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PubMed1989

Right ventricular function under acute cor pulmonale.

Many investigators have reported the hemodynamics in acute cor pulmonale clinically and experimentally. However, earlier studies have not made quantitative evaluations of the effects of coronary perfusion pressure and hypoxia on right ventricular contractility. We simulated acute cor pulmonale in nine isolated canine hearts and investigated the relationship of the process to cardiac deterioration and restoration. The afterload and preload of the right ventricle were controlled with a computer-assisted load control servosystem. Coronary perfusion pressure (COPP) was also controlled at either normal or variable levels identical to products of measured cardiac output and assumed values of systemic vascular resistance. Critical state (CS) was defined as a condition with an initial decrease in peak systolic pressure despite increased afterload. Within the normal range of PaO2 (105 +/- 5.3 mmHg), CS developed at a COPP of 51 +/- 5.1 mmHg, while under low PaO2 (51 +/- 2.3 mmHg), it developed at a COPP of 59 +/- 8.8 mmHg. As long as the COPP was normal (90 mmHg), the contractility of the right ventricle did not decrease despite hypoxia (PaO2 51 +/- 2.3 mmHg). An increase in systemic vascular resistance or administration of a beta-stimulant at CS restored the contractility of the right ventricle. However, an increase in preload decreased the contractility of the right ventricle.

Acute Disease↗
PubMed1979

Short-term immobilization of healthy men: right ventricular function and metabolism during graded exercise.

Five healthy male volunteers were subjected to graded exercise tests on a bicycle ergometer (600 kpm/min for 8 minutes) with simultaneous catheterization of the right cardiac ventricle and radial artery, first before immobilization and them after five-day bed rest in the head-down posture (the foot bed end was elevated 4.5 degrees). After immobilization, during exercise the stroke index did not increase, the tachycardia was more marked, the indicators of right ventricular contractility increased [+ max dp/dt, mas (dp/dt) /P, --mas dp/dt], the arterial pressure decreased, and the lactic acid level in mixed venous blood rose. Possible causes of haemodynamic and metabolic alterations, occurring in healthy volunteers during graded exercise following short-term hypokinesis, are discussed.

Adult↗
PubMed1985

Effect of coronary artery recanalization on right ventricular function in patients with acute myocardial infarction.

The effects of coronary artery recanalization by intracoronary administration of streptokinase on left ventricular function during acute myocardial infarction have received increasing attention in recent years. Although myocardial dysfunction is often more pronounced in the right ventricle than in the left ventricle in patients with acute inferior wall myocardial infarction, the effect of coronary artery recanalization on right ventricular dysfunction has not been previously addressed. Accordingly, in this investigation, 54 patients who participated in a prospective, controlled, randomized trial of recanalization during acute myocardial infarction were studied. Among 30 patients with inferior wall infarction, 19 had right ventricular dysfunction on admission; 11 of these 19 had positive uptake of technetium-99m pyrophosphate in the right ventricle, indicative of right ventricular infarction. Patients with successful recanalization (n = 6) exhibited improved right ventricular ejection fraction from admission to day 10 (26 +/- 7 to 39 +/- 14%, p less than 0.03). However, control patients (n = 6) and patients who did not undergo recanalization (n = 7) also exhibited improvement (20 +/- 7 to 29 +/- 11% [p less than 0.02] and 30 +/- 8 to 40 +/- 6% [p less than 0.03], respectively). Improvement in several other variables of right ventricular dysfunction evolved at an equal rate with the ejection fraction changes. Patients with or without right ventricular infarction improved similarly. These data indicate that the right ventricular dysfunction commonly associated with inferior wall infarction is often transient, and improvement is the rule, irrespective of early recanalization of the "infarct vessel."

Aged↗
PubMed1990

Prostacyclin and right ventricular function in patients with pulmonary hypertension associated with ARDS.

