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Background: Noninvasive risk stratification aims to detect abnormalities in the pathophysiological mechanisms underlying ventricular arrhythmias. We studied the predictive value of repeating risk stratification in patients with an implantable cardioverter-defibrillator (ICD)., Methods: The EUTrigTreat clinical study was a prospective multicenter trial including ischemic and nonischemic cardiomyopathies and arrhythmogenic heart disease. Left ventricular ejection fraction ≤40% (LVEF), premature ventricular complexes >400/24 hr (PVC), non-negative microvolt T-wave alternans (MTWA), and abnormal heart rate turbulence (HRT) were considered high risk. Tests were repeated within 12 months after inclusion. Adjusted Cox regression analysis was performed for mortality and appropriate ICD shocks., Results: In total, 635 patients had analyzable baseline data with a median follow-up of 4.4 years. Worsening of LVEF was associated with increased mortality (HR 3.59, 95% CI 1.17-11.04), as was consistent abnormal HRT (HR 8.34, 95%CI 1.06-65.54). HRT improvement was associated with improved survival when compared to consistent abnormal HRT (HR 0.10, 95%CI 0.01-0.82). For appropriate ICD shocks, a non-negative MTWA test or high PVC count at any moment was associated with increased arrhythmic risk independent of the evolution of test results (worsening: HR 3.76 (95%CI 1.43-9.88) and HR 2.50 (95%CI 1.15-5.46); improvement: HR 2.80 (95%CI 1.03-7.61) and HR 2.45 (95%CI 1.07-5.62); consistent: HR 2.47 (95%CI 0.95-6.45) and HR 2.40 (95%CI 1.33-4.33), respectively). LVEF improvement was associated with a lower arrhythmic risk (HR 0.34, 95%CI 0.12-0.94)., Conclusions: Repeating LVEF and HRT improved the prediction of mortality, whereas stratification of ventricular arrhythmias may be improved by repeating LVEF measurements, MTWA and ECG Holter monitoring., (© 2020 The Authors. Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.)

Objective: A new end point called ICD-resistant mortality was evaluated to assess the clinical efficacy of ICD implantations., Methods and Results: In 302 ICD patients with ischaemic cardiomyopathy, we investigated which clinical parameters predicted useful ICD implantations using cumulative incidence competing risk analysis. Implantation was deemed clinically useful when the ICD provided appropriate therapy and the patient survived implantation by 1 year and the first shock by 30 days. ICD-resistant mortality (ICDRM) was defined as death within 30 days after the first shock, within 1 year of implantation or without previous appropriate ICD therapy. After 5 years, ICDRM occurred in 23% of implantations, while 36% were clinically useful. After multivariable analysis, ICDRM was associated with LVEF <35% (HR: 2.63; p = .005), beta-blocker dose <50% (HR: 2.0; p = .01) and anterior or diffuse infarct location (HR: 3.61; p = .001 and HR: 2.89; p = .02). Useful ICD implantations were associated with beta-blocker dose <50% (HR: 1.64; p = .02) and non-anterior infarct location (HR: 3.22 vs anterior and 1.59 vs diffuse; combined p<.001)., Conclusions: Five years after implantation, an ICD could be classified as useful in 1 out of 3, while ICDRM occurred in one out of four patients. At 10 years, up to 80% of implantations could be categorized. Lower LVEF was related with significantly higher incidence of ICDRM. Anterior infarcts were associated with more ICDRM and less useful implantations than non-anterior infarcts. Future risk stratification for ICD should focus more on the discrimination between arrhythmic risk, probably preventable by ICDs and ICD-resistant mortality risk.

