Mortality In Implantable Cardioverter Defibrillator Patients Research Articles

Myocardial strain assessment using cardiovascular magnetic resonance imaging in recipients of implantable cardioverter defibrillators

BackgroundCardiovascular magnetic resonance (CMR) is increasingly used in the evaluation of patients who are potential candidates for implantable cardioverter-defibrillator (ICD) therapy to assess left ventricular (LV) ejection fraction (LVEF), myocardial fibrosis, and etiology of cardiomyopathy. It is unclear whether CMR-derived strain measurements are predictive of appropriate shocks and death among patients who receive an ICD. We evaluated the prognostic value of LV strain parameters on feature-tracking (FT) CMR in patients who underwent subsequent ICD implant for primary or secondary prevention of sudden cardiac death.MethodsConsecutive patients from 2 Canadian tertiary care hospitals who underwent ICD implant and had a pre-implant CMR scan were included. Using FT-CMR, a single, blinded, reader measured LV global longitudinal (GLS), circumferential (GCS), and radial (GRS) strain. Cox proportional hazards regression was performed to assess the associations between strain measurements and the primary composite endpoint of all-cause death or appropriate ICD shock that was independently ascertained.ResultsOf 364 patients (mean 61 years, mean LVEF 32%), 64(17.6%) died and 118(32.4%) reached the primary endpoint over a median follow-up of 62 months. Univariate analyses showed significant associations between GLS, GCS, and GRS and appropriate ICD shocks or death (all p < 0.01). In multivariable Cox models incorporating LVEF, GLS remained an independent predictor of both the primary endpoint (HR 1.05 per 1% higher GLS, 95% CI 1.01–1.09, p = 0.010) and death alone (HR 1.06 per 1% higher GLS, 95% CI 1.02–1.11, p = 0.003). There was no significant interaction between GLS and indication for ICD implant, presence of ischemic heart disease or late gadolinium enhancement (all p > 0.30).ConclusionsGLS by FT-CMR is an independent predictor of appropriate shocks or mortality in ICD patients, beyond conventional prognosticators including LVEF. Further study is needed to elucidate the role of LV strain analysis to refine risk stratification in routine assessment of ICD treatment benefit.

Circulating Soluble ST2 Predicts All-Cause Mortality in Severe Heart Failure Patients with an Implantable Cardioverter Defibrillator

Background Heart failure (HF) is the terminal stage of all cardiovascular events. Although implantable cardioverter defibrillator (ICD) therapies have reduced mortality among the high-risk HF population, it is necessary to determine whether certain factors can predict mortality even after cardiac device implantation. Growth stimulation expressed gene 2 (ST2) is an emerging biomarker for HF patient stratification in different clinical settings. Aims This study aimed to investigate the relationship between baseline soluble ST2 (sST2) levels in serum and the clinical outcomes of high-risk HF patients with device implantation. Methods Between January 2017 and August 2018, we prospectively recruited consecutive patients implanted with an ICD for heart failure, with LVEF ≤35% as recommended, and analyzed the basic characteristics, baseline serum sST2, and NT-proBNP levels, with at least 1-year follow-up. All-cause mortality was the primary endpoint. Results During a 643-day follow-up, all-cause mortality occurred in 16 of 150 patients (10.67%). Incidence of all-cause mortality increased significantly in patients with sST2 levels above 34.98846 ng/ml (16.00% vs. 5.33%, P = 0.034). After adjusting the model (age, gender, device implantation, prevention of sudden death, LVEDD, LVEF, WBC and CLBBB, hsTNT, etiology, and eGFR) and the model combined with NT-proBNP, the risk of all-cause death was increased by 2.5% and 1.9%, respectively, per ng/ml of sST2. The best sST2 cutoff for predicting all-cause death was 43.42671 ng/ml (area under the curve: 0.72, sensitive: 0.69, and specificity: 0.69). Compared to patients with sST2 levels below 43.42671 ng/ml, the risk of all-cause mortality was higher in those with values above the threshold (5.1% vs. 21.2%, P = 0.002). ST2 level ≥43.42671 ng/ml was an independent predictor of all-cause mortality (HR: 3.30 [95% CI 1.02–10.67]). Age (HR: 1.06 [95% CI: 1.01–1.12]) and increased NT-proBNP per 100 (HR: 1.02 [95% CI: 1.01–1.03]) were also associated with all-cause mortality in ICD patients. Conclusions sST2 level was associated with risk of all-cause mortality, and a threshold of 43.43 ng/ml showed good distinguishing performance to predict all-cause mortality in patients with severe heart failure, recommended for ICD implantation. Patients with sST2 levels more than 43.42671 ng/ml even after ICD implantation should therefore be monitored carefully.