Eight patients who developed pulmonary artery hypertension during the adult respiratory distress syndrome (ARDS) were treated with an infusion of prostacyclin (PGI2, 12.5-35.0 ng.kg-1.min-1) for 45 min. We examined whether reducing the right ventricular (RV) outflow pressures by PGI2 infusion would increase the right ventricular ejection fraction (RVEF) measured by thermodilution. PGI2 reduced the pulmonary artery pressure (PAP) from 35.6 to 29.1 mmHg (p less than 0.01). The cardiac index (CI) increased from 4.2 to 5.81.min-1.m-2 (p less than 0.01) partly due to an increased stroke volume. The decreased PAP together with the increased CI resulted in a fall of the calculated pulmonary vascular resistance index (PVRI, from 5.1 to 2.5 mmHg.min.m2.1-1, p less than 0.01). In the patients with subnormal baseline RVEF the increased stroke volume was associated with an increased RVEF (from 47.6% to 51.8%, p less than 0.05) suggesting improved RV function. This result was underscored by a significant relationship between the changes in PVRI and RVEF (r = 0.789, delta % RVEF = 2.11.delta PVRI-1.45). Despite an increased venous admixture from 27.8% to 36.9% (p less than 0.05) the arterial PO2 remained constant resulting in an increased oxygen delivery from 657 to 894 ml.min-1.m-2 (p less than 0.01). We conclude that short term infusions of PGI2 increased CI concomitant to improved RV function parameters when baseline RVEF was depressed. Since improved oxygen availability should be a major goal in the management of patients with ARDS PGI2 may be useful to lower pulmonary artery pressure in ARDS.

Adult↗
PubMed1984

Right ventricular function in coronary artery disease as assessed by two-dimensional echocardiography.

Two-dimensional echocardiography (2DE) was performed in 64 patients with coronary artery disease. There were 46 men and 18 women, aged 58.7 +/- 11.4 years. An apical four-chamber view, a two-chamber right ventricular (RV) view, and a subcostal four-chamber view were obtained in 58 of 64 (91%) patients. Regional wall motion abnormalities ( RWMA ) of the RV free or diaphragmatic wall were detected in 4 of 18 (22%) patients with acute inferior myocardial infarction (IMI) and in 3 of 14 (21%) patients with old IMI. All seven patients with RWMA by 2DE had two or more of the following findings: hypotension, second- or third-degree atrioventricular block, atrial arrhythmias, or ventricular tachycardia. The RV ejection fraction by first-pass radionuclide angiography was 19.7 +/- 8.3% in patients with IMI and RV RWMA by 2DE compared to 35.3 +/- 9.6% (p less than 0.005) in patients without. A hyperdynamic RV wall motion was seen in 12 of 15 (80%) patients with acute anterior MI (AMI). No RV RWMA was observed in 17 patients with greater than 75% obstruction of right coronary artery and absent infarction. Thus, RWMA of the right ventricle were detected by 2DE in 22% of patients with IMI and identified patients with clinically significant RV dysfunction, probably due to RV infarction; a compensatory hyperdynamic RV wall motion was observed in 80% of patients with acute AMI.

Adult↗
PubMed1999

Estimation of left ventricular function in right ventricular volume and pressure overload. Detection of early left ventricular dysfunction by Tei index.

Although the effects of right ventricular (RV) volume and pressure overload (RVVO and RVPO) on ventricular septal motion are different, the differential effect on left ventricular (LV) function is still controversial. The Doppler-derived index (Tei index) combining systolic and diastolic ventricular function, defined as the sum of isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) divided by ejection time (ET), has been demonstrated to be a useful index to estimate LV function and to predict the prognosis of patients with congestive heart failure. This study was designed to evaluate the differential effects of RVVO and RVPO on LV function using the Tei index. Study patients consisted of 26 age-matched normal subjects, 22 patients with atrial septal defect (ASD) with normal or borderline RV pressure and 25 with primary pulmonary hypertension (PPH). All subjects had normal LV ejection fractions measured with 2-dimensional echocardiogram using biplane Simpson's method (61 +/- 4 vs 61 +/- 4 vs 63 +/- 8%, normal vs ASD vs PPH). Tei index was easily obtained in all subjects from transthoracic Doppler echocardiogram of LV inflow and outflow. Patients with ASD had normal ICT, IRT and ET, resulting in normal Tei index, however, patients with PPH had significantly prolonged ICT and IRT with shortened ET, resulting in a significant increase in Tei index (0.38 +/- 0.04 vs 0.36 +/- 0.03 vs 0.61 +/- 0.22, p < 0.001). Although RVVO due to ASD has no significant effects on LV function, RVPO due to PPH can adversely affect LV function. The Tei index is a simple and sensitive measure to assess LV function caused by RVVO or RVPO.

Adult↗
PubMed1988

Effect of oral combination therapy with mexiletine and quinidine on left and right ventricular function.