Background: A proportion of patients with an implantable cardioverter-defibrillator (ICD) in prevention of sudden cardiac death will only receive their first appropriate ICD therapy (AT) after device replacement. Clinical reassessment at the time of replacement could be helpful to guide the decision to replace or not in the future., Methods: All patients with an ICD for primary or secondary prevention in ischemic (ICM) or nonischemic cardiomyopathy were included in a single-center retrospective registry. The association of changes in left ventricular ejection fraction (LVEF; cut-off at 35%), worsening renal function (decrease in estimated glomerular filtration rate > 15 mL/min), and worsening New York Heart Association class at elective device replacement with mortality and AT was analyzed using adjusted Cox regression analysis., Results: A total of 238 (33%) out of 727 patients received elective device replacement (86.1% male, 74.4% ICM, 42.9% primary prevention). During this replacement 20.2% received a device upgrade. The mean time to replacement was 6.4 ± 2.0 years and mean follow-up after replacement was 3.4 ± 3.0 years. Of patients who did not receive AT before replacement 23.1% received their first AT after replacement. Worsening renal function (hazard ratio [HR] 2.79, 95% confidence interval [CI] 1.50-5.18) and a consistently LVEF ≤35% compared to a consistently LVEF >35% (HR 2.15, 95% CI 1.10-4.19) at the time of replacement were independent predictors of mortality. Independent predictors of first AT after replacement could not be identified., Conclusion: Although reassessment of LVEF and renal function at replacement can be helpful in predicting total mortality, the clinical utility to guide reimplantation seemed limited. Our experience indicates that approximately 25% of patients received their first AT only after replacement., (© 2017 Wiley Periodicals, Inc.)

Aims: QRS fragmentation (fQRS) has been proposed as a predictor of sudden cardiac death (SCD) and all-cause mortality in ischemic (ICM) and non-ischemic cardiomyopathy patients. However the value of fQRS in patients with a LVEF <35% is a matter of debate., Methods: All consecutive patients with an indication for an ICD in primary prevention of SCD were included in a retrospective registry from 1996 until 2013. Twelve lead electrocardiograms before implant were analyzed for the presence of fQRS in different regions. Adjusted Cox regression analysis for first appropriate ICD shock (AS) and all-cause mortality was performed., Results: In total 407 patients were included with a mean follow-up of 4.2±3.3y (age 60.6±11.9y, 15.7% female and 52.8% ICM). fQRS was present in 46.7% of patients, predominantly inferior (30.7%) followed by anterior (21.4%) and lateral (11.1%) coronary artery territories. fQRS was significantly more prevalent in ICM (p=0.004). Inferior fQRS was an independent predictor of a first AS within 1y (HR 2.55, 95%CI 1.28-5.07) and 3y (HR 1.90, 95%CI 1.14-3.18) after implantation. Whereas, anterior fQRS was an independent predictor of all-cause mortality within 1y (HR 4.58, 95%CI 1.29-16.19), 3y (HR 3.92, 95%CI 1.77-8.65) and the complete follow-up (HR 2.22, 95%CI 1.33-3.69). Lateral fQRS was only a predictor of late (>3y of follow-up) all-cause mortality (HR 2.04, 95%CI 1.09-3.81)., Conclusions: fQRS in a specific coronary artery territory might be promising to discriminate arrhythmic from mortality risk. Inferior fQRS was a predictor of early arrhythmia, while anterior fQRS was related to mortality., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Clinical guidelines on implantable cardioverter defibrillator (ICD) therapy changed significantly in the last decades with potential inherent effects on therapy efficacy. We aimed to study therapy rates in time and the association between therapies and mortality., Methods: All patients receiving an ICD, primary and secondary prevention, were included in a single-center retrospective registry. Information on first appropriate and inappropriate therapies was documented. Dates of implant were divided in P1: 1996-2001, P2: 2002-2008, and P3: 2009-2014., Results: A total of 727 patients, 84.9% male-66.4% ischemic cardiomyopathy (ICM)-56% primary prevention-mean follow-up 5.2 ± 4.1 years, were included. There was a shift from secondary to primary prevention indications, from ischemic to non-ICM, and from single chamber to cardiac resynchronization therapy defibrillator devices. The annual 1- and 3-year appropriate shock (AS) rate declined from 29.4% and 15.1% in P1, over 13.3% and 9.2% in P2 to 7.8% and 5.7% in P3 (log-rank P < 0.001), while inappropriate shock (IAS) rates remained unchanged (log-rank P = 0.635). After multivariate regression analysis a higher age at implant, lower left ventricular ejection fraction, history of stroke, diabetes mellitus, intake of loop diuretics or digitalis, higher creatinine, and longer QTc were independent predictors of mortality., Conclusion: These changes in clinical practice with a shift to primary prevention and rise in non-ICM implants caused a significant decrease in AS incidence, while IAS remained stable. Receiving AS or IAS was not an independent predictor of mortality in our real-life cohort., (© 2016 Wiley Periodicals, Inc.)

