American heart journal
-
American heart journal · May 2002
Cardiogenic shock complicating acute myocardial infarction in elderly patients: does admission to a tertiary center improve survival?
The role of early revascularization among patients with acute myocardial infarction complicated by cardiogenic shock remains controversial. Angioplasty registries, while suggesting a benefit, are subject to selection bias, and clinical trials have been underpowered to detect early benefits. If an invasive strategy is beneficial in this population, patients admitted to hospitals with onsite coronary revascularization might be expected to have a better prognosis. We sought to determine whether access to cardiovascular resources at the admitting hospital influenced the prognosis of patients with acute myocardial infarction complicated by cardiogenic shock. ⋯ In a community-based cohort, patients with acute myocardial infarction complicated by cardiogenic shock did not have significantly different adjusted 30-day and 1-year mortality, irrespective of the revascularization capabilities of the admitting hospital.
-
American heart journal · Apr 2002
Comparative efficacy of fibrinogen and platelet supplementation on the in vitro reversibility of competitive glycoprotein IIb/IIIa receptor-directed platelet inhibition.
Platelet surface glycoprotein IIb/IIIa (alphaIIb/beta3) receptor inhibition, with prevention of fibrinogen binding and platelet aggregation, concomitantly attenuates arterial thrombotic capacity and impairs protective hemostasis, 2 divergent platelet-dependent processes. ⋯ The reversibility of glycoprotein IIb/IIIa-directed platelet inhibition is influenced by cell surface receptor availability and intrinsic pharmacodynamic mechanism of action. Fibrinogen supplementation with fresh frozen plasma or cryoprecipitate either alone or in combination with platelet transfusion represents an important and readily available treatment consideration for restoring hemostatic potential and managing major hemorrhagic complications associated with the administration of small-molecule, competitive glycoprotein IIb/IIIa receptor antagonists.
-
American heart journal · Apr 2002
Effects of thyroid replacement therapy on arterial blood pressure in patients with hypertension and hypothyroidism.
Hypothyroidism is frequently accompanied by cardiac dysfunction, increased vascular resistance, and a greater prevalence of hypertension. Treatment of hypothyroidism may lead to normalization of blood pressure, although some patients may exhibit sustained hypertension. The mechanism of this condition may be the alterations in aortic stiffness. ⋯ Patients with hypertension and hypothyroidism have increased aortic stiffness. Aortic stiffness is decreased in all patients, whereas hypertension is completely reversible in 50% of patients by hormone replacement therapy. Sustained hypertension may be due to increased aortic stiffness.
-
This study was performed to evaluate the impact of beta blockers on QT adaptation to heart rate during the exercise and recovery phases of exercise testing in long QT syndrome. ⋯ Beta blockers reduce QT hysteresis in patients with long QT syndrome to values seen in normal patients. This improved QT adaptation to changes in heart rate may explain the clinical benefit of beta blockers in long QT syndrome.
-
American heart journal · Mar 2002
A noninvasive measure of baroreflex sensitivity without blood pressure measurement.
Baroreflex sensitivity (BRS) and heart rate variability (HRV) are attenuated in cardiovascular disease and can give important prognostic information. Conventional measures of BRS require expensive or invasive equipment for the beat-to-beat measure of blood pressure (BP). We examined the possibility of developing a simple protocol that would provide a relatively standardized BP stimulus, which might obviate the need to measure BP beat-by-beat. ⋯ During 0.1-Hz breathing, the marked difference in BRS between patients with CHF and age-matched control subjects is the result of smaller R-R interval oscillations. In young patients with diabetes, these R-R interval oscillations are significantly smaller than age-matched control subjects, even when some measures of spontaneous HRV are not different between groups. Breathing at 0.1 Hz provides a standard BP stimulus and concentrates spectral power of heart rate at one frequency, enabling simple evaluation of BRS even when BP measurement is not available.