on behalf of the Cardiac Disease in Pregnancy (CARPREG) InvestigatorsBackground-The maternal and neonatal risks associated with pregnancy in women with heart disease receiving comprehensive prenatal care have not been well defined. Methods and Results-We prospectively enrolled 562 consecutive pregnant women with heart disease and determined the outcomes of 599 pregnancies not ending in miscarriage. Pulmonary edema, arrhythmia, stroke, or cardiac death complicated 13% of pregnancies. Prior cardiac events or arrhythmia, poor functional class or cyanosis, left heart obstruction, and left ventricular systolic dysfunction independently predicted maternal cardiac complications; the cardiac event rate can be predicted using a risk index incorporating these predictors. Neonatal complications (20% of pregnancies) were associated with poor functional class or cyanosis, left heart obstruction, anticoagulation, smoking, and multiple gestations. Conclusions-Pregnancy in women with heart disease is associated with significant cardiac and neonatal complications, despite state-of-the-art obstetric and cardiac care. Maternal cardiac risk can be predicted with the use of a risk index.

Background-Tetralogy of Fallot is the most common form of congenital heart disease in implantable cardioverterdefibrillator (ICD) recipients, yet little is known about the value of ICDs in this patient population. Methods and Results-We conducted a multicenter cohort study in high-risk patients with Tetralogy of Fallot to determine actuarial rates of ICD discharges, identify risk factors, and characterize ICD-related complications. A total of 121 patients (median age 33.3 years; 59.5% male) were enrolled from 11 sites and followed up for a median of 3.7 years. ICDs were implanted for primary prevention in 68 patients (56.2%) and for secondary prevention in 53 (43.8%), defined by clinical sustained ventricular tachyarrhythmia or resuscitated sudden death. Overall, 37 patients (30.6%) received at least 1 appropriate and effective ICD discharge, with a median ventricular tachyarrhythmia rate of 213 bpm. Annual actuarial rates of appropriate ICD shocks were 7.7% and 9.8% in primary and secondary prevention, respectively (Pϭ0.11). A higher left ventricular end-diastolic pressure (hazard ratio 1.3 per mm Hg, Pϭ0.004) and nonsustained ventricular tachycardia (hazard ratio 3.7, Pϭ0.023) independently predicted appropriate ICD shocks in primary prevention. Inappropriate shocks occurred in 5.8% of patients yearly. Additionally, 36 patients (29.8%) experienced complications, of which 6 (5.0%) were acute, 25 (20.7%) were late lead-related, and 7 (5.8%) were late generator-related complications. Nine patients died during follow-up, which corresponds to an actuarial annual mortality rate of 2.2%, which did not differ between the primary and secondary prevention groups. Conclusions-Patients with tetralogy of Fallot and ICDs for primary and secondary prevention experience high rates of appropriate and effective shocks; however, inappropriate shocks and late lead-related complications are common.

Background-Transposition of the great arteries with intra-atrial baffle repair is among the congenital heart defects at highest risk of sudden death. Little is known about mechanisms of sudden death and the role of implantable cardioverter defibrillators. Methods and Results-We conducted a multicenter cohort study in patients with transposition of the great arteries to determine actuarial rates of implantable cardioverter defibrillator shocks, identify risk factors, assess underlying arrhythmias, and characterize complications. Overall, 37 patients (age, 28.0Ϯ7.6 years; 89.2% male) were enrolled from 7 sites. Implantable cardioverter defibrillators were implanted for primary prevention in 23 (62.1%) patients and secondary prevention in 14 patients (37.8%). Annual rates of appropriate shocks were 0.5% and 6.0% in primary and secondary prevention, respectively (Pϭ0.0366). Independent predictors were a secondary prevention indication (hazard ratio, 18.0; Pϭ0.0341) and lack of ␤-blockers (hazard ratio, 16.7; Pϭ0.0301). In patients with appropriate shocks, intracardiac electrograms documented supraventricular tachycardia preceding or coexisting with ventricular tachycardia in 50%. No patient with inducible ventricular tachycardia received an appropriate shock in comparison with 37.5% of noninducible patients (Pϭ0.0429). Inappropriate shocks occurred in 6.6% per year, more so in patients of lesser weight (hazard ratio, 0.91 per kg; Pϭ0.0168). Additionally, 14 patients (37.8%) experienced complications: 5 (13.5%) acute, 1 (2.7%) late generator related, and 12 (32.4%) late lead related. Conclusion-In

Background-The mechanism for the beneficial effect of ␤-blocker therapy in patients with left ventricular (LV) dysfunction is unclear, but it may relate to an energy-sparing effect that results in improved cardiac efficiency. C-11 acetate kinetics, measured using positron-emission tomography (PET), are a proven noninvasive marker of oxidative metabolism and myocardial oxygen consumption (MV O 2 ). This approach can be used to measure the work-metabolic index, which is a noninvasive estimate of cardiac efficiency. Methods and Results-The aim of this study was to determine the effect of metoprolol on oxidative metabolism and the work-metabolic index in patients with LV dysfunction. Forty patients (29 with ischemic and 11 with nonischemic heart disease; LV ejection fraction Ͻ40%) were randomized to receive metoprolol or placebo in a treatment protocol of titration plus 3 months of stable therapy. Seven patients were not included in analysis because of withdrawal from the study, incomplete follow-up, or nonanalyzable PET data. The rate of oxidative metabolism (k) was measured using C-11-acetate PET, and stoke volume index (SVI) was measured using echocardiography. The work-metabolic index was calculated as follows: (systolic blood pressureϫSVIϫheart rate)/k. No significant change in oxidative metabolism occurred with placebo (kϭ0.061Ϯ0.022 to 0.054Ϯ0.012 per minute). Metoprolol reduced oxidative metabolism (kϭ0.062Ϯ0.024 to 0.045Ϯ0.015 per minute; Pϭ0.002). The work-metabolic index did not change with placebo (from 5.29Ϯ2.46ϫ10 6 to 5.14Ϯ2.06ϫ10 6 mm Hg ⅐ mL/m 2 ), but it increased with metoprolol (from 5.31Ϯ2.15ϫ10 6 to 7.08Ϯ2.36ϫ10 6 mm Hg ⅐ mL/m 2 ; PϽ0.001). Conclusions-Selective ␤-blocker therapy with metoprolol leads to a reduction in oxidative metabolism and an improvement in cardiac efficiency in patients with LV dysfunction. It is likely that this energy-sparing effect contributes to the clinical benefits observed with ␤-blocker therapy in this patient population.