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PubMedDate not supplied

[Simultaneous test of ventricular function and myocardial perfusion, during exercise, using a new agent labeled with Tc99m].

One a tribute of a Tc 99m labeled myocardial agent is the possibility to measure both ventricular function and myocardial perfusion with a single injection. To assess this, normal volunteers, 14 patients with coronary artery disease (CAD) and two suffering from cardiomyopathy with normal coronaries, were injected with 8-10 mci carbomethoxy-isopropyl-isonitrile or 20 mci Rp-30 Tc 99m at peak semi-recumbent bicycle exercise and again at rest. Thirty msec per frame first pass data, and 5 min static anterior, 40(0-) and 70(0-) left anterior oblique images were obtained. Standard Thallium 201 stress test were also done, within one month, and were at the same level of exercise. The left ventricular ejection fraction (EF) increased with exercise (69%-76%) in normal patients. All studies showed normal myocardial perfusion on exercise. In CAD patients the EF increased in some patients who had ischemia. Perfusion images with Tc 99m during exercise and at rest had an identical correlation with Thallium 201. The results support the concept of dual ventricular function and perfusion studies using a single Tc 99m labelled myocardial agent, and suggest that this could become the standard radionuclide stress tests in the future.

Angina Pectoris↗
PubMed1991

Influence of dialysate exchange on cardiac left ventricular function in children treated with CAPD.

The influence of peritoneal dialysate exchange on the ventricular function in 11 children on continuous ambulatory peritoneal dialysis (CAPD) therapy was studied before and after instillation dialysate. Systolic blood pressure, pulse rate, and echocardiographical data (shortening fraction and pre-ejection period/left ventricle ejection time-ratio) were obtained before and after instillation. There were no differences present with respect to the measured parameters after the abdomen was filled. It is concluded that in children treated with CAPD the exchange of normal volumes of dialysate has no influence on the function of the left ventricle.

Child, Preschool↗
PubMed1996

Cardiac sympathetic responses to acute vasodilation. Normal ventricular function versus congestive heart failure.

BACKGROUND: Although there is indirect evidence of impaired baroreflex control of sympathetic outflow directed at heart muscle, the regulation of cardiac sympathetic activity in the setting of heart failure is largely unexplored. We used the norepinephrine spillover method to address the hypothesis that baroreflex control of cardiac sympathetic activity is reduced in heart failure. METHODS AND RESULTS: Twenty-three patients were studied, 17 in a group with heart failure and 6 in a group with normal ventricular function. In both groups, cardiac norepinephrine spillover was assessed in response to nitroprusside infused to steady-state conditions. Nitroprusside resulted in significant reductions in mean systemic arterial pressure (normal group, -15 +/- 3% [mean +/- SEM]; heart failure group, -13 +/- 1%) and mean pulmonary artery pressure (normal group, -25 +/- 10%; heart failure group, -29 +/- 4%). In response to nitroprusside, there was a 98 +/- 16% increase in cardiac norepinephrine spillover in the normal group (from 81 +/- 10 to 159 +/- 25 pmol/min, P < .05). Despite similar hemodynamic responses to nitroprusside in the heart failure group, there was only a 28 +/- 14% increase in cardiac spillover (from 211 +/- 71 to 245 +/- 59 pmol/ min, P = NS), a response that was significantly smaller than that seen in the normal group. CONCLUSIONS: In patients with heart failure compared with subjects with normal ventricular function, there was a significantly smaller increase in cardiac sympathetic activity in response to a steady-state infusion of nitroprusside. This result provides evidence for reduced baroreflex control of cardiac sympathetic activity in heart failure.

Blood Pressure↗
PubMed1988

Evaluation of global and regional left ventricular function using two-dimensional and M-mode echocardiography in patients with an automatic implantable cardioverter defibrillator.

The effects of glued epicardial patch electrodes of the automatic implantable cardioverter defibrillator on the left ventricular function was studied by two-dimensional and M-mode echocardiography in 15 patients. Pre- and postoperative end-diastolic and end-systolic left ventricular cross-sectional areas were evaluated using planimetry. Regional left ventricular wall motion at the level of the left ventricular patch electrode was analyzed by two end-diastolic and end-systolic perpendicular axes. Left ventricular end-diastolic and end-systolic diameters as well as E-point-septal-separation and fractional shortening were analyzed using M-mode echocardiography. The mean time interval between preoperative echocardiograms and implantation of the automatic defibrillator was 0.3 X 1.3 (less than 1-2) months. Postoperative echocardiograms were recorded 6.6 +/- 6.9 (0.5-24) months after implantation of the device. There were no significant differences between pre- and postoperative mean values of end-diastolic and end-systolic areas and axes as well as M-mode echocardiographic parameters. Our data show that left ventricular patch electrodes do not significantly alter global or regional left ventricular function in patients after implantation of the automatic defibrillator.

