Right Ventricular Ejection Research Articles

Optimized assessment of both left and right ventricular parameters from multi-slice acquisitions of single orientations using reconstructed 3D cine data

Background The assessment of global left-ventricular (LV) parameters from a stack of multiple slices is usually performed in short-axis orientation, whereas transversal orientation is commonly preferred for the assessment of right-ventricular (RV) parameters. Other choices carry the risk of inaccuracies due to hindered delineation of valvular planes. The purpose of our study was to reconstruct 3D cine data sets in short-axis orientation from transversal image data and vice versa, and to assess the accuracy of global LV and RV parameters derived from these reconstructed data sets as compared to that from data sets with targeted acquisition in both orientations. Methods In 10 patients with congenital heart disease (age 16 to 46 years, 4 male), multi-slice cine data sets encompassing both ventricles were acquired in both short-axis and transversal orientation (balanced steady-state free precession, 30 phases, slice thickness 6 mm, no inter-slice gap). LV and RV end-diastolic volumes (EDV), end-systolic volumes (ESV), and ejection fraction (EF) were derived from the acquired data sets. Using a custombuilt CMR analysis program (CAIPI), transversal data sets were reconstructed from images acquired in shortaxis orientation, and short-axis data sets were reconstructed from images acquired in transversal orientation. The same biventricular parameters were then derived from the reconstructed data sets using a semi-automatic contour detection tool from CAIPI. Results On the acquired data sets, mean differences between ventricular parameters as assessed from short-axis and transversal orientation ranged from 0.4+/-10.4% (RV EF) to 12.3+/-9.7% (RV ESV). Bland-Altman comparison showed better agreement between LV parameters derived from reconstructed short-axis and acquired short-axis data sets than between acquired transversal and acquired short-axis data sets. In concordance, there was higher agreement between RV parameters derived from reconstructed transversal and acquired transversal data sets than between acquired short-axis and transversal data sets. Conclusions

Effect of Testosterone and Resistance Training on Cardiac Mass and Contractility in Men with COPD

Introduction: Testosterone therapy and resistance training have been demonstrated to improve muscle mass and strength in patients with testosterone deficiency. However the effects on cardiac mass and contractility of these interventions have not been identified in prospective placebo-controlled trials. The hypothesis of this trial was that resistance training and testosterone replacement would improve cardiac mass and contractility in male COPD patients with low testosterone levels. Methods: We conducted a 10 week trial in a 2 by 2 factorial design, randomizing 53 patients to replacement doses of testosterone enanthate (100 mg weekly) or placebo, as well as to a program of lower extremity resistance training or no exercise. We performed rest and exercise cardiac computed tomography (CCT) studies before and after 10 weeks of therapy to evaluate right and left heart function. Patients were injected with 40-50 ml of non-ionic, iodinated contrast and cine CCT images were obtained at rest. Patients were exercised to 60% of their maximal work rate on a semi-supine ergometer, then re-injected with another bolus of 40-50 ml of contrast and re-imaged. We evaluated cardiac output and left ventricular (LV) and right ventricular (RV) mass, LV and RV stroke volume, ejection fractions and end-diastolic volumes at rest and exercise, before and after therapy. Results: 42 men with COPD (mean FEV1=40%pred. pre-bronchodilator) and low testosterone levels (mean=320ng/dl) completed the 10 week protocol. Factorial analysis demonstrated that testosterone, but not resistance training increased LV and RV mass (by 4.9% and 8.3%, respectively). Resistance training, but not testosterone, was associated with increased LV ejection fraction at rest and during exercise (by 5.5% and 4.4%, respectively). In the entire study group, increases in both left and right ventricular mass were correlated with increases in lean body mass (assessed by DEXA) (r=0.49 and r=0.65, respectively). Conclusions: In men with COPD, testosterone replacement and strength training are associated with distinct alterations in cardiac structure and function. Specifically, resistance training improved ejection fraction, while testosterone increased lean body mass and LV mass.