Mortality after implantable cardioverter defibrillators in dialysis patients: a nationwide study

Abstract Background Although randomized clinical trials have shown that implantable cardioverter defibrillators (ICDs) reduce mortality in selected patients, patients on dialysis are excluded from these trials. Thus, data on mortality risk after ICD implantation in these patients are sparse. Purpose To examine all-cause mortality in patients receiving an ICD according to dialysis status and to identify factors associated with all-cause mortality in patients on dialysis. Methods Using Danish nationwide registries from 2000–2017, all patients ≥18 years old undergoing first-time ICD implantation were included. Patients on dialysis were identified prior to ICD implantation and followed for up to five years. The cumulative incidence of all-cause mortality according to dialysis status was assessed. Factors associated with all-cause mortality after ICD implantation in dialysis patients were examined using multivariable Cox proportional hazard regression. Results A total of 14,681 ICD patients were identified, of which 218 (1.5%) were on dialysis prior to ICD implantation. Compared with ICD patients not on dialysis, those on dialysis were younger (median age 64 years [IQR: 58–70] vs. 66 years [IQR: 57–72], p=0.02), more likely to receive an ICD for secondary prophylaxis (69.7% vs 53.7%), and had more comorbidities including ischaemic heart disease (60.6% vs. 46.3%), diabetes (28.4% vs. 20.4%), and peripheral vascular disease (10.1% vs. 5.6%) (p for all &amp;lt;0.05). The median time to death among ICD patients on dialysis and not on dialysis were 1.3 years (IQR: 0.4–2.8 years] and 2.2 years [IQR: 1.0–3.5 years], respectively. One-year mortality among ICD patients on dialysis (13.0%) was significantly higher compared with ICD patients not on dialysis (4.7%), p&amp;lt;0.001 (Figure). Five-year mortality was significantly higher in ICD patients on dialysis than those not on dialysis (42.2% vs 23.6%), p&amp;lt;0.001 (Figure). Factors associated with increased risk of all-cause mortality among ICD patients on dialysis were age ≥65 years at time of implantation (reference: age &amp;lt;65 years) (HR 1.90 [95% CI: 1.13–3.19]), primary prophylactic ICD (HR 1.81 [95% CI 1.08–3.05]), and diabetes (HR 1.87 [95% CI 1.14–3.07]). Sex, ischaemic heart disease, heart failure, stroke, chronic obstructive pulmonary disease, and malignancy were not associated with the risk of mortality (p&amp;gt;0.05 for all). Cardiovascular causes of death were common both in patients with- and without dialysis, 69.6% and 60.0%, respectively. Conclusion Five-year mortality in ICD patients on dialysis was 42% and twice as high compared with ICD patients not on dialysis. Age ≥65 years, primary prophylactic indication, and diabetes were factors associated with increased mortality. Careful evaluation of the potential benefit from an ICD implantation in dialysis patients is important considering the overall high mortality rates. Funding Acknowledgement Type of funding source: None

A Device Histogram‐Based Simple Predictor of Mortality Risk in ICD and CRT‐D Patients: The Heart Rate Score

