Noninvasive analysis of cardiac function of elite distance runners--echocardiography, vectorcardiography, and cardiac intervals.
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Cardiomegaly↗
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A computer-assisted image processing method for determining relative cardiac function in the chick embryo.
The general objective of this study was to develop a noninvasive method for efficiently and reproducibly determining relative cardiac function parameters in the chick embryo. The specific objectives of the study were 1) to develop several methods for computer-assisted image processing and quantitation of relative intraventricular blood volumes in the 3-day-old embryonic chick heart and 2) to compare methods for precision and with a previously established manual processing method. Images of the embryonic chick heart in ovo were recorded on videocassette tape, digitized, and enhanced by computer-aided histogram equalization. The area occupied by blood within the common ventricle was extracted by region-growing and spurious region removal algorithms and defined by the determination of edge-pixel coordinates. Edge-pixel coordinates of the longitudinal and transverse axes of the common ventricular blood region were located by three different methods, the lengths of the axes calculated, and volumes computed from the equation for determining volume of a prolate spheroid. Twenty-five images of the embryonic heart were randomly selected and processed. Volumes were calculated with each of the three methods on six different occasions. A coefficient of variation was calculated for each method. The intraobserver mean coefficient of variation for each method was 7.4%. When a 2-way ANOVA was conducted, mean coefficients of variation did not differ significantly for the three methods. However, computer processing (in addition to significantly reducing the time required to generate data) reduced the coefficient of variation observed in manual processing by 56.5%.
Analysis of Variance↗
Noninvasive assessment of cardiac function and pulmonary hypertension in persistent pulmonary hypertension of the newborn.
This article describes the application and limitations of noninvasive techniques to assess cardiac function and to diagnose pulmonary hypertension in newborn infants in whom PPHN is suspected.
Echocardiography↗
Subclinical disturbances in cardiac function at rest and in gas exchange during exercise are common findings after autologous bone marrow transplantation.
A study was undertaken to examine the effects of autologous bone marrow transplantation (BMT) on cardiac function at rest (n = 111) and pulmonary gas exchange during exercise (n = 110). Left ventricular cardiac ejection fraction (LVEF) was measured by radionuclide ventriculography before autologous BMT and after 6 months and 1, 3 and 5 years. Expired gas volume per oxygen consumption (VE/VO2) and transcutaneous PO2 were measured at rest and during submaximal exercise before and 6 and 12 months after autologous BMT, and the alveolar-arterial oxygen difference was calculated after 12 months. In lymphoma patients conditioned with BCNU, cyclophosphamide, etoposide and cytarabine, a long-lasting reduction in LVEF of 11 +/- 14% mean (+/- SD) was noted. The risk of cardiac deterioration was not increased by a subnormal LVEF before autologous BMT or total body irradiation (TBI). Impaired gas exchange during exercise was a common feature, but severe disturbances were uncommon. During exercise transcutaneous PO2 fell pathologically in 15% and 20% of the patients examined after 6 and 12 months, respectively, and the alveolar-arterial oxygen difference increased pathologically in 50% after 12 months. The VE/VO2 ratio increased significantly during exercise 6 months after autologous BMT in TBI-treated patients.
Adolescent↗
Evaluation of cardiac function with magnetic resonance imaging.
A large body of evidence has accumulated to substantiate the accuracy of functional MR measurements of both ventricles. Because of good accuracy and superior reproducibility, MR imaging may be considered the gold standard for in vivo quantification of left and right ventricular ejection fraction, myocardial mass, and wall stress. New prospects for functional MR imaging include determination of the end-systolic volume-pressure relation as an index of myocardial contractility. The ability of MR imaging to detect wall motion disturbances may be enhanced further by combining myocardial tagging techniques with finite element analysis. Conventional MR imaging is limited by long examination times, but recent ultrafast modifications of echo-planar imaging allow completion of a functional heart study within seconds. Implementation of ultrafast MR imaging will greatly increase the usefulness of MR imaging for routine evaluation of cardiac function.
Cardiac Volume↗
Effects of acetate and bicarbonate hemodialysis on cardiac function in chronic dialysis patients.
