Classification of death in antiarrhythmia trials

Temporal and Global Trends of the Incidence of Sudden Cardiac Death in Hypertrophic Cardiomyopathy

BACKGROUND

Since the initial clinical description of hypertrophic cardiomyopathy (HCM) over 60 years ago, sudden cardiac death (SCD) has been the most visible and feared complication of HCM.

OBJECTIVES

This study sought to characterize the temporal, geographic, and age-related trends of reported SCD rates in adult HCM patients.

METHODS

Electronic databases were systematically searched up to November 2021 for studies reporting on SCD event rates in HCM patients. Patients with SCD equivalents (appropriate implantable cardioverter-defibrillator [ICD] shocks and nonfatal cardiac arrests) were not included. A random-effects model was used to pool study estimates calculating the overall incidence rates (IR) for each time-era, geographic region, and age group. We analyzed 2 periods (before vs after 2000, following clinical implementation of ICD in HCM). Following 2000, 5-year intervals were used to demonstrate the temporal change in SCD rates.

RESULTS

A total of 98 studies (N = 70,510 patients and 431,407 patient-years) met our inclusion criteria. The overall rate of HCM SCD was 0.43%/y (95% CI: 0.37-0.50%/y; I² = 75%; SCD events: 1,938; person-years of follow-up: 408,715), with young patients (<18 years of age) demonstrating a >2-fold-risk for sudden death vs adult patients 18-60 years of age (IR: 1.09%; 95% CI: 0.69%-1.73% vs IR: 0.43%; 95% CI: 0.37%-0.50%) (P value for subgroup differences <0.01). Contemporary SCD rates from 2015 to present were 0.32%/y and significantly lower compared with 2000 or earlier (IR: 0.32%; 95% CI: 0.20%-0.52% vs IR: 0.73%; 95% CI: 0.53%-1.02%, respectively). Reported SCD rates for HCM were lowest in North America (IR: 0.28%; 95% CI: 0.18%-0.43%,) and highest in Asia (IR: 0.67%; 95% CI: 0.54%-0.84%).

CONCLUSIONS

Contemporary HCM-related SCD rates are low (0.32%/y) representing a 2-fold decrease compared with prior treatment eras. Young HCM patients are at the highest risk. The maturation of SCD risk stratification strategies and the application of primary prevention ICD to HCM are likely responsible for the notable decline over time in SCD events. In addition, worldwide geographic disparities in SCD rates were evident, underscoring the need to increase access to SCD prevention treatment for all HCM patients.

Relationship of LVEF and Myocardial Scar to Long-Term Mortality Risk and Mode of Death in Patients With Nonischemic Cardiomyopathy

BACKGROUND

Nonischemic cardiomyopathy is a leading cause of reduced left ventricular ejection fraction (LVEF) and is associated with high mortality risk from progressive heart failure and arrhythmias. Myocardial scar on cardiovascular magnetic resonance imaging is increasingly recognized as a risk marker for adverse outcomes; however, left ventricular dysfunction remains the basis for determining a patient's eligibility for primary prophylaxis with implantable cardioverter-defibrillator. We investigated the relationship of LVEF and scar with long-term mortality and mode of death in a large cohort of patients with nonischemic cardiomyopathy.

METHODS

This study is a prospective, longitudinal outcomes registry of 1020 consecutive patients with nonischemic cardiomyopathy who underwent clinical cardiovascular magnetic resonance imaging for the assessment of LVEF and scar at 3 centers.

RESULTS

During a median follow-up of 5.2 (interquartile range, 3.8, 6.6) years, 277 (27%) patients died. On survival analysis, LVEF ≤35% and scar were strongly associated with all-cause (log-rank test P=0.002 and P<0.001, respectively) and cardiac death (P=0.001 and P<0.001, respectively). Whereas scar was strongly related to sudden cardiac death (SCD; P=0.001), there was no significant association between LVEF ≤35% and SCD risk (P=0.57). On multivariable analysis including established clinical factors, LVEF and scar are independent risk markers of all-cause and cardiac death. The addition of LVEF provided incremental prognostic value but insignificant discrimination improvement by C-statistic for all-cause and cardiac death, but no incremental prognostic value for SCD. Conversely, scar extent demonstrated significant incremental prognostic value and discrimination improvement for all 3 end points. On net reclassification analysis, the addition of LVEF resulted in no significant improvement for all-cause death (11.0%; 95% CI, -6.2% to 25.9%), cardiac death (9.8%; 95% CI, -5.7% to 29.3%), or SCD (7.5%; 95% CI, -41.2% to 42.9%). Conversely, the addition of scar extent resulted in significant reclassification improvement of 25.5% (95% CI, 11.7% to 41.0%) for all-cause death, 27.0% (95% CI, 11.6% to 45.2%) for cardiac death, and 40.6% (95% CI, 10.5% to 71.8%) for SCD.

CONCLUSIONS

Myocardial scar and LVEF are both risk markers for all-cause and cardiac death in patients with nonischemic cardiomyopathy. However, whereas myocardial scar has strong and incremental prognostic value for SCD risk stratification, LVEF has no incremental prognostic value over clinical measures. Scar assessment should be incorporated into patient selection criteria for primary prevention implantable cardioverter-defibrillator placement.

Death with an implantable cardioverter-defibrillator: a MADIT-II substudy

AIMS

There are limited data regarding factors that identify implantable cardioverter-defibrillator (ICD) patients who will experience either ventricular tachyarrhythmic (VTA) or non-arrhythmic (NA) mortality, and the commonly used clinical classification of sudden cardiac death (SCD) vs. non-sudden cardiac death (NSCD) may not be accurate enough. We aimed to correlate clinical adjudication of mortality events to device interrogation data and to identify risk factors for VTA mortality in Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II).

METHODS AND RESULTS

Of the 746 patients who received an ICD in MADIT-II, 44 died from cardiac causes and had available interrogation data at the time of death. Sudden cardiac death vs. NSCD was defined by an adjudication committee. Ventricular tachyarrhythmic and NA arrhythmic deaths were categorized by the presence or absence of ventricular tachycardia or fibrillation (VT/VF) during the terminal event. Mode of death was found to be inaccurate when validated by device interrogation for VTA events: 50% patients adjudicated as SCD did not have a VTA event at the time of death; and 25% of adjudicated NSCD were found to have VT/VF during the mortality event. Multivariate analysis showed that factors independently associated with VTA mortality included: VT/VF >72 h prior to the mortality event [hazard ratio (HR) 8.0; P < 0.001], hospitalization for heart failure (HR 6.7; P = 0.001), and a history of hypertension (HR 4; P = 0.04).

CONCLUSION

Current classification of SCD vs. NSCD fails to identify VTA events at the time of death in a significant proportion of patients, and simple clinical parameters can be used to identify ICD recipients with increased risk for VTA mortality.

Deactivation of implantable defibrillators at end of life - Can we do better?

INTRODUCTION

Dying patients with implantable defibrillators (ICD) have a risk of receiving unnecessary shocks before death. The aim of this study was to investigate if deactivation of shock therapy at end-of-life has increased since publication of new guidelines in 2010 on ICD management.

METHOD AND RESULTS

This is a study of two groups of ICD patients who died in hospitals before and after publication of new guidelines. Group 1 consists of 89 patients who died between 2003 and 2010. Group 2 consists of 252 patients, the total number of ICD patients in Sweden who died in hospital during 2014. Data was obtained from the Swedish ICD and Pacemaker Registry, Swedish Tax Agency and patient medical notes. Two-thirds died in wards other than Cardiology. Fifty-four percent in group 1 had a Do-Not-Resuscitate-order (DNR) compared to 73% in group 2. Shock deactivation was present in 52% in group 1 and 67% in group 2. The difference in shock deactivation between group 1 and 2 was only significant (p = 0.014) for DNR-patients treated in Cardiology. A significant difference (p = 0.036) was found in deactivation within group 2 between DNR-patients in Cardiology vs. DNR-patients in Non-Cardiology wards.

