Predictors of ventricular tachyarrhythmia in patients with a wearable cardioverter defibrillator: an international multicenter registry.

BACKGROUND AND AIMS: Wearable cardioverter defibrillator (WCD) can protect patients from sudden cardiac death due to ventricular tachyarrhythmias and serve as a bridge to decision of definite defibrillator implantation. The aim of this analysis from an international, multicenter WCD registry was to identify predictors of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) in this population. METHODS: One thousand six hundred seventy-five patients with WCD were included in a multicenter registry from 9 European centers, with a median follow-up of 440 days (IQR 120-893). The primary study end point was the occurrence of sustained VT/VF. RESULTS: Sustained VT was detected by WCD in 5.4% and VF in 0.9% of all patients. Of the 30.3% of patients receiving ICD implantation during follow-up, sustained VT was recorded in 9.3% and VF in 2.6%. Non-ischemic cardiomyopathy (HR 0.5, p < 0.001), and medication with angiotensin-converting enzyme inhibitors (HR 0.7, p = 0.027) and aldosterone antagonists (HR 0.7, p = 0.005) were associated with a significantly lower risk of VT/VF. CONCLUSIONS: Patients who received WCD due to a transient increased risk of sudden cardiac death have a comparatively lower risk of VT/VF in the presence of non-ischemic cardiomyopathy. Of note, optimal medical treatment for heart failure not only results in an improvement in left ventricular ejection fraction but also in a reduction in the risk for VT/VF.

Prognostic value of extended cardiac risk assessment before elective open abdominal aortic surgery.

BACKGROUND: Major vascular surgery is associated with a high perioperative risk and significant mortality. Despite advances in risk stratification, monitoring, and management of perioperative complications, cardiac complications are still common. Stress echocardiography is well established in coronary artery disease diagnostics; however, its prognostic value before high-risk aortic surgery is unknown. This prospective, single-center study compared the outcome of patients undergoing extended cardiac risk assessment before open abdominal aortic surgery with the outcome of patients who had received standard preoperative assessment. METHODS: The study included patients undergoing elective open abdominal aortic surgery. Patients who underwent standard preoperative assessment before the start of a dedicated protocol were compared with patients who had extended cardiac risk assessment, including dobutamine stress echocardiography, as part of a stepwise interdisciplinary cardiovascular team approach. The combined primary endpoint was cardiovascular death, myocardial infarction, emergency coronary revascularization, and life-threatening arrhythmia within 30 days. The secondary endpoint was acute renal failure and severe bleeding. RESULTS: In total, 77 patients (mean age 68.1 ± 8.1 years, 70% male) were included: 39 underwent standard and 38 underwent cardiac risk assessment. The combined primary endpoint was reached significantly more often in patients before than after implementation of the extended cardiac stratification procedure (15% vs. 0%, p = 0.025). The combined secondary endpoint did not differ between the groups. CONCLUSIONS: Patients with extended cardiac risk assessment undergoing elective open abdominal aortic surgery had better 30-day outcomes than did those who had standard preoperative assessment.

Use of the Wearable Cardioverter-Defibrillator Among Patients With Myocarditis and Reduced Ejection Fraction or Ventricular Tachyarrhythmia: Data From a Multicenter Registry.

Background Data on the use of the wearable cardioverter-defibrillator (WCD) among patients with myocarditis remain sparse. Consequently, evidence for guideline recommendations in this patient population is lacking. Methods and Results In total, 1596 consecutive patients were included in a multicenter registry from 8 European centers, with 124 patients (8%) having received the WCD due to myocarditis and reduced left ventricular ejection fraction or prior ventricular tachyarrhythmia. The mean age was 51.6±16.3 years, with 74% being male. Patients were discharged after index hospitalization on heart failure medication: Angiotensin-converting enzyme inhibitors (62.5%), angiotensin-receptor-neprilysin inhibitor (22.9%), aldosterone-antagonists (51%), or beta blockers (91.4%). The initial median left ventricular ejection fraction was 30% (22%-45%) and increased to 48% (39%-55%) over long-term follow-up (P<0.001). The median BNP (brain natriuretic peptide) level at baseline was 1702 pg/mL (565-3748) and decreased to 188 pg/mL (26-348) over long-term follow-up (P=0.022). The mean wear time was 79.7±52.1 days and 21.0±4.9 hours per day. Arrhythmic event rates documented by the WCD were 9.7% for nonsustained ventricular tachycardia, 6.5% for sustained ventricular tachycardia, and 0% for ventricular fibrillation. Subsequently, 2.4% of patients experienced an appropriate WCD shock. The rate of inappropriate WCD shocks was 0.8%. All 3 patients with appropriate WCD shock had experienced ventricular tachycardia/ventricular fibrillation before WCD prescription, with only 1 patient showing a left ventricular ejection fraction <35%. Conclusions Patients with myocarditis and risk for occurrence of ventricular tachyarrhythmia may benefit from WCD use. Prior ventricular arrhythmia might appear as a better risk predictor than a reduced left ventricular ejection fraction <35% in this population.