Previous studies have suggested that acetate hemodialysis causes myocardial depression. This study examines the acute effects of hemodialysis using, alternately, bicarbonate and acetate in the dialysate, on cardiac function in ten patients. These patients were also studied during acetate dialysis using a large surface area (SA) dialyzer. Each patient was dialyzed for 4 hr with: (1) 1.0 m2 SA dialyzer and bicarbonate dialysate; (2) 1.0 m2 SA dialyzer and acetate bath, and; (3) 2.5 m2 SA dialyzer and acetate dialysate. All studies were performed during isovolemic dialysis to separate the effects of changes in cardiac filling volume with hemodialysis, from changes in myocardial contractility. Myocardial function, as assessed by pre- and postdialysis echocardiographically derived fractional shortening (Fs) and mean velocity of circumferential shortening (VCF), improved (P less than 0.05) to the same extent, after all three dialysis treatments. This occurred despite greater increases (P less than 0.002) in pH and bicarbonate after bicarbonate dialysis and decreases (P less than 0.05) in PO2, PCO2 and bicarbonate after acetate dialysis with 2.5 m2 SA dialyzer. These results indicate that diffusive dialysis with both acetate and bicarbonate dialysate improves myocardial function and do not support the view that acetate influx during dialysis can lead to myocardial depression.
Acetates↗
Pacing techniques in assessing cardiac function in the horse.
The problem of transitory cardiac arrhythmias in equidae is discussed particularly with regard to the referral of suspect cases to specialist institutions for second opinion. Recently developed electro-stimulation techniques designed to uncover problem arrythmias, are briefly described and their potential in the analysis of cardiac electrical function under varying conditions is reviewed. The author cautions on the too rapid evaluation of the techniques for this purpose while remaining optimistic of the potential of electro-stimulation in the objective analysis of cardiac electric parameters.
Animals↗
Acute effects of intravenous nicardipine on hemodynamics and cardiac function in patients with a healed myocardial infarction and no evidence of congestive heart failure.
Acute effects of intravenous nicardipine (10 micrograms/kg) on systemic hemodynamics and cardiac function were evaluated in 17 patients with a healed myocardial infarction and no evidence of congestive heart failure. Mean New York Heart Association functional class was 1.6 +/- 0.5 (mean +/- standard deviation). Aortic systolic pressure (p less than 0.001) and left ventricular end-diastolic pressure decreased (10 +/- 3 to 8 +/- 3 mm Hg, p less than 0.01), and systemic vascular resistance decreased significantly (p less than 0.001), whereas pulmonary and right atrial pressure and pulmonary arteriolar resistance did not change. Cardiac and stroke indexes showed biphasic changes. Although positive and negative maximal rate of left ventricular pressures decreased significantly (p less than 0.05 and p less than 0.01, respectively), they did not change significantly when aortic systolic pressure was corrected. There was a significant inverse correlation between the negative rate of left ventricular pressure/aortic systolic pressure before nicardipine infusion and its maximal percent increase after infusion (r = -0.56, p less than 0.05), indicating a beneficial effect on diastolic relaxation in patients with impaired diastolic function. Our data show that a low dose (10 micrograms/kg) of intravenous nicardipine exerts a favorable effect on impaired diastolic function, but depresses left ventricular pump function with much less effect on right heart circulation.
Adult↗
Effect of slow-release ISDN on cardiac function in patients with coronary heart disease during bicycle ergometry.
In 10 patients with coronary heart disease (CHD), the effect of a single doses of slow-release isosorbide dinitrate (ISDN) on cardiac function was investigated. Haemo-dynamics was examined by right heart catheterization and thermodilution measurement of cardiac output. After placebo and after 2 and 6 hours with 40 mg ISDN, the heart rate (HR), cardiac index (CI), pressure values in the pulmonary artery (PASP, PAMP, PAEDP) and in the aorta (AoSP, AoMP, AoEDP) and systemic vascular resistance (SVR) were measured at rest and during bicycle ergometry. At rest, PASP and PAMP were significantly reduced only 6 hours after ISDN. Under exercise conditions, significantly reduced pressure values in the pulmonary artery were found 2 and 6 hours after ISDN. AoSP was likewise reduced 2 and 6 hours after ISDN. HR, CI and SVR showed no significant differences compared with placebo values. Thus, an effective reduction of left ventricular preload and afterload was seen in patients with CHD during bicycle ergometry.