We hypothesized that survival in implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) patients is predicted by baseline Heart Rate Score. Heart Rate Score is determined from the atrial paced and sensed histogram of a DDD ICD or CRT-D, and defined as percent of beats in the histogram in the tallest 10 beats/min range bin. It was calculated at initial remote monitoring for patients enrolled in LATITUDE® without persistent atrial fibrillation, and with pulse generators implanted in 2006-2011. Univariate, multivariate, and Kaplan-Meier analyses determined the impact of Heart Rate Score on survival. Of 57,893 ICDs and 67,929 CRT-Ds followed for 2.4 ± 1.5 years, each 10% increase in Heart Rate Score was associated with decreased survival (CRT-D hazard ratio [HR] 1.07 95%, confidence interval 1.06-1.07, P < 0.0001; ICD HR 1.05, 95% confidence interval 1.04-1.06, P < 0.0001). Multivariate analysis showed survival decreased with increasing age, atrial fibrillation, presence of a shock in first-year follow-up, and increasing programmed lower pacing rate in ICD and CRT-D patients. Increased percent right ventricular pacing predicted mortality in ICD patients, while male gender and lower percent left ventricular pacing predicted mortality in CRT patients. Heart Rate Score predicted survival independent of those variables. Heart Rate Score correlates with heart rate variability (standard deviation of average R-R intervals [SDANN]) when both are obtainable, but SDANN was only present in 6% of patients with Heart Rate Score >70%. A simple device histogram measure, Heart Rate Score, predicts survival in ICD and CRT-D patients independent of the available variables, and even when SDANN is unavailable.

Association of Implantable Cardioverter Defibrillator Therapy with All-Cause Mortality-A Systematic Review and Meta-Analysis.

Implantable cardioverter defibrillators (ICDs) have become the standard approach for prevention of sudden cardiac death. Whether ICD therapy is an independent predictor of all-cause mortality is controversial. We made the systematic review and meta-analysis to estimate the impact of ICD therapy on mortality. We searched the PubMed and Embase databases for studies evaluating the effect of ICD shocks or antitachycardia pacing (ATP) on mortality. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using random effects models. Thirteen cohort studies were identified. Mean ejection fraction of the population was 23-35%; 68.0% had ischemic etiology, and 74.5% received a primary prevention ICD implantation. Appropriate shocks were an independent predictor of increased mortality compared with no-shock or no-therapy patients (HR 2.07, 2.76, respectively). In contrast, inconsistent results were obtained during inappropriate-shock analyses: when compared with no-shock patients, inappropriate shocks were associated with an increased risk of death (HR 1.54, 95% CI: 1.25-1.89, P < 0.0001); however, when compared to no-therapy patients, there was no relationship between inappropriate shocks and mortality (HR 1.20, 95% CI: 0.90-1.61, P = 0.22). Subgroup analysis in heart failure patients also did not find any difference in mortality between inappropriate-shock and no-therapy patients. No increased risk of mortality was found in the patients who experienced appropriate or inappropriate ATP only. Appropriate shocks were associated with an increased mortality in ICD patients. However, whether inappropriate shocks worsened the clinical outcome was controversial, and larger prospective trials are needed to clarify the issue.

Anxiety predicts mortality in ICD patients: results from the cross-sectional national CopenHeartICD survey with register follow-up.