Cardiopatía congénita con estenosis pulmonar y comunicaciones intracardiacas asociadas en adulto: tratamiento anestésico

A 66-year-old man with complex congenital heart defects (atrial septal defects, with incomplete cor triatriatum, an aneurysmal sac in the membranous septum, ventricular communication and pulmonary valve stenosis) was scheduled for surgery for progressive dyspnea even at rest. During anesthetic induction, effort was made to avoid increased shunting. Surgery consisted of resection of the cor triatriatum membrane, closure of communications with pericardial patches, pulmonary valve replacement, replacement of the root with a porcine root, and pulmonary artery aneurysmorrhaphy. Severely decreased contractility developed while the patient was still in the operating room; inotropic support with adrenaline and dobutamine was required. Extubation was completed in the postoperative recovery unit with no further complications. Echocardiography showed a left-ventricular ejection fraction of 45%. We found few published reports of cases of complex congenital heart disease treated surgically in adulthood. In such cases, cardiac pathophysiology must be carefully considered, and maneuvers that increase systemic resistance or right-ventricular ejection fraction should be avoided. Postoperative pulmonary vascular resistance should be kept as low as possible.

Case report: paradoxical ventricular septal motion in the setting of primary right ventricular myocardial failure

In this report, a case of right ventricular (RV) failure, hemodynamic instability, and systemic organ failure is described to highlight how paradoxical ventricular systolic septal motion (PVSM), or a rightward systolic displacement of the interventricular septum, may contribute to RV ejection. Multiple inotropic medications and vasopressors were administered to treat right heart failure and systemic hypotension in a patient following combined aortic and mitral valve replacement. In the early postoperative period, echocardiographic evaluation revealed adequate left ventricular systolic function, akinesis of the RV myocardial tissues, and PVSM. In the presence of PVSM, RV fractional area of contraction was > or =35% despite akinesis of the primary RV myocardial walls. The PVSM appeared to contribute toward RV ejection. As a result, the need for multiple inotropes was re-evaluated, in considering that end-organ dysfunction was the result of systemic hypotension and prolonged vasopressor administration. After discontinuation of phosphodiesterase inhibitors, native vascular tone returned and the need for vasopressors declined. This was followed by recovery of systemic organ function. Echocardiographic re-evaluation two years later, revealed persistent akinesis of the RV myocardial tissues and PVSM, the latter appearing to contribute toward RV ejection. This case highlights the importance of left to RV interactions, and how PVSM may mediate these hemodynamic interactions.

Prolonged RV endocardial activation duration: A novel marker of arrhythmogenic right ventricular dysplasia/cardiomyopathy

Parietal block, defined as intra right ventricular (RV) conduction slowing, is a major diagnostic criterion for arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). We evaluated the utility of total RV endocardial activation duration (EAD) measured by 3-dimensional electroanatomic mapping during sinus rhythm in the diagnosis of ARVD/C. Twenty-five consecutive patients with frequent left bundle branch block morphology premature ventricular complexes who underwent electroanatomic mapping as a part of the evaluation for ARVD/C were included in the study. All patients were evaluated using standard protocol that included electrocardiogram (ECG), signal-averaged ECG, Holter monitoring, echocardiography, and magnetic resonance imaging. Invasive testing was performed as indicated. Total RV EAD was measured as the time interval between the onset of RV activation to the latest activated region in the RV. The mean age of the study subjects was 38 +/- 11 years, and 32% were men. Fourteen subjects were diagnosed with ARVD/C using task force criteria, and the remainder had idiopathic ventricular tachycardia. Although the surface QRS durations were similar, the total RV EAD was significantly prolonged in ARVD/C compared with idiopathic VT (83.9 +/- 10 ms vs. 50.8 +/- 7 ms, P <.001). None of the idiopathic VT subjects had RV EAD of >65 ms. RV EAD also showed significant negative correlation with RV ejection fraction. Total RV EAD obtained by 3-dimensional electroanatomic mapping is a sensitive marker of intra-RV conduction delay in ARVD/C, and a total RV EAD of >65 ms accurately differentiates ARVD/C from idiopathic VT.

Pulmonary hypertension in chronic respiratory tract obstruction: a combined study on haemodynamics and radionuclide ventriculography

In 44 patients with chronic obstruction of the respiratory passages pulmonary artery pressures were measured by Swan-Ganz catheter and right-ventricular ejection fraction by radionuclide ventriculography (equilibrium method). Although there was no linear correlation between the haemodynamic parameters of afterload or preload of the right ventricle and global right-ventricular ejection fractions, sensitivity and specificity of radionuclide ventriculography were very good (87% and 83%, respectively) for the recognition of pulmonary hypertension during exercise tests. Global right-ventricular ejection fraction in patients without pulmonary arterial hypertension had a normal and significant rise from 52% to 58% on exercise. In the group with pulmonary hypertension mean right-ventricular ejection fraction fell during exercise from 47% to 46%. Radionuclide ventriculography in the assessment of right ventricular function, especially during exercise, provides useful pointers to the diagnosis of pulmonary hypertension due to chronic respiratory-tract obstruction.