Adult↗
PubMed1983

Effect of rate-dependent left bundle branch block on global and regional left ventricular function.

Seven subjects with rate-dependent left bundle branch block (RDLBBB) and 13 subjects with normal conduction (control group) underwent upright bicycle exercise radionuclide angiography to determine the effects of the development of RDLBBB on global and regional left ventricular function. Six of the seven subjects with RDLBBB had atypical chest pain syndromes; none had evidence of cardiac disease based on clinical examination and either normal cardiac catheterization or exercise thallium-201 scintigraphy. Radionuclide angiograms were recorded at rest and immediately before and after RDLBBB in the test group, and at rest and during intermediate and maximal exercise in the control group. The development of RDLBBB was associated with an abrupt decrease in left ventricular ejection fraction (LVEF) in six of seven patients (mean decrease 6 +/- 5%) and no overall increase in LVEF between rest and maximal exercise (65 +/- 9% and 65 +/- 12%, respectively). In contrast, LVEF in the control group was 62 +/- 8% at rest and increased to 72 +/- 8% at intermediate and 78 +/- 7% at maximal exercise. The onset of RDLBBB was associated with the development of asynchronous left ventricular contraction in each patient and hypokinesis in four of seven patients. All patients in the control group had normal wall motion at rest and exercise. These data indicate that the development of RDLBBB is associated with changes in global and regional ventricular function that may be confused with development of left ventricular ischemia during exercise.

Adult↗
PubMed2000

Magnetic resonance real-time imaging for the evaluation of left ventricular function.

New ultrafast gradient systems and hybrid imaging sequences make it possible to acquire a complete image in real time, without the need for breathholding or electrocardiogram (ECG) triggering. In 21 patients, left ventricular function was assessed by the use of a turbo-gradient echo technique, an echo-planar imaging (EPI) technique, and a new real-time imaging technique. End-diastolic and end-systolic volumes, left ventricular muscle mass, and ejection fraction of the ultrafast techniques were compared with the turbo-gradient echo technique. Inter- and intraobserver variability was determined for each technique. Image quality was sufficient for automated contour detection in all but two patients in whom foldover occurred in the real-time images. Results of the ultrafast imaging techniques were comparable with conventional turbo-gradient echo techniques. There was a tendency to overestimate the end-diastolic volume by 3.9 and 1.3 ml with EPI real-time imaging, the end-systolic volume by 0.9 and 5.0 ml, and the left ventricular mass by 2.6 and 23.8 g. Ejection fraction showed a tendency to be overestimated by 1.1% with EPI and underestimated by 4.5% with real-time imaging. Correlation between EPI real-time imaging and turbo-gradient echo were 0.94 and O.95, respectively, for end-diastolic volumes, 0.98 and 0.96, respectively, for end-systolic volumes, and 0.96 and 0.89, respectively, for left ventricular mass. Inter- and intraobserver variability was low with all three techniques. Real-time imaging allows an accurate determination of left ventricular function without ECG triggering. Scan times can be reduced significantly with this new technique. Further studies will have to assess the value of real-time imaging for the detection of wall motion abnornmalities and the imaging of patients with atrial fibrillation.

Analysis of Variance↗
PubMed2003

Prognostic value of combined assessment of regional left ventricular function and myocardial perfusion by dobutamine and rest gated SPECT in patients with uncomplicated acute myocardial infarction.