Age differences of patients treated with wearable cardioverter defibrillator: Data from a multicentre registry.

BACKGROUND: Wearable cardioverter defibrillators (WCD) are used as a 'bridging' technology in patients, who are temporarily at high risk for sudden cardiac death (SCD). Several factors should be taken into consideration, for example patient selection, compliance and optimal drug treatment, when WCD is prescribed. We aimed to present real-world data from seven centres from Germany and Switzerland according to age differences regarding the outcome, prognosis, WCD data and compliance. MATERIALS AND METHODS: Between 04/2012 and 03/2021, 1105 patients were included in this registry. Outcome data according to age differences (old ≥45 years compared to young <45 years) were analysed. At young age, WCDs were more often prescribed due to congenital heart disease and myocarditis. On the other hand, ischaemic cardiomyopathy (ICM) was more present in older patients. Wear days of WCD were similar between both groups (p = .115). In addition, during the WCD use, documented arrhythmic life-threatening events were comparable [sustained ventricular tachycardia: 5.8% vs. 7.7%, ventricular fibrillation (VF) .5% vs. .6%] and consequently the rate of appropriate shocks was similar between both groups. Left ventricular ejection fraction improvement was documented over follow-up with a better improvement in younger patients as compared to older patients (77% vs. 63%, p = .002). In addition, at baseline, the rate of atrial fibrillation was significantly higher in the older age group (23% vs. 8%; p = .001). The rate of permanent cardiac implantable electronic device implantation (CiED) was lower in the younger group (25% vs. 36%, p = .05). The compliance rate defined as wearing WCD at least 20 h per day was significantly lower in young patients compared to old patients (68.9% vs. 80.9%, p < .001). During the follow-up, no significant difference regarding all-cause mortality or arrhythmic death was documented in both groups. A low compliance rate of wearing WCD is predicted by young patients and patients suffering from non-ischaemic cardiomyopathies. CONCLUSION: Although the compliance rate in different age groups is high, the average wear hours tended to be lower in young patients compared to older patients. The clinical events were similar in younger patients compared to older patients.

Sex differences and adherence of patients treated with wearable cardioverter-defibrillator: Insights from an international multicenter register.

AIMS: Treatment with the wearable cardioverter defibrillator (WCD) may protect against sudden cardiac death (SCD) as a bridging therapy until a cardioverter-defibrillator may be implanted. We analyzed in a multicenter setting a consecutive patient cohort wearing WCD to explore sex differences. METHODS AND RESULTS: We analyzed 708 consecutive patients, 579 (81.8%) from whom were males and 129 (18.2%) females (age, 60.5 ± 14 vs. 61.6 ± 17 years old; p = .44). While the rate of ischemic cardiomyopathy (ICM) as a cause of prescription of WCD was significantly higher in males as compared to females (42.7% vs. 26.4%; p = .001), females received it more frequently due to nonischemic cardiomyopathy (NICM) (55.8% vs. 42.7%); p = .009). The wear time of WCD was equivalent in both groups (21.1 ± 4.3 h/days in males vs. 21.5 ± 4.4 h/days in females; p = .27; and 62.6 ± 44.3 days in males vs. 56.5 ± 39 days in females; p = .15). Mortality was comparable in both groups at 2-year-follow-up (6.8% in males vs. 9.7% in females; p = .55). Appropriate WCD shocks and the incidence of ICD implantations were similar in both groups (2.4% in males vs. 3.9% in females; p = .07) (35.1% in males vs. 31.8% in females; p = .37), respectively. In age tertile analysis, compliance was observed more in 73-91 years old group as compared with 14-51 years old group (87.8% vs. 68.3%; p < .001). CONCLUSION: Compliance for wearing WCD was excellent regardless of sex. Furthermore, mortality and the incidence of ICD implantations were comparable in both sexes. Appropriate WCD shocks were similar in both sexes.