CONCLUSION

Two-thirds of ICD patients die in wards other than Cardiology. Since publication of guidelines on ICD management there is a general increase in shock deactivation for DNR-patients, but only significant for patients in Cardiology. This implicate that actions have to be taken for patients treated in Non-Cardiology wards to bridge the gap between guidelines recommendations and clinical practice.

Trends in time in the management of the implantable cardioverter defibrillator in the last phase of life: a retrospective study of medical records

BACKGROUND

The implantable cardioverter defibrillator (ICD) might give unwanted shocks in the last month of life. Guidelines recommend deactivation of the ICD prior to death.

AIMS

The aims of this study were to examine trends in time (2007-2016) in how and when decisions are made about ICD deactivation, and to examine patient- and disease-related factors which may have influenced these decisions. In addition, care and ICD shock frequency in the last month of life of ICD patients are described.

METHODS

Medical records of a sample of deceased patients who had their ICD implanted in 1999-2015 in a Dutch university (n = 308) or general (n = 72) hospital were examined.

RESULTS

Median age at death was 71 years, and 88% were male. ICD deactivation discussions increased from 6% for patients who had died between 2007 and 2009 to 35% for patients who had died between 2013 and 2016. ICD deactivation rates increased in these periods from 16% to 42%. Presence of do-not-resuscitate (DNR) orders increased from 9% to 46%. Palliative care consultations increased from 0% to 9%. When the ICD remained active, shocks were reported for 7% of patients in the last month of life. Predictors of ICD deactivation were the occurrence of ICD deactivation discussions after implantation (OR 69.30, CI 26.45-181.59), DNR order (OR 6.83, CI 4.19-11.12), do-not-intubate order (OR 6.41, CI 3.75-10.96), and palliative care consultations (OR 8.67, CI 2.76-27.21).

CONCLUSION

ICD deactivation discussions and deactivation rates have increased since 2007. Nevertheless, ICDs remain active in the majority of patients at the end of life, some of whom experience shocks.

Implantable cardiac defibrillators for people with non-ischaemic cardiomyopathy

BACKGROUND

There is evidence that implantable cardioverter-defibrillator (ICD) for primary prevention in people with an ischaemic cardiomyopathy improves survival rate. The evidence supporting this intervention in people with non-ischaemic cardiomyopathy is not as definitive, with the recently published DANISH trial finding no improvement in survival rate. A systematic review of all eligible studies was needed to evaluate the benefits and harms of using ICDs for primary prevention in people with non-ischaemic cardiomyopathy.

OBJECTIVES

To evaluate the benefits and harms of using compared to not using ICD for primary prevention in people with non-ischaemic cardiomyopathy receiving optimal medical therapy.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and the Web of Science Core Collection on 10 October 2018. For ongoing or unpublished clinical trials, we searched the US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), and the ISRCTN registry. To identify economic evaluation studies, we conducted a separate search to 31 March 2015 of the NHS Economic Evaluation Database, and from March 2015 to October 2018 on MEDLINE and Embase.

SELECTION CRITERIA

We included randomised controlled trials involving adults with chronic non-ischaemic cardiomyopathy due to a left ventricular systolic dysfunction with an ejection fraction of 35% or less (New York Heart Association (NYHA) type I-IV). Participants in the intervention arm should have received ICD in addition to optimal medical therapy, while those in the control arm received optimal medical therapy alone. We included studies with cardiac resynchronisation therapy when it was appropriately balanced in the experimental and control groups.

DATA COLLECTION AND ANALYSIS

The primary outcomes were all-cause mortality, cardiovascular mortality, sudden cardiac death, and adverse events associated with the intervention. The secondary outcomes were non-cardiovascular death, health-related quality of life, hospitalisation for heart failure, first ICD-related hospitalisation, and cost. We abstracted the log (hazard ratio) and its variance from trial reports for time-to-event survival data. We extracted the raw data necessary to calculate the risk ratio. We summarised data on quality of life and cost-effectiveness narratively. We assessed the certainty of evidence for all outcomes using GRADE.

MAIN RESULTS

We identified six eligible randomised trials with a total of 3128 participants. The use of ICD plus optimal medical therapy versus optimal medical therapy alone decreases the risk of all-cause mortality (hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.66 to 0.92; participants = 3128; studies = 6; high-certainty evidence). An average of 24 patients need to be treated with ICD to prevent one additional death from any cause (number needed to treat for an additional beneficial outcome (NNTB) = 24). Individuals younger than 65 derive more benefit than individuals older than 65 (HR 0.51, 95% CI 0.29 to 0.91; participants = 348; studies = 1) (NNTB = 10). When added to medical therapy, ICDs probably decrease cardiovascular mortality compared to not adding them (risk ratio (RR) 0.75, 95% CI 0.46 to 1.21; participants = 1781; studies = 4; moderate-certainty evidence) (possibility of both plausible benefit and no effect). Implantable cardioverter-defibrillator was also found to decrease sudden cardiac deaths (HR 0.45, 95% CI 0.29 to 0.70; participants = 1677; studies = 3; high-certainty evidence). An average of 25 patients need to be treated with an ICD to prevent one additional sudden cardiac death (NNTB = 25). We found that ICDs probably increase adverse events (possibility of both plausible harm and benefit), but likely have little or no effect on non-cardiovascular mortality (RR 1.17, 95% CI 0.81 to 1.68; participants = 1781; studies = 4; moderate-certainty evidence) (possibility of both plausible benefit and no effect). Finally, using ICD therapy probably has little or no effect on quality of life, however shocks from the device cause a deterioration in quality of life. No study reported the outcome of first ICD-related hospitalisations.

AUTHORS' CONCLUSIONS

The use of ICD in addition to medical therapy in people with non-ischaemic cardiomyopathy decreases all-cause mortality and sudden cardiac deaths and probably decreases mortality from cardiovascular causes compared to medical therapy alone. Their use probably increases the risk for adverse events. However, these devices come at a high cost, and shocks from ICDs cause a deterioration in quality of life.

The incidence and impact of implantable cardioverter defibrillator shocks in the last phase of life: An integrated review

BACKGROUND

Although the implantable cardioverter defibrillator is successful in terminating life threatening arrhythmias, it might give unwanted shocks in the last phase of life if not deactivated in a timely manner.

AIMS

This integrated review aimed to provide an overview of studies reporting on implantable cardioverter defibrillator shock incidence and impact in the last phase of life.

METHODS AND RESULTS

We systematically searched five electronic databases. Studies reporting on the incidence and/or impact of implantable cardioverter defibrillator shocks in the last month of life were included. Fifteen studies were included. Two American studies published in 1996 and 1998 reported on the incidence of shocks in patients who died non-suddenly: incidences were 24% and 33%, respectively, in the last 24 hours, and 7% and 14%, respectively, in the last hour of life. Six American studies and one Danish study published between 1991-1999 reported on patients dying suddenly: incidences were 41% and 68% in the last 24 hours and 22-66% in the last hour. Four American studies and two Swedish studies published between 2004-2015 did not distinguish the cause of death: incidences were 17-32% in the last month, 3-32% in the last 24 hours, and 8% and 31% in the last hour of life. Three American studies published between 2004-2011 reported that shocks in dying patients are painful and distressing for patients, and distressing for relatives and professional caregivers.

CONCLUSION

If the implantable cardioverter defibrillator is not deactivated in a timely manner, a potentially significant proportion of implantable cardioverter defibrillator patients experience painful and distressing shocks in their last phase of life.

Postmortem ICD interrogation in mode of death classification

BACKGROUND

The definition of sudden death due to arrhythmia relies on the time interval between onset of symptoms and death. However, not all sudden deaths are due to arrhythmia. In patients with an implantable cardioverter defibrillator (ICD), postmortem device interrogation may help better distinguish the mode of death compared to a time-based definition alone.

