The impact of supraventricular arrhythmias on the outcomes of guideline-compliant implantable cardioverter defibrillator programming.

INTRODUCTION: Several implantable cardioverter defibrillators (ICD) programming strategies are applied to minimize ICD therapy, especially unnecessary therapies from supraventricular arrhythmias (SVA). However, it remains unknown whether these optimal programming recommendations only benefit those with SVAs or have any detrimental effects from delayed therapy on those without SVAs. This study aims to assess the impact of SVA on the outcomes of ICD programming based on 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines. METHODS: Consecutive patients who underwent ICD insertion for primary prevention were classified into four groups based on SVA status and ICD programming: (1) guideline-concordant group (GC) with SVA, (2) GC without SVA, (3) nonguideline concordant group (NGC) with SVA, and (4) NGC without SVA. Cox proportional hazard models were analyzed for freedom from ICD therapies, shock, and mortality. RESULTS: Seven hundred and seventy-two patients (median age, 64 years) were enrolled. ICD therapies were the most frequent in NGC with SVA (24.0%), followed by NGC without SVA (19.9%), GC without SVA (11.6%), and GC with SVA (8.1%). Guideline concordant programming was associated with 68% ICD therapy reduction (HR 0.32, p = .007) and 67% ICD shock reduction (HR 0.33, p = .030) in SVA patients and 44% ICD therapy reduction in those without SVA (HR 0.56, p = .030). CONCLUSION: Programming ICDs in primary prevention patients based on current guidelines reduces therapy burden without increasing mortality in both SVA and non-SVA patients. A greater magnitude of reduced ICD therapy was found in those with supraventricular arrhythmias.

The Challenges of Diagnosis and Treatment of Arrhythmogenic Cardiomyopathy: Are We there yet?

Background: we sought to review the evolution in the diagnosis and treatment of Arrhythmogenic Cardiomyopathy (ACM), a clinically multifaceted entity beyond the observation of ventricular arrhythmias, and the outcome of therapies aiming at sudden death prevention in a single center experience. Methods: retrospective analysis of the data of consecutive patients with an implanted cardioverter-defibrillator (ICD) and a confirmed diagnosis of ACM according to the proposed Padua Criteria, who were referred to our center from January 1992 to October 2021. Results: we enrolled 72 patients (66% males, mean age at implant 46 ± 16 years), 63.9% implanted for primary prevention. At the time of ICD implant, 29 (40.3%) patients had a right ventricular involvement, 24 (33.3%) had a dominant LV involvement and 19 (26.4%) had a biventricular involvement. After a median follow-up of 6,1 years [IQR: 2.5-9.9], 34 patients (47.2%) had 919 sustained episodes of ventricular arrhythmias (VA). 27 patients (37.5%) had 314 episodes of life-threatening arrhythmias (LT-VA), defined as sustained ventricular tachycardia ≥ 200 beats/min. Considering only the patients with an ICD capable of delivering ATP, 80.4% of VA and 65% of LT-VA were successfully terminated with ATP. 16 (22.2%) patients had an inappropriate ICD activation, mostly caused by atrial fibrillation, while in 9 patients (12.5%) there was a complication needing reintervention (in 3 cases there was a loss of ventricular sensing dictating lead revision). During the follow-up 11 (15.3%) patients died, most of them due to heart failure, and 8 (11.1%) underwent heart transplantation. Conclusions: ACM is increasingly diagnosed owing to heightened suspicion at ECG examination and to improved imaging technology and availability, though the diagnostic workflow is particularly challenging in the earliest disease stages. ICD therapy is the cornerstone of sudden death prevention, albeit its efficacy is not based on controlled studies, and VT ablation/medical therapy are complementary to this strategy. The high burden of ATP-terminated VA makes shock-only devices debatable. The progressive nature of ACM leads to severe biventricular enlargement and refractory heart failure, which pose significant treatment issues when a predominant RV dysfunction occurs owing to the reduced possibility for mechanical circulatory assistance.

Effectiveness of Implantable Cardioverter Defibrillator in Patients With Non-Ischemic Heart Failure With Systolic Dysfunction　- Subanalysis of the Nippon Storm Study.