Adult↗
Effects of pyridoxalated hemoglobin polyoxyethylene conjugate and stroma-free hemoglobin on cardiac function in isolated rat heart.
Effects of a newly introduced modified hemoglobin, pyridoxalated hemoglobin polyoxyethylene conjugate (PHP), and stroma-free hemoglobin (SFH) on cardiac rhythm and contractility were examined in isolated rat hearts. Hearts were perfused with HEPES-buffered Krebs solution containing 6% PHP, 6% SFH, or 6% hydroxyethylstarch (HES). Arrhythmia was not observed in PHP-perfused hearts, but marked sinus bradycardia occurred in SFH-perfused hearts. Ventricular contractility assessed by left ventricular pressure and pressure-volume relationship in both PHP and SFH-perfused hearts were well maintained during perfusion. There was no significant difference to the coronary flow resistance between hearts perfused with PHP and HES solutions, indicating that PHP has little vasoactive effect. The flow resistance in SFH-perfused hearts decreased significantly when compared with other groups. Results demonstrate that PHP solution can preserve cardiac function and have no toxic effects in isolated rat hearts.
Animals↗
[Relationship between 123I-BMIPP imaging and cardiac function in acute myocardial infarction].
We evaluated the relationship between free fatty acid metabolism using 123I beta-methyl-iodophenyl pentadecanoic acid (BMIPP) and cardiac function in acute myocardial infarction. Twenty-five patients were examined with 123I-BMIPP and 201Tl dual SPECT. The 123I-BMIPP images were compared with the 201Tl images and the left ventricular wall motions. The 123I-BMIPP images showed a larger uptake defect than the 201Tl images. This was marked in the patients after revascularization therapy. The uptake decrease of 123I-BMIPP was in good agreement with the decrease in regional wall motion. The incidence of accordance was 79% of the wall segments. The correlation between 123I-BMIPP defect size and ejection fraction was higher (r = -0.54) than that of 201Tl (r = -0.44). Subtraction of ejection fractions four weeks and soon after infarction correlated well with the subtraction of 123I-BMIPP and 201Tl defect sizes (r = 0.55). In conclusion, 123I-BMIPP is more closely related to wall motion, than 201Tl and might be valuable in predicting the functional improvement of acute myocardial infarction.
Adult↗
Radionuclide assessment of cardiac performance in cystic fibrosis. Reproducibility and effect of theophylline on cardiac function.
A study was designed to evaluate the reproducibility of right and left ventricular ejection fraction measurements (RVEF, LVEF) by equilibrium radionuclide angiography in cystic fibrosis (CF) and to determine the effect of the acute administration of aminophylline on RVEF and LVEF in this disease. Both RVEF and LVEF were measured at rest and during incremental supine bicycle exercise by equilibrium radionuclide angiography in 18 patients with CF. In 9 of these patients, radionuclide studies were repeated after an infusion of aminophylline (9 mg/kg), whereas the remaining patients had radionuclide studies repeated after a placebo infusion. No significant increase in mean RVEF or LVEF values either at rest or at peak exercise was seen after aminophylline infusion. In the patients who underwent sequential radionuclide studies without intervening active drug intervention, the mean (+/- standard deviation) variability in RVEF and LVEF measurements between the 2 studies was 2.6 +/- 2% and 3.6 +/- 2.9%, respectively. We conclude that (1) equilibrium radionuclide angiography is a reasonably reproducible technique for serial assessment of biventricular function at rest and during exercise in CF, and that (2) the acute administration of aminophylline does not augment cardiac function either at rest or during exercise in this disease.
Adolescent↗
Direct assessment of cardiac function.
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Cardiac Catheterization↗
Clinical evaluation of cardiac function by ambulatory ventricular scintigraphic monitoring (VEST): validation and study of the effects of nitroglycerin and nifedipine in patients with and without coronary artery disease.