Aims: In high-risk patients, implantable cardioverter-defibrillators (ICDs) can convert the mode of death from arrhythmic to pump failure death. Therefore, we introduced the concept of 'ICD-resistant mortality' (IRM), defined as death (a) without previous appropriate ICD intervention (AI), (b) within 1 month after the first AI, or (c) within 1 year after the initial ICD implantation. Implantable cardioverter-defibrillator implantation in patients with a high risk of IRM should be avoided., Methods and Results: Implantable cardioverter-defibrillator patients with ischaemic heart disease were included if a digitized 24 h Holter was available pre-implantation. Demographic, electrocardiographic, echocardiographic, and 24 h Holter risk factors were collected at device implantation. The primary endpoint was IRM. Cox regression analyses were used to test the association between predictors and outcome. We included 130 patients, with a mean left ventricular ejection fraction (LVEF) of 33.6 ± 10.3%. During a follow-up of 52 ± 31 months, 33 patients died. There were 21 cases of IRM. Heart rate turbulence (HRT) was the only Holter parameter associated with IRM and total mortality. A higher New York Heart Association (NYHA) class and a lower body mass index were the strongest predictors of IRM. Left ventricular ejection fraction predicted IRM on univariate analysis, and was the strongest predictor of total mortality. The only parameter that predicted AI was non-sustained ventricular tachycardia., Conclusion: Implantable cardioverter-defibrillator implantation based on NYHA class and LVEF leads to selection of patients with a higher risk of IRM and death. Heart rate turbulence may have added value for the identification of poor candidates for ICD therapy. Available Holter parameters seem limited in their ability to predict AI., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2013. For permissions please email: journals.permissions@oup.com.)

Background: Randomized controlled trials have proven the efficacy of implantable cardioverter/defibrillators (ICDs) to prevent sudden cardiac death (SCD) in primary prevention. However,long-term data on the incidence of appropriate and inappropriate interventions in real life and on the predictive value of commonly used clinical variables to guide patient selection are scarce., Methods: We retrospectively studied 101 patients who received an ICD for primary prophylaxis of SCD: 63.4% with ischaemic heart disease (IHD) and 36.6% with idiopathic dilated cardiomyopathy (IDCM). The mean follow-up period was 26.2 (+/- 14.8; median 27.8; range 5.6-70.5) months. Age, left ventricular ejection fraction (LVEF), QRS duration, NYHA class and electrophysiological study (EPS) outcome were evaluated as predictors of ICD intervention., Results: At 2 years the cumulative incidence of appropriate (17.5% in IHD; 28% in IDCM; P= 0.63) and inappropriate (12.8% in IHD, 15.4% in IDCM; P = 0.62) interventions was similar in both groups. Atrial fibrillation was the most common cause of inappropriate interventions in the IHD group, sinus tachycardia in the IDCM group. Advanced age was associated with less inappropriate interventions (HR: 0.96 (95% confidence interval (CI) 0.94-0.98); P < 0.01), and a better LVEF with less appropriate interventions (HR: 0.97 (95% Cl 0.94-0.99); P < 0.01). This amounted in a significant absolute difference in the number of appropriate interventions between the group with a LVEF < 25% and 25-34% after 3 years of follow-up of 42% in IHD (48% vs 6%). A prolonged QRS duration was associated with a slightly elevated risk for appropriate interventions only in the IHD group (HR: 1.01 (95% CI 1.00-1.03); P = 0.04). On the other hand, increased NYHA class was only associated with increased risk for appropriate interventions in the IDCM group (HR: 5.24 (95% CI1.11-24.74); P= 0.04). No significant statistical association was found between a positive EPS and appropriate or inappropriate interventions., Conclusions: In primary prevention, during a mean follow-up of 2 years, one in five patients had a possibly live-saving appropriate intervention. However, the incidence of inappropriate interventions was substantial. Predictors for appropriate interventions were: (i) LVEF in the total study group, (ii) NYHA class in the IDCM group and (iii) QRS duration in the IHD group.