BACKGROUND: The prospective observational Nippon Storm Study aggregated clinical data from Japanese patients receiving implantable cardioverter-defibrillator (ICD) therapy. This study investigated the usefulness of prophylactic ICD therapy in patients with non-ischemic heart failure (NIHF) enrolled in the study.Methods and Results: We analyzed 540 NIHF patients with systolic dysfunction (left ventricular ejection fraction <50%). Propensity score matching was used to select patient subgroups for comparison; 126 patients were analyzed in each of the primary (PP) and secondary (SP) prophylaxis groups. The incidence of appropriate ICD therapy during follow-up in the PP and SP groups was 21.4% and 31.7%, respectively (P=0.044). The incidence of electrical storm (ES) was higher in SP than PP patients (P=0.024). Cox proportional hazard analysis revealed that increased serum creatinine in SP patients (hazard ratio [HR] 1.18; 95% confidence interval [CI] 1.02-1.33; P=0.013) and anemia in PP patients (HR 0.92; 95% CI 0.86-0.98; P=0.008) increased the likelihood of appropriate ICD therapy, whereas long-lasting atrial fibrillation in PP patients (HR, 0.64 [95% CI, 0.45-0.91], P=0.013) decreased that likelihood. CONCLUSIONS: In propensity score-matched Japanese NIHF patients, the incidence of appropriate ICD therapy and ES was significantly higher in SP than PP patients. Impaired renal function in SP patients and anemia in PP patients increased the likelihood of appropriate ICD therapy, whereas long-lasting atrial fibrillation reduced that likelihood in PP patients.

Inappropriately long post-ventricular atrial blanking leading to 'unnecessary' defibrillator discharge.

A 55-year-old lady with non-ischemic cardiomyopathy (NICM) was referred for multiple implantable cardioverter defibrillator (ICD) shocks. Stored electrograms (EGM) revealed atrial flutter (AFL) with A > V. Morphology match was good and RR-intervals were irregular. Despite all these, the dual-chamber-ICD (Abbott medical) classified this as ventricular tachycardia (VT-2) via V > A algorithm where it did not analyze morphology/stability and delivered therapy. Anti-tachycardia-pacing (ATP) was delivered which induced a true VT (rate in VF-zone) and immediate shock was delivered. It was hence appropriate but an 'unnecessary' shock. The offender was found to be an inappropriately programmed long post-ventricular atrial-blanking (PVAB) of 200 ms which led to undersensing of several atrial electrograms, falsely making V > A during a clear AFL.

Subcutaneous implantable cardioverter-defibrillator electrode fracture: Follow-up, troubleshooting, and evaluation.

The subcutaneous-implantable cardioverter-defibrillator (S-ICD) and its electrode were developed to avoid long-term complications of transvenous leads in the vasculature. We report a case of unexpected, inappropriate S-ICD shocks due to oversensing of high-amplitude, nonphysiologic, electrical noise artifacts that were not preceded by high-impedance alerts or sensing electrogram noise detections. Following explant, high-magnification X-ray imaging of the S-ICD electrode demonstrated partial fracture of the distal sensing conductor located near a short radius bend in the electrode at the electrode-header interface. Clinicians should be aware of a potential for fatigue failure fracture of the S-ICD electrode. Recommendations for systematic S-ICD follow-up and troubleshooting are discussed.

Clinical characteristics and risk factors of arrhythmia during follow-up of patients with idiopathic ventricular fibrillation.

AIMS: The current knowledge of idiopathic ventricular fibrillation (IVF) is limited. We aimed to investigate the nature of IVF, including clinical assessment and later diagnosis, and risk factors of implantable cardioverter defibrillator (ICD) therapy in the follow-up period. METHODS: Between 2007 and 2019 we systematically identified all patients from Rigshospitalet, Denmark, with a resuscitated sudden cardiac arrest (SCA) with no identifiable cause. All patients were followed routinely in the ICD outpatient clinic and the majority also in an inherited heart disease outpatient clinic. Outcomes were analysed with Cox regressions models and cumulative incidence curves. RESULTS: We identified 84 patients with an initial diagnosis of IVF; of these, three (3.6%) patients were later diagnosed with a cardiac disease. The remaining IVF patients (n = 81, median age 45 years; men 71.6%) were followed a median follow-up of 5.2 years (interquartile range, 2.0-7.6). A total of 24 (29.6%) patients had appropriate ICD therapy and 12 (14.8%) patients had inappropriate ICD therapy. No predominant type of ventricular arrhythmia at first appropriate ICD therapy was observed. Early repolarization at baseline was not associated with an increased risk of appropriate ICD therapy (P = .842). Repeated cardiac arrest at index SCA increased the risk of appropriate ICD therapy (hazard ratio, 2.63 [95% CI, 1.08-6.40; P = .033]). CONCLUSION: Most patients remained idiopathic throughout the follow-up period and the overall long-term prognosis of IVF was good. Repeated cardiac arrest at index SCA was a risk factor of appropriate ICD therapy and early repolarization was not associated with an increased risk of appropriate ICD therapy.