UNLABELLED: Gated SPECT allows combined assessment of regional myocardial perfusion and left ventricular function. The aim of this study was to address the prognostic value of gated SPECT performed during dobutamine stress testing and during rest on patients with acute myocardial infarction treated with thrombolysis. METHODS: Eighty-eight consecutive patients with uncomplicated acute myocardial infarction who underwent predischarge (3-7 d after admission) dobutamine (5-40 microg/kg of body weight per minute in 3-min dose increments) and rest gated (99m)Tc-sestamibi SPECT were followed for a mean of 48 mo (range, 4-64 mo). RESULTS: Eighteen cardiac events (8 cardiac deaths and 10 nonfatal myocardial infarctions) occurred. Ischemia at dobutamine SPECT imaging (summed difference score or=>or= 1) was present in 60% of the patients. In patients without ischemia, there was a lower event rate (11%), compared with patients with mild ischemia (18%) and moderate-to-severe ischemia (40%) (P < 0.05). Patients with events showed also a higher summed difference score, compared with patients without events (2.3 +/- 1.6 vs. 1.3 +/- 1.6, P < 0.05). Independent predictors of events were the number of segments with preserved (99m)Tc-sestamibi uptake at rest and the number of akinetic or dyskinetic segments with preserved (99m)Tc-sestamibi uptake and preserved wall thickening (global chi(2) of the model, 13.6; P < 0.01). The assessment of the incremental prognostic value of variables added sequentially showed that the addition of the summed difference score added information to perfusion status at rest (P < 0.05). Combined assessment of regional myocardial perfusion and left ventricular function at rest further improved the model (P < 0.05). CONCLUSION: The present study indicated that predischarge (99m)Tc-sestamibi gated SPECT gives prognostic information on patients recovering from acute myocardial infarction. Patients with preserved systolic wall thickening should be regarded as a high-risk subgroup, requiring closer follow-up for appropriate treatment.

Dobutamine↗
PubMed1986

Long term improvement in global left ventricular function after early thrombolytic treatment in acute myocardial infarction. Report of a randomised multicentre trial of intracoronary streptokinase in acute myocardial infarction.

The effect of reperfusion achieved by early intracoronary streptokinase in acute myocardial infarction on left ventricular function was studied in 533 patients enrolled in a prospective randomised multicentre study. Two hundred and sixty four patients were allocated to conventional treatment and 269 patients to thrombolysis. At the end of the procedure patency of the infarct related vessel was achieved in 198 (85%) of 234 patients in whom coronary angiography was performed. The median interval from onset of symptoms till the angiographic documentation of patency was 200 minutes. Data were analysed according to the original treatment allocation. Global left ventricular ejection fraction was determined by radionuclide angiography in 418 patients within two days of admission, in 361 patients after two weeks, and in 307 patients after three months. Global left ventricular function remained unchanged throughout the observation period in the control group, whereas it improved during the first two weeks in patients allocated to thrombolytic treatment. Improved function in these patients persisted up to three months after the infarction. Global left ventricular ejection fraction was significantly better in the thrombolysis group than in the control group at two days, two weeks, and at three months. In patients with anterior myocardial infarction the left ventricular ejection fraction was 9% better than in the control group at two weeks and at three months. In the patients with inferior myocardial infarction differences between the two treatment groups were smaller because of photon attenuation within the body. Angiographic evidence suggested that the improvement in function seen after thrombolysis is indeed associated with the patency of the infarct related artery.

Aged↗
PubMed1992

Effects of oral isradipine on left ventricular function at rest and during exercise in patients with stable chronic angina: a double-blind, placebo-controlled crossover study.

We evaluated the effects of a single oral dose of 5 mg of isradipine compared to placebo in a randomized, double-blind, crossover study using gated radionuclide angiography at rest and during exercise in 20 patients with stable chronic angina. Isradipine improved both anginal symptomatology and ST-segment depression during exercise, with a concomitant favorable effect on the isotopic parameters exploring systolic and diastolic left ventricular function. There was a marked increase of the ejection fraction during exercise with isradipine compared to placebo (61 +/- 14% vs. 55 +/- 15%, respectively, p less than 0.001) as well as a significant improvement in the peak ejection rate and the peak filling rate at rest [2.56 +/- 0.62 vs. 2.16 +/- 0.54 end diastolic volume (EDV) per second and 2.14 +/- 0.59 vs. 1.87 +/- 0.37 EDV/s, respectively] and during exercise (3.49 +/- 0.97 vs. 3.10 +/- 1.07 EDV/s and 4.05 +/- 1.34 vs. 3.65 +/- 1.25 EDV/s, respectively). We conclude that isradipine has a beneficial effect on the clinical and electrocardiographic signs of exercise-induced ischemia, leading to a significant improvement of the systolic and diastolic parameters of left ventricular function. Therefore, isradipine is potentially a useful treatment for patients with exertional angina and hypertension, alone or associated with beta blocker medication.

Adult↗
PubMed1997

Prognostic value of slow resolution of ST-segment elevation following successful direct percutaneous transluminal coronary angioplasty for recovery of left ventricular function.