Combination therapy with mexiletine (MEX) and quinidine (Q) may be more efficacious than monotherapy with either drug in suppressing ventricular arrhythmias, but its effects on ventricular performance are not known. Thus, right ventricular ejection fraction (RVEF) and left ventricular ejection fraction (LVEF) and wall motion score (WMS) were assessed in 14 patients with ventricular tachycardia before antiarrhythmic therapy, during MEX and Q monotherapies, and during combination therapy. During monotherapy, the daily doses and serum drug levels were: MEX, 621 mg/day and 3.4 microM/L; Q, 1573 mg/day and 8.3 microM/L, respectively. With combination therapy, the daily doses and serum drug levels were: MEX, 636 mg/day and 3.3 microM/L; Q, 1643 mg/day and 9.5 microM/L, respectively. Drug therapy did not affect group LVEF (drug free = 36 +/- 19%, MEX = 34 +/- 18%, Q = 36 +/- 19%, and combination MEX-Q = 35 +/- 19%), RVEF (drug free = 34 +/- 11%, MEX = 35 +/- 11%, Q = 36 +/- 13%, and combination MEX-Q = 36 +/- 12%), or WMS. Ventricular function reserve was assessed in five patients. Drug therapy did not affect group exercise LVEF (drug free = 44 +/- 14%, MEX = 42 +/- 12%, Q = 43 +/- 13%, and MEX-Q = 45 +/- 12%), RVEF (drug free = 38 +/- 10%, MEX = 40 +/- 11%, Q = 39 +/- 12%, and MEX-Q = 40 +/- 12%), WMS, or exercise duration. Combination MEX-Q therapy did not have a significant effect on exercise performance or ventricular function in seven additional patients in whom no exercise studies were done during monotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1982

[Studies on dose-dependent effect of ouabain on right ventricular function and pulmonary circulation].

The clinical utility of digitalis glycoside for the treatment of cor pulmonale induced by chronic pulmonary disease has not been clarified. In the present study, a rational use of this drug for the treatment of cor pulmonale was investigated especially concerning it's dose. In normal open-chested anesthetized dogs, the effect of ouabain was studied with special reference to pulmonary vascular resistance and right ventricular myocardial contractility by changing dose of 0.01 mg/kg, 0.02 mg/kg and 0.03 mg/kg. Pulmonary vascular resistance was increased extremely when the dogs were treated with 0.03 mg/kg, but not changed remarkably with 0.02 mg/kg and 0.01 mg/kg. On the other hand, right ventricular myocardial contractility was increased equally in dogs treated with 0.03 mg/kg and 0.02 mg/kg but slightly in dogs treated with 0.01 mg/kg. From these data, the existence of the optimum therapeutic dose of ouabain for cor pulmonale which increases myocardial contractility enough but has no significant pulmonary vasoconstrictive effect may be suggested. Then this dose of ouabain was given to acute experimental pulmonary hypertensive dogs (mean PA pressure 40-50 mmHg) due to recurrent miliary pulmonary embolization. The other group of pulmonary embolization was not treated with ouabain. Pulmonary vascular resistance was not increased in both groups, but myocardial contractility and cardiac output were increased significantly only in the ouabain treated group. In conclusion, though the dose-response relationship was observed in increasing myocardial contractility and pulmonary vasoconstriction by ouabain, the dose which increases myocardial contractility was less than that which evokes pulmonary vasoconstriction in normal and pulmonary hypertensive dogs.

Animals↗
PubMed1982

[Pulmonary circulation and right ventricular function in an experimental model of acute altitude-induced pulmonary edema].

The article deals with hemodynamic shifts that occur during the development of high-altitude pulmonary edema in rabbits. The principal hemodynamic disturbances occur in pulmonary circulation, while the main functional lead falls within the right heart. It was concluded that the increased pulmonary blood content and elevated pulmonary circulation pressure play a certain pathogenetic role in the origin of the syndrome under consideration.

Acute Disease↗
PubMed1989

Right ventricular function and high-frequency positive-pressure ventilation during coronary artery bypass grafting.

The hemodynamic and respiratory consequences of two modes of ventilation, conventional intermittent positive-pressure ventilation with a frequency of 10 cycles/min and high-frequency positive-pressure ventilation at 70 cycles/min were investigated before and after cardiopulmonary bypass in 6 patients having coronary artery bypass grafting. All patients were adequately ventilated with each mode. During prebypass and postbypass periods, the group with high-frequency ventilation had significantly lower peak airway pressures (p = 0.0001) and mean airway pressure (p less than 0.05). There were, however, no significant differences in right ventricular performance or pulmonary vascular resistance between the two modes of ventilation. No significant differences in other cardiovascular and respiratory variables were noted. High-frequency positive-pressure ventilation, with the advantage of quieter operating conditions and improved surgical access, can be safely applied when meticulous operation or hemostasis is required or during dissection of the internal mammary artery.

