. The Nationwide Readmission Database 2016 to 2019 was queried for all hospitalizations with a primary diagnosis of VT with subsequent ICD during the same admission. Hospitalizations were later stratified according to whether a VT ablation was performed. All catheter ablation of VT were performed before ICD implantation. The outcomes of interest were in-hospital mortality and 90-day readmission. A total of 29,385 VT hospitalizations were included. VT ablation was performed with subsequent ICD placement in 2,255 (7.6%), whereas 27,130 (92.3%) received an ICD only. No differences were found regarding in-hospital mortality (adjusted odds ratio [aOR] 0.83, 95% confidence interval [CI] 0.35 to 1.9, p = 0.67) and all-cause 90-day readmission rate (aOR 1.1, 95% CI 0.95 to 1.3, p = 0.16). An increase in readmission because of recurrent VT was noted in the VT ablation group (aOR 1.53, 8% vs 5% CI 1.2 to 1.9, p <0.01); the VT ablation group encompassed a higher number of patients with heart failure with reduced ejection fraction (p <0.01), cardiogenic shock (p <0.01), and mechanical circulatory support use (p <0.01). In conclusion, the use of VT ablation in patients admitted with sustained VT is low and reserved for higher risk patients with significant co-morbidities. Despite the higher risk profile of VT ablation cohort, no differences were found in the short-term mortality and readmission rate between the groups.