Our objective was to investigate the significance of the slow resolution of ST-segment elevation following a successful direct percutaneous transluminal coronary angioplasty (PTCA). ST-segment elevations were calculated from electrocardiograms recorded before PTCA and 1 hour after reperfusion. Forty-nine patients experiencing their first anterior acute myocardial infarction and who had undergone direct PTCA were classified into 3 groups: 17 patients with rapid ST resolution (group I), 23 patients with persistent ST elevation (group II), and 9 patients with ST reelevation (group III). Left ventricular function was evaluated by using single-plane cineventriculography performed in the acute stage, at discharge, and 4 months later. Peak creatine kinase activity was significantly increased: group III (4,046 +/- 634 IU), group II (3,336 +/- 772 IU), and group I (2,410 +/- 994 IU); p <0.05. Ejection fraction and regional wall motion in the acute stage were identical in each group. However, they were significantly higher in group I (67 +/- 6%, -1.01 +/- 0.30), followed by group II (56 +/- 6%, -1.90 +/- 0.41) and group III (38 +/- 7%, -2.79 +/- 0.46); p <0.01 4 months later. Multiple regression analysis revealed that the ST resolution was the only significant variable that indicated the recovery of regional wall motion. A good linear correlation was documented between the ST resolution and the recovery of regional wall motion. We concluded that a slow ST resolution after successful direct PTCA is a negative predictor of recovery of left ventricular function, especially when ST reelevation is evident.

Aged↗
PubMed1987

Cardiac response to daily activities and exercise in normal subjects assessed by an ambulatory ventricular function monitor.

The cardiac response to a variety of daily activities was assessed in 18 healthy adult subjects (mean age 31 years, range 21 to 39) with an ambulatory ventricular function monitor (VEST), which records serial beat-to-beat radionuclide and electrocardiographic data. The VEST was positioned and calibrated using data recorded during a multigated blood pool scan. It was worn for an average of 3.0 +/- 1.1 hours, while the subjects performed the following activities: sitting quietly (baseline); standing in place; walking; climbing stairs; bicycle or treadmill exercise; eating; sitting in a room at 4 degrees C for 20 minutes; and urinating. To calculate ejection fraction (EF), relative end-diastolic counts, relative cardiac output and heart rate, the beat-to-beat data were averaged over 15 to 30 seconds. Compared with baseline, standing increased EF by 0.03 +/- 0.04 and decreased end-diastolic volume by 10.9 +/- 4.7%. Walking and climbing stairs increased EF by 0.10 +/- 0.05 and 0.18 +/- 0.09, respectively, and increased end-diastolic volume by 7.8 +/- 5.3% and 12.8 +/- 4.3% (p less than 0.001). Eating increased EF by 0.02 +/- 0.03 and decreased end-diastolic volume by 11.3 +/- 6.1% (p less than 0.001). Cold stimuli and urinating decreased EF by 0.05 +/- 0.04 and 0.03 +/- 0.04, respectively (p less than 0.001 and less than 0.05). Serial left ventricular function monitoring during graded bicycle and treadmill exercise revealed a rapid increase in EF in the early stages of exercise, with no further change in the late stages. Heart rate and systolic blood pressure increased progressively with each successive stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed2001

Reduction of exercise-induced myocardial ischemia during add-on treatment with the angiotensin-converting enzyme inhibitor enalapril in patients with normal left ventricular function and optimal beta blockade.

OBJECTIVES: We sought to study the effect of angiotensin-converting enzyme inhibition on exercise-induced myocardial ischemia. BACKGROUND: Although angiotensin-converting enzyme inhibitors have been shown to reduce ischemic events after myocardial infarction, few data are available regarding their direct anti-ischemic effects in patients with coronary artery disease. METHODS: We studied 43 patients (average age 63 +/- 8 years) with exercise-induced myocardial ischemia (> or =0.1 mV ST depression, despite optimal beta blockade) and normal left ventricular function (ejection fraction >0.50). In a double-blind, placebo-controlled parallel design, patients were treated with angiotensin-converting enzyme inhibitor (enalapril 10 mg twice daily) or placebo. Assessments were made after three weeks (short-term) and 12 weeks (long-term). RESULTS: At baseline, the groups were well matched for all clinical characteristics. After three weeks, there was a slight but not significant increase in time to 0.1 mV ST depression in both groups (p = NS); rate pressure product (RPP = heart rate x systolic blood pressure) was also unaffected. After 12 weeks, however, time to 0.1 mV ST depression further increased in the enalapril group (5.6 +/- 1.9 min) but was unchanged in the placebo group (4.4 +/- 1.3 min; p < 0.05 between groups). In contrast, RPP was not affected. Concentrations of both atrial and brain natriuretic peptides at peak exercise tended to be lower by enalapril, if compared to placebo (p = NS). CONCLUSIONS: Angiotensin-converting enzyme inhibition may reduce exercise-induced myocardial ischemia in patients with normal left ventricular function. Further studies are needed to elucidate the mechanisms involved.

