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PubMed2002

Doppler echocardiographic evaluation of right ventricular diastolic function in hypertrophic cardiomyopathy.

AIMS: Left ventricular diastolic function in patients with hypertrophic cardiomyopathy has been adequately studied. In contrast there are few studies concerning right ventricular diastolic function in hypertrophic cardiomyopathy. We studied right ventricular diastolic function in patients with hypertrophic cardiomyopathy using Doppler echocardiography. METHODS AND RESULTS: We studied 20 patients with hypertrophic cardiomyopathy (mean age 43.6+/-13.8 years) and 20 healthy volunteers (control group, mean age 43+/-13.8 years). We calculated left ventricular and right ventricular diastolic indices using pulsed Doppler echocardiography. Hypertrophic cardiomyopathy patients compared with controls had significantly lower right ventricular-E/A ratio (1.01+/-0.40 vs 1.30+/-0.28, P<0.04), significantly prolonged right ventricular isovolumic relaxation time (170+/-72 vs 32+/-23 ms, P<0.001), and also significantly prolonged right ventricular deceleration time (160+/-58 vs 118+/-35 ms, P<0.01). There was also strong significant correlation between right ventricular deceleration time and left ventricular deceleration time (r=0.78), right ventricular-E/A ratio and left atrial filling fraction (r=-0.55) and between right atrial filling fraction and left atrial filling fraction (r=0.75). CONCLUSIONS: Right ventricular diastolic function in patients with hypertrophic cardiomyopathy is impaired, reflecting abnormal relaxation. Right ventricular diastolic indices correlate well with those of left ventricle.

Adolescent↗
PubMed1996

Physiology of univentricular versus biventricular support.

Right ventricular failure unresponsive to pharmacologic treatment occurs in approximately 20% to 30% of patients supported with a left ventricular assist device (LVAD). The effect of the assistance on right ventricular function is highly controversial. Increased venous return produced by an LVAD can affect right ventricular function by increasing preload. On the other hand, an LVAD can improve the filling of the right ventricle by unloading the left ventricle, reducing its chamber size and shifting the septum back to the left. Right ventricular function is highly afterload dependent, the ventricular function depending on the pulmonary vascular resistance. With a normal pulmonary vascular bed, the LVAD can improve right ventricular function by reducing right ventricular afterload. If there is a fixed high pulmonary pressure, however, the LVAD can increase right ventricular afterload and volume. We conclude that the right ventricle is dispensable if the pulmonary vascular bed is normal.

Cardiac Output, Low↗
PubMedDate not supplied

Echocardiographic assessment of left and right ventricular diastolic functions in children with dilated cardiomyopathy.

We evaluated left and right ventricular diastolic functions by pulsed Doppler echocardiography in 16 children with dilated cardiomyopathy and in 20 healthy age-matched control subjects. The cardiomyopathy group demonstrated an abnormal relaxation pattern of the left ventricle. In the cardiomyopathy group compared to normal subjects, peak early filling velocities (43.3 +/- 11 cm/s versus 60.4 +/- 11 cms/s, p < 0.01), the corresponding velocity-time integrals (3.3 +/- 1.4 cm versus 4.6 +/- 1.2 cm, p < 0.01) and the ratio of peak early filling velocity to late filling velocity (1.22 +/- 0.47 versus 1.49 +/- 0.23, p < 0.05) were significantly lower whereas isovolumic relaxation time was significantly longer (58.9 +/- 19.8 ms versus 49.7 +/- 8.9 ms, p < 0.05). In addition, right ventricular diastolic filling was also impaired in children with dilated cardiomyopathy. Peak early filling velocities (41 +/- 7.9 cm/s versus 47.5 +/- 8.8 cm/s, p < 0.05) and the corresponding velocity time integrals (3.0 +/- 1.0 cm versus 3.87 +/- 1.1 cm, p < 0.05) were significantly decreased, while isovolumic relaxation time was significantly increased (60.6 +/- 16.3 ms versus 52.2 +/- 12.8 ms, p < 0.05) in the cardiomyopathy group. The study suggests that abnormalities of both right and left ventricular diastolic function may occur, and should be searched for, in pediatric patients with dilated cardiomyopathy.

Adolescent↗
PubMed1996

Right ventricular myocardial function in ARF patients. PEEP as a challenge for the right heart.