OBJECTIVE

This study aims to assess the proportion of "sudden" cardiac deaths in patients with an ICD that have confirmed arrhythmia.

METHODS

We conducted a literature search for studies using postmortem ICD interrogation and a time-based classification of the mode of death. A modified QUADAS-2 checklist was used to assess risk of bias in individual studies. Outcome data were pooled where sufficient data were available.

RESULTS

Our search identified 22 studies undertaken between 1982 and 2015 with 23,600 participants. The pooled results (excluding studies with high risk of bias) suggest that ventricular arrhythmias are present at the time of death in 76% of "sudden" deaths (95% confidence interval [CI] 67-85; range 42-88).

CONCLUSION

Postmortem ICD interrogation identifies 24% of "sudden" deaths to be nonarrhythmic. Postmortem device interrogation should be considered in all cases of unexplained sudden cardiac death.

The Effect of Chronic Kidney Disease on Mortality with Cardiac Resynchronization Therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) improves functional status, reduces heart failure hospitalizations, and decreases mortality. Several comorbidities including renal function affect outcomes with CRT. However, moderate to severe chronic kidney disease (CKD) was an exclusion criterion in the large randomized control trials.

OBJECTIVE

To evaluate the association of renal function on survival following CRT implantation.

METHODS

This was a retrospective analysis of 432 consecutive patients implanted with an implantable cardioverter defibrillator with CRT (CRT-D). The primary end point was defined as death by any cause, and it was determined using hospital records and the U.S. Social Security Death Index. A Kaplan-Meier analysis was performed separating renal dysfunction into renal stage based on glomerular filtration rate. Multivariate analysis was performed to assess the clinical predictors of mortality.

RESULTS

Patients were followed for up to 12 years with a mean follow-up time of 4.3 ± 3.2 years. A total of 164 patients (39.3%) died over the course of the study. Patients with normal and mild renal diseases (Stages 1 and 2) had improved survival compared with those with moderate-, severe-, or end-stage (Stages 3-5) renal disease. This effect remained statistically significant after multivariate analysis. The estimated 5-year mortality was 36.3% for stage 1, 33.4% for stage 2, 40.6% for stage 3, and 62.1% for stage 4/5 kidney disease (P = 0.004 by log-rank test).

CONCLUSION

CKD is a strong and an independent predictor of long-term mortality among patients undergoing CRT-D implantation.

Prognostic significance of myocardial extracellular volume fraction in nonischaemic dilated cardiomyopathy

AIMS

In nonischaemic dilated cardiomyopathy (NICM), replacement myocardial fibrosis as detected by late gadolinium enhancement (LGE) at cardiovascular magnetic resonance (CMR) is associated with poor prognosis. We investigated the as-yet unexplored prognostic significance of interstitial fibrosis in NICM, using T1-mapping CMR.

METHODS

Eighty-nine NICM patients (63 men, age 59 ± 14 years) with left ventricular systolic dysfunction (ejection fraction 41 ± 13%) underwent comprehensive clinical and CMR evaluation, with extracellular volume fraction (ECV) estimation from pre and postcontrast T1 mapping. Fifteen healthy individuals (11 men, mean age 52 ± 11 years) were used as controls. The end-point was a composite of cardiovascular death, hospitalization for heart failure and appropriate defibrillator intervention.

RESULTS

Myocardial ECV was higher in NICM patients (0.31 ± 0.05) than controls (0.25 ± 0.04, P < 0.01). In NICM patients, myocardial ECV correlated with left ventricular ejection fraction (R = 0.13), LGE extent (R = 0.17), Doppler E/E' (R = 0.17) and ventricular tachycardias (R = 0.21) at 24-h ECG monitoring (P < 0.05 for all). During a median follow-up of 24 months (interquartile range 12-42 months), 12 events occurred and higher myocardium ECV was independently associated with the occurrence of the composite end-point (P < 0.01).

CONCLUSION

In NICM patients, myocardial ECV was increased compared with normal individuals, likely reflecting extracellular matrix remodelling and collagen deposition, and resulted an independent prognostic predictor beyond all other conventional clinical, electrocardiographic and echocardiographic parameters.

[Status of cardiac resynchronization therapy in Catalonia, Spain: Results of the prospective multicentric study TRC-CAT]

INTRODUCTION AND OBJECTIVES

Results of cardiac resynchronization therapy (CRT) have been extensively published. However, there is limited data in unselected populations. The objective of the study was to analyse the efficacy and safety of CRT in Catalonia.

METHODS

A prospective study was performed of consecutive patients implanted with CRT over one year in 7 university hospitals in Catalonia, representing 90% of the implanted patients. Echocardiographic reverse remodelling was defined as 5 points improvement in left ventricular ejection fraction and clinical responders were defined as patients with an increase>10% of six-minute walk test or one point of New York Heart Association functional class at 12 months. Patients were followed up for one year and hospital admissions and mortality were analyzed.

RESULTS

Of the 200 patients included in the study, 99% met the indications of the current CRT clinical guidelines and 68% received CRT with implantable cardioverter-defibrillator. The rate of complications was 12.5%. During follow-up 16 patients (8%) died. Fifty-two percent (104) of the population was considered to respond clinically and 62% (124) presented improved echocardiographic parameters. Compared to the year prior to implant, hospital admissions decreased by 82% (P<.001).

CONCLUSIONS

In an unselected population of Catalonia, we observe that CRT was effective and decreased the number of hospital admissions.

Intra-operative defibrillation testing and clinical shock efficacy in patients with implantable cardioverter-defibrillators: the NORDIC ICD randomized clinical trial

AIMS

This trial was designed to test the hypothesis that shock efficacy during follow-up is not impaired in patients implanted without defibrillation (DF) testing during first implantable cardioverter-defibrillator (ICD) implantation.

METHODS AND RESULTS

Between February 2011 and July 2013, 1077 patients were randomly assigned (1 : 1) to first time ICD implantation with (n = 540) or without (n = 537) DF testing. The intra-operative DF testing was standardized across all participating centres, and all ICD shocks were programmed to 40 J irrespective of DF test results. The primary end point was the average first shock efficacy (FSE) for all true ventricular tachycardia and fibrillation (VT/VF) episodes during follow-up. The secondary end points included procedural data, serious adverse events, and mortality. During a median follow-up of 22.8 months, the model-based FSE was found to be non-inferior in patients with an ICD implanted without a DF test, with a difference in FSE of 3.0% in favour of the no DF test [confidence interval (CI) -3.0 to 9.0%, Pnon-inferiority <0.001 for the pre-defined non-inferiority margin of -10%). A total of 112 procedure-related serious adverse events occurred within 30 days in 94 patients (17.6%) tested compared with 89 events in 74 patients (13.9%) not tested (P = 0.095).

CONCLUSION

Defibrillation efficacy during follow-up is not inferior in patients with a 40 J ICD implanted without DF testing. Defibrillation testing during first time ICD implantation should no longer be recommended for routine left-sided ICD implantation.

Defibrillator patients should not be denied a peaceful death

BACKGROUND

Implantable defibrillators (ICDs) prevent sudden cardiac death. With declining health, ICD therapy may prolong death and expose the patient to unnecessary pain and anxiety. Few studies have addressed end of life care in ICD patients. The objective of this study was to investigate end of life in ICD patients, with respect to location of death; duration between do-not-resuscitate (DNR)-orders and deactivation of ICD therapy or DNR and time of death.

METHODS AND RESULTS

A descriptive analysis of 65 deceased ICD patients, all whom had a written DNR-order before death, is presented. The majority (86%) was treated in hospitals, mainly (63%) university hospitals, and many (33%) in cardiology wards. Despite DNR-order, ICD shock therapy was active in 51% of all patients. In those with therapy deactivated at death, therapy deactivation was carried out two days or more after DNR-order in more than a third (38%). The time from DNR decision to death in patients with therapy active had a median of four days (IQR 1-38). During the last 24h of life, 24% of the patients experienced shock treatment.

