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Stratifying Risk in SCD: Planning for the Future

Stratifying Risk in SCD: Planning for the Future

Heart disease remains the leading cause of death in the United States and is responsible for more than 600,000 mortalities each year, according to data from the National Center for Health Statistics. About half of these mortalities are classified as sudden cardiac death (SCD). Of these deaths, about half occur as a victim’s first recognized cardiac event. Research suggests that only a small number of those suffering out-of-hospital cardiac arrests will ultimately survive these events. “SCD is a high priority public health problem that requires multipronged treatment and prevention approaches,” explains Jeffrey J. Goldberger, MD, a professor at Northwestern University’s Center for Cardiovascular Innovation. Recent reports indicate that the incidence of ventricular fibrillation as a cause of out-of-hospital cardiac arrest has been declining but continues to be a leading cause of SCD. Implantable cardioverter-defibrillators (ICDs) are effective but costly and have had a meaningful but, so far, limited impact on SCD. As a result, there are opportunities for new approaches to address SCD (Figure). Approximately $2.4 billion is spent each year on ICDs, but the medical community still has yet to identify the optimal method for determining which patients need these devices most. “Conducting research initiatives to improve our ability to predict risk would enable providers to target ICD use to the most appropriate recipients,” says Dr. Goldberger. “Under current prediction protocols, ICDs are not systematically reaching many patients who can benefit from receiving these devices. By assembling the right resources, there is hope that we can establish risk stratification standards that use medical resources wisely while saving the most lives.” Stratifying Sudden Cardiac Death Risk Developing effective strategies...

Exploring Variances in Dual-Chamber ICD Use

Each year in the United States, approximately 140,000 implantable cardioverter-defibrillators (ICDs) are implanted in cardiac patients. Physicians often face challenges when working with patients to decide whether it’s best to use a single- or dual-chamber device. Some patients have a clear indication for a dual-chamber device because they have an indication for a pacemaker. For patients without an indication for a pacemaker, the decision is much less clear. The potential benefits of dual-chamber devices remain to be proven, and they may have more complications. Clinical trial data to guide physicians on which option to choose have been lacking. Currently, nearly two-thirds of patients undergoing ICD implantation for primary prevention receive dual-chamber devices. Variations in Dual-Chamber ICD Use In a study published in the April 23, 2012 Archives of Internal Medicine, my colleagues and I set out to explore hospital-level variation in the use of dual-chamber ICDs across the U.S. Using the Medicare-mandated National Cardiovascular Data Registry (NCDR) ICD registry, we looked at 87,115 patients from 2006 to 2009 receiving an ICD as primary prevention without a documented indication for a pacemaker. We only wanted to analyze patients for whom it wasn’t clear whether a single- or dual-chamber ICD was the appropriate choice. Of these patients, about 58% received a dual-chamber ICD. More importantly, use of each ICD type varied significantly by hospital and by physician. In some hospitals and with some physicians, 100% of patients without a clear indication for a dual-chamber ICD received such a device. At other hospitals and with other physicians, 0% of these patients received a dual-chamber ICD. “Differences in the local culture and practice...

Heart Rhythm 2012

Examining Criteria for ICD Primary Prevention Therapy The Particulars: Studies have suggested that nearly 25% of implantable cardioverter-defibrillators (ICDs) for primary prevention are implanted outside of evidence-based criteria. Currently, there is little information comparing the long-term outcomes among patients receiving ICDs within evidence-based guidelines and those outside of such criteria. Data Breakdown: A retrospective analysis of patients who received ICDs for primary prevention found that those who received their device outside of evidence-based criteria experienced similar results to those within such criteria. Similar findings were observed in time to first appropriate ICD therapy, risk of death, and time of first inappropriate ICD therapy. Take Home Pearl: Patients who receive ICDs for primary prevention outside of evidence-based criteria appear to experience similar therapeutic benefits and outcomes as patients who receive their device within evidence-based criteria. Real-World Results With Subcutaneous ICD The Particulars: The Subcutaneous Implantable Cardioverter-Defibrillator (S-ICD) System does not require the intravascular leads used in typical transvenous implantable cardioverter-defibrillator (ICD) procedures. The device is inserted under the skin and outside the ribcage of patients at risk for sudden cardiac arrest (SCA). Long-term performance of the S-ICD System, including patient quality of life and long-term resource use, has yet to be studied. Data Breakdown: Researchers reviewed the real-world experiences of 230 recipients of the S-ICD System in nine countries. They found a conversion rate of more than 98% for induced and ambulatory ventricular tachycardia or fibrillation. No patients received therapy for any supraventricular tachycardia within a programmed conditional shock zone. Take Home Pearl: According to real-world experiences, the S-ICD System appears to be a safe and effective option for most...
Precursors of Sudden Cardiac Death Elusive in Athletes

Precursors of Sudden Cardiac Death Elusive in Athletes

According to the findings of a study led by researchers from Stanford University, cardiologists appear to make mistakes frequently when interpreting the results of young athletes’ pre-participation screening ECGs. Pediatric cardiologists who participated in the study had an accuracy rate of just 69%. The study, according to the authors, suggests that diseases underlying sudden cardiac death are difficult to interpret in athletes. The accuracy rate did not differ significantly in respondents, despite variations in length of time practicing pediatric cardiology, the number of ECGs read per month, or practice type. In the investigation, 53 pediatric cardiologists were asked to interpret a series of 18 ECGs of athletes with either normal hearts or conditions that would lead to sudden cardiac death. Per cardiologist, the average number of correct interpretations was 12.4. Sensitivity for detecting a cardiac abnormality was 68%, and specificity was 70%. False-positive results were 30%, and false-negative results were 32%. An accurate restriction of athletic participation was given in 81% of cases, compared with 74% of cases in which healthy patients were accurately allowed to participate in sports. The most common cases in which correct guidance was provided were for long-QT syndrome and myocarditis. Correct guidance was provided least often in cases of hypertrophic cardiomyopathy and Wolff-Parkinson-White syndrome. This finding was particularly “disappointing” to the researchers, who noted that the most frequent cause of sudden cardiac death in the United States is hypertrophic cardiomyopathy. Read Athlete Screening ECG Study Abstract Physicians Weekly wants to know… What consequences could arise from the false sense of security offered to patients and families when choices are made by cardiologist to not...
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