Diagnostic Value of sST2, VCAM-1, and Adiponectin in Patients with Breast Cancer to Predict Anti-Tumour Treatment-Related Cardiac Events: A Pilot Study.

AIM: The present exploratory study investigated the diagnostic value of inflammatory markers in patients with breast cancer to predict anti-tumour treatment-related cardiac events. METHODS: Twenty-one patients with breast cancer were enrolled in this prospective observational study and followed over 6 months. Transthoracic echocardiography and measurement of cardiac (N-terminal prohormone of brain natriuretic peptide (NT-proBNP), troponin I (TnI)) and inflammatory biomarkers (vascular adhesion molecule 1 (VCAM-1), soluble suppression of tumorigenesis-2 (sST2), adiponectin) was performed at 3-month intervals (baseline, follow-up, final visit). Cardiac events were defined as decrease in left ventricular ejection fraction (LVEF, decrease by 10% or <50%) or increase in global longitudinal strain (GLS, increase by 15% or > -16%), as a more sensitive marker of LV function. RESULTS: Cardiac deterioration was observed in 9 out of 21 patients (event group). While LVEF did not differ significantly between the two groups (event vs. no event) at any visit, GLS was significantly higher during follow-up (follow-up: event -16 ± 3.3% vs. no event -18 ± 1.6%, p = 0.04; final visit: event -16 ± 2.1% vs. no event -19 ± 1.9%, p = 0.003). NT-proBNP was numerically higher in patients with a cardiac event during all visits, with NT-proBNP negatively correlated with LVEF and MAPSE (both r = -0.33, p = 0.02), whereas GLS (r = 0.40, p = 0.006), TnI (r = 0.44, p = 0.001), and VCAM-1 (r = 0.48, p = 0.003) showed a positive association with NT-proBNP. In comparison, higher VCAM-1 and sST2 concentrations were detected in the event group at both baseline and the final visit, with a significant difference for baseline (VCAM-1: p = 0.02; sST2: p = 0.03). Adiponectin was also lower in patients with a treatment-related event. Thresholds for VCAM-1 >762 ng/mL and sST2 >18.7 ng/mL, as detected by ROC analysis, correlated best with the primary endpoint. CONCLUSION: Cardiac events during anti-tumour treatment in patients with breast cancer are relatively common. Inflammatory markers such as VCAM-1 or sST2 were associated with an increased likelihood for occurrence of a treatment-related event, which may therefore hold the promise to better identify patients at high risk.

Adverse Cardiovascular Effects of Anti-tumor Therapies in Patients With Breast Cancer: A Single-center Cross-sectional Analysis.

BACKGROUND/AIM: Cardiotoxicity due to antitumor therapy is a dreaded complication and could thus impact the prognosis of patients with breast cancer. This study sought to analyze the occurrence of adverse cardiovascular events and to identify potential risk factors. PATIENTS AND METHODS: A total of 136 patients with breast cancer were divided into two groups based on the occurrence of treatment-related cardiovascular toxicity [event 47 (35%) vs. no event 89 (65%)]. Patients were followed over a median of 45 months (range=37-83 months). RESULTS: Most common events were thromboembolic complications (26%), followed by heart failure (15%) and acute toxic cardiomyopathy (5%), with a reduced left ventricular ejection fraction [LVEF (%), no event 59±5.0 vs. event 55±11, p=0.01 ]. Patients with leftsided breast cancer and an advanced stage disease had a higher risk of developing adverse cardiovascular events. The highest risk was found for patients with a high number of cardiovascular risk factors. In addition to LVEF, mitral annular plane systolic excursion was also significantly reduced in the event group, while there was a trend for higher global longitudinal strain. During follow-up, 26 patients (19.1%) deceased, whereof 12 had a treatment-related cardiovascular event, but without statistical difference. CONCLUSION: Treatment-related cardiovascular events are relatively common in about one third of patients with breast cancer. Women with a cardiovascular risk profile or an advanced stage disease had a higher risk for adverse events. Despite the treatment-related cardiac deterioration, no difference in mortality was observed during follow up.

