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Background We previously reported that 6 to 12 weeks of dual-chamber (DDD) pacing results in clinical and hemodynamic improvement in obstructive hypertrophic cardiomyopathy (HCM). This study examines the long-term results of DDD pacing in obstructive HCM.Methods and Results DDD devices were implanted in 84

Contemporary cardiac intensive care units (CICUs) provide care for an aging and increasingly complex patient population. The medical complexity of this population is partly driven by an increased proportion of patients with respiratory failure needing noninvasive or invasive positive pressure ventilation (PPV). PPV often plays an important role in the management of patients with cardiogenic pulmonary edema, cardiogenic shock, or cardiac arrest, and those undergoing mechanical circulatory support. Noninvasive PPV, when appropriately applied to selected patients, may reduce the need for invasive mechanical PPV and improve survival. Invasive PPV can be lifesaving, but has both favorable and unfavorable interactions with left and right ventricular physiology and carries a risk of complications that influence CICU mortality. Effective implementation of PPV requires an understanding of the underlying cardiac and pulmonary pathophysiology. Cardiologists who practice in the CICU should be proficient with the indications, appropriate selection, potential cardiopulmonary interactions, and complications of PPV.

Background. Patients with hypertrophic cardiomyopathy (HCM) frequently have arrhythmias and hemodynamic abnormalities and are prone to sudden death and syncope. An important need exists for improved risk stratification and definition of appropriate investigation and therapy.Methods and Results. The relation of 31 clinical, Holter, cardiac catheterization, and electrophysiological (EP) variables to subsequent cardiac events in 230 HCM patients was examined by multivariate analysis. Studies were for cardiac arrest (n=32), syncope (n=80), presyncope (n=52), ventricular tachycardia (VT) on Holter (n=36), a strong family history of sudden death (n=9), and palpitations (n=21). Nonsustained VT on Holter was present in 115 patients (50%o). Sustained ventricular arrhythmia was induced in 82 patients (36%). Seventeen cardiac events (eight sudden deaths, one cardiac arrest, and eight syncope with defibrillator discharges) occurred during a follow-up of 28±19 months. The 1-year and 5-year event-free rates were 99%, and 79%o, respectively. Two variables were significant independent predictors of subsequent

CACNA2D2 is a putative tumor suppressor gene located in the human chromosome 3p21.3 region that shows frequent allelic imbalances in lung, breast, and other cancers. The ␣2␦-2 protein encoded by the gene is a regulatory subunit of voltage-dependent calcium channels and is expressed in brain, heart, and other tissues. Here we report that mice homozygous for targeted disruption of the Cacna2d2 gene exhibit growth retardation, reduced life span, ataxic gait with apoptosis of cerebellar granule cells followed by Purkinje cell depletion, enhanced susceptibility to seizures, and cardiac abnormalities. The Cacna2d2 tm1NCIF null phenotype has much in common with that of Cacna1a mutants, such as cerebellar neuro-degeneration associated with ataxia, seizures, and premature death. A tendency to bradycardia and limited response of null mutants to isoflurane implicate ␣2␦-2 in sympathetic regulation of cardiac function. In summary, our findings provide genetic evidence that the ␣2␦-2 subunit serves in vivo as a component of P/Q-type calcium channels, is indispensable for the central nervous system function, and may be involved in hereditary cerebellar ataxias and epileptic disorders in humans. (Am J

These findings suggest that (1) patients with HCM caused by beta-MHC gene mutations exhibit labile repolarization quantified by QT variability analysis and, hence, may be more at risk for sudden death from ventricular arrhythmias, and (2) indices of QT variability may be particularly abnormal in patients with beta-MHC gene mutations that are associated with a poor prognosis.

Background Myocardial perfusion scans contribute up to 20% of the estimated annual collective radiation dose to the U.S. population. We estimated potential future cancer risk from these scans by age at exposure and current frequency of use in the U.S. Methods and Results Usage patterns were determined from national survey data, and radionuclide dosage was based on current guidelines. Cancer risk projection models were generated based on the National Research Council Biologic Effects of Ionizing Radiation VII report, under the assumption that risk has a linear relationship with radiation exposure even at low doses. The mean projected number of radiation-related incident cancers and 95% uncertainty intervals (UI) were estimated using Monte Carlo simulations. Estimated risks for a scan performed at age 50 years ranged from 2 cancers/10,000 scans (95%UI:1–15) for a positron emission tomography ammonia-13 test to 25 (95%UI:9–58) cancers/10,000 scans for a dual-isotope (thallium-201+technetium-99m) scan. Risks were 50% lower at age 70 years, but were similar for males and females. Combination of cancer risk estimates with data on frequency of use suggested that the 9.1 million myocardial perfusion scans performed annually in the U.S. could result in 7400 (95%UI:3300–13700) additional future cancers. Conclusions The lifetime cancer risk from a single myocardial perfusion scan is small, and should be balanced against likely benefit and appropriateness of the test. The estimates depend on a number of assumptions including life-expectancy. They apply directly to asymptomatic individuals with life-expectancies similar to the general population. For individuals with a symptomatic clinical profile, on whom such scans are typically performed, the risks will be lower because of shorter life-expectancy.

This investigation provides evidence of subclinical coronary vascular disease among individuals infected with HIV in early life. Increased duration of ART, hyperlipidemia, and smoking contributed to proximal RCA thickening, independent of atherosclerotic plaque quantified by CT. These modifiable risk factors appear to influence early atherogenesis as measured by coronary wall thickness and may be important targets for CVD risk reduction.