Although highly effective in preventing arrhythmic death, patients receiving an implantable cardioverter defibrillator (ICD) may still experience psychological difficulties such as anxiety, depression, and reduced quality of life. The objectives of this study were to describe patient-reported outcomes among ICD patients: (1) compared to a matched healthy population, (2) compared by ICD indication, (3) factors predicting patient-reported outcomes, and (4) if patient-reported outcomes predicted mortality. The study was a mailed survey to an unselected group of patients 18+ years old receiving ICD between January 1, 2011 and June 30, 2011 (n = 499). The following instruments were used: SF-36, Hospital Anxiety and Depression Scale, HeartQoL, EQ-5D, and the Multidimensional Fatigue Inventory. The response rate was 72%. Mean age was 65.5 years and 82% patients were males. Fifty-three percent of patients had primary prevention indication ICD. Compared to an age- and gender-matched population without disease, the ICD population had worse mental health (55.0 vs 51.7 points) and physical health (52.6 vs 41.9 points). Patients with primary prevention indication had lower levels of perceived health, quality of life, and fatigue; for example, physical health 39.8 versus 44.3 points, compared to secondary prevention indication. Anxiety, poor perceived health, fatigue, and low quality of life were all predictors of mortality, anxiety being the strongest with an adjusted odds ratio of 4.17 (1.49; 11.66). Patients with primary prevention ICD had lower levels of perceived health, quality of life, and more fatigue. Anxiety, poor perceived health, fatigue, and low quality of life were all predictors of mortality.

Development and validation of a risk score to predict early mortality in recipients of implantable cardioverter-defibrillators

Current guidelines do not recommend implantable cardioverter-defibrillator (ICD) implantation in patients with a life expectancy of <1 year. Better methods are needed for identifying patients at high risk for early mortality despite ICD therapy. To develop and validate a risk prediction score to identify patients at high risk for death within 1 year despite ICD therapy. Detailed clinical data were collected on a large observational cohort of ICD patients from 3 tertiary care centers. One-third of the patients were randomly selected to form the prediction group (PG) from which a risk score was developed using logistic regression. This score was then applied to the remaining two-thirds of the cohort (validation group [VG]) to assess the risk score's predictive accuracy. The total cohort included 2717 ICD patients (mean age = 64.6 ± 14.5, male = 77.2%, primary prevention = 74.7%). A simple risk score incorporating peripheral arterial disease, age ≥ 70 years, creatinine ≥ 2.0 mg/dL, and ejection fraction ≤20% (PACE) accurately predicted 1-year mortality in the VG. Patients with a risk score of ≥3 had a >4-fold excess 1-year mortality compared with patients with a risk score of <3 (16.5% vs 3.5%; P <.0001). Risk reduction provided by ICD therapy in this cohort is not known given the lack of a control group. A simple risk score accurately predicts 1-year mortality in ICD patients, as patients with a PACE risk score of ≥3 are at high risk despite ICD therapy.

Shocks burden and increased mortality in implantable cardioverter-defibrillator patients

Implantable cardioverter-defibrillator (ICD) shocks are associated with an increased risk of death. It is unclear whether ICD shocks are detrimental per se or a marker of higher risk patients. We aimed to assess the association between ICD shocks and time to death after correction for baseline mortality based on the Seattle Heart Failure Model (SHFM). The primary analysis compared time-to-death between patients receiving no shocks and patients receiving shocks of any type adjusted for SHFM score at time of implantation and other comorbidities. Subgroup analyses were performed to further describe the relationship between shocks and mortality risk. Over a median follow-up of 41 months (interquartile range 23-64), one or more shock episodes occurred in 59% of 425 patients and 40% of the patients died. Patients receiving shocks of any type had increased risk of death (hazard ratio 1.55; 95% confidence interval 1.07-2.23; P = .02) versus patients receiving no shocks. While patients with 1-5 days with shock (shock days) did not show evidence of increased risk of death (1.30 [0.88-1.94]; P = 0.19), those with 6-10 shock days (2.22 [1.21-4.08]; P <.01) and >10 shock days (3.66 [1.86-7.19]; P <.01) had increasingly higher risk. There was no increased hazard for death (0.73 [0.34-1.57]; P = .41) in patients treated only with antitachycardia pacing (ATP). ICD shocks were associated with increased mortality risk after adjustment for SHFM-predicted mortality, and the burden of shocks played a role in this association. ATP did not increase mortality risk, suggesting that shocks may themselves be detrimental.