Insights on arrhythmia termination and type 2 breaks after ICD therapy delivery.

Introduction of anti-tachycardia pacing (ATP) therapy and longer detection intervals delivery have allowed to safely reduce unnecessary shocks, improving survival and quality of life in implantable cardioverter defibrillator (ICD) patients. However, there are still outstanding issues, especially regarding the mode of arrhythmias termination after ATP or shock delivery. Regardless of ICD therapy efficacy, the arrhythmia interruption does not always occur abruptly, indeed both nonsustained tachy- or bradyarrhythmias have been described after ICD therapy delivery, being the former classified as type 2 interruption. Several physiopathological mechanisms have been suggested to be responsible for this phenomenon. Our aim is to review current data on postshock and post-ATP arrhythmias and to give insights on their possible mechanisms.

Effectiveness of high rate and delayed detection ICD programming by race: A MADIT-RIT substudy.

INTRODUCTION: Data on inappropriate and appropriate ICD therapy, and efficacy of ICD programing strategies by race are limited. METHODS: In MADIT-RIT, we evaluated the risk of ICD therapy by race, and the efficacy of high rate cut-off ventricular tachycardia (VT) zone ≥200 beats per minute (bpm) (Arm B), or 60 seconds delay in VT zone 170-199 bpm (Arm C), compared to 2.5 seconds delay at 170 bpm (Arm A) among black and white patients. RESULTS: MADIT-RIT enrolled 272 (20%) black and 1119 (80%) white patients. The risk of inappropriate therapy was similar among blacks and whites, HR 1.25, 95% CI (0.82-1.93), P  =  0.30. High rate cut-off or delayed VT therapy was associated with significant reductions in inappropriate therapy among whites, Arm B versus Arm A, HR 0.15, 95% CI (0.08-0.29), P < 0.0001, Arm C versus Arm A, HR 0.19, 95% CI (0.11-0.33), P < 0.001, and black individuals Arm B versus Arm A, HR 0.24, 95% CI (0.01-0.56), P  =  0.0001, Arm C versus Arm A, HR 0.30, 95% CI (0.13-0.68), P  =  0.004, P interaction > 0.10). However, delayed VT therapy was associated with a trend toward greater reduction in appropriate therapy in black individuals, HR 0.08, 95% CI (0.03-0.27), P < 0.0001 relative to white individuals, HR 0.27, 95% CI (0.16-0.43), P < 0.0001, P interaction  =  0.077. CONCLUSION: In MADIT-RIT, high rate and delayed detection ICD programming provided similar benefit with reductions in both inappropriate therapy and unnecessary appropriate therapy among black and white individuals. CLINICALTRIALS. GOV IDENTIFIER: NCT00947310.

Evaluation of Need for Implantable Cardioverter-Defibrillator by Thallium-201 Scintigraphy Among Japanese Patients With Prior Myocardial Infarction.

BACKGROUND: Identifying who among current Japanese patients with prior myocardial infarction (MI) would benefit from an implantable cardioverter-defibrillator (ICD) is imperative. Accordingly, this study seeks to determine whether single-photon emission computed tomography (SPECT) can help identify such patients. Methods and Results: This retrospective study enrolled 60 consecutive patients with prior MI who underwent stress thallium-201 SPECT and ICD implantation from February 2000 to October 2014. Occurrence of arrhythmic death and/or or appropriate ICD therapy, defined as shock or antitachycardia pacing for ventricular fibrillation or tachycardia, was identified until November 2016. During the median follow-up interval of 6.6 years, 18 (30%) patients experienced arrhythmic death and/or appropriate ICD therapy. Multivariate Cox proportional hazard regression analysis revealed that the summed stress score (SSS) [hazard ratio (HR)=1.14; P=0.005] and left ventricular ejection fraction (LVEF) at rest (HR=0.92; P=0.038) were significantly associated with the occurrence of arrhythmic events. Patients with SSS ≥21 and LVEF ≤30%, which were determined to be the best cutoff points, had significantly higher incidence of the arrhythmic events than the other patients (64% vs. 11%; HR=7.18; log-rank P=0.001). CONCLUSIONS: SSS using stress thallium-201 SPECT in combination with LVEF can help determine the need for ICD therapy among current Japanese patients with prior MI.