Contrast enhanced-cardiovascular magnetic resonance imaging in patients with pulmonary hypertension

To determine the presence and extent of delayed contrast enhancement (DCE) in patients with pulmonary hypertension (PHT) using contrast enhanced-cardiovascular magnetic resonance imaging (ce-CMR). Twenty-five patients with PHT underwent ce-CMR and right heart catheterization. Right ventricular (RV) and left ventricular (LV) volumes, ejection fraction, mass, and DCE mass were determined with ce-CMR. Mean pulmonary artery pressure (mean PAP) averaged 43 (12) mmHg and cardiac output 4.3 (1.2) L/min. DCE was demonstrated in 23 out of 25 patients. DCE was confined to the RV insertion points (RVIPs) in seven patients and extended into the interventricular septum (IVS) in the remaining 16 patients. In these 16 patients, septal contrast enhancement was associated with IVS bowing. The extent of contrast enhancement correlated positively with RV end-diastolic volume/body surface area, RV mass, mean PAP, and pulmonary vascular resistance and correlated inversely with RV ejection fraction. DCE was present within the RVIPs and IVS of most patients with PHT studied. Extent of DCE correlated with RV function and pulmonary haemodynamics. DCE was associated with IVS bowing and may provide a novel marker for occult septal abnormalities directly relating to the haemodynamic stress experienced by these patients.

1328 Haemodynamic classification based on right-ventricular ejection fraction and pulmonary pressure identifies etiology and predicts prognosis in patients with ischaemic and non-ischaemic heart failure

1328 Haemodynamic classification based on right-ventricular ejection fraction and pulmonary pressure identifies etiology and predicts prognosis in patients with ischaemic and non-ischaemic heart failure

P2121 Cardiac resyncronization therapy: what effects on left and right-ventricular ejection fraction during exercise?

P2121 Cardiac resyncronization therapy: what effects on left and right-ventricular ejection fraction during exercise?

10.56 A comparative evaluation of gated blood pool and thermodilution method for determination of right-ventricular ejection fraction at rest and during exercise

10.56 A comparative evaluation of gated blood pool and thermodilution method for determination of right-ventricular ejection fraction at rest and during exercise

Heterogeneous immediate effects of partial left ventriculectomy on cardiac performance.

Partial left ventriculectomy (PLV) is a novel surgical treatment for severe heart failure consisting of resection of a large wedge of myocardium to reduce wall stress and restore the normal mass-volume ratio. Although ejection fraction (EF) has been shown to improve after PLV, few other physiological data describing its immediate effects on left ventricular (LV) performance are available. Eight patients, 58+/-5 years old, with severe clinical heart failure and EF of 12+/-3% were studied before and immediately after PLV. LV performance was assessed by the predominantly load-insensitive measures of pressure-area relations with high-fidelity pressure catheters and transesophageal automated echocardiographic measures of cross-sectional area as a surrogate for volume. LV end-diastolic volume decreased from 200+/-60 to 89+/-17 mL, EF increased from 12+/-3% to 41+/-8%, and right ventricular (RV) fractional area change increased from 24+/-12% to 37+/-16% (all P<.05 versus before). Changes in pressure-area relations were variable: end-systolic elastance, 6.5+/-3.4 to 4.3+/-2.5 mm Hg/cm2 and preload recruitable stroke work, 33+/-16 to 34+/-19 mm Hg (P=NS versus before). End-diastolic stiffness increased from 0.13+/-0.06 to 0.19+/-0.07 mm Hg/cm2 (P<.05 versus before). Improvement in LV performance was inversely correlated with semiquantitative histological assessment of myocardial fibrosis and positively correlated with nuclear enlargement and hyperchromasia, indicative of myocyte hypertrophy. No long-term follow-up data were available. PLV resulted in reductions in LV volumes, increases in EF and RV ejection, but increases in LV stiffness. Estimates of LV performance revealed variable results associated with the degree of myocardial fibrosis. Further study of these effects in relation to patient outcome is warranted.