Real life experience with the wearable cardioverter-defibrillator in an international multicenter Registry.

Patients at high risk for sudden cardiac death (SCD) may benefit from wearable cardioverter defibrillators (WCD) by avoiding immediate implantable cardioverter defibrillator (ICD) implantation. Different factors play an important role including patient selection, compliance and optimal drug treatment. We aimed to present real world data from 4 centers from Germany and Switzerland. Between 04/2012 and 03/2019, 708 patients were included in this registry. Patients were followed up over a mean time of 28 ± 35.5 months. Outcome data including gender differences and different etiologies of cardiomyopathy were analyzed. Out of 708 patients (81.8% males, mean age 61.0 ± 14.6), 44.6% of patients had non-ischemic cardiomyopathy, 39.8% ischemic cardiomyopathy, 7.9% myocarditis, 5.4% prior need for ICD explantation and 2.1% channelopathy. The mean wear time of WCD was 21.2 ± 4.3 h per day. In 46% of patients, left ventricular ejection fraction (LVEF) was > 35% during follow-up. The younger the patient was, the higher the LVEF and the lower the wear hours per day were. The total shock rate during follow-up was 2.7%. Whereas an appropriate WCD shock was documented in 16 patients (2.2%), 3 patients received an inappropriate ICD shock (0.5%). During follow-up, implantation of a cardiac implantable electronic device was carried out in 34.5% of patients. When comparing German patients (n = 516) to Swiss patients (n = 192), Swiss patients presented with longer wear days (70.72 ± 49.47 days versus 58.06 ± 40.45 days; p = 0.001) and a higher ICD implantation rate compared to German patients (48.4% versus 29.3%; p = 0.001), although LVEF at follow-up was similar between both groups. Young age is a negative independent predictor for the compliance in this large registry. The most common indication for WCD was non-ischemic cardiomyopathy followed by ischemic cardiomyopathy. The compliance rate was generally high with a decrease of wear hours per day at younger age. Slight differences were found between Swiss and German patients, which might be related to differences in mentality for ICD implantation.

Gender aspects in cardiooncology.

BACKGROUND: Cardiooncology is a relatively new subspeciality, investigating the side effects of cytoreductive therapies on the cardiovascular (CV) system. Gender differences are well known in oncological and CV diseases, but are less elucidated in cardiooncological collectives. METHODS: Five hundred and fifty-one patients (278 male, 273 female) with diagnosed cancer who underwent regular cardiological surveillance were enrolled in the 'MAnnheim Registry for CardioOncology' and followed over a median of 41 (95% confidence interval: 40-43) months. RESULTS: Female patients were younger at the time of first cancer diagnosis [median 60 (range 50-70) vs. 66 (55-75), P = 0.0004], while the most common tumour was breast cancer (49.8%). Hyperlipidaemia was more often present in female patients (37% vs. 25%, P = 0.001). Male patients had a higher cancer susceptibility than female patients. They suffered more often from hypertension (51% vs. 67%, P = 0.0002) or diabetes (14% vs. 21%, P = 0.02) and revealed more often vitamin D deficiency [(U/l) median 26.0 (range 17-38) vs. 16 (9-25), P = 0.002] and anaemia [(g/dl) median 11.8 (range 10.4-12.9) vs. 11.7 (9.6-13.6), P = 0.51]. During follow-up, 140 patients died (male 77, female 63; P = 0.21). An increased mortality rate was observed in male patients (11.4% vs. 14%, P = 0.89), with even higher mortality rates of up to 18.9% vs. 7.7% (P = 0.02) considering tumours that can affect both sexes compared. CONCLUSIONS: Although female patients were younger at the time of first cancer diagnosis, male patients had both higher cancer susceptibility and an increased mortality risk. Concomitant CV diseases were more common in male patients.

Blood Cholesterol and Outcome of Patients with Cancer under Regular Cardiological Surveillance.