Differences in effects of electrical therapy type for ventricular arrhythmias on mortality in implantable cardioverter-defibrillator patients

Implantable cardioverter-defibrillator (ICD) shocks have been associated with an increased risk of death. It is unknown whether this is due to the ventricular arrhythmia (VA) or shocks and whether antitachycardia pacing (ATP) termination can reduce this risk. The purpose of this study was to determine whether mortality in ICD patients is influenced by the type of therapy (shocks of ATP) delivered. Cox models evaluated effects of baseline characteristics, ventricular tachycardia (VT; <188 bpm), fast VT (FVT; 188-250 bpm), ventricular fibrillation (VF; >250 bpm), and therapy type (shocks or ATP) on mortality among 2135 patients in four trials of ATP to reduce shocks. Over 10.8 +/- 3.3 months, 24.3% patients received appropriate shocks (50.6%) or ATP only (49.4%), and 6.6% died. Mortality predictors were age (hazard ratio 1.07, 95% confidence interval 1.04-1.08, P <.0001), New York Heart Association class III/IV (3.50 [2.27-5.41]; P <.0001), coronary disease (3.08 [1.31-7.25]; P = .01), and cumulative VA (VT + FVT + VF) episodes shocked (1.20 [1.13, 1.29]; P <.0001). Beta-blockers (0.65, 0.46-0.92; P <.0001) and remote myocardial infarction (0.53, [0.38-0.76] P = .0004) predicted reduced risk. Since 92% of VT and all VF received a single therapy type (ATP and shocks, respectively), the effect of therapy on episode risk could not be established. For FVT (32% shocked, 68% ATP), episode and therapy effects could be uncoupled; ATP-terminated FVT did not increase episode mortality risk, whereas shocked FVT increased risk by 32%. Survival rates were highest among patients with no VA (93.8%) of ATP-only (94.7%) and lowest for shocked patients (88.4%). Monthly episode rates were 80% higher among shocked versus ATP-only patients. Shocked VA episodes are associated with increased mortality risk. Shocked patients have substantially higher VA episode burden and poorer survival compared with ATP-only-treated patients.

Long-term predictors of mortality in ICD patients with non-ischaemic cardiac disease: impact of renal function

Randomized trials have demonstrated that implantable cardioverter defibrillator (ICD) therapy may reduce the risk of death in patients with non-ischaemic cardiomyopathy (CMP). In this study, we aimed at determining the long-term benefit of ICD therapy among patients with dilated CMP (DCM) and among those with other non-ischaemic cardiac diseases (NICDs). We performed a single-centre longitudinal study to assess the outcomes of 176 patients with NICDs who were implanted with an ICD for primary or secondary prevention of cardiac death. The cumulative survival rate after 1, 2, 5, and 10 years was 91, 87, 78, and 65%, respectively. Mortality risk did not differ significantly between patients with DCM and those with other NICDs. Atrial fibrillation, recurrent ventricular arrhythmias requiring ICD therapy, and right ventricular pacing, but not delayed intrinsic ventricular conduction, were associated with higher risk. New York Heart Association (NYHA) functional class > or =III was an independent predictor of adverse outcome among patients with DCM [hazard ratio (HR) 5.27, P = 0.01], whereas reduced left ventricular function with ejection fraction <35% (HR 12.1, P < 0.001) and anti-arrhythmic drug use (HR 4.82, P = 0.03) were independent predictors among those with other NICDs. Renal insufficiency with estimated glomerular filtration rate <60 mL/min/1.73 m(2) (HR 5.9, P < 0.001) was a strong independent predictor of mortality among all patients with NICD, irrespective of underlying cardiac condition. In ICD patients with DCM, higher NYHA functional class is associated with adverse outcomes. Impaired left ventricular function and anti-arrhythmic drug use predict higher mortality among patients with non-dilated, NICDs. Impaired renal function is a strong predictor of mortality in all patients with NICD.