CONCLUSIONS

The majority of ICD patients with a DNR-order were treated in university hospitals. More than half still had shock treatment active at time of death with a median of four days or more between DNR decision and death. Patients with therapy deactivated, two days or more elapsed in more than a third from DNR decision to deactivation of therapy, exposing patients to a high risk of painful shocks before death.

EAARN score, a predictive score for mortality in patients receiving cardiac resynchronization therapy based on pre-implantation risk factors

AIMS

The beneficial effects of CRT in patients with advanced heart failure, wide QRS, and low LVEF have been clearly established. Nevertheless, mortality remains high in some patients. The aims of our study were to identify the predictors of mortality in patients treated with CRT and to design a risk score for mortality.

METHODS AND RESULTS

A cohort of 608 consecutive patients treated with CRT from 2000 to 2011 in our centre was prospectively analysed. Baseline clinical and echocardiography variables were analysed and mortality data were collected. During a mean follow-up of 36.2 ± 29.2 months, 174 patients died: 123/174 (71%) due to cardiovascular causes, 25/174 (14%) non-cardiac causes, and 26/174 (15%) unknown aetiology. In a multivariate analysis the predictors of mortality were NYHA class IV [hazard ratio (HR) 2.54, 95% confidence interval (CI) 1.7-3.7, P < 0.001], glomerular filtration rate (GFR) <60 mL/min/1.73 m2 (HR 1.61, 95% CI 1.14-2.30, P = 0.008), AF (HR 1.67, 95% CI 1.19-2.3, P = 0.01), age ≥70 years (HR 1.44, (95% CI 1.04-2.00, P = 0.02), and LVEF <22% (HR 1.83, 95% CI 1.33-2.52, P ≤ 0.001). The EAARN score (EF, Age, AF, Renal dysfunction, NYHA class IV) summarizes the predictors. Each additional predictor increased the mortality: one predictor, HR 3.28 (95% CI 1.37-7.8, P = 0.008); two, HR 5.23 (95% CI 2.24-12.10, P < 0.001); three, HR 9.63 (95% CI 4.1-22.60, P < 0.001); and four or more, HR 14.38 (95% CI 5.8-35.65, P < 0.001).

CONCLUSION

The predictors of mortality have a significant add-on predictive effect on mortality. The EAARN score could be useful to stratify the prognosis of CRT patients.

Implantable cardioverter-defibrillator therapy before death: high risk for painful shocks at end of life

BACKGROUND

Several trials have demonstrated improved survival with implantable cardioverter-defibrillator (ICD) therapy. The cause and nature of death in the ICD population have been insufficiently investigated. The objective of this study was to analyze ICDs from deceased patients to assess the incidence of ventricular tachyarrhythmias, the occurrence of shocks, and possible device malfunction.

METHODS AND RESULTS

We prospectively analyzed intracardiac electrograms in 125 explanted ICDs. The incidence of ventricular tachyarrhythmia, including ventricular fibrillation, and shock treatment was assessed. Ventricular tachyarrhythmia occurred in 35% of the patients in the last hour of their lives; 24% had an arrhythmic storm, and 31% received shock treatment during the last 24 hours. Arrhythmic death was the primary cause of death in 13% of the patients, and the most common cause of death was congestive heart failure (37%). More than half of the patients (52%) had a do-not-resuscitate order, and 65% of them still had the ICD shock therapies activated 24 hours before death. Possible malfunctions of the ICD were found in 3% of all patients.

CONCLUSIONS

More than one third of the patients had a ventricular tachyarrhythmia within the last hour of life. Cardiac death was the primary cause and heart failure the specific cause of death in the majority of the cases. Devices remained active in more than half of the patients with a do-not-resuscitate order; almost one fourth of these patients received at least 1 shock in the last 24 hours of life.

Complete atrioventricular block does not reduce long-term mortality in patients with permanent atrial fibrillation treated with cardiac resynchronization therapy

AIMS

A maximum percentage of ventricular pacing is mandatory to obtain a good response to CRT. Atrioventricular junction (AVJ) ablation has been recommended to attain this objective in patients with AF.

THE AIMS OF OUR STUDY WERE

(i) to determine whether the presence of complete AVJ block (induced or spontaneous) improves survival in patients with permanent AF treated with CRT and (ii) to analyse the predictors of mortality in AF patients treated with CRT.

METHODS AND RESULTS

From a series of 608 patients treated with CRT in our centre from 2000 to 2011, a cohort of 155 patients with permanent AF was analysed. Patients in AF were divided into two groups, AF + AVJ block [76 (49%)] and AF non-AVJ block [79 (51%)]. Mean follow-up was 30 months (interquartile range 13-51 months). During the follow-up, 62 patients died. Overall and cardiovascular mortality were similar between both groups: hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.51-1.39, P = 0.51 and HR 0.94, 95% CI 0.52-1.68, P = 0.82. Multivariate analysis identified three independent predictors of mortality: basal NYHA functional class IV (HR 2.25, 95% CI 1.12-4.22, P = 0.03), glomerular filtration rate (HR 0.98, 95% CI 0.96-0.99, P = 0.03), and LVEF (HR 0.94, 95% CI 0.89-0.99, P = 0.02).

CONCLUSIONS

AVJ block did not improve survival for patients in AF treated with CRT. Basal NYHA functional class IV, poor renal function, and LVEF were the independent predictors of mortality.

Passive-fixation lead failure rates and long-term patient mortality in subjects implanted with Sprint Fidelis electrodes

AIMS

To evaluate passive-fixation lead failure rates and long-term patient survival in subjects implanted with Sprint Fidelis electrodes.

METHODS AND RESULTS

We identified 748 subjects who received a Sprint Fidelis (n = 429; Medtronic models 6948: 94.8%, 6949: 2.6%, 6930: 1.9%, 6931: 0.7%) or a Sprint 'non-Fidelis' implantable cardioverter defibrillator lead (n = 319, Medtronic models 6944: 68.6%, 6947: 17.9%, 6942: 7.8%, 6943: 3.4%, 6945: 2.2%) at our centre between 1998 and 2008. Kaplan-Meier patient survival was lower in the Fidelis group than in the Control cohort (68.4 vs. 77.0% at 5 years, P = 0.0061), but multivariate analyses revealed no significant association between mortality and implanted lead type. Passive-fixation lead failure rate at 5 years was 14.4% (95% confidence interval (CI) [9.2, 19.3]) in the Fidelis (n = 414) group and 1.8% (95% CI [0.0-3.8]) in the Control (n = 241) cohort (P < 0.001 upon multivariate comparison).

CONCLUSION

Failure rates of passive-fixation Sprint Fidelis leads are increased and similar to those previously reported for active-fixation Fidelis electrodes. Despite the elevated risk for lead failure and its potential sequelae, the Sprint Fidelis has no obvious impact on long-term mortality.

Multicenter automatic defibrillator implantation trial: reduce inappropriate therapy (MADIT-RIT): background, rationale, and clinical protocol

The implantable cardioverter defibrillator (ICD) is highly effective in reducing mortality due to cardiac arrhythmias in high-risk cardiac patients. However, inappropriate therapies caused predominantly by supraventricular tachyarrhythmias (SVTs) remain a significant side effect of ICD therapy despite medical treatment, affecting 8-40% of patients. The MADIT-RIT is a global, prospective, randomized, nonblinded, three-arm, multicenter clinical investigation to be performed in the Unites States, Europe, Canada, Israel and Japan, and will utilize approximately 90 centers with plan to enroll 1500 patients programmed to three treatment arms. The objective of the MADIT-RIT trial is to determine if dual-chamber ICD or CRT-D devices with high rate cutoff (MADIT-RIT-Arm B) and/or long delay in combination with detection enhancements (MADIT-RIT-Arm C) are associated with fewer patients experiencing inappropriate therapies than standard programming (MADIT-RIT-Arm A) during postimplant follow-up of patients with indication for primary prevention device therapy. This paper describes design and analytic plan for the MADIT-RIT trial.