Right Ventricular Performance and Left Ventricular Assist Device Filling

Background. Right ventricular (RV) function is believed to be an important determinant of left ventricular assist device (LVAD) filling. This study was designed to demonstrate this relation in patients.Methods. To demonstrate the interaction between RV ejection and LVAD filling, 10 patients (mean age, 49 ± 13 years) supported with an LVAD were studied. Right ventricular pressure–area loops from cross-sectional area using transesophageal echocardiographic automated border detection and high-fidelity RV pressure were recorded simultaneously with LVAD volume during intraoperative inferior vena cava occlusion. Beat-by-beat RV ejection phase indices were calculated: stroke area, peak ejection rate, and stroke work. The LVAD filling rate was calculated as the first derivative of the volume, and the peak filling rate and the mean filling rate during RV systole were determined for each cardiac cycle.Results. Right ventricular stroke area, peak ejection rate, and stroke work were closely correlated with LVAD peak filling rate (r = 0.87 ± 0.09, r = 0.83 ± 0.09, and r = 0.85 ± 0.10, respectively). Also, baseline LVAD mean filling rate correlated with RV stroke work (r = 0.77) and LVAD peak filling rate with RV peak ejection rate for the group (r = 0.75).Conclusions. These correlations demonstrate predictable associations of RV ejection with LVAD filling.(Ann Thorac Surg 1997;63:1044–9)

Effects of enoximone on right-ventricular function in patients with impaired myocardial performance.

The effects of an enoximone monotherapy on left-ventricular and especially on right-ventricular haemodynamics were investigated in fourteen patients with impaired left-ventricular function secondary to coronary artery disease. Anaesthesia was induced and maintained with fentanyl and flunitrazepam. After reaching steady state, a bolus of 0.5 mg/kg enoximone was administered, followed by an infusion of 0.5 microgram/kg/min. Besides the common haemodynamic parameters particulary the right-ventricular ejection fraction (RVEF) was measured using a special thermodilution technique. The predefined time points were: before administration of enoximone (baseline) and 5 min, 10 min, 15 min, 20 min, and 30 min after bolus injection of enoximone. Compared to the baseline the maximum effects of enoximone were a 28% increase of cardiac index accompanied by a 39% decline of systemic vascular resistance and an unchanged left-ventricular stroke-work index. While central venous pressure and mean pulmonary artery pressure remained unchanged. RVEF (+20%) and right-ventricular stroke-work index (+30%) were significantly augmented, augmented, indicating improved right-ventricular performance. No adverse effects of the enoximone administration were observed perioperatively. We conclude that an enoximone monotherapy is beneficial for patients with impaired myocardial function undergoing cardiac surgery.

RIGHT VENTRICULAR PERFORMANCE AND LEFT VENTRICULAR ASSIST DEVICE FILLING

Mandarino, W A; Winowich, S; Gorcsan, J III; Gasior, T A; Pham, S; Griffith, B P; Kormos, R L Author Information

Correlation of atrial natriuretic peptide and cyclic guanosine monophosphate plasma concentrations in patients with heart disorders during rest and exercise.

The concentration of atrial natriuretic peptide was measured in order to evaluate its importance in patients suffering from a variety of cardiac diseases. There was a correlation between plasma concentrations of atrial natriuretic peptide and its "second messenger" cyclic guanosine monophosphate (cGMP) in all of the cases examined. We investigated the relationship between atrial natriuretic peptide and cGMP plasma concentrations during rest and exercise in comparison with the scintigraphically assessed left- and right-ventricular ejection fraction in patients with chronic heart disease (n = 20), and after orthotopic heart transplantation (n = 16); plasma concentrations were also measured in healthy controls (n = 14). Atrial natriuretic peptide and cGMP concentrations showed a similar correlation during rest and exercise with r = 0.74 and r = 0.81, respectively. With the exception of patients after heart transplantation, a significant negative correlation was seen between the left ventricular ejection fraction and atrial natriuretic peptide or cGMP plasma concentrations during rest conditions (r = 0.76 or 0.58, respectively). No correlation was apparent between plasma concentrations of atrial natriuretic peptide or cGMP and the left- or right ventricular ejection fraction during exercise. The concentrations of atrial natriuretic peptide and cGMP in plasma differed significantly between healthy controls and patients during rest and exercise. It is noteworthy that atrial natriuretic peptide and cGMP concentrations were markedly higher in patients after heart transplantation than in patients suffering from chronic heart disease. Our results indicate that plasma atrial natriuretic peptide and cGMP concentrations are sensitive markers of cardiac impairment.