Global left ventricular function and ECGs were continuously monitored by radionuclide ambulatory ventricular function monitoring (VEST) and validated against multigated blood pool analysis (MUGA) and left ventriculography in 26 subjects (study 1). Ejection fraction by VEST (Y) showed good correlation with Y = 5.5 +/- 0.79 X (r = 0.91), Y = 1.7 +/- 0.86 X' (r = 0.91), and Y = 11.6 + 0.68 X" (r = 0.82) to sitting and supine MUGA and left ventriculography, respectively. In study 2 left ventricular function and ECGs were evaluated at rest and during exercise without any drug (control), with nitroglycerin, and with nifedipine in 21 patients with coronary disease (group I) and six normal subjects (group II). In group I abnormal ejection fraction responses (exercise increase less than or equal to 6%) during the control exercise period were found in 15 patients (71%), ST segment abnormalities in seven (33%), and chest pain in four (18%). Control exercise increased end-diastolic volume (100 to 112 +/- 8%) and end-systolic volume (53 +/- 15% to 63 +/- 22%) and decreased the ejection fraction (47 +/- 15% to 43 +/- 21%). The ejection fraction during exercise increased after nitroglycerin (50 +/- 22%) or nifedipine (54 +/- 21%) (p less than 0.05). In group II the ejection fraction was unchanged between rest and exercise with or without nitroglycerin or nifedipine. Thus combined radionuclide and ECG monitoring by VEST could detect changes in left ventricular function at rest and during exercise over a prolonged period and demonstrated that nitroglycerin and nifedipine improved cardiac function in the ischemic setting with an increased ejection fraction in the upright position.
Coronary Disease↗
Short-term responses to cardiac rehabilitation after acute myocardial infarction. Cardiac function evaluation before and after physical training at rest and during stress test.
Whether physical training, soon after myocardial infarction (MI), has effects upon intrinsic cardiac function at rest and during exertion remains unresolved. We have evaluated ventricular function using radionuclide angiography at rest and during stress testing before and after 3 months' physical training. This has been correlated with the site of MI and with changes in the ST segment during the maximal exercise test performed before the postmyocardial infarction rehabilitation program. We have studied 27 patients, mean age 54 +/- 10 years, in NYHA class I or II. Twelve showed no changes in the ST segment during erogmetric stress test (group 1); seven showed ST segment depression greater than 1 mm in leads different from those of MI (group 2); eight showed ST segment elevation of 2 mm (group 3). Twelve patients had had anterior MI only (AMI group); twelve inferior MI only (IMI group). After rehabilitation, all patients showed an increased work capacity and a decreased double product at the same work load. In the total group, significant increases were found in the left ventricular ejection fraction (LVEF) and in the contractile regional performance (LVwm) at rest, as well as a lesser decrease in the LVEF during handgrip test. Group 1 showed a significant increase in LVEF, associated with a decrease in left ventricular end-diastolic volume (EDV) at rest. Group 2 showed unchanged variables after rehabilitation. Group 3 showed a better LVEF during handgrip with an increase of EDV at rest. The AMI group showed a better LVEF and LVwm at rest and a better LVEF during handgrip. IMI group showed a better right ventricular ejection fraction during handgrip without improvement in LVEF. No patient with IMI had septal asynergy. We conclude that the effects of rehabilitation were linked to the site of MI and to the functional dynamic status of both ventricles.
Electrocardiography↗
Systemic hemodynamic and cardiac function changes in patients undergoing orthotopic liver transplantation.
The objective of this study was to determine the changes in systemic hemodynamics (systemic vascular resistance [SVR], cardiac output [CO], systemic blood pressure [SBP]) and cardiac function (pulmonary artery pressure [PAP] and pulmonary wedge pressure [PWP]) during the 96 hours following orthotopic liver transplantation (OLT) and correlate these with changes in hepatic and renal function and patient outcome. The study took place in a 12-bed medical respiratory intensive care unit in a large teaching hospital. Twenty-one patients had OLT performed over a 21.5-month period (January 1988 to October 15, 1989) for end stage liver disease (ESLD) from a variety of causes. A flow-directed right heart catheter and an indwelling arterial cannula were inserted for hemodynamic monitoring over a 96-hour postoperative period. Liver and renal function studies, total serum calcium, serum albumin, and fluid balance were determined daily. The SVR increased significantly to 12.8 +/- 0.6 U at 48 hours compared with immediate (less than 8 hours) postoperative levels (p less than 0.05) and remained elevated for 96 hours. The CO fell progressively and was significantly lower than baseline values from 64 to 96 hours. There was significant inverse correlation between the increase in SVR and the fall in CO (r = .85, p less than 0.01). The SBP was stable except for a small, but significant fall at 16 and 24 hours postoperatively. The PWP increased significantly from a baseline value of 12.5 +/- 0.9 mm Hg to 15 +/- 0.9 mm Hg at 32 hours and remained elevated through 96 hours (p less than 0.05). The serum bilirubin level fell progressively postoperatively and the prothrombin time and partial thromboplastin time (PTT) shortened significantly. Bile flow increased progressively from 107 +/- 120 ml/24 hours at the end of the first 24 hours to 188 +/- 125 ml/24 hours by 96 hours postoperatively. Five patients died from nine to 43 days postoperatively. These patients' hemodynamic parameters were not significantly different from the patients who survived. Successful OLT is associated with a rapid increase in SVR and a fall in CO without changes in SBP. These findings tend to parallel the improvement found in results of liver function tests. However, there is no correlation between the improvement in the hemodynamic state and long-term survival.