OBJECTIVE: To examine the hemodynamic effects of external positive end-expiratory pressure (PEEP) on right ventricular (RV) function in acute respiratory failure (ARF) patients. DESIGN: Prospective, with retrospective analysis on the basis of RV volume response to PEEP. SETTING: General intensive care unit in a university teaching hospital. PATIENTS: 20 mechanically ventilated ARF patients (mean lung injury score = 2.6 +/- 0.45 SD). INTERVENTION: Incremental levels of PEEP (0-5-10-15 cmH2O) were applied and RV hemodynamics were studied by means of a Swan-Ganz catheter with a fast-response thermistor for right ventricular ejection fraction (RVEF) measurement. According to their response to PEEP 15, two groups of patients were defined: group A (9 patients) with unchanged or increased RV end-diastolic volume index (RVEDVI) and group B (11 patients) with decreased RVEDVI. MEASUREMENTS AND RESULTS: At zero PEEP (ZEEP) the hemodynamic parameters of the two groups did not differ. In group A, cardiac index (CI) and stroke volume index (SI) decreased at all PEEP levels (5, 10, and 15 cmH2O), while RVEF started to decrease only at a PEEP of 10 cmH2O (-10.8%), and RVES(systolic)VI increased only at PEEP 15 cmH2O (+21.5%). RVEDVI was not affected by PEEP. In group B, CI and SI decreased at all PEEP levels (5, 10, and 15 cmH2O). Similarly, RVEDVI started to decrease at PEEP 5 cmH2O, while RVESVI decreased only at PEEP 15 cmH2O (-21.4%). RVEF was not affected by PEEP in this group. In each patient the slope of the relationship between RVEDVI and right ventricular stroke work index (RVSWI), expressing RV myocardial performance, was studied. This relationship was significant (no change in RV contractility) in 8 of 11 patients in group B and in only 2 patients in group A. In 4 patients in group A, PEEP shifted the RVSWI/RVEDVI ratio rightward in the plot, indicating a decrease in RV myocardial performance in these patients. CONCLUSIONS: PEEP affects RV function in ARF patients. The decrease in cardiac output is more often associated with a preload decrease and no change in RV contractility. On the other hand, the finding of increased RV volumes with PEEP may be associated with a reduction in RV myocardial performance. Thus, these results suggest that assessment of RV function by PEEP and preload recruitable stroke work may disclose otherwise unpredictable alterations in RV function.

Adult↗
PubMed1995

[The hemodynamic status and right ventricular diastolic function of bronchial asthma patients].

Doppler echocardiographic study of ventricular diastolic function in 90 BA patients gave evidence for diastolic left and right ventricular dysfunction in patients with moderately and gravely running BA. The above disorders were noted by changes in the speed of transmitral and transtricuspid flows: early filling rate (E) slowing, atrial systole filling rate (A) acceleration, E/A decrease. The degree of right ventricular diastolic dysfunction depends on right ventricular hypertrophy and total pulmonary resistance. Left ventricular diastolic function is related to right ventricular after-load.

Adolescent↗
PubMed1999

Valve-preserving treatment of Ebstein's anomaly: perioperative and follow-up results.

BACKGROUND: Ebstein's anomaly is a rare congenital cardiac defect of the tricuspid valve (TV) leading to severe tricuspid insufficiency (TI). METHODS: In ten patients, 6 adults (39-53 years) and 4 children (5-10 years), operated between 1989 and 1995 echocardiography was performed pre and post repair and at follow-up. Patients were assessed in our institution at two cut-off points, resulting in a mean first follow-up of 17 +/-15 months and a mean second follow-up of 53+/-23 months. All patients had additional congenital cardiac defects (ASD,VSD). In all patients the TV was repaired by techniques described by Carpentier et al. with some modifications. The goal of this reparative attempt is to mobilize restricted leaflet tissue and aid coaptation through implantation of a ring. RESULTS: Echocardiographically we were able to identify significant characteristics for the successful repair of Ebstein's anomaly. The severity of the disease is represented by the size and function of the right ventricle and the atrialized chamber, the most advanced cases exhibiting a dilated right ventricle with poor contractility. There was severe preoperative TI ( mean grade 3.2 +/- 0.3). Postoperatively TI was significantly reduced to a mean grade of 2+/-0.2. 60% of the patients demonstrated an improvement in the ratio of atrialized chamber to functional right ventricle. Right-ventricular function was improved, the mean score being 2.8+/-0.1. At follow-up I and II right-ventricular function and tricuspid insufficiency was improved in most patients and all patients benefited in quality of life. CONCLUSION: These results suggest that surgical correction should not be delayed until severe right heart failure develops as, particularly in children, good results are achieved, improving the quality of life.