Clinical evaluation of defibrillation testing in an unselected population of 2,120 consecutive patients undergoing first implantable cardioverter-defibrillator implant

OBJECTIVES

The purpose of this study is to assess the effectiveness of defibrillation testing (DT) in patients undergoing implantable cardioverter-defibrillator (ICD) insertion.

BACKGROUND

Although DT is considered a standard procedure during ICD implantation, its usefulness has not been definitively proven.

METHODS

The SAFE-ICD (Safety of Two Strategies of ICD Management at Implantation) study is a prospective observational study designed to evaluate the outcome of 2 strategies: performing defibrillation testing (DT+) versus not performing defibrillation testing (DT-) during de novo ICD implants. No deviation from the centers' current practice was introduced. In all, 2,120 consecutive patients (836 DT+ and 1,284 DT-) age ≥18 years were enrolled at 41 Italian centers from April 2008 to May 2009 and followed up for 24 months until June 2011. The primary endpoint was a composite of severe complications at ICD implant and sudden cardiac death or resuscitation at 2 years.

RESULTS

The primary endpoint occurred in 34 patients: 12 intraoperative complications (8 in DT+ group; 4 in DT- group) and 22 during follow-up (10 in DT+ group; 12 in DT- group). Overall, the estimated yearly incidence (95% confidence interval) was DT+ 1.15% (0.73 to 1.83) and DT- 0.68% (0.42 to 1.12). The difference between the 2 groups was negligible: 0.47% per year (-0.15 to 1.10). Mortality from any cause was similar at 2 years (adjusted hazard ratio: 0.97 [0.76 to 1.23], p = 0.80).

CONCLUSIONS

In this large cohort of new ICD implants, event rates were similar and extremely low in both groups. These data indicate a limited clinical relevance for DT testing, thus supporting a strategy of omitting DT during an ICD implant. (Safety of Two Strategies of ICD Management at Implantation [SAFE-ICD]; NCT00661037).

ADHD drugs and serious cardiovascular events in children and young adults

BACKGROUND

Adverse-event reports from North America have raised concern that the use of drugs for attention deficit-hyperactivity disorder (ADHD) increases the risk of serious cardiovascular events.

METHODS

We conducted a retrospective cohort study with automated data from four health plans (Tennessee Medicaid, Washington State Medicaid, Kaiser Permanente California, and OptumInsight Epidemiology), with 1,200,438 children and young adults between the ages of 2 and 24 years and 2,579,104 person-years of follow-up, including 373,667 person-years of current use of ADHD drugs. We identified serious cardiovascular events (sudden cardiac death, acute myocardial infarction, and stroke) from health-plan data and vital records, with end points validated by medical-record review. We estimated the relative risk of end points among current users, as compared with nonusers, with hazard ratios from Cox regression models.

RESULTS

Cohort members had 81 serious cardiovascular events (3.1 per 100,000 person-years). Current users of ADHD drugs were not at increased risk for serious cardiovascular events (adjusted hazard ratio, 0.75; 95% confidence interval [CI], 0.31 to 1.85). Risk was not increased for any of the individual end points, or for current users as compared with former users (adjusted hazard ratio, 0.70; 95% CI, 0.29 to 1.72). Alternative analyses addressing several study assumptions also showed no significant association between the use of an ADHD drug and the risk of a study end point.

CONCLUSIONS

This large study showed no evidence that current use of an ADHD drug was associated with an increased risk of serious cardiovascular events, although the upper limit of the 95% confidence interval indicated that a doubling of the risk could not be ruled out. However, the absolute magnitude of such an increased risk would be low. (Funded by the Agency for Healthcare Research and Quality and the Food and Drug Administration.).

Secondary prevention in heart failure

Although most recent investigations into sudden cardiac death prevention in heart failure patients have been focused on primary prevention, secondary indications for defibrillators and medical therapy remain vitally important in this complex patient group. Antiarrhythmic therapy is currently used primarily as adjuvant therapy to implantable defibrillators. Secondary prophylaxis defibrillator trials have shown clear benefit in preventing recurrent sudden cardiac death, despite concern over inappropriate shocks and the potential detrimental effects of appropriate shocks. Device programming for secondary prophylaxis can help ameliorate these issues. This article discusses these issues as well as the continued underuse of defibrillators in specific populations.

Myocardial delayed enhancement in paucisymptomatic nonischemic dilated cardiomyopathy

OBJECTIVES

We investigated the prognostic role of myocardial fibrosis by delayed enhancement (DE) cardiovascular magnetic resonance (CMR) in nonischemic dilated cardiomyopathy (NICM) patients with no or mild symptoms of heart failure (HF).

METHODS

A prospective cohort of 125 NICM patients (82 males, age 59±14years, mean±SD) with echocardiographic evidence of left ventricular (LV) systolic dysfunction (mean ejection-fraction 33±10%), without (stage B) or with history of mild HF symptoms (stage C, NYHA classes I-II) was enrolled. The end-point was a composite of cardiac death and HF hospitalization.

RESULTS

Fifty (40%) patients showed myocardial DE, representing 12±7% of LV mass. During a median follow-up of 14.2months, 16 (32%) patients with DE experienced a composite event versus only 6 (8%) patients without DE (Kaplan-Meier survival curve, p=0.001). After correction for age, CMR-derived LV and right ventricular volumes, echocardiographic measurements of LV diastolic function and Doppler-estimated systolic pulmonary artery pressure, the presence of DE remained a strong and independent predictor of cardiac death or HF hospitalization (hazard ratio: 5.32, 95% confidence intervals 1.60 to 17.63, p=0.006).

CONCLUSIONS

In NICM patients with no or mild HF symptoms, the presence of myocardial DE is a strong predictor of worse clinical outcome even after correction for other established prognostic determinants. Contrast-enhanced CMR may be useful in prognostic stratification from the early stages of NICM.

Fatal ischemic stroke due to dissecting aneurysm of the intracranial arteries presenting as sudden unexpected death in childhood

Sudden unexpected death is any nontraumatic death in healthy individuals with normal activities for age until acute demise. Whereas not uncommon in adults and infants, it is considered a rarity in children, with most cases due to infection or occult cardiovascular abnormalities. Pathologic intracranial findings are rarely found in sudden unexpected death in childhood, with most cases due to occult intracranial neoplasms. Cerebral arterial dissection is an uncommon cause of arterial ischemic stroke in childhood. Outcome is poor, with more than 20% of patients dying. We report 4 cases of sudden unexpected death due to arterial ischemic stroke after cerebral arterial dissection in childhood and present a review of the literature.

Detection of myocardial damage in patients with sarcoidosis

BACKGROUND

In patients with sarcoidosis, sudden death is a leading cause of mortality, which may represent unrecognized cardiac involvement. Delayed-enhancement cardiovascular magnetic resonance (DE-CMR) can detect minute amounts of myocardial damage. We sought to compare DE-CMR with standard clinical evaluation for the identification of cardiac involvement.