Cardiovascular (CV) diseases and cancer share several similarities, including common risk factors. In the present investigation we assessed the relationship between cholesterol levels and mortality in a cardiooncological collective. In total, 551 patients receiving anticancer treatment were followed over a median of 41 (95% CI 40, 43) months and underwent regular cardiological surveillance. A total of 140 patients (25.4%) died during this period. Concomitant cardiac diseases were more common in patients who deceased (53 (37.9%) vs. 67 (16.3%), p < 0.0001), as well as prior stroke. There were no differences in the distribution of classical CV risk factors, such as hypertension, diabetes or nicotine consumption. While total cholesterol (mg/dL) was significantly lower in patients who deceased (157 ± 59 vs. 188 ± 53, p < 0.0001), both HDL and LDL cholesterol were not differing. In addition, cholesterol levels varied between different tumour entities; lowest levels were found in patients with tumours of the hepatopancreaticobiliary system (median 121 mg/dL), while patients with melanoma, cerebral tumours and breast cancer had rather high cholesterol levels (median > 190 mg/dL). Cholesterol levels were significantly lower in patients who died of cancer; lowest cholesterol levels were observed in patients who died of tumours with higher mitotic rate (mesenchymal tumours, cerebral tumours, breast cancer). Cox regression analysis revealed a significant mortality risk for patients with stem cell transplantation (HR 4.31) and metastasised tumour stages (HR 3.31), while cardiac risk factors were also associated with a worse outcome (known cardiac disease HR 1.58, prior stroke/TIA HR 1.73, total cholesterol HR 1.70), with the best discriminative performance found for total cholesterol (p = 0.002).

Prognostic Impact of Pretherapeutic Hemoglobin Levels on All-cause Mortality in Cardiooncology.

BACKGROUND/AIM: We investigated the prognostic impact of hemoglobin (Hb) levels in tumour patients receiving routine cardiological surveillance during anticancer treatment. The aim of the study was to identify independent predictors of all-cause mortality in a cardio-oncological collective. PATIENTS AND METHODS: A total of 551 patients (273 males, 278 females) were enrolled in the Mannheim Registry for Cardiooncology and were included in the present analysis. Median follow-up was 41 months (95% CI=40-43). RESULTS: Patients were grouped according to a pretherapeutic Hb-threshold (determined by ROC analysis) into cohorts with Hb<11.4 g/dl (n=232, 42.1%) and Hb >11.4 g/dl (n=319, 57.9%). Patients with lower Hb levels were older at the time of first diagnosis (63.8±14.4 vs. 59.9±15.4 years, p=0.003) and were more likely to have advanced tumour stages (92 (39.7%) vs. 83 (26.0%), p=0.0007). There were no differences regarding cardiovascular comorbidities such as hypertension or diabetes, while chronic kidney disease was more common in patients with lower Hb. Anticoagulants were used more often in patients with lower Hb (88 (37.9%) vs. 84 (26.3%), p=0.01). Left ventricular ejection fraction (LVEF) was lower in patients with Hb <11.4 g/dl (51.9±11.0% vs. 55.1±9.7%, p=0.003). Correlation analysis revealed a significant correlation of Hb levels and LVEF (R2=0.07, p<0.0001). During follow-up, a total of 140 patients (25.4%) were deceased, with significantly more deaths occurring in the group of patients with low Hb values [108 (46.6%) vs. 32 (10.0%), p<0.0001]. In multivariable analysis, Hb was identified as independent predictor for mortality (OR=5.3, CI=0.41-0.89, p<0.0001). CONCLUSION: Low Hb levels were identified as an independent predictor of mortality in patients with cancer. There was a significant correlation of Hb and LVEF, suggesting that low Hb values are not solely due to anaemia, but rather reflect the severity of cancer.

Comparison of the Outcome of Patients Protected by the Wearable Cardioverter Defibrillator (WCD) for <90 Wear Days versus ≥90 Wear Days.

BACKGROUND/AIM: The wearable cardioverter/defibrillator (WCD) is recommended to prevent sudden cardiac death (SCD). Guidelines suggest a 90 days' period, but prolongation of WCD wear time until increasing the ejection fraction (≥35%) might be suggested. PATIENTS AND METHODS: A cohort of 153 patients with prescribed WCD were divided into two groups: A <90 wear days' group (n=112) vs. ≥90 wear days' group (n=41) and followed. RESULTS: In the first group, WCD shock occurred in 3.6% of patients, 47.3% improved in left ventricular ejection fraction (LVEF) after 3 months, and 37.5% had a cardiac implantable electronic device (CIED) implantation with appropriate implantable cardioverter defibrillator (ICD) shock events occurring in 6 patients. Two of these patients already received WCD shock therapy due to ventricular fibrillation. A 20.5% improved in LVEF after 6-12 months, but 73% were already implanted with ICD. In the second group, 4.9% received WCD shock, 34.1% improved in LVEF after 3 months, 48.8% were implanted with ICD, and 2 had ICD shocks during follow up time. LVEF improvement after 6-12 months occurred in 26.8%. ICD implantation was prevented in 7.3% of patients due to LVEF recovery. CONCLUSION: Prolonging wearing days of WCD may reduce the number of inappropriate ICD implantation.