Adult↗
PubMed1988

Incidence of exertional right ventricular wall motion abnormalities in patients with coronary artery disease.

To evaluate the role of analysis of right ventricular function with exercise in patients with presumed coronary artery disease referred for radionuclide ventriculography, the records of 55 patients referred to our laboratory over a 19-month period were reviewed. All underwent rest and exercise first-pass radionuclide stress testing and cardiac catheterization within a period of four months. Three groups were identified: (1) patients with normal exercise right ventricular function (n = 24); (2) patients with exercise-induced right ventricular regional wall motion abnormalities (n = 15); and, (3) patients with abnormal resting right ventricular function without new exercise abnormalities (n = 16). Patients in each group were similar in age, sex, baseline left ventricular function, medication usage, and indication for study. The incidence of right coronary artery disease was identical in the three groups, as was the incidence of left ventricular functional abnormalities with exercise. Patients with proximal right coronary artery disease were more likely to have reduced left ventricular ejection fraction and more extensive coronary artery disease than those without disease at this site. We conclude that: (1) analysis of rest and exercise right ventricular function does not allow prediction of coronary anatomy in an unselected group of patients; (2) normal right ventricular function with exercise is compatible with extensive coronary artery disease, including proximal right coronary artery disease; and (3) abnormal exercise right ventricular function may be due to exertional left ventricular dysfunction in the absence of proximal right coronary artery disease.

Cardiac Catheterization↗
PubMed2001

Echocardiographic evaluation of right ventricular systolic functions in pure mitral stenosis.

Detailed echocardiographic evaluation of right ventricular muscle thickness and systolic functions was performed in twenty two cases of isolated rheumatic mitral stenosis without clinical signs of systemic venous congestion, tricuspid regurgitation or atrial fibrillation. Twenty two age and sex matched normal persons formed the control group. Right ventricular thickness was significantly increased in the patients with mitral stenosis. End-diastolic and end-systolic long axis measurements and areas were significantly increased and fractional shortening of these parameters was significantly reduced in the patient group. Our results show that right ventricular systolic functions are significantly impaired even in absence of clinical signs of systemic venous congestion. This impairment of systolic function did not correlate with pulmonary flow acceleration time. Myocardial involvement in rheumatic process could be one possibility. Systolic movement of the Tricuspid annulus and right ventricular mid cavity short axis dimension were not sensitive in detecting right ventricular systolic dysfunction.

Female↗
PubMed2005

Association between adenoidal-nasopharyngeal ratio and right ventricular diastolic functions in children with adenoid hypertrophy causing upper airway obstruction.

OBJECTIVE: Adenoid hypertrophy causing upper airway obstruction can cause cardiovascular complications, including pulmonary hypertension and right heart failure in children. Adenoidal-nasopharyngeal ratio (ANR) is a practical, non-invasive and reliable method to evaluate adenoid enlargement. Our aim was to evaluate a possible association between ANR and echocardiographic parameters of right ventricle. METHODS: Twenty-one children who were affected by upper respiratory obstruction symptoms due to adenoid hypertrophy were included in this study (male/female: 12/9; mean age was 6.0 +/- 1.5 years). ANRs were calculated as the ratio of adenoidal depths to the nasopharyngeal depths on lateral cephalometric radiographs. Pulmonary arterial pressures, right ventricular diastolic filling parameters (peak E, peak A, E/A ratio), right ventricular end-diastolic diameters, and left ventricular ejection fractions were measured using echocardiography both preoperatively and also 3 months after the operation. RESULTS: Preoperative pulmonary arterial pressure, E/A ratio, right ventricular end-diastolic diameter, and left ventricular ejection fraction values were 23.10 +/-3.43 mmHg, 1.01 +/- 0.20, 1.95 +/- 0.16 cm, and 69.43 +/- 3.68%, respectively. Postoperative pulmonary arterial pressure, E/A ratio, right ventricular end-diastolic diameter, and left ventricular ejection fraction values were 16.94 +/- 1.45 mmHg, 1.24 +/- 0.14, 1.72 +/- 0.15 cm, and 69.77 +/- 2.17%, respectively. There were significant differences between preoperative and postoperative pulmonary arterial pressures, E/A ratios, and right ventricular end-diastolic diameters (p < 0.01 for each), while left ventricular ejection fraction values did not significantly change after the operation (p > 0.05). There was a negative correlation between E/A ratio and ANR-Ba (p < 0.05, r = -0.44). CONCLUSION: ANR can give information about the right ventricular functions in children with enlarged adenoids causing obstructive symptoms.