Adult↗
Early adaptations in gas exchange, cardiac function and haematology to prolonged exercise training in man.
In order to determine the effect of short-term training on central adaptations, gas exchange and cardiac function were measured during a prolonged submaximal exercise challenge prior to and following 10-12 consecutive days of exercise. In addition, vascular volumes and selected haematological properties were also examined. The subjects, healthy males between the ages of 19 and 30 years of age, cycled for 2 h per day at approximately 59% of pre-training peak oxygen consumption (VO2) i.e., maximal oxygen consumption (VO2max). Following the training, VO2max (l.min-1) increased (P less than 0.05) by 4.3% (3.94, 0.11 vs 4.11, 0.11; mean, SE) whereas maximal exercise ventilation (VE,max) and maximal heart rate (fc,max) were unchanged. During submaximal exercise, VO2 was unaltered by the training whereas carbon dioxide production (VE) and respiratory exchange ratio were all reduced (P less than 0.05). The altered activity pattern failed to elicit adaptations in either submaximal exercise cardiac output or arteriovenous O2 difference. fc was reduced (P less than 0.05). Plasma volume (PV) as measured by 125I human serum albumin increased by 365 ml or 11.8%, while red cell volume (RCV) as measured by 51chromium-labelled red blood cells (RBC) was unaltered. The increase in PV was accompanied by reductions (P less than 0.05) in haematocrit, haemoglobin concentration (g.100 ml-1), and RBCs (10(6) mm-3). Collectively these changes suggest only minimal adaptations in maximal oxygen transport during the early period of prolonged exercise training. However, as evidenced by the changes during submaximal exercise, both the ventilatory and the cardiodynamic response were altered.(ABSTRACT TRUNCATED AT 250 WORDS)
Adaptation, Physiological↗
Improved recovery of cardiac function after 24 h of hypothermic arrest in the isolated rat heart: comparison of a prostacyclin analogue (ZK 36 374) and a calcium entry blocker (diltiazem).
The effects of a stable prostacyclin analogue (ZK 36 374; 4 nM) and a calcium entry blocker (diltiazem; 50 nM) on the recovery of cardiac function after 24 h of hypothermic (10 degrees C) cardiac arrest were studied in the isolated rat heart. Recovery of the pressure-rate index of treated hearts was significantly better [59 +/- 10% for diltiazem (p less than 0.05) and 51 +/- 7% for ZK 36 374 (p less than 0.05)] than in untreated hearts (27 +/- 9%). Untreated hearts had second- and higher-degree atrioventricular block, with an average ventricular rate of 60 +/- 6% of control. All drug-treated hearts, however, were in sinus rhythm at their initial frequency without a significant alteration in PQ interval. Moreover, the incidence of severe arrhythmias was significantly reduced by ZK 36 374 (p less than 0.02) and diltiazem (p less than 0.01). ZK 36 374 reduced total purine overflow upon reperfusion (503 +/- 51 vs. 223 +/- 22 nmol min-1 g dry weight-1; p less than 0.0005). The delayed overflow of adenosine, a proposed marker of reperfusion damage, was not affected by ZK 36 374 treatment. In contrast, diltiazem had no effect on total purine overflow upon reperfusion, but nearly abolished delayed adenosine overflow. It is concluded from these results that both ZK 36 374 and diltiazem improve myocardial recovery after 24 h of hypothermic cardiac arrest.
Adenosine↗