Clinical parameters to optimize patient selection for subcutaneous and transvenous implantable defibrillator therapy.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (S-ICD) lacks the antitachycardia pacing (ATP) capability of tranvenous ICDs (TV-ICD). S-ICD patient selection can be challenging as some patients may benefit from ATP. We aim to identify clinical predictors of ATP benefit, in order to improve patient selection for S-ICD or TV-ICD therapy. METHODS: De novo single- and dual-chamber TV-ICD patients implanted between March 2011 and December 2015 were included. Ventricular arrhythmias terminated by ATP and not followed by a shock were considered successful ATP therapy. Cox proportional hazard analysis was performed to assess the adjusted effect of multiple predictors for appropriate ATP and shock therapy. RESULTS: Note that 431 patients were included with a median follow-up of 26 months. Ninety-nine patients (23%) received appropriate ATP therapy, which terminated the arrhythmia in 67%. A history of nonsustained ventricular tachycardia (NSVT) or monomorphic VT (MVT) was the only predictor of appropriate ATP therapy in the multivariable model (hazard ratio [HR] 2.73, P < 0.001). Sixty-five of 221 patients with a history of NS (VT) received appropriate ATP (29%) versus 24 patients (11%) without a history NS (VT) (P < 0.001). A secondary prevention indication was the only predictor in the multivariate model for appropriate shock therapy (HR 1.82, P  =  0.05). CONCLUSION: A history of NSVT or MVT is a significant predictor for appropriate and successful ATP therapy. One in three patients with NSVT or MVT received appropriate ATP versus one in 10 patients without a history of NSVT or MVT over a 2-year period of follow-up.

Substrate-dependent risk stratification for implantable cardioverter defibrillator therapies using cardiac magnetic resonance imaging: The importance of T1 mapping in nonischemic patients.

INTRODUCTION: The role of implantable cardioverter defibrillators (ICDs) in nonischemic cardiomyopathy is unclear and better risk-stratification is required. We sought to determine if T1 mapping predicts appropriate defibrillator therapy in patients with nonischemic cardiomyopathy. We studied a mixed cohort of ischemic and nonischemic patients to determine whether different cardiac magnetic resonance (CMR) applications (T1 mapping, late gadolinium enhancement, and Grayzone) were selectively predictive of therapies for the different arrhythmic substrates. METHODS AND RESULTS: We undertook a prospective longitudinal study of consecutive patients receiving defibrillators in a tertiary cardiac center. Participants underwent CMR myocardial tissue characterization using T1 mapping and conventional CMR scar assessment before device implantation. QRS duration and fragmentation on the surface electrocardiogram were also assessed. The primary endpoint was appropriate defibrillator therapy. One-hundred thirty patients were followed up for a median of 31 months (IQR ± 9 months). In nonischemic patients, T1_native was the sole predictor of the primary endpoint (hazard ratio [HR] 1.12 per 10 millisecond increment in value [95% confidence interval [CI] 1.04-1.21; P ≤ 0.01]). In ischemic patients, Grayzone_2SD-3SD was the strongest predictor of appropriate therapy (HR 1.34 per 1% left ventricular increment in value [95% CI 1.03-1.76; P = 0.03]). QRS fragmentation correlated well with myocardial scar core (receiver operating characteristic area under the curve [ROC AUC] 0.64; P = 0.02) but poorly with T1_native (ROC AUC 0.4) and did not predict appropriate therapy. CONCLUSIONS: In the medium-long term, T1_native mapping was the only independent predictor of therapy in nonischemic patients, whereas Grayzone was a better predictor in ischemic patients. These findings suggest a potential role for T1_native mapping in the selection of patients for ICDs in a nonischemic population.

Heart failure severity, inappropriate ICD therapy, and novel ICD programming: a MADIT-RIT substudy.

