The American journal of cardiology
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Overlapping homogenous drug-eluting stents (DESs) may be used instead of overlapping bare metal stents (BMSs) to treat coronary lesions longer than available stents. Yet, no data are available on patients treated with overlapping heterogenous DESs or DESs and BMSs. We prospectively assessed 9-month clinical outcome and 6-month angiographic late loss (evaluated at 5 different lesion segments) in a consecutive series of 40 patients who received overlapping homogenous DESs (sirolimus-eluting stent [SES] or paclitaxel-eluting stent [PES]), heterogenous DESs (SES + PES), or overlapping DESs and BMSs. ⋯ Late lumen loss at the site of stent overlap showed significant differences according to type of overlapped stent (1.00 +/- 0.76 mm in DES-BMS overlap, 0.32 +/- 0.55 mm in PES-PES overlap, 0.13 +/- 0.11 in SES-PES overlap, and 0.08 +/- 0.10 mm in SES-SES overlap, p = 0.005). In conclusion, the present study suggests that overlap of DESs and BMSs should be avoided because the antirestenotic effect of DESs is skewed by contiguous BMS implantation. Overlap between SESs and PESs in this very preliminary report was associated with no specific adverse event.
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Prolonged and labile ventricular repolarization and decreased heart rate variability may be associated with susceptibility to ventricular fibrillation (VF) after myocardial infarction (MI). The response of ventricular repolarization related to abrupt heart rate changes may also be associated with arrhythmia vulnerability. We investigated whether diurnal maximal values or changing capacities of QT and T-wave peak to T-wave end (TPE) intervals are different in patients after MI with and without a history of VF. ⋯ Capacity to change QT and TPE intervals correlated with vagally mediated measurements of heart rate variability (r from 0.35 to 0.46, p from 0.01 to <0.001, respectively). In conclusion, long maximal QT interval may not be the key factor exposing patients after MI to VF. Impaired capacity to change QT and TPE intervals seems to be associated with risk of VF after MI.
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Interventions involving calcium cycling may represent a promising approach to heart failure (HF) therapy because calcium handling is known to be deranged in human and experimental HF. Istaroxime is a sodium-potassium adenosine triphosphatase (ATPase) inhibitor with the unique property of increasing sarcoplasmic reticulum calcium ATPase (SERCA) isoform 2a (SERCA2a) activity. Because this was demonstrated in normal experimental models, we investigated whether istaroxime is able to improve global cardiac function and stimulate SERCA in failing hearts. ⋯ In left ventricular sarcoplasmic reticulum microsomes from AoB animals, 100 nmol/L istaroxime normalized the depressed (-32%) SERCA2a maximum velocity and increased SERCA activity (+17%). In muscle strips from hearts from patients undergoing cardiac transplantation, istaroxime (0.1-1.0 micromol/L) increased (in a concentration-dependent manner) developed tension, the maximum and minimum first derivative of tension, and absolute velocity of contraction, while stimulating SERCA activity in sarcoplasmic reticulum microsomes at physiologic free calcium concentrations. In conclusion, istaroxime is presently the only available compound that stimulates SERCA2a activity and produces a luso-inotropic effect in HF.
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This study compared different measurements of repolarization duration in patients after infarction with and without conduction disturbances and evaluated the prognostic significance of repolarization parameters for predicting mortality in patients with conduction abnormalities. The study population consisted of 3,282 patients after recent myocardial infarction. Repolarization duration was measured using Bazett QTc and JTc (QTc minus QRS) and Rautaharju QT and JT(RR) formulas. ⋯ Repolarization parameters were uniformly dichotomized at the 75th percentile (QTc interval >490 ms, JTc interval >360 ms, QT(RR,QRS) interval >433 ms, JT(RR) interval >359 ms) to determine their prognostic significance for predicting mortality. After adjustment for significant clinical predictors of mortality, the hazard ratios were 1.65 for QTc interval (p = 0.062), 1.46 for JTc interval (p = 0.168), 1.71 for QT(RR,QRS) interval (p = 0.043), and 1.70 for JT(RR) interval (p = 0.044)(.) In conclusion, patients with left bundle branch block, right bundle branch block, or indeterminate ventricular conduction disturbances show longer repolarization duration than patients without these conduction disturbances, and QT(RR,QRS) and JT(RR) intervals reflect better than QTc repolarization duration in patients with conduction disturbances. QT(RR) and JT(RR) intervals significantly and independently predict mortality in patients after infarction with conduction disturbances.
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The customary interpretation of active-controlled noninferiority trials is founded on a number of unverifiable assumptions. These assumptions can be circumvented, and the semantic and statistic interpretation of the trials placed on a more rational foundation, if treatment comparisons are analyzed from a Bayesian perspective. In conclusion, the resultant probabilistic measures thereby render the meaning of noninferiority more transparent and clinically relevant.