Adolescent↗
PubMed1998

Protein kinase C inhibition improves ventricular function after thermal trauma.

OBJECTIVE: To examine the effect of protein kinase C (PKC) inhibition on cardiac performance and intracellular Ca2+ homeostasis. DESIGN: Previous studies have shown that trauma impairs cardiac mechanical function, and recent studies suggest that PKC activation and subsequent perturbations in Ca2+ sequestration/release contribute to this cardiac dysfunction. In this study, anesthetized guinea pigs were given third-degree scald burns over 43 +/- 1% of the total body surface area and resuscitated with lactated Ringer's solution (LR) 4 mL/kg per percent of burn, Parkland formula. Animals with sham burns served as controls (n = 18). Burns were randomly divided into two groups: LR alone (N = 18) or LR + PKC inhibitor, calphostin C (0.1 mg/kg, intravenous bolus), given 30 minutes and 3, 6, and 21 hours after burn (n = 18). MATERIALS AND METHODS: Cardiac function was assessed by Langendorff preparation 24 hours after burn in 8 to 12 animals per group. Intracellular calcium concentration ([Ca2+]i) was measured in cardiac myocytes (collagenase digestion) from additional animals in each experimental group (n = 5-9 per group) after Fura-2 AM loading of myocytes; fluorescence ratios were measured with a Hitachi spectrofluorometer. RESULTS: Cardiac dysfunction occurred 24 hours after burn in LR burns as indicated by lower left ventricular pressure and a reduced rate of left ventricular pressure rise and fall, +/-dP/dt (61 +/- 3 mm Hg, 1,109 +/- 44 mm Hg/s, and 880 +/- 40 mm Hg/s, respectively) compared with values measured in sham-burned animals (86 +/- 2 mm Hg, 1365 +/- 43 mm Hg/s, and 1183 +/- 30 mm Hg/s, respectively; p < 0.05). Ventricular function curves confirmed significant postburn contractile depression despite aggressive fluid resuscitation. Cardiac injury in burned animals was indicated by an increase in perfusate creatine kinase and lactate dehydrogenase, and Ca2+ dyshomeostasis was confirmed by increased myocyte [Ca2+]i (sham 151 +/- 6 vs. burn 307 +/- 20 nmol/L, p < 0.05). PKC inhibition improved all indices of cardiac performance, producing left ventricular pressure (82 +/- 3 mm Hg), +/-dP/dt (1,441 +/- 48 and 1,294 +/- 32 mm Hg/s), and left ventricular function curves that were comparable with those of sham-burned animals. In addition, [Ca2+]i in calphostin-treated burned animals (154 +/- 11 nmol/L) was identical to values in sham-burned animals. CONCLUSION: Our data suggest that PKC may serve as a final common pathway in signal transduction events mediating postburn cardiac dysfunction.

Animals↗
PubMed1991

Ventricular function during the acute rejection of heterotopic transplanted heart: gated blood-pool studies.

Twenty patients who had undergone a heterotopic heart transplant were studied prospectively to determine the relationship between rejection and ventricular dysfunction assessed from gated blood-pool studies. A fully automated method for detecting ventricular edges was implemented; its success rate for the grafted left and right ventricles was 94% and 77%, respectively. The parameters, peak ejection and filling rates, were calculated pixel per pixel using a two-harmonic Fourier algorithm and then averaged over the ventricular region of interest. Peak filling and ejection rates were closely related with the severity of the rejection, while the left ventricular ejection fraction was not. Peak filling rates of both ventricles were the indices closely related to the presence of moderate rejection. Despite the low number of patients, these data suggested that gated blood-pool-derived indices of ventricular function are associated with ventricular dysfunction resulting from myocarditis rejection. Radionuclide ventriculography provides parametric data which are accurate and reliable for the diagnosis of rejection.

Algorithms↗
PubMed1993

Intracoronary papaverine but not adenosine reduces regional ventricular function.