BACKGROUND: The effects of heart failure (HF) severity on risk of inappropriate implantable cardioverter-defibrillator (ICD) therapy have not been thoroughly investigated. We aimed to study the association between HF severity and inappropriate ICD therapy in MADIT-RIT. METHODS: MADIT-RIT randomized 1,500 patients to three ICD programming arms: conventional (Arm A), high-rate cut-off (Arm B: ≥200 beats/min), and delayed therapy (Arm C: 60-second delay for ≥170 beats/min). We evaluated the association between New York Heart Association (NYHA) class III (n = 256) versus class I-II (n = 251) and inappropriate ICD therapy in Arm A patients with ICD-only and cardiac resynchronization therapy with defibrillator (CRT-D). We additionally assessed benefit of novel ICD programming in Arms B and C versus Arm A by NYHA classification. RESULTS: In Arm A, the risk of inappropriate therapy was significantly higher in those with NYHA III versus NYHA I-II for both ICD (hazard ratio [HR] = 2.55, confidence interval [CI]: 1.51-4.30, P < 0.001) and CRT-D patients (HR = 3.73, CI: 1.14-12.23, P = 0.030). This was consistent for inappropriate ATP and inappropriate ICD therapy < 200 beats/min, but not for inappropriate shocks. Novel ICD programming significantly reduced inappropriate therapy in patients with both NYHA III (Arm B vs Arm A: HR = 0.08, P < 0.001; Arm C vs Arm A: HR = 0.17, P < 0.001) and NYHA I-II (Arm B vs Arm A: HR = 0.25, P < 0.001; Arm C vs Arm A: HR = 0.28, P < 0.001). CONCLUSION: Patients with more severe HF are at increased risk for inappropriate ICD therapy, particularly ATP due to arrhythmias < 200 beats/min. Novel programming with high-rate cut-off or delayed detection reduces inappropriate ICD therapies in both mild and moderate HF.

[Sudden cardiac death : Epidemiology, pathophysiology and risk stratification]. / Plötzlicher Herztod : Epidemiologie, Pathophysiologie und Risikostratifizierung.

Sudden cardiac death (SCD) remains a major public health burden despite revolutionary progress in the last three decades in the treatment of ventricular tachyarrhythmia with the use of implantable cardioverter defibrillator (ICD) therapy. Survivors of sudden cardiac arrest are at high risk for recurrent tachyarrhythmia events. Early recognition of low left ventricular ejection fractions (≤35%) as a strong predictor of mortality and the causal association between ventricular tachyarrhythmia and SCD has led to a significant development of not only pharmacological antiarrhythmic therapy but also device-based prevention of SCD. The ICD therapy is nowadays routinely used for primary prevention of SCD in patients with significant structural cardiomyopathy and primary electrical arrhythmia syndromes, which are associated with high a risk and secondary prevention in survivors of sudden cardiac arrest. Additionally, effective approaches exist to significantly reduce the recurrence rate of ventricular tachyarrhythmia of various origins by complex electrophysiological endocardial and epicardial catheter ablation procedures.

Effect of ICD Therapies on Mortality in the OMNI Trial.

BACKGROUND: Analyses from primary prevention trials on implantable cardioverter defibrillator (ICD) therapy have shown an association between shocks and increased mortality. Recent data suggest a similar association with antitachycardia pacing (ATP). OBJECTIVE: The OMNI study is an observational study of pacemaker and ICD use. We aim to examine associations between ICD therapies and mortality in this setting. METHODS: A total of 2,255 OMNI patients with ICDs were included. Treated episodes were classified as appropriate or inappropriate. Patients were assigned into 1 of 3 groups depending on whether the episode required ATP only, single shock, or multiple shocks, and then followed for all-cause mortality. Additionally, we aimed to determine the frequency with which inappropriate ATP precipitated ventricular arrhythmias that led to shock, since this has been suggested as a mechanism of harm. RESULTS: Over a mean follow-up of 39 ± 19 months, there were a total of 470 deaths (21%). Compared to patients with no treated episodes, patients with appropriate therapy had greater risk of death. Hazard ratios were 1.46 (95% confidence interval [CI] 1.05-2.02; P = 0.023) for the ATP-only group, 2.11 (95% CI 1.51-2.96; P < 0.001) for the single-shock group, and 2.55 (95% CI 1.43-4.57; P = 0.002) for the multishock group. There was no significant association between any type of inappropriate therapy and increased mortality. We identified only 7 instances of inappropriate ATP precipitating ventricular arrhythmia resulting in shock. CONCLUSIONS: Patients receiving appropriate therapy of all types had increased mortality compared to those with no episodes. Furthermore, inappropriate ATP rarely precipitates ventricular arrhythmias.

