To define the relationship between infarct size and ventricular performance, we performed hemodynamic studies in rats 21 days after left coronary artery occlusion. Ventricular performance was assessed under ether anesthesia by measurements of baseline hemodynamics stressed as determined peak cardiac output stroke volume obtained during intravenous loading developed pressure occlusion ascending aorta. Infarct planimetry endocardial circumference each four histological slices ventricle. Rats...

To determine whether the relationship between infarct size and ventricular performance, volume, compliance could be altered favorably, captopril was administered to rats for 3 months following coronary artery ligation. Baseline left right systemic arterial pressures aortic blood flow, maximal stroke volume cardiac indices attained during a loading, were measured. Passive pressure-volume relations of ventricle determined, slopes segments this relation analyzed characterize chamber stiffness....

Although vasodilator therapy has been shown to improve functional capacity in patients with congestive heart failure, there is no evidence that such can prolong survival. Coronary artery ligation the rat was used produce a wide range of myocardial infarct sizes and resultant spectrum left ventricular dysfunction. To determine relationship between size infarction long-term survival test hypothesis captopril could after infarction, 302 rats were randomly assigned either placebo or 14 days...

Ventricular dilatation may have important prognostic implications for the survival of patients with left ventricular (LV) dysfunction. To determine manner and extent to which ventricle rat remodels dilates after myocardial infarction, we obtained passive pressure-volume relationships, chamber stiffness constants, mass during both early late phases. In moderate large infarcts as inflammation edema developed, LV weight increased then progressively decreased a thin scar formed, returning normal...

To determine the effects of healed myocardial infarction on diastolic compliance left ventricle, we studied 36 rats 26 days after coronary artery ligation. Peak cardiac output and stroke volume were measured under ether anesthesia during loading, peak ventricular developed pressure was determined occlusion ascending aorta. During a slow infusion saline into potassium-arrested continuously over range -5 to 30 mm Hg. Infarct size by planimetry serial sections taken from each heart at 1-mm...

To determine whether chronic antihypertensive therapy prevents the progression of cardiac hypertrophy and deterioration in performance observed spontaneously hypertensive rats (SHR) with long-term hypertension, 14-month-old female SHR normotensive American Wistar (NWR) were treated for 10 months an inhibitor angiotensin I-converting enzyme, captopril (2 g/liter drinking water). Captopril reduced marked left ventricular 24-month-old (untreated, 4.37 +/- 0.2 mg/g body weight; treated, 3.01 0.1...

To determine the effects of a chronic pressure load on cardiac function and morphology, spontaneously hypertensive rats (SHR) two normotensive strains Wistar (WKY NWR) were studied under ether anesthesia at 13, 25, 52, 90 wk age. Although resting index SHR was comparable to that WKY NWR all ages, peak output stroke volume per gram left ventricle determined during rapid intravenous infusion Tyrode solution markedly reduced in only Autonomic inhibition did not alter attained, but ages each...

The purpose of the present study was to gain a better understanding relation between ventricular remodeling and heart failure by assessing adaptation through time graded myocardial injury in presence patent coronary circulation. Left (LV) is dynamic response critical component development failure. However, most previous studies have been an occluded vessel, which may itself effect remodeling. Male Wistar rats received two subcutaneous injections either 0, 85, 170, or 340 mg isoproterenol per...

To characterize the hemodynamic events responsible for alterations in renal function during administration of atrial natriuretic peptide, we studied systemic, renal, and glomerular circulatory effects intravenous rANP[126-149], administered as a 4 micrograms/kg prime 0.5 microgram/kg per minute continuous infusion anesthetized, euvolemic rats. With this protocol, small decline mean systemic arterial blood pressure occurred context markedly enhanced urinary sodium excretion,...

Glomerular and tubule functions were assessed by micropuncture in rats with extensive myocardial infarction produced ligation of the left coronary artery 4 weeks prior to study. When compared sham-operated control rats, involving 40 +/- 4% ventricular circumference had lower mean arterial pressure (96 5 vs. 122 mm Hg, P less than 0.005), higher end-diastolic (24 3 0 0.001). Renal cortical microcirculatory dynamics characterized reduced glomerular plasma flow rate (75 8 165 17 nl/min, but a...

Cardiac pumping ability was assessed during the natural development of left ventricular hypertrophy by elevating venous pressure infusing Tyrode's solution intravenously to produce peak cardiac output. This experiment performed on spontaneously hypertensive rats (SHR) three age groups (11, 24, and 83 weeks). From 11 24 weeks, output SHR increased in direct proportion abnormally mass; Thus per gram ventricle (LV) remained stable. Similar results were obtained for two strains normotensive at...

We studied the systemic and renal hemodynamic effects of leukotriene C4 (2 micrograms/kg per min for 5 minutes, iv) in rat. During period its infusion, produced a significant elevation mean arterial pressure reductions cardiac output blood flow, as measured by electromagnetic flow probes. These were abolished FPL55712 , putative antagonist sulfidopeptide leukotrienes, but not saralasin or indomethacin. Leukotriene also resulted an average loss 20% plasma volume which, during postinfusion...

A subset of Wistar-Kyoto (WKY) rats that spontaneously develops biventricular hypertrophy (BVH) in response to increased cardiac output was evaluated for ventricular expression the atrial natriuretic factor (ANF) gene. Normal WKY had low levels left ANF mRNA and minimally detectable transcripts right ventricle. In contrast, BVH showed a sixfold greater concentration ventricle than age-matched controls. equaled those found ventricles were dramatically Unlike experimental models hypertrophy,...

Female spontaneously hypertensive and normotensive rats were studied at 6, 12, 18, 24 months of age to determine which characteristics myocardial performance herald the onset left ventricular dysfunction. Peak ejection fraction index was derived from measurements peak stroke volume (in vivo loading) passive pressure-volume relations. The stiffness constant (km, slope incremental modulus-stress relation, EINC = km sigma), chamber (kc, stiffness-pressure dP/dV kcP), cavitary volume-to-wall...

To determine whether chronic antihypertensive therapy reduces cardiac mass and improves performance in spontaneously hypertensive rats (SHR) with marked left ventricular hypertrophy evidence of dysfunction, 12-mo-old male female SHR age- sex-matched normotensive (NORM) were treated for 6 mo either tap water or containing hydralazine guanethidine. Cardiac was assessed by the peak stroke volume indices attained during loading maximum pressure developed an aortic occlusion. Passive diastolic...

Spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats were treated with beta-adrenergic receptor inhibiting drugs (either propranolol or timolol) from conception until 12 weeks of age to determine if this therapy would alter the development systemic hypertension left ventricular hypertrophy. Therapy (propranolol timolol, 500 mg/liter drinking water) was initiated breeding parents continued throughout pregnancy, nursing, postweaning periods. Although heart rates inhibited WKY SHR...

The relation between left ventricular function and renal excretion of sodium (Na+) was studied in rats with myocardial infarction (MI) varying degrees dysfunction. Three groups were defined: 1) control sustained no infarct, 2) small to moderate infarcts involved 10-40% the circumference, 3) large greater than 40%. In conscious rats, Na+ measured after administration saline load by gavage. Four hours load, MI excreted less one half amount whereas an intermediate amount. a second group...

To study the role of atrial natriuretic peptide (ANP) in chronic heart failure, ANP synthesis, storage, and release were examined by measuring messenger ribonucleic acid (mRNA) levels plasma concentrations rats with myocardial infarction produced coronary artery ligation. Three groups defined as following: 1) controls, sham-operated, or operated, but noninfarcted; 2) moderate infarcts, involving 5-30% left ventricular circumference; 3) large infarcts (greater than equal to 30%). In addition,...

The relationship between arterial pressure and left ventricular (LV) functional capacity LV mass during the natural development of cardiac hypertrophy was assessed in Dahl-resistant (R) -sensitive (S) hypertensive rats maintained on three dietary NaCl regimens (0.4%, 4.0%, 8.0% for 9 weeks, then 4.0%) from 5 until 20 weeks age. In R rats, were unaffected by diet. contrast, S demonstrated levels that graded according to NaCl. Hemodynamic studies under ether anesthesia elevation produced...

Measurement of aortic input impedance in the rat is complicated by a high basal heart rate but possible if appropriate compensation made for frequency-dependent errors modulus and phase resulting from analog filters equipment nonalignment pressure flow sensors. Because complex quantity, accurate values both are required before meaningful interpretation data can be made. We measured electromagnetic ascending blood mature, ether-anesthetized, open-chest male Wistar rats. Pressure waveforms...

Endothelin type 1 (ET-1) is an endothelial cell-derived 21-amino acid peptide with potent contractile effects on isolated vascular smooth muscle. The systemic hemodynamic of bolus intravenous injections ET-1 and angiotensin II (ANG II, 300 pmol) were examined in anesthetized male Munich-Wistar rats by measurements mean arterial (AP) right atrial (RAP) blood pressures cardiac index (CI, electromagnetic flowmetry) over a 60-min period. induced biphasic pressure response: transient hypotension...