Keeping you up to date on recent headlines in cardiovascular healthcare.
Imaging system developed to study cardiac arrest . . . A research team at Vanderbilt University (Nashville, Tennessee) has developed an optical system designed to simultaneously image electrical activity and metabolic properties in the same region of a heart, to study the complex mechanisms that lead to sudden cardiac arrest. According to the National Heart, Lung and Blood Institute (NHLBI), part of the National Institutes of Health, the system could advance scientists' understanding of the relationship between metabolic disorders and heart rhythm disturbances in humans that can lead to cardiac arrest and death, and provide a platform for testing new treatments to prevent or stop potentially fatal irregular heartbeats, known as arrhythmias. The NHLBI is supporting the research. The Vanderbilt Institute for Integrative Biosystems Research and Education (VIIBRE; Nashville), the American Heart Association (Dallas), and the Simons Center for Systems Biology at the Institute for Advanced Study have also provided additional support for the project. The design and use of the dual camera system is described in the Nov. 1 issue of Experimental Biology and Medicine. "The challenge in understanding cardiac rhythm disorders is to discern the dynamic relationship between multiple cardiac variables," said John Wikswo, PhD, one of the co-authors of the paper and the project's principal investigator. Wikswo is a Gordon A. Cain University Professor and VIIBRE director. "This dual camera system opens up a new window for correlating metabolic and electrophysiological events, which are usually studied independently." According to Wikswo, the 11-year-old research project would have been terminated this year due to lack of funding. But a $566,000 American Recovery and Reinvestment Act grant from the NHLBI is enabling the 13-member research team to continue developing and testing the system. According to the agency, Recovery Act funds are also allowing the team to buy a pair of $60,000 high-speed and highly sensitive digital cameras to record the changes in the metabolic and electrical activity of isolated cardiac tissue using low-intensity fluorescent dyes under conditions associated with heart failure, ischemia, fibrillation and other pathological circumstances.
Study examines cardiac screening of athletes . . . Cardiovascular diseases are difficult to screen for, but the practice of doing so is critical to ensure safe athletic participation, according to a new study published in the November/December issue of Sports Health: A Multidisciplinary Approach. The study gives a comprehensive overview of the current guidelines and controversies surrounding cardiovascular screening of athletes. The screening challenges arise, the study notes, from trying to identify very rare and often clinically silent, but potentially fatal cardiac diseases in a large number of athletes competing at various levels. "Athletes are two and a half times as likely to experience sudden cardiac death (SCD) than nonathletes," according to study author Sharlene Day, MD, assistant professor of Cardiovascular Medicine, and director of the Hypertrophic Cardiomyopathy Program at the University of Michigan (Ann Arbor). "This statistic should impress upon us the need for cardiovascular disease screening in our athletes. It is important to emphasize to athletes the importance of reporting symptoms that could reflect underlying heart disease." The study notes that screening of participants with a pre-participation history and physical examination should take place before the start of training. It also recommends that a physician perform the cardiac portion of the exam. If a physician is not available to do the screening, the sports medicine staff should refer any athlete who demonstrates concerning symptoms. "The main objective of the cardiac portion of pre-participation screening is to identify those athletes at risk for SCD triggered by competitive athletics," Day said.
Canadian heart patients not being told about driving restrictions after angioplasty . . . More than half of patients with acute coronary syndrome (ACS) don't get any counseling on their ability to drive after angioplasty - and this could be putting lives in danger, Ravi Bajaj, MD, told the 2009 Canadian Cardiovascular Congress, co-hosted by the Heart and Stroke Foundation of Canada (Ottawa, Ontario) and the Canadian Cardiovascular Society (CCS; Ottawa). "If a patient is discharged from the hospital following a cardiac event there is always a risk of another serious cardiac event or complication within a short period of time," Bajaj says. "That is why patients are advised not to operate a motor vehicle during the time when risks of an event are high. Should they continue to drive, it poses a risk to the patient and others on the road." ACS is a constellation of cardiac symptoms, including angina or chest pain, and reduced blood flow to the heart. One treatment can be angioplasty, a non-surgical procedure to open up blood vessels in the heart that have been narrowed by plaque build-up. In his study, Bajaj found that 57% of patients who were released from the hospital after having the procedure did not receive any counseling about driving before discharge. The remaining 43% had varying advice from their doctors, which was mostly inconsistent with the 2003 guidelines released by the CCS.
Heart patients willing to take part in trials fair better . . . Patients with chronic heart failure who agree to take part in clinical trials have a better prognosis than those who do not, according to a study reported in the November European Journal of Heart Failure. The study was a follow-up of 2,332 consecutive patients diagnosed with chronic heart failure at Castle Hill Hospital (Hull, UK). At their initial visit to the clinic all were asked if they would be willing to take part in clinical research projects. After a median follow-up of 55.7 months, analysis of the full cohort showed that 792 (34%) had died. However, survival was significantly associated with a willingness to take part in clinical trials, which more than halved the risk of death. The authors note that outcomes for patients with chronic heart failure are generally very poor; epidemiological studies show that around 40% of patients diagnosed with chronic heart failure die within a year of diagnosis. "However," says investigator Andrew Clark, MD, from Castle Hill Hospital, "two-year mortality rate in recent trials of chronic heart failure trials has been in the order of 20%. And even in studies of very sick patients, mortality has only been 30%. So we wanted to see if taking part in a clinical trial was associated with a beneficial outcome." Additionally, to explore the effect on survival of actually entering a clinical trial (rather than simply indicating a willingness to take part) survival after the first year was compared between "willing" patients who were recruited to a trial and willing patients who were not. The single most powerful predictor of all-cause mortality in the whole cohort was willingness to take part in a trial. However, results from the second analysis showed that actually being recruited into a clinical trial was not predictive of outcome. The investigators are unable to offer an obvious explanation for the findings, finding no systematic difference between their two study groups. They do, however, suggest "being prepared to take part in a trial is a marker for better compliance with, and acceptance of, treatment." They add that "patients' attitudes to their illness and its treatment is an important aspect of their care."
Heart attack survival improves in younger women . . . In recent years, women, particularly younger women, experienced larger improvements in hospital mortality after heart attack than men, according to a study published in the Oct. 26, issue of Archives of Internal Medicine. Over the last decade several studies showed that younger women, but not older ones, are more likely to die in the hospital after a heart attack than age-matched men. A team of Emory University (Atlanta) researchers examined whether such mortality differences have declined in recent years. "We found that the number of younger women who die in the hospital after a heart attack, compared with men in the same age group, has narrowed over the last few years," said study leader Viola Vaccarino, MD, PhD, professor of medicine (cardiology), and director of the Emory Program in Cardiovascular Outcomes Research and Epidemiology. Vaccarino says changes in patient characteristics and treatments over time accounted in part for the changing mortality trends. The researchers investigated heart attack mortality trends according to gender and age in five age groups during a 12-year period from 1994 to 2006. The study population included 916,380 heart attack patients from the National Registry of Myocardial Infarction who had a confirmed diagnosis of heart attack. The researchers found that hospital mortality declined markedly between 1994 and 2006 in all patients, but more so in women than in men in virtually every age group. The mortality reduction in 2006 relative to 1994 was largest in women under the age of 55 years (53%) and lowest in men under the age of 55 (33%). In patients younger than 55, the absolute decline in mortality was three times larger in women than in men (2.7% vs 0.9%). According to the study, the gender difference in mortality decline became progressively lower in older patients. As a result, the death rate in younger women compared with men was less pronounced in 2004-2006 than in 1994-1995.
— Compiled by Amanda Pedersen, MDD