T-peak to T-end Interval Predicts Appropriate Shocks in Patients with Heart Failure Undergoing Implantable Cardioverter Defibrillator Implantation for Primary Prophylaxis.

BACKGROUND: T-wave peak to T-wave end interval (Tp-e) correlates with dispersion of ventricular repolarization. The purpose of this study was to assess the ability of Tp-e to predict appropriate implantable cardioverter defibrillator (ICD) shocks and all-cause mortality in patients who underwent ICD implantation for primary prophylaxis. METHODS: Two hundred twenty-eight patients with left ventricular ejection fraction ≤35% and an ICD implanted were followed-up prospectively. Patients divided into two subgroups according to presence of appropriate ICD shocks (Group 1: 112 patients with ICD shocks, Group 2: 116 patients without shocks). End points were appropriate ICD therapy due to ventricular tachycardia (VT)/ventricular fibrillation (VF), death, and a combined end point of VT/VF or death. RESULTS: During a mean follow-up of 22.3 ± 7.7 months, appropriate ICD shocks were observed in 112 of 228 patients (49.1%). The mean duration of the Tp-e Group 1 was significantly longer than Group 2 (115.3 ± 22.2 vs 104.7 ± 20.2 ms, P < 0.001). Ischemic etiology and Tp-e duration were found to be independent predictors of ICD therapy. When the patients were divided into two groups based on Tp-e interval, there was no significant difference regarding the mortality between groups (21.2% vs 21.8%, P: 0.186). However, appropriate ICD shocks due to VT/VF (37.5% vs 58.8%, P < 0.001) and combined end point (39.4% vs 64.5%, P: 0.002) were significantly higher in patients with longer Tp-e group. CONCLUSIONS: Tp-e interval independently predicts appropriate ICD shocks in patients with systolic dysfunction and ICDs implanted for primary prevention.

The effect of ICD programming on inappropriate and appropriate ICD Therapies in ischemic and nonischemic cardiomyopathy: the MADIT-RIT trial.

INTRODUCTION: The MADIT-RIT trial demonstrated reduction of inappropriate and appropriate ICD therapies and mortality by high-rate cut-off and 60-second-delayed VT therapy ICD programming in patients with a primary prophylactic ICD indication. The aim of this analysis was to study effects of MADIT-RIT ICD programming in patients with ischemic and nonischemic cardiomyopathy. METHODS AND RESULTS: First and total occurrences of both inappropriate and appropriate ICD therapies were analyzed by multivariate Cox models in 791 (53%) patients with ischemic and 707 (47%) patients with nonischemic cardiomyopathy. Patients with ischemic and nonischemic cardiomyopathy had similar incidence of first inappropriate (9% and 11%, P = 0.21) and first appropriate ICD therapy (11.6% and 14.1%, P = 0.15). Patients with ischemic cardiomyopathy had higher mortality rate (6.1% vs. 3.3%, P = 0.01). MADIT-RIT high-rate cut-off (arm B) and delayed VT therapy ICD programming (arm C) compared with conventional (arm A) ICD programming were associated with a significant risk reduction of first inappropriate and appropriate ICD therapy in patients with ischemic and nonischemic cardiomyopathy (HR range 0.11-0.34, P < 0.001 for all comparisons). Occurrence of total inappropriate and appropriate ICD therapies was significantly reduced by high-rate cut-off ICD programming and delayed VT therapy ICD programming in both ischemic and nonischemic cardiomyopathy patients. CONCLUSION: High-rate cut-off and delayed VT therapy ICD programming are associated with significant reduction in first and total inappropriate and appropriate ICD therapy in patients with ischemic and nonischemic cardiomyopathy.

Reduction in Inappropriate ICD Therapy in MADIT-RIT Patients Without History of Atrial Tachyarrhythmia.

