Does stress echocardiography add incremental value to baseline ejection fraction for the early identification of candidates for implantable defibrillators?

Objective: A reduction in left ventricular ejection fraction (EF) remains the strongest indicator of increased risk of sudden cardiac death after an acute myocardial infarction (AMI). Guidelines recommend that patients with an EF ≤35%, 6-12 weeks after AMI should be considered for implantable cardioverter defibrillator (ICD) therapy. Stress echocardiography is a safe method to detect viability in a stunned myocardium. The purpose of this study was to investigate if stress echocardiography early after AMI could identify ICD candidates before discharge. Methods: Ninety-six patients with EF ≤40% early after AMI were prospectively included in a cohort study, and investigated by baseline and stress echocardiography before discharge. Follow-up echocardiography was performed after 3 months. EF, mitral annular plane systolic excursion (MAPSE) and peak systolic velocity (PSV) were determined for each examination. Results: There were 80 (83%) patients who completed the baseline, stress and follow-up echocardiography. Among them there were 32 (40%) patients who met the ICD criteria of EF ≤35% at 3 months. For these patients, EF, MAPSE and PSV were significantly lower than for those patients who recovered. The area under the receiver operating characteristic curve (AUC) was 85% (95% CI 0.74 to 0.94) for baseline EF to predict non-recovery. None of the other variables had a higher AUC. Conclusion: Patients who met the ICD criteria of EF ≤35% at 3 months after myocardial infarction had lower EF, MAPSE and PSV on baseline and stress echocardiograph before discharge. Stress echocardiography did not add additional value in predicting non-recovery.

Clinical risk profile score predicts all cause mortality but not implantable cardioverter defibrillator intervention rate in a large unselected cohort of patients with congestive heart failure.

BACKGROUND: Primary prophylactic implantable cardioverter defibrillator (ICD) therapy is indicated for patients with reduced left ventricular ejection fraction (LVEF). We aimed to determine if preoperative clinical risk profiling can predict long-term benefit, and if clinical risk scores can be applied and improved in a patient cohort outside the clinical trial setting. METHODS: Using registry data, 789 patients with reduced LVEF who received ICDs for primary prevention during 2006-2011 were identified (age 64 ± 11 years, 82% men, 63% ischemic etiology, 52% cardiac resynchronization therapy with defibrillator). The patients were divided into three risk groups, based on the presence of baseline clinical risk factors (age >70, QRS duration >120 ms, New York Heart Association class III-IV, atrial fibrillation history, or creatinine >106 µmol/L). Endpoints were all-cause mortality and survival free of adequate ICD therapy. RESULTS: Mean follow-up was 39 ± 18 months. Annual mortality was 7.6%, and increased with risk group (p < .001). Rates of appropriate antitachycardia pacing and shock therapy were not statistically different between the groups, and ranged from 11%-16% and 6%-14%, respectively. By combining the previous risk score with data on diabetes, a better independent prediction of mortality was achieved; mortality rates then ranged from 11% (low-risk) to 46% (high-risk) (p < .0001). CONCLUSIONS: Implantable cardioverter defibrillator therapies occur across the spectrum of comorbidities in a population with systolic heart failure. However, all-cause mortality is considerably higher in the group of patients with accumulated risk factors, and using the proposed scoring system can be helpful for the evaluation and risk stratification of the patient prior to making a decision for a primary prophylactic ICD implantation.

Evolution of left ventricular ejection fraction after acute myocardial infarction: implications for implantable cardioverter-defibrillator eligibility.

BACKGROUND: Implantable cardioverter-defibrillator therapy improves survival in patients with reduced left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI). Although the risk of sudden cardiac death is highest in the first month after AMI, there is no survival benefit of early implantable cardioverter-defibrillator implantation, and the optimal time frame has yet to be established. Thus, the aim of this study was to investigate what proportion of post-AMI patients had improved LV function to such an extent that the indication for implantable cardioverter-defibrillator was no longer present. METHODS AND RESULTS: Patients admitted for AMI with reduced LVEF (≤40%) were eligible for inclusion. Repeat echocardiographic examinations were performed 5 days, 1 month, and 3 months after the AMI. We prospectively included 100 patients with LVEF of 31±5.8% after AMI. At the 1-month follow-up, 55% had an LVEF >35%. The main improvement in LVEF had occurred by 1 month. The mean difference in LVEF over the next 2 months was small, 1.9 percentage units. During the first 9 weeks, 10% of the patients suffered from life-threatening arrhythmias. CONCLUSIONS: Most patients have improved LVEF after AMI, and in the majority, the improvement can be confirmed after 1 month, implying that further delay of implantable cardioverter-defibrillator implantation may not be warranted. Life-threatening arrhythmias occurred in 10% of the patients, illustrating the high risk for sudden cardiac death in this population.

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.

Primary prevention of defibrillator implantation after myocardial infarction: clinical practice and compliance to guidelines.

AIMS: The purpose of this study is to investigate compliance to established guidelines regarding primary prevention with implantable cardioverter-defibrillator (ICD) in patients with left ventricular dysfunction after acute myocardial infarction (AMI) in a clinical setting. METHODS AND RESULTS: A retrospective study of medical records from patients admitted to two hospitals in Stockholm during 2008-2009 with a diagnosis of AMI and who at discharge had a left ventricular ejection fraction ≤35%. An evaluation of follow-up and echocardiographic recordings was performed 1-3 months after AMI. A total of 2023 patients <80 years, with AMI discharged from hospital, were screened for left ventricular dysfunction defined as ejection fraction (EF) ≤35%. Altogether 187 patients were identified and an ICD was implanted in 25 (13%) patients. In 52 (28%) patients, there were contraindications for ICD therapy. An improved EF at follow-up, making ICD treatment redundant, was observed in 48 (41%) patients who underwent an ECHO at follow-up or later. Seventeen (9%) patients without an ICD died during follow-up and out of these five patients died from sudden cardiac death (SCD), they had no contraindication to ICD therapy. An inadequate follow-up according to guidelines was found in 59 (32%) patients. CONCLUSION: The follow-up of post-myocardial infarction patients with left ventricular dysfunction according to guidelines was insufficient in this population and may have increased the risk for SCD. A significant proportion of patients experienced improved left ventricular function during short-term follow-up making preventive ICD treatment redundant.