OBJECTIVES: Whether intracoronary papaverine or adenosine leads to reductions in regional left ventricular function was tested. METHODS: Fifteen anaesthetised dogs were prepared to record aortic pressure, left ventricular pressure dP/dt, electrocardiogram, regional ventricular shortening, and phasic and mean left circumflex coronary blood flow, and to give intracoronary boluses of papaverine (2, 4, or 6 mg) or adenosine (0.37 and 1.87 mg). RESULTS: Injected doses were chosen to mimic those given in the clinical setting. Papaverine (6 mg) reduced aortic pressure (mean 96(SD 17) to 89(18) mm Hg; p < 0.05), segmental shortening of the infused left circumflex zone (12(5) to 7(9)%; p < 0.05), and area of the pressure-length loop of the infused zone (120(71) to 53(47) mm.mm Hg; p < 0.05). Papaverine increased coronary blood flow (48(25) to 259(95) ml.min-1; p < 0.05), coronary vascular conductance (0.40(0.20) to 2.93(0.94) ml.mm Hg-1.min-1; p < 0.05), heart rate (88(27) to 100(28) beats.min-1; p < 0.05), and the segmental shortening (17(6) to 19(3)% p < 0.05) and area of the pressure-length loop (130(32) to 177(33) mm.mm Hg; p < 0.05) of the non-infused left anterior descending region. The hyperaemia elicited by papaverine was greater than that of reactive hyperaemia (p = 0.008). Papaverine also increased the QT interval corrected for heart rate (0.35(0.04) to 0.45(0.05) s; p < 0.05). When adenosine was given, coronary blood flow and coronary vascular conductance were increased to similar degrees as those during reactive hyperaemia (41(12) to 210(75) ml.min-1 and 0.46(0.14) to 2.43(0.83) mm Hg.ml-1.min-1, respectively; NS). No effects on segmental shortening or the area of the pressure-length loop in either zone were found. Also, adenosine had no effect on the QT interval. CONCLUSIONS: These adverse effects of intracoronary papaverine have important implications in its use in patients, particularly in those in whom abnormal cardiac function already exists. Adenosine, on the other hand, seems to be without deleterious effects.

Adenosine↗
PubMed1997

[Assessment of left ventricular function by pressure-volume loop in VSD and TOF before and after operation].

This study estimates the perioperative left ventricular function of VSD and TOF by using Pressure-Volume (PV) loop. The most characteristic hemodynamic change of VSD is a decreased volume load. Although ejection fraction significantly decreased after the operation, this change did not mean a deteriorated left ventricular contractility. Emax, which is an index of left ventricular contractility on PV loop, improved and pressure-volume area (PVA) which is correlated with 02 consumption of left ventricule was reduced. Mechanical efficiency of left ventricular energetic state did not significantly change. Left ventricular volume and ejection fraction in TOF slightly increased after the operation. Increased ejection fraction reflected a compensation to volume overload after surgery. Emax slightly decreased and PVA increased. Meanwhile mechanical efficiency increased after the operation indicating well preserved ventricular contractility. In particular, the shape of PV loop of both VSD and TOF eventually became usual square after operation due to recover of the isovolumic contraction and relaxation phase. These characteristics had better to be concerned for improvement of surgical techniques as in conotruncal repair, particularly in TOF in the setting of better quality of life with low atrial pressure.

Child↗
PubMed1991

The effect of acute hypoxia on right ventricular function in healthy adults.

Right ventricular ejection fraction and right ventricular volumes were derived in 12 healthy male subjects using krypton-81m equilibrium radionuclide ventriculography whilst subjects breathed 30% (high inspired oxygen) and then 8-12% oxygen in nitrogen mixture (hypoxia). 'Physiological' tricuspid valve regurgitation was identified in 7 of the subjects by Doppler echocardiography, and right ventricular peak systolic pressure was estimated during high inspired oxygen and during hypoxia. Mean right ventricular peak systolic pressure was 24.1 +/- 3.3 mmHg during high inspired oxygen and increased to 41.3 +/- 8.4 mmHg during hypoxia (P less than 0.01). Mean right ventricular ejection fraction was 0.612 +/- 0.075 during high inspired oxygen and was unchanged at 0.590 +/- 0.073 during hypoxia. There was no significant change in right ventricular end-diastolic volume or stroke volume in response to hypoxia. The systolic performance of the normal right ventricle is well-maintained during an acute rise in afterload induced by hypoxia.

Acute Disease↗