Abstract 1534: Diabetes Mellitus Is An Independent Predictor Of Mortality In Defibrillator Recipients

Background: Previous studies have shown an increased morbidity and mortality risk in patients with diabetes mellitus (DM) undergoing percutaneous coronary interventions and cardiac surgery. However, the impact of DM on mortality in patients with implantable cardioverter defibrillators (ICDs) is unknown. Aim: to investigate whether DM was associated with increased mortality risk in patients with ICDs Methods: A retrospective review of all ICD patients followed within a consecutive 2.5 year period was performed. Baseline characteristics and mortality data were compared between DM and non-DM patients. Mann Whitney test was used to analyze the differences between the means, and multivariate logistic regression analysis was performed to identify independent predictors of mortality. Results: A total of 336 patients with ICDs (including 141 patients with DM and 195 without DM) were studied. The mean age was 66.8 ± 9.6 years in the overall population, with no significant difference in baseline characteristics between the 2 groups, except for beta-blocker therapy, creatinine, and estimated glomerular infiltration rate (EGFR). Use of beta-blockers was greater in the non-DM group (92.8% vs 84.4%, p=0.02). Renal function was worse in the DM group, as documented by a higher serum creatinine (1.6 ± 0.8 mg/dl in DM vs 1.38 ± 0.74 mg/dl in non-DM, p = 0.003) and a lower EGFR (55.9 ± 22.9 ml/min/1.73m 2 vs 63.5 ± 19.9 ml/min/1.73m 2 , p=0.0005). Although the incidence of VT was not significantly different between the two groups, there was a significantly higher mortality in the DM group (27.7% vs 11.3% in non-DM, p=0.0002). On multivariate stepwise logistic regression analysis, DM was a significant independent predictor of mortality (OR 2.38, 95% CI 1.3– 4.36, p =0.005). Conclusion: DM is an independent predictor of mortality in ICD patients. Prevention of DM, as well as early diagnosis and intervention, should be emphasized in order to reduce the growing epidemic of type 2 DM and its associated complications.

QRS duration: a simple marker for predicting cardiac mortality in ICD patients with heart failure

Patients resuscitated from ventricular tachyarrhythmias benefit from implantable cardioverter-defibrillators (ICDs) as opposed to medical treatment. Patients with increased QRS duration receiving an ICD in the presence of heart failure are at greatest risk of cardiac death and benefit most from ICD therapy. To determine whether an increased QRS duration predicts cardiac mortality in ICD recipients. Consecutive patients with heart failure in New York Heart Association functional class III were grouped according to QRS duration (< 150 ms, n = 139, group 1; v ≥150 ms, n = 26, group 2) and followed up for (mean (SD)) 23 (20) months. 165 patients were studied (80% men, 20% women); 73% had coronary artery disease and 18% had dilated cardiomyopathy. Their mean age was 62 (10) years and mean ejection fraction (EF) was 33 (14)%. They presented either with ventricular tachycardia (VT) or ventricular fibrillation (VF).

Complications of implantable cardioverter defibrillator therapy: follow-up of 241 patients.

In order to determine the incidence of complications of implantable cardioverter defibrillator (ICD) therapy, 241 patients with a total of 353 ICD implantations were followed for 24 +/- 20 months. Complications were defined as any untoward effects experienced by the patient related to the ICD implantation and function or death within 4 weeks of implant or before hospital discharge. During follow-up, 129 of 241 patients (53%) had a total of 166 complications. An operative procedure was required to correct the complication in 50 of the 241 patients (21%). No patient died intraoperatively, but eight patients died within 4 weeks postoperatively or before hospital discharge. ICD infection required removal of the device in 13 patients (5%). Twenty-six patients (11%) had postoperative respiratory complications. Postoperative bleeding and/or thrombosis occurred in 11 patients (4%). Endocardial lead migration was observed in nine patients (4%) and lead adapter or insulation break occurred in nine patients (4%). Fifty-four patients (22%) experienced ECG-documented discharges for non-VT rhythm. In conclusion, although perioperative mortality in ICD patients is low, the majority of patients have complications during follow-up. Recognition of these complications may allow for advances in ICD technology and management strategies to avoid their occurrence.