. Serial noninvasive assessment of progressive pulmonary hypertension in a rat model. Am J Physiol Heart Circ Physiol 283: H364-H371, 2002; 10.1152/ajpheart.00979.2001.-Current methods used to investigate pulmonary hypertension in rat models of the disease allow for only one to two measurements of pulmonary artery (PA) pressure in the life of a rat. We investigated whether transthoracic echocardiography can be used to assess the progression of pulmonary hypertension in rats at multiple time points. Serial echocardiographic measurements were performed over a 6-wk period on rats injected with monocrotaline (MCT) or placebo. Development of a midsystolic notch in the PA waveform, a decrease in the PA flow acceleration time (PAAT), an increase in right ventricular (RV) free-wall thickness, and the development of tricuspid regurgitation (TR) were observed as pulmonary hypertension developed. Changes in the PA waveform and PAAT began in week 3 of disease development as the PA systolic pressure (PASP) reached 25-30 mmHg according to right heart catheterization. The RV free-wall thickness increased significantly by week 5 (PASPs 40-50 mmHg). Development of quantifiable TR occurred in week 6 or at PASPs Ͼ 65 mmHg. A linear correlation was found between the PAAT and PASP in the range of 30-65 mmHg and between the RV-right atrial pressure gradient (derived from TR velocity) and PASP at pressures Ͼ65 mmHg, which enabled a noninvasive estimate of the PASP over a wide range of pressures based on these parameters. These data indicate that transthoracic echocardiography can be used for monitoring the progress of pulmonary hypertension in a rat model. echocardiography; monocrotaline; pulmonary artery acceleration time IN ANIMAL STUDIES OF PULMONARY hypertension (9), a rat model has often been used in which a single monocrotaline (MCT) injection induces pulmonary hypertension over a period of 3-5 wk. Performing right heart catheterization to measure right ventricular (RV) systolic pressure has been central to establishing the presence and quantifying the severity of pulmonary hypertension. Furthermore, gross and histological evaluation of heart and lung tissue has been performed to gain information as to the severity of disease development (7,8,10). However, these methods are limited by the number of measurements performed in the rat and in the ability to characterize rigorously the time course of pulmonary hypertension. Rat models are increasingly being utilized to evaluate the effectiveness of various therapeutic interventions for pulmonary hypertension. Because transthoracic echocardiography (TTE) is noninvasive and allows for multiple assessments of progressive pulmonary hypertension, it can be a useful complement to traditional methods of evaluating pulmonary hypertension in rats.In humans, TTE is one modality for observing the progression of pulmonary hypertension. Although not the "gold standard" for identifying prognostic determinants in patients with pulmonary hypertension, qualitative parameters such as RV hypertrophy an...
Despite the younger age, lower rate of anterior MI, and higher prevalence of single-vessel coronary disease of RV compared with LV shock patients, and their similar benefit from revascularization, mortality is unexpectedly high in patients with predominant RV shock and similar to patients with LV shock.
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