METHODS AND RESULTS

Eighty-one consecutive patients with biopsy-proven extracardiac sarcoidosis were prospectively recruited for a parallel and masked comparison of cardiac involvement between (1) DE-CMR and (2) standard clinical evaluation with the use of consensus criteria (modified Japanese Ministry of Health [JMH] guidelines). Standard evaluation included 12-lead ECG and at least 1 dedicated non-CMR cardiac study (echocardiography, radionuclide scintigraphy, or cardiac catheterization). Patients were followed for 21+/-8 months for major adverse events (death, defibrillator shock, or pacemaker requirement). Patients were predominantly middle-aged (46+/-11 years), female (62%), and black (73%) and had chronic sarcoidosis (median, 7 years) and preserved left ventricular ejection fraction (median, 56%). DE-CMR identified cardiac involvement in 21 patients (26%) and JMH criteria in 10 (12%, 8 overlapping), a >2-fold higher rate for DE-CMR (P=0.005). All patients with myocardial damage on DE-CMR had coronary disease excluded by x-ray angiography. Pathology evaluation in 15 patients (19%) identified 4 with cardiac sarcoidosis; all 4 were positive by DE-CMR, whereas 2 were JMH positive. On follow-up, 8 had adverse events, including 5 cardiac deaths. Patients with myocardial damage on DE-CMR had a 9-fold higher rate of adverse events and an 11.5-fold higher rate of cardiac death than patients without damage.

CONCLUSIONS

In patients with sarcoidosis, DE-CMR is more than twice as sensitive for cardiac involvement as current consensus criteria. Myocardial damage detected by DE-CMR appears to be associated with future adverse events including cardiac death, but events were few, and this needs confirmation in a larger cohort.

Rationale and design for the Defibrillators to Reduce Risk by Magnetic Resonance Imaging Evaluation (DETERMINE) trial

BACKGROUND

Cardiac magnetic resonance imaging (CMR) can accurately determine infarct size. Prior studies using indirect methods and CMR to assess infarct size have shown that patients with larger myocardial infarctions have worse prognoses. Implantable cardioverter defibrillators (ICD) have been shown to improve survival among patients with severe left ventricular (LV) dysfunction. However, the majority of cardiac arrests occur in patients with higher ejection fractions.

METHODS

The Defibrillators To Reduce Risk By Magnetic Resonance Imaging Evaluation study (DETERMINE) is a prospective, multicenter, randomized, clinical trial in patients with coronary artery disease (CAD) and mild-to-moderate LV dysfunction. The purpose of this trial is to test the hypothesis that patients with an infarct size > or = 10% of LV mass, randomized to ICD plus appropriate medical therapy will have improved survival compared with patients randomized to medical therapy alone. Cine and myocardial delayed contrast CMR will be performed in patients with CAD. The primary endpoint will be death from any cause. At least 10,000 patients with CAD will undergo CMR. The target enrollment is 1,550 patients with an estimated 36-month enrollment period. The patients will be followed up for 24 months after the last patient randomization. During the follow-up period, 330 deaths are estimated to occur. This study is powered to detect a 28% reduction in mortality by ICD therapy.

CONCLUSION

The DETERMINE trial will assess the efficacy of ICD therapy to improve survival among patients with CAD, mild-to-moderate LV dysfunction, and infarct size > or = 10% of LV mass as measured by CMR.

A simplified biventricular defibrillator with fixed long detection intervals reduces implantable cardioverter defibrillator (ICD) interventions and heart failure hospitalizations in patients with non-ischaemic cardiomyopathy implanted for primary prevention: the RELEVANT [Role of long dEtection window programming in patients with LEft VentriculAr dysfunction, Non-ischemic eTiology in primary prevention treated with a biventricular ICD] study

Aims

To investigate the efficacy and safety of a cardiac resynchronization therapy with cardioverter–defibrillator (CRT-D) device with simplified ventricular tachycardia management in patients with non-ischaemic heart failure (HF) and primary prevention implantable cardioverter defibrillator (ICD) indication.

Methods and results

Prospective, controlled, parallel, multicentre, non-randomized study enrolling 324 primary prevention non-ischaemic HF patients implanted with CRT-D devices from 2004 to 2007: Protect group, 164 patients implanted with a Medtronic Insync III Protect device and Control group, 160 patients utilizing other Medtronic CRT-D devices.

Efficacy was assessed by computing appropriate and inappropriate detections and therapies during follow-up; safety compared hospitalizations and syncopal events between groups. Ninety per cent of both ventricular and supraventricular tachyarrhythmias terminated within the 13–29 beat detection interval with the Protect algorithm. The Protect group showed a significantly better event-free survival to first delivered therapy for total (P = 0.0001), appropriately treated (P = 0.002), and inappropriately treated episodes (P = 0.017). The total number of delivered shocks was significantly lower in the Protect group (22 vs. 59, P < 0.0001). In the Protect group, a significantly reduced HF hospitalization (hazard ratio 0.38, 95% CI 0.15–0.98, P = 0.044) was observed without any increase of syncope or death.

Conclusion

A simplified CRT-D device with fixed long detection reduced overall ICD therapy burden and HF hospitalizations without entailing any additional adverse events in primary prevention non-ischaemic HF patients.

Electrocardiographic abnormalities and ventricular tachyarrhythmias after myocardial infarction

AIMS

To assess the association of electrocardiographic repolarization and depolarization patterns to vulnerability to ventricular tachyarrhythmias.

METHODS

In the present case-control study, a 12-lead ECG, signal-averaged ECG (SAECG), T-wave and QRS morphology, and T-wave alternans (TWA) were analyzed in post-MI patients with and without documented sustained ventricular tachycardia (VT) or fibrillation (VF) (VT/VF group, n=40, Non-VT/VF group, n=37, respectively) and healthy subjects (n=41).

RESULTS

The QRS complex duration, measured from standard ECG (128 +/- 32 ms vs. 102 +/- 21 ms, p<0.001) or SAECG (125 +/- 25 ms vs. 99 +/- 20 ms, p<0.001), was significantly longer in the VT/VF than Non-VT/VF group. Several T-wave morphology variables, e.g., the total cosine of the angle between the main vectors of T-wave and QRS loops (TCRT), were different in the VT/VF (-0.13 +/- 0.58) and Non-VT/VF group (-0.11 +/- 0.48) compared to the healthy controls (0.47 +/- 0.50, p<0.001). However, there were no significant differences in any of the T-wave morphology variables including TWA between the two post-MI groups.

CONCLUSION

Abnormalities in ventricular depolarization are more common among post-MI patients with prior VT/VF than in those without documented ventricular tachyarrhythmias. Abnormal T-wave morphology and TWA seem to reflect the heart disease rather than specifically vulnerability to VT/VF.

Effects of the end point adjudication process on the results of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS)

BACKGROUND AND PURPOSE

End point adjudication committees (EPAC) are widely used in large-scale clinical trials to ensure the robustness of diagnosis for end points.

METHODS

The Perindopril Protection Against Recurrent Stroke Study (PROGRESS) was a double-blind randomized trial of blood pressure lowering in 6105 participants with pre-existing cerebrovascular disease. Separate estimates of the effects of randomized treatment were determined using Cox regression models that were based on the unadjudicated events initially reported by the investigator and on the final events assigned by the EPAC.

RESULTS

There were 992 strokes initially reported by the investigators and 894 (90%) retained these diagnoses after adjudication by the EPAC. The hazard ratios (95% CIs) for the effect of randomized treatment on stroke were 0.74 (0.64 to 0.85) based on the investigator diagnoses and 0.72 (0.62 to 0.83) based on the EPAC diagnoses (P homogeneity=0.7). For each stroke subtype reported, the corresponding numbers of diagnoses (investigators/EPAC) were ischemic (593/565), hemorrhagic (124/111), and unknown (124/93) with no impact of the EPAC review on the estimates of treatment effects (all P homogeneity >0.3). There was likewise no detectable effect of reclassification of diagnoses for the effect estimates calculated for myocardial infarction or the main causes of death (all P homogeneity >0.5).

CONCLUSIONS

The EPAC process had no discernible impact on the trial conclusions. Very large trials powered to detect effects on stroke subtypes might obtain real scientific gain from an EPAC, but in the case of PROGRESS, the value of the EPAC was in the reassurance it provided.