Hemodynamic and antiischemic effects of tedisamil in humans

Twenty-four patients with angiographically documented coronary artery disease, chronic stable angina, and reproducible ST-segment depression took part in this openlabel, baseline-controlled study on the hemodynamic, antiischemic, metabolic, and neurohumoral effects of tedisamil following IV doses of 0.1, 0.2, and 0.3 mg/kg (eight patients in each dose group). Tedisamil produced a dose-dependent decrease in both heart rate [rest: 2.4, 7.5 (p .01), resp.]. While cardiac output was found decreased due to the heart-rate reduction both at rest [−8.5%, −5.7%, and −10.2% (p<.05), respectively] and during exercise (2–8%), being significant only at rest in the highest dose group, stroke volume remained unaltered. Pulmonary artery pressure, pulmonary capillary wedge pressure, right-ventricular ejection fraction, and pulmonary vascular resistance were without significant changes. Blood pressure and systemic vascular resistance tended to increase, associated with a decrease in plasma catecholamines (20–40%). Tedisamil produced a dose-dependent prolongation of QTc duration [+2%, +6%, +12% (p<.05), respectively] with PQ and QRS unaltered. The elimination half-life of tedisamil IV ranges between 6.8 and 7.8 hours. In conclusion, tedisamil, at a dose of 0.3 mg/kg IV, was well tolerated and was found to have favorable hemodynamic and antiischemic effects in patients with ischemic heart disease.

Right-ventricular contractility in chronic obstructive pulmonary disease: a combined radionuclide and hemodynamic study.

The effect of pulmonary artery hypertension on right-ventricular performance in patients with chronic obstructive pulmonary disease (COPD) is unclear. Decreased values of right-ventricular ejection fraction (RVEF) have been reported, but most patients with stable COPD are not in cardiac failure and have normal or even increased cardiac outputs. We therefore hypothesized that RVEF may be afterload dependent, and thus a poor parameter of cardiac function, and that right-ventricular contractility may be normal even in COPD patients with pulmonary hypertension. We therefore studied 24 COPD patients using a combined hemodynamic and radionuclide approach. RVEF and thermodilution stroke volume index were measured simultaneously at rest in all 24 patients and also during bicycle ergometry in 9 patients. We then calculated end-diastolic and end-systolic volume indices and derived right-ventricular systolic pressure-volume relations in all and the slopes (E) of the pressure-volume line in 9 patients. RVEF was normal in COPD patients without pulmonary hypertension, but was reduced in those with pulmonary hypertension. A strong inverse linear relation between RVEF and mean pulmonary artery pressure (r = -0.73; p less than 0.001) and pulmonary vascular resistance (r = -0.69; p less than 0.001) could be demonstrated, indicating RVEF to be highly afterload dependent. Right-ventricular end-diastolic volume index was significantly higher in patients with pulmonary hypertension, indicating increased preload as the major mechanism to maintain adequate stroke volume in the face of an increased afterload. Right-ventricular end-systolic pressure-volume relations, a good parameter to define right-ventricular contractility independent of systolic loading conditions, were not different between COPD patients with or without pulmonary hypertension, nor did the slopes of the pressure-volume lines in the 9 patients studied during exercise show any difference. From these data we conclude that (a) RVEF is a poor indicator of overall right-ventricular function; (b) right-ventricular contractility is well preserved in stable COPD patients; (c) the major mechanism of maintaining stroke volume in the face of increased right-ventricular afterload seems to be preload augmentation.

Assessment of right ventricular ejection fraction during intravenous 133Xe pulmonary ventilation study

Intravenous 33Xe in saline was used to estimate right-ventricular ejection fraction (RVEF In three healthy volunteers, the first pass RVEF with 133Xe was followed by RVEF estimation by intravenous 99 m Tc-pertechnetate. There was agreement between the 133Xe and 99 m Tc determined values. Subjects rebreathed the liberated 133Xe gas, allowing an estimation of regional pulmonary ventilation. Intravenous 133Xe in saline may have potential use in measuring RVEF, as well as in evaluating pulmonary function in cor pulmonary.