Perception of atrial fibrillation in dependence of neuroticism.

OBJECTIVE: Atrial fibrillation (AF) is associated with a varying symptom burden, which ranges from completely unawareness to disabling conditions. The present cross-sectional study tried to assess if neuroticism is associated with a greater degree of perception of AF related symptoms. METHODS: 162 patients who were considered for catheter ablation of AF were included. AF related symptom burden was quantified according to the European Heart Rhythm Association (EHRA) score. Personality traits were assessed using the Big Five personality traits (5BT). RESULTS: Female patients reported higher symptom burden. Higher EHRA scores were furthermore associated with treatment with antiarrhythmic agents, digitalis, direct oral anticoagulants (DOAC), and antidepressant treatment, as well as suffering from heart failure or chronic kidney disease. Neuroticism showed a positive correlation to AF related symptom burden with significantly higher neuroticism scores in patients with higher EHRA scores (Rho = 0.41; 95%CI 0.26 to 0.53; p < .001), while no association was demonstrated for the other four personality traits. Multiple linear regression analysis revealed neuroticism as strongest independent predictor for symptomatic AF, followed by treatment with antiarrhythmic agents and DOAC. CONCLUSIONS: Perception of AF related symptoms is a multifactorial process, which in our cohort was independently associated with neuroticism. Patients with higher symptom burden were also more likely to receive antiarrhythmic agents and DOAC, as well as antidepressants. TRIAL REGISTRATION: German registry for clinical studies (DRKS), DRKS00019007.

The Wearable Cardioverter-Defibrillator: Experience in 153 Patients and a Long-Term Follow-Up.

Background: The wearable cardioverter-defibrillator (WCD) is available for patients at high risk for sudden cardiac death (SCD) when immediate implantable cardioverter-defibrillator (ICD) implantation is not possible or indicated. Patient selection remains challenging especially in primary prevention. Long-term data on these patients is still lacking. METHODS: 153 patients were included in this study. They were prescribed the WCD between April 2012 and March 2019 at the University Medical Center, Mannheim, Germany. The mean follow-up period was 36.2 ± 15.6 months. Outcome data, including all-cause mortality, were analyzed by disease etiology and ICD implantation following WCD use. RESULTS: We analyzed 56 patients with ischemic cardiomyopathy, 70 patients with non-ischemic cardiomyopathy, 16 patients with prior need for ICD/CRT-D (device for cardiac resynchronization therapy with defibrillator) explanation, 8 patients with acute myocarditis and 3 patients with congenital diseases. 58% of the patients did not need ICD/CRT-D implantation after WCD use. 4% of all patients suffered from appropriate WCD shocks. 2 of these patients (33%) experienced appropriate ICD shocks after implantation due to ventricular tachyarrhythmias. Long-term follow-up shows a good overall survival. All-cause mortality was 10%. There was no significant difference between patients with or without subsequent ICD implantation (p = 0.48). Patients with ischemic cardiomyopathy numerically showed a higher long-term mortality than patients with non-ischemic cardiomyopathy (14% vs. 6%, p = 0.13) and received significantly more ICD shocks after implantation (10% of ischemic cardiomyopathy (ICM) patients versus 3% of non-ischemic cardiomyopathy (NICM) patients, p = 0.04). All patients with ventricular tachyarrhythmias during WCD use or after ICD implantation survived the follow-up period. CONCLUSION: Following WCD use, ICD implantation could be avoided in 58% of patients. Long-term follow-up shows good overall survival. The majority of all patients did not suffer from WCD shocks nor did receive ICD shocks after subsequent implantation. Patient selection regarding predictive conditions on long-term risk of ventricular tachyarrhythmias needs further risk stratification.