Prediction of fatal or near-fatal cardiac arrhythmia events in patients with depressed left ventricular function after an acute myocardial infarction

Aims

To determine whether risk stratification tests can predict serious arrhythmic events after acute myocardial infarction (AMI) in patients with reduced left ventricular ejection fraction (LVEF ≤ 0.40).

Methods and results

A total of 5869 consecutive patients were screened in 10 European centres, and 312 patients (age 65 ± 11 years) with a mean LVEF of 31 ± 6% were included in the study. Heart rate variability/turbulence, ambient arrhythmias, signal-averaged electrocardiogram (SAECG), T-wave alternans, and programmed electrical stimulation (PES) were performed 6 weeks after AMI. The primary endpoint was ECG-documented ventricular fibrillation or symptomatic sustained ventricular tachycardia (VT). To document these arrhythmic events, the patients received an implantable ECG loop-recorder. There were 25 primary endpoints (8.0%) during the follow-up of 2 years. The strongest predictors of primary endpoint were measures of heart rate variability, e.g. hazard ratio (HR) for reduced very-low frequency component (<5.7 ln ms²) adjusted for clinical variables was 7.0 (95% CI: 2.4–20.3, P < 0.001). Induction of sustained monomorphic VT during PES (adjusted HR = 4.8, 95% CI, 1.7–13.4, P = 0.003) also predicted the primary endpoint.

Conclusion

Fatal or near-fatal arrhythmias can be predicted by many risk stratification methods, especially by heart rate variability, in patients with reduced LVEF after AMI.

Reduced ejection fraction, sudden cardiac death, and heart failure death in the mode selection trial (MOST): implications for device selection in elderly patients with sinus node disease

Sudden Cardiac Death in Elderly Pacemaker Patients.

BACKGROUND

The purpose of this study was to describe the incidence and predictors of sudden cardiac death (SCD) and heart failure (HF) death, and coexisting indications for ICDs and CRT, in patients with sinus node disease (SND) treated with pacemakers.

METHODS AND RESULTS

Baseline variables were used to predict SCD and HF death among 1,135 patients in the Mode Selection Trial, a 6-year trial of pacing mode in SND. There were 73 deaths among 177 patients with EF <or= 35% (41.2%), 46/156 (29.5%) with EF 36-49%, and 147/802(18.3%) with EF >or= 50%. SCD accounted for 21.9%, 23.9%, and 14.3% of deaths with EF <or= 35%, 36-49%, and >or= 50%. HF deaths accounted for 23.3%, 19.6%, and 3.4% of deaths with EF <or= 35%, 36-49%, and >or= 50%. EF <or= 35% predicted SCD (hazard ratio [HR] 3.68, 95% confidence interval [CI] 1.72-7.89, P = 0.002) and HF death (HR 10.17, 95% CI 3.35, 30.82, P = 0.001). Four-year SCD rate with EF <or= 35% was 15.5% (3.9% annually). Nearly one-fifth of patients qualified for ICDs (EF <or= 35%) and half of these had QRS >or= 120 ms. However, >40% died within 33 months (4-year noncardiac death rate approximately 22%).

CONCLUSIONS

Reduced EF predicts SCD and HF death in SND treated with pacemakers. SCD rates among patients with EF <or= 35% are similar to control arms of primary prevention ICD trials, but mortality rates are significantly higher. Whether ICDs or CRT to provide bradycardia support would prolong life in elderly patients with EF <or= 35% and SND merits prospective investigation.

Electrocardiographic predictors of sudden cardiac death

Sudden cardiac death (SCD) is widespread and the most serious of the cardiac diseases, accounting for over half of cardiovascular mortality in adults in the United States, and nearly 1 in 3 of these patients does not report symptoms of cardiac disease before the sudden death. Quantifying the left ventricular ejection fraction is currently the best way to risk-stratify patients for SCD and identify those who are most likely to benefit from the insertion of an implantable cardiac defibrillator (ICD). The strategy of systemically placing ICDs in patients at risk of SCD is expensive and leads to substantial psychological hardship. However, noninvasive electrocardiographic indices of depolarization and repolarization may better identify patients who are at an increased risk of SCD. Therefore, developing an approach to identify electrocardiographic changes associated with the highest risk of arrhythmic death could markedly improve patient selection for ICD therapy. This report describes electrocardiographic parameters that may be useful in identifying patients at risk of SCD. The state of the science currently suggests that it is unlikely that a single electrocardiographic parameter will predict SCD, but rather a risk stratification algorithm based on a combination of electrocardiographic parameters may yield the best result.

Long-term survival in patients undergoing cardiac resynchronization therapy: the importance of performing atrio-ventricular junction ablation in patients with permanent atrial fibrillation

AIMS

To investigate the effects of cardiac resynchronization therapy (CRT) on survival in heart failure (HF) patients with permanent atrial fibrillation (AF) and the role of atrio-ventricular junction (AVJ) ablation in these patients.

METHODS AND RESULTS

Data from 1285 consecutive patients implanted with CRT devices are presented: 1042 patients were in sinus rhythm (SR) and 243 (19%) in AF. Rate control in AF was achieved by either ablating the AVJ in 118 patients (AVJ-abl) or prescribing negative chronotropic drugs (AF-Drugs). Compared with SR, patients with AF were significantly older, more likely to be non-ischaemic, with higher ejection fraction, shorter QRS duration, and less often received ICD back-up. During a median follow-up of 34 months, 170/1042 patients in SR and 39/243 in AF died (mortality: 8.4 and 8.9 per 100 person-year, respectively). Adjusted hazard ratios were similar for all-cause and cardiac mortality [0.9 (0.57-1.42), P = 0.64 and 1.00 (0.60-1.66) P = 0.99, respectively]. Among AF patients, only 11/118 AVJ-abl patients died vs. 28/125 AF-Drugs patients (mortality: 4.3 and 15.2 per 100 person-year, respectively, P < 0.001). Adjusted hazard ratios of AVJ-abl vs. AF-Drugs was 0.26 [95% confidence interval (CI) 0.09-0.73, P = 0.010] for all-cause mortality, 0.31 (95% CI 0.10-0.99, P = 0.048) for cardiac mortality, and 0.15 (95% CI 0.03-0.70, P = 0.016) for HF mortality.

CONCLUSION

Patients with HF and AF treated with CRT have similar mortality compared with patients in SR. In AF, AVJ ablation in addition to CRT significantly improves overall survival compared with CRT alone, primarily by reducing HF death.

Designation and distribution of events in the Multicenter UnSustained Tachycardia Trial (MUSTT)

Patients with coronary artery disease, depressed left ventricular ejection fraction, and nonsustained ventricular tachycardia (VT) have a high mortality rate due to arrhythmic (arrhythmic death/cardiac arrest) and other cardiac causes. The Multicenter UnSustained Tachycardia Trial (MUSTT) investigated whether electrophysiologic study (EPS) was helpful in choosing drug or defibrillator therapy in patients induced into sustained VT. The events committee attempted to categorize follow-up events in patients in MUSTT and to present a detailed breakdown of events. A derivative of the Hinkle-Thaler classification was used, incorporating lessons from other multicenter studies. The committee was blinded to results of EPS and implantable cardioverter-defibrillator (ICD) or other antiarrhythmic therapy status of patients. The primary end point was cardiac arrest or death from arrhythmia. Secondary end points were death from all causes, cardiac causes, and spontaneous sustained VT. Classifications were death and cardiac arrest. Each was similarly divided as arrhythmic with 14 subcategories, e.g., unwitnessed or related to EPS and nonarrhythmic with 10 subcategories, e.g., ischemia. Terminal VF in progressive heart failure was considered nonarrhythmic. Events were reviewed by 2 members. Disagreements were resolved by the 2 members or, if needed, by the full committee. Of the 2,202 patients in MUSTT, there were 902 deaths. Sustained VT requiring cardioversion occurred in 182 patients. An additional 94 patients had resuscitated cardiac arrests. Events occurred in 1,027 patients, and all were reviewed. The 3 leading events were deaths that were classed as sudden/unwitnessed (23% of 902), due to progressive heart failure (22%), or due to noncardiovascular causes (18%). Arrhythmic deaths or cardiac arrests were highest in inducible patients randomized to no antiarrhythmic therapy; next were inducible patients receiving an ICD; and lowest were in patients who were noninducible. In conclusion, the classification system provided a detailed breakdown of events in consistent categories, showing utility for event analysis and interpretation and development of therapeutic strategies. The classifications assigned by the committee were used in all MUSTT outcomes reports, thus affecting all reported outcomes and overall interpretations of the MUSTT.