CLINICAL PATHOPHYSIOLOGICAL STUDIES ON THE MEASUREMENT OF RIGHT VENTRICULAR EJECTION TIME AND MECHANICAL EFFECT. II. METHOD OF MEASURING THE AVERAGE PULMONARY ARTERIAL PRESSURE AND MECHANICAL EFFECT DURING THE RIGHT VENTRICULAR EJECTION TIME

METHOD OF MEASURING THE AVERAGE PULMONARY ARTERIAL PRESSURE AND MECHANICAL EFFECT DURlNG THE RIGHT VENTRICULAR EJECTION TIME Many papers have been written on the measurement of ventricular mechanical effect. The study in this part was undertaken to observe the value of the mechanical effect per unit of the ejection time on the basis of the right ventricular ejection time measured in the previous part and to compare the result with other methods which are generally adopted. Material and Calculation 1 ) Sub jects The subjects are the same as in Part I. The cardiac output which was calculated by the Fick's method on 12 subjects was 9.34 l/min. at the maximum, 3.28 l/min. at the minimum, and 6.68 l/min. on the average. The mean pulmonary arterial pressure was 1 9 mmHg at the maximum and 6.5 mmHg at the minimum, with the average of 13.4 mmHg. 2) Calculation method of the mechanical effect of the right ventricle A. Calculation per minute i) Calculation of the right ventricular work against pressure by Dextor W(Dexter)=(C.I. × 1.055)(P^-pa ×13.6) /1000 kg/min/M2 where C.I. =cardiac index in liters per min per square meter body surface, 1.055 = specific gravity of blood, P^-pa=mean pressure in the pulmonary artery in mmHg, and 13.6 =specific gravity of mercury. ii) Calculation of right ventricular cardiac index Cardiac Index=Mean pulmonary arterial pressure × Heart rate iii) Calculation of myocardial tension = PP^-p × 13.6 × 1.05 ×980/10 × 1.05 × 3√S/3.2 × Heart Rate dynes per cm, where S=stroke volume cc. B. Calculation with the use of the systole or ejection time (TE) as a factor The above-mentioned three methods of do not include the conception of the ejection time. Meanwhile, it is during the poriod of ejection or the period when ventricular pressure ejects blood against the arterial pressure that the heart actually does the pressure work. Sarnoff tried to express the myocardial mechanical effect by putting the systole into consideration.

CLINICAL PATHOPHYSIOLOGICAL STUDIES ON THE MEASUREMENT OF RIGHT VENTRICULAR EJECTION TIME AND MECHANICAL EFFECT. I. EXAMINATION OF METHOD OF MEASURING THE RIGHT VENTRICULAR EJECTION TIME

EXAMINATION OF METHOD OF MEASURING THE RIGHT VENTRICULAR EJECTION TIME Cardiopulmonary hemodynamics has been clarified by the development of venous catheterization and examinations of coronary circulation and myocardial metabolism have become possible on human bodies. The ventricular mechanical work, chiefly of the left heart, was determined by DEXTER, KATZ, RODBARD and SARNOFF. With the rapid development of studies on pulmonary circulation, importance has come to be attached on observation of the mechanical effect of the right ventricle. The ventricular mechanical work seems to be done during the period in which the arterial valves are open. To investigate the right ventricular mechanical effect, the author considered it essential to confirm the method of measuring the ventricular ejection time. Method and Materials The tip of a double lumen catheter is placed in the trunk of the pulmonary artery with its side hole in the right ventricle and through V. basilica. The pressure curves of both the right ventricle and pulmonary artery are recorded on an Oscillographic paper, simultaneously with the electrocardiograph and phonocardiograph. Among 1 6 patients investigated in this study, eight with cardiovascular disease, six with chronic pulmonary disease and two others were free from evidence of congestive heart failure. Patients with congenital heart failure or atrial fibrillation were not used in this study. The heart rate, systemic blood pressure and hemoglobin cntents of these cases were all within the normal range. Result and Discussion 1 ) Measurement with a Double Lumen Catheter : In the simultaneous recording of the right ventricular and pulmonary arterial pressure curves, duration between the first intersecting point and the second intersecting point, of these pressure curves was 0.23 seconds, which is 30.4 %±4.4 % of the R-R time. This period does not correspond exactly with the systolic phase, but includes the protodiastole. It is highly probable that the right ventricle performs some ejection work in this protodiastolic phase, because the right ventricular pressure is higher than the pulmonary arterial until the second intersecting point of the two curves during which the pulmonary valve is kept open. It may therefore be induced that the time, including the abovementioned period. which is required until the second intersecting point, corresponds to the right ventricular ejection time.