Adult↗
PubMed2004

Quantitative assessment of right ventricular systolic function by the analysis of right ventricular contrast time-intensity curve.

To study reliability and reliable indices of quantitative assessment of right ventricular systolic function by time-intensity curve (TIC) with right ventricular contrast, 5% sonicated human albumin was injected intravenously at a does of 0.08 ml/kg into 10 dogs at baseline status and cardiac insufficiency. Apical four-chamber view was observed for washin and washout of contrast agent from right ventricle. The parameters of TIC were obtained by curve fitting. The differences of parameters were analyzed in different states of cardiac functions. Among the parameters derived from TIC, the time constant (k) was decreased significantly with decline of cardiac function (P<0.001). But half-time of decent of peak intensity (HT) and mean-transit-time (MTT) of washout were increased significantly (P<0.001). The k was strongly related to cardiac output of right ventricle (CO) and ejection fraction (EF) of left ventricle and fractional shortening (FS) of left ventricle. Right ventricular systolic function could be assessed reliably by the parameters derived from TIC with right ventricular contrast echocardiography. The k, HT and MTT are reliable indices for quantitative assessment of right ventricular systolic function.

Animals↗
PubMedDate not supplied

Myocardial fibrosis and right ventricular function of heterotopically transplanted hearts in rats treated with cyclosporin.

The aim was to determine whether treatment of rats with cyclosporin A (CsA) leads to deleterious side effects on heterotopically iso- or allotransplanted hearts when compared with recipient native in situ hearts. Four experimental groups were employed: inbred (Lewis) rats receiving either no immunosuppression or CsA at a dose of 15 mg.kg-1 per day for 7 days after surgery, and outbred (Wistar) rats receiving CsA at the same daily dose for either 7 or 21 days. One month following surgery, the mass of all transplanted hearts decreased and resulting atrophy was associated with relative myocardial fibrosis. Treatment with CsA significantly increased the concentration and content of collagen in the right and left ventricles of all transplanted and recipient hearts. No appreciable difference was observed between corresponding hearts of inbred and outbred groups receiving the identical dose of CsA, and between hearts in outbred groups treated for either 7 or 21 days. No signs of right ventricular mechanical dysfunction, as assessed on the isolated perfused "working' preparation, were observed after CsA treatment in both transplanted and recipient hearts. The maximal steady state developed pressure (RVDevP) and the rate of its development [(+dP/dt)max] were slightly higher in transplants than in the corresponding recipients, and in CsA-treated versus untreated hearts, while the index of contractile state [(+dP/dt)/P] was similar in all groups. The data suggest that treatment of rats with CsA can induce a similar degree of fibrosis both in heterotopic cardiac transplants and in recipient native hearts without impairment of their contractile performance.

Animals↗
PubMed1981

[Right ventricular function in patients with transposition of the great arteries after atrial inversion (Mustard procedure) (author's transl)].

Twenty-nine patients with transposition of the great arteries (TGA) and intact ventricular septum underwent hemodynamic and angiocardiographic investigation 18,8 +/- 5,8 months after inflow correction (Mustard). The mean age at operation was 14,6 +/- 7,5 months and in all, a good anatomical result was achieved. The hemodynamic parameters such as cardiac index, pressures in all heart chambers as well as in the venous channels and arterial vessels were found within normal limits. The end-diastolic volume of the right ventricle (RVEDV) was closely correlated to body surface area (r = 0,697). It increased, however, more rapidly than in children with normal hearts. Mean RVEDV/m2 was 86 +/- 8 ml which is 123 +/- 10% of the normal values for children (70 +/- 13 ml) according to Graham et al. The mean ejection fraction (EF) of the right ventricle (58 +/- 7%) was only slightly below the normal range (65 +/- 7%). Thus, a good hemodynamic function of the RV can be assumed at least for the early postoperative years after a Mustard operation. It remains open, however, if the more rapid increase of RVEDV/m2 expresses the RV adjustment to the afterload of the systemic circulation or if this should be interpreted as an early sign of RV functional impairment.

Angiocardiography↗