Ascertainment of cause-specific mortality in COPD: operations of the TORCH Clinical Endpoint Committee

BACKGROUND

TORCH (Towards a Revolution in COPD Health) is an international multicentre, randomised, placebo-controlled clinical trial of inhaled fluticasone propionate/salmeterol combination treatment and its monotherapy components for maintenance treatment of moderately to severely impaired patients with chronic obstructive pulmonary disease (COPD). The primary outcome is all-cause mortality. Cause-specific mortality and deaths related to COPD are additional outcome measures, but systematic methods for ascertainment of these outcomes have not previously been described.

METHODS

A Clinical Endpoint Committee (CEC) was tasked with categorising the cause of death and the relationship of deaths to COPD in a systematic, unbiased and independent manner. The key elements of the operation of the committee were the use of predefined principles of operation and definitions of cause of death and COPD-relatedness; the independent review of cases by all members with development of a consensus opinion; and a substantial infrastructure to collect medical information.

RESULTS

911 deaths were reviewed and consensus was reached in all. Cause-specific mortality was: cardiovascular 27%, respiratory 35%, cancer 21%, other 10% and unknown 8%. 40% of deaths were definitely or probably related to COPD. Adjudications were identical in 83% of blindly re-adjudicated cases (kappa = 0.80). COPD-relatedness was reproduced 84% of the time (kappa = 0.73). The CEC adjudication was equivalent to the primary cause of death recorded by the site investigator in 52% of cases.

CONCLUSION

A CEC can provide standardised, reliable and informative adjudication of COPD mortality that provides information which frequently differs from data collected from assessment by site investigators.

Long-term survival of patients with heart failure and ventricular conduction delay treated with cardiac resynchronization therapy

This multicenter longitudinal observational trial was designed to analyze the long-term outcome of patients with heart failure (HF) treated with cardiac resynchronization therapy (CRT) alone or with implantable cardioverter-defibrillator (ICD) backup in a daily practice scenario. It is unknown whether the magnitude of survival benefits conferred by CRT in a daily practice scenario is comparable to what has been observed in randomized controlled trials and whether this benefit is sustained over the long term. The outcome of 1,303 consecutive patients with ischemic or nonischemic cardiomyopathy on optimal pharmacologic therapy treated from August 1, 1995 to August 1, 2004 at 4 European centers with CRT alone (44%) or with ICD backup for symptomatic HF and prolonged QRS duration was assessed. Cumulative event-free survival was evaluated for a combined end point, defined as death from any cause, urgent transplantation, or implantation of a left ventricular assist device. The cumulative incidence of competing events, HF, sudden cardiac death, and noncardiac death, was also assessed. Event-free survival was similar across the different centers. At 1 and 5 years, cumulative event-free survivals were 92% (95% confidence interval [CI] 91 to 94) and 56% (95% CI 48 to 64), respectively. The cumulative incidence of HF deaths was 25.1% (95% CI 19 to 31.7), whereas that of sudden death was 9.5% (95% CI 5.1 to 15.7). Using multivariate analysis, CRT with an ICD backup was associated with a nonsignificant decrease in mortality by 20% (hazard ratio 0.83, 95% CI 0.58 to 1.17, p = 0.284), with a highly significant protective effect against sudden cardiac death (hazard ratio 0.04, 95% CI 0.04 to 0.28, p <0.002). In conclusion, patients with advanced HF and a wide QRS complex routinely treated with CRT have a favorable long-term outcome that was reproducible at different centers. The leading cause of death in these patients remained HF, and this mode of death was competing with other causes in determining outcome. Total mortality was 20% lower with ICD backup (95% CI 42% lower to 17% higher) due to a protective effect against sudden cardiac death.

Cardiovascular Magnetic Resonance, Fibrosis, and Prognosis in Dilated Cardiomyopathy

OBJECTIVES

We studied the prognostic implications of midwall fibrosis in dilated cardiomyopathy (DCM) in a prospective longitudinal study.

BACKGROUND

Risk stratification of patients with nonischemic DCM in the era of device implantation is problematic. Approximately 30% of patients with DCM have midwall fibrosis as detected by late gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR), which may increase susceptibility to arrhythmia and progression of heart failure.

METHODS

Consecutive DCM patients (n = 101) with the presence or absence of midwall fibrosis were followed up prospectively for 658 +/- 355 days for events.

RESULTS

Midwall fibrosis was present in 35% of patients and was associated with a higher rate of the predefined primary combined end point of all-cause death and hospitalization for a cardiovascular event (hazard ratio 3.4, p = 0.01). Multivariate analysis showed midwall fibrosis as the sole significant predictor of death or hospitalization. However, there was no significant difference in all-cause mortality between the 2 groups. Midwall fibrosis also predicted secondary outcome measures of sudden cardiac death (SCD) or ventricular tachycardia (VT) (hazard ratio 5.2, p = 0.03). Midwall fibrosis remained predictive of SCD/VT after correction for baseline differences in left ventricular ejection fraction between the 2 groups.

CONCLUSIONS

In DCM, midwall fibrosis determined by CMR is a predictor of the combined end point of all-cause mortality and cardiovascular hospitalization, which is independent of ventricular remodeling. In addition, midwall fibrosis by CMR predicts SCD/VT. This suggests a potential role for CMR in the risk stratification of patients with DCM, which may have value in determining the need for device therapy.

Effects of Statin Therapy on Arrhythmic Events and Survival in Patients With Nonischemic Dilated Cardiomyopathy

OBJECTIVES

We sought to evaluate whether statins were associated with a survival benefit and significant attenuation in life-threatening arrhythmias in patients with nonischemic dilated cardiomyopathy.

BACKGROUND

Statins are associated with a reduction in appropriate implantable cardioverter-defibrillator (ICD) therapy in patients with coronary artery disease and improved clinical status in nonischemic dilated cardiomyopathy.

METHODS

The effect of statin use on time to death or resuscitated cardiac arrest and time to arrhythmic sudden death was evaluated in 458 patients enrolled in the DEFINITE (DEFIbrillators in Non-Ischemic cardiomyopathy Treatment Evaluation) study. The effect of statin use on time to first appropriate shock was analyzed only in the 229 patients who were randomized to ICD therapy.

RESULTS

The unadjusted hazard ratio (HR) for death among patients on versus those not on statin therapy was 0.22 (95% confidence interval [CI] 0.09 to 0.55; p = 0.001). When controlled for statin effects, ICD therapy was associated with improved survival (HR 0.61; 95% CI 0.38 to 0.99; p = 0.04). There was one arrhythmic sudden death in the 110 patients receiving statin therapy (0.9%) versus 18 of 348 patients not receiving statins (5.2%; p = 0.04). The unadjusted HR for arrhythmic sudden death among patients on versus those not on statin therapy was 0.16 (95% CI 0.022 to 1.21; p = 0.08). The HR for appropriate shocks among patients on versus those not on statin therapy was 0.78 (95% CI 0.34 to 1.82) after adjustment for baseline differences in the two groups.

CONCLUSIONS

Statin use in the DEFINITE study was associated with a 78% reduction in mortality. This reduction was caused, in part, by a reduction in arrhythmic sudden death. These findings should be confirmed in a prospective, randomized clinical trial.