BACKGROUND: There are limited data whether history of atrial tachyarrhythmia (AT) modifies the risk of inappropriate ICD therapy, or the efficacy of novel ICD programming to reduce inappropriate ICD therapy events. METHODS: In MADIT-RIT, we investigated the effects of novel ICD programming with high-rate cut-off VT zone ≥ 200 bpm (arm B), or 60-second delayed therapy in the VT zone 170-199 bpm (arm C), compared to conventional programming VT zone>170 bpm (arm A) on first inappropriate ICD therapy in those with or those without AT prior to enrollment. RESULTS: In patients with prior AT (n = 203, 14%) there was a higher risk of inappropriate ICD therapy (HR = 2.10, 95% CI: 1.38-3.20, P < 0.001), and inappropriate ICD shock (HR = 2.56, 95% CI: 1.38-4.74, P = 0.003) compared to those with no prior AT. The effects of innovative programming to reduce inappropriate ICD therapy with either high-rate cut-off or delayed VT therapy were similar in patients with prior AT (arm B vs. A HR = 0.11, P < 0.001, arm C vs. A HR = 0.17, P < 0.001), and also in patients without prior AT before enrollment (arm B vs. A HR = 0.15, P < 0.001, arm C vs. A HR = 0.24, P < 0.001, interaction P-values >0.10 for all). CONCLUSIONS: Novel ICD programming with a high-rate cut-off or delayed therapy is equally beneficial to reduce inappropriate ICD therapy in patients with or without prior AT, despite the lower risk of inappropriate ICD therapy in patients without prior AT.

Influence of smoking dosage and chronic obstructive lung disease on the incidence of appropriate therapies and mortality in patients with structural heart disease and an implantable cardioverter defibrillator.

BACKGROUND: Smoking is known as a relevant risk factor for severe cardiac morbidities and mortality. This study was initiated to explore the influence of smoking dosage and presence of chronic obstructive lung disease (COPD) on the incidence of appropriate implantable cardioverter defibrillator (ICD) interventions and on mortality. METHODS: Prior studies on patients equipped with an ICD suggested that nicotine consumption increases the risk of experiencing an appropriate ICD therapy. There is no substantial data regarding the influence of cigarette smoking dosage on overall mortality in such endangered patients. A total of 349 patients with structural heart disease, either coronary artery disease or nonischemic cardiomyopathy equipped with an ICD, were included. Every patient answered a questionnaire regarding his smoking status and performed a spirometry and body plethysmography. RESULTS: A total of 104 patients (30%) suffered from COPD. Fifty-eight patients (17%) were "current smokers," 196 patients (56%) were revealed as "former smokers," while 93 (27%) patients were registered as "never smokers." A total of 163 patients (47%) received at least one appropriate ICD intervention during follow-up (median 48 ± 8 months). Twenty-three patients died during this study (6.6%). There was no association of COPD with the incidence of appropriate ICD therapies or mortality. Smoking dosage revealed as a significant risk factor for both appropriate ICD interventions (hazard ratio [HR] 1.5 for 60 pack years [PY] P = 0.04) and mortality (HR 2.3 for 60 PY P = 0.02). CONCLUSION: This study demonstrates a dose-related increased risk of smokers for appropriate ICD interventions and mortality. The results of this trail urge a strict nicotine abstinence, especially in patients with a structural heart disease undergoing ICD therapy.

Implantable cardioverter-defibrillator therapy in a 34-year-old patient with eating disorders and after the third sudden cardiac arrest.

Eating disorders (ED) such as anorexia nervosa and bulimia are psychiatric diseases associated with the highest mortality rate of any other psychiatric disorders. More recently, long-term outcome studies with follow-up of over 20 years report a mortality of between 15% and 18% (Casiero and Frishman, Cardiol Rev 14(5), 227, 2006). The sudden death secondary to arrhythmias is often the cause of death in these patients (Casiero and Frishman, Cardiol Rev 14(5), 227, 2006). A case of life-threatening ventricular arrhythmia (VA) in a patient with ED is presented. Clinical records (cardiologic, psychiatric), electrocardiograms, echocardiogram, coronary angiogram, cardiac magnetic resonance, and endocrine diagnostics were performed. Finally a cardioverter-defibrillator (ICD) was implanted in the patient after her third cardiac arrest. An optimal approach to antiarrhythmic therapy in such patients is a real challenge for a cardiologist.