Preventing Sudden Death in a Special Population
Implanting a cardioverter-defibrillator in patients who suffer from arrhythmogenic right ventricular cardiomyopathy/dysplasia reduced the incidence of sudden death, said Italian researchers in a report in this week’s issue of the journal Circulation (Circulation. 2003;108:3084–3091OpenUrl).
Patients with this disorder faced an increased risk of sudden death, said the researchers, led by Domenico Corrado, MD, PhD, of the Universita di Padova in Padov, Italy. In this multinational, multicenter trial, the researchers implanted defibrillators in 93 men and 39 middle-aged women with the disease. Thirteen of the patients had suffered a cardiac arrest, 82 had had sustained ventricular tachycardia, and 21 had had syncope. In the 39 months (on average) that patients were monitored, 64 patients experienced a needed firing of the defibrillator, termed an appropriate intervention. Twenty-one had inappropriate interventions, and 19 suffered complications related to the implantable cardioverter-defibrillator.
Four patients died during the follow-up period, said the researchers, and 32 had ventricular fibrillation or flutter that would have resulted in sudden death without the intervention of the device. At 36 months, the rate of survival was 96% in this population. Survival rate without ventricular fibrillation/flutter was 72%.
The researchers concluded that in this particular population, implantable cardioverter-defibrillators “provided life-saving protection by effectively terminating life-threatening ventricular arrhythmias.”
Pulmonary Stenosis After Radiofrequency Ablation
Better imaging techniques that insure ostial isolation and guide the titration of the power used during radiofrequency ablation for atrial fibrillation lessen the incidence of severe pulmonary stenosis, said an international group of researchers in a report in this week’s issue of the journal Circulation (Circulation. 2003;108:3102–3107OpenUrl).
In this study, led by Eduardo B. Saad, MD, of the Cleveland Clinic Foundation, researchers analyzed the effect of various ablation strategies on the incidence of pulmonary vein stenosis in 608 patients. In 71, an electroanatomic approach was used. Circular mapping was chosen for 537. In those 537, 25 had distal isolation, and 102 had ostial isolation based on pulmonary vein angiography. In 140, the procedure was guided by intracardiac echocardiography, and in 270, energy delivery was based on visualization of microbubbles. Twenty-one patients had severe narrowing of the pulmonary vein, 27 had moderate narrowing, and 47 had mild narrowing.
Symptoms occurred in patients with severe narrowing, whereas all patients with narrowing considered mild or moderate were asymptomatic. Scans of lung perfusion were normal in all but 4 of the patients with mild to moderate narrowing. Researchers also concluded that the diagnosis of mild narrowing at 3 months did not preclude future development of severe stenosis and advised repeat imaging studies to monitor for progress of the problem.
New Risk for Lupus Patients
Patients with systemic lupus erythematosus are at significant risk of developing premature atherosclerosis, said researchers in the December 18, 2003, issue of The New England Journal of Medicine (N Engl J Med. 2003;349:2399–2406OpenUrlCrossRefPubMed).
Researchers led by Mary J. Roman, MD, matched 197 lupus patients with 197 controls. Each subject underwent carotid ultrasonography, echocardiography, and an assessment of cardiovascular disease risk factors and clinical and inflammatory markers that indicate the risk of cardiovascular disease. All patients had similar risk factors for cardiovascular disease at the beginning of the study.
Patients with lupus were more than twice as likely to have carotid plaque than the controls (37.1% versus 15.2%). Compared with patients without plaque, those who had it were older, had had lupus longer, had suffered more damage related to their disease, and were less likely to have autoantibodies or to have been treated with prednisone, cyclophosphamide, or hydroxychloroquine.
The researchers, building on foreknowledge that myocardial infarction occurs more frequently in patients with lupus, concluded that atherosclerosis occurs prematurely in patients with systemic lupus erythematosus and is independent of traditional risk factors for atherosclerosis.
No Fitness Early; Cardiovascular Disease Later
Young adults who are not physically fit face an increased risk of developing cardiovascular disease later in life, said researchers from Northwestern University’s Feinberg School of Medicine in Chicago, Ill, in a report in the December 17, 2003, issue of the Journal of the American Medical Association (JAMA. 2003;290:3092–3100OpenUrlCrossRefPubMed).
A total of 5115 subjects aged 18 to 30 years were recruited in various parts of the United States for participating in the Coronary Artery Risk Development In young Adults (CARDIA) study. Subjects completed a treadmill examination at baseline and were followed up from 1985–1986 through 2000–2001. Nearly half the subjects repeated the exercise test in 1992–1993.
Subjects who had fitness levels at less than the 20th percentile were 3 to 6 times more likely to develop cardiovascular risk factors such as diabetes, hypertension, and metabolic syndrome than were those with fitness levels at the 60th percentile or higher.
“Improved fitness over 7 years was associated with a reduced risk of developing diabetes and the metabolic syndrome, but the strength and significance of these associations was reduced after accounting for changes in weight.”
“Our findings demonstrate the importance of low cardiorespiratory fitness in young adulthood as a risk factor for developing cardiovascular comorbidities (related illnesses) in middle age,” the authors wrote. “Given the current obesity epidemic and observations of a decline in daily energy expenditure in the population, improving cardiorespiratory fitness in young men and women and developing public health policies that encourage physical activity should be important health policy goals.”