Adenoidectomy↗
PubMed2002

Nitric oxide modulates right ventricular flow and oxygen consumption during norepinephrine infusion.

This study was designed to test if nitric oxide (NO) contributes to norepinephrine-induced right coronary vasodilation and if NO blunts the norepinephrine-induced increase in myocardial oxygen consumption (MVO(2)) in the right ventricle. In five anesthetized, open-chest dogs, mean aortic pressure, heart rate, right ventricular rate of pressure development over time (dP/dt), right coronary blood flow, and right ventricular MVO(2) were measured before and during graded intracoronary infusions of norepinephrine in the absence and presence of a NO synthase blocker, N(omega)-nitro-L-arginine methyl ester (L-NAME; 150 microg/min i.c.). During both conditions, right coronary blood flow and right ventricular MVO(2) significantly increased with graded infusions of norepinephrine. L-NAME significantly blunted the coronary hyperemic response to norepinephrine, although L-NAME did not alter the relationship between right ventricular MVO(2) and norepinephrine dose. However, when right ventricular function was indexed by heart rate x right ventricular maximum dP/dt x peak right ventricular systolic pressure, L-NAME significantly increased the oxygen cost of right ventricular function. These results indicate that NO contributes to norepinephrine-induced right coronary vasodilation and improves right ventricular oxygen utilization efficiency.

Animals↗
PubMed2002

Automatic backscatter analysis of regional right ventricular systolic function using colour kinesis in patients with inferior wall acute myocardial infarction with or without right ventricular involvement.

BACKGROUND: In patients with inferior acute myocardial infarction (AMI), right ventricular (RV) function is an important determinant of global cardiac performance, prognosis, and exercise capacity. Several echocardiographic methods for quantifying RV function have been developed over the years but the usefulness of colour kinesis (CK) and acoustic quantification (AQ) have not yet been investigated. AIM: To test whether AQ and CK may provide quantitative assessment of global and regional RV function in patients with inferior AMI. METHODS: Thirty two consecutive patients with recent inferior AMI with or without RV involvement (n=17 and n=15, respectively), and 15 age- and gender-matched controls were studied. The graphs of RV fractional area change were displayed along with ECG and the concurrent cross sectional image. CK digitised end-systolic images of RV and were evaluated by reviewing the stored loops obtained from normal subjects and patients. To evaluate the entire RV systolic endocardial excursion, further quantitative CK analysis was performed by measuring the systolic segmental endocardial motion (SEM). RESULTS: In comparison with the control group, patients with inferior AMI with or without RV involvement had reduced RV fractional area change (30+/-7%, 36+/-6%,45+/-6%, p<0.05, p<0.01 respectively), reduced mean free wall SEM (3.9+/-1.1 mm, 5.2+/-1.3 mm, 6.3+/-1.4 mm, p<0.05, p<0.01 respectively) and mean septal wall SEM (4.9+/-1.2 mm, 6.4+/-1.5 mm, 7.2+/-1.4 mm, p<0.05, p<0.05, respectively). CONCLUSIONS: Our results confirmed that RV systolic functions are significantly more altered in patients with inferior AMI than in controls, and that RV abnormalities are more pronounced in patients with rather than without RV involvement. AQ and CK are able to detect wall motion disturbances in patients with inferior AMI with RV involvement.

Journal Article↗
PubMed2004

Nitric oxide contributes to oxygen demand-supply balance in hypoperfused right ventricle.

OBJECTIVE: The present study examined the role of nitric oxide (NO) in oxygen demand-supply balance in hypoperfused canine right ventricular myocardium. METHODS: The right coronary artery of anesthetized, open-chest dogs was perfused at pressures of 80, 60, and 40 mm Hg, and right ventricular myocardial oxygen consumption, right coronary blood flow and other hemodynamic and cardiac function variables were measured. Right ventricular mechanical function was indexed as the product of heart rate x peak right ventricular systolic pressure x right ventricular dP/dt(max). NO synthesis blocker N(omega)-nitro-L-arginine methyl ester (L-NAME, 150 mug/min) was infused into the right coronary artery to block NO synthesis. RESULTS: Neither hypoperfusion nor L-NAME altered right ventricular function. Right ventricular myocardial oxygen consumption fell with coronary perfusion pressure, but less steeply after L-NAME, and at all perfusion pressures was elevated above control. The increase in myocardial oxygen consumption in the absence of NO was met by increased oxygen extraction and by non-NO dependent vasodilation, but the relationship between flow and oxygen consumption was displaced downward after L-NAME. As right coronary perfusion pressure was reduced, the relationship between right ventricular oxygen consumption and right coronary venous PO(2) became steeper after L-NAME, and right coronary venous PO(2) was significantly reduced. CONCLUSIONS: During right coronary hypoperfusion, right ventricular function is well maintained, but myocardial oxygen consumption falls, reflecting an increase in oxygen utilization efficiency. NO contributes to this adaptation to hypoperfusion by restraining myocardial oxygen consumption, and by promoting coronary vasodilation with less severe reduction in myocardial PO(2). NO has an important role in right ventricular oxygen demand-supply balance when right coronary perfusion pressure is reduced.

Animals↗
PubMed2001

Normal myocardial function in severe right ventricular volume overload hypertrophy.

Severe left ventricular volume overloading causes myocardial and cellular contractile dysfunction. Whether this is also true for severe right ventricular volume overloading was unknown. We therefore created severe tricuspid regurgitation percutaneously in seven dogs and then observed them for 3.5-4.0 yr. All five surviving operated dogs had severe tricuspid regurgitation and right heart failure, including massive ascites, but they did not have left heart failure. Right ventricular cardiocytes were isolated from these and from normal dogs, and sarcomere mechanics were assessed via laser diffraction. Right ventricular cardiocytes from the tricuspid regurgitation dogs were 20% longer than control cells, but neither the extent (0.171 +/- 0.005 microm) nor the velocity (2.92 +/- 0.12 microm/s) of sarcomere shortening differed from controls (0.179 +/- 0.005 microm and 3.09 +/- 0.11 microm/s, respectively). Thus, despite massive tricuspid regurgitation causing overt right heart failure, intrinsic right ventricular contractile function was normal. This finding for the severely volume-overloaded right ventricle stands in distinct contrast to our finding for the left ventricle severely volume overloaded by mitral regurgitation, wherein intrinsic contractile function is depressed.

Animals↗
PubMed1985

Two-dimensional echocardiographic evaluation of right ventricular size and function in newborns with severe right ventricular outflow tract obstruction.

Critical pulmonary stenosis or atresia with intact ventricular septum represents a congenital cardiac lesion for which the long-term prognosis appears to depend partly on the size of the right ventricle. Thus, the capability of noninvasive assessment of right ventricular size to predict operative outcome was examined in 15 infants (aged 1 to 30 days, mean 5.6) with severe right ventricular outflow tract obstruction (either critical pulmonary stenosis [7 patients] or pulmonary atresia with intact ventricular septum [8 patients]). Using echocardiography in two orthogonal subxiphoid views, right ventricular volume, wall thickness, area change fraction, ejection fraction and tricuspid anulus dimension were measured. All patients with a normalized right ventricular enddiastolic volume of less than 5 ml/m2 and a normalized tricuspid anulus dimension of less than 1.0 cm/m2/3 required a shunt operation. Only one patient with a volume of more than 6 ml/m2 and a normalized tricuspid anulus dimension of more than 1.4 cm/m2/3 required more than relief of right ventricular outflow tract obstruction. In this patient, residual severe pulmonary stenosis necessitated the shunt procedure. One patient with a volume of more than 6 ml/m2 had an anulus diameter of less than 1.4 cm/m2/3 and one patient with an anulus diameter of more than 1.4 cm/m2/3 had a volume of less than 6 ml/m2; both required shunt procedures. It therefore appears that if either the ventricular volume or tricuspid anulus size is excessively small, a shunt procedure is necessary. Wall thickness, area change fraction and ejection fraction measurements were not significantly correlated with right ventricular volume or postoperative outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Volume↗
PubMed1977

[Hemodynamic profile of acute myocardial infarction as a function of electrocardiographic localization].

The haemodynamic profiles of 147 cases of myocardial infarction investigated within 30 hours of the clinical onset were studies in relation to the topography of the necrosis on the ECG: there were 36 inferior (I), 29 postero-inferior (PI), 22 antero-septal (AS), 38 antero-lateral (AL), 15 deep septal (DS), and 7 strictly posterior or lateral (PL). Simultaneous recordings of the diastolic pulmonary arterial pressures and the left ventricular diastolic pressures (pre-and post-a) have shown different degrees of correlation with the topographical site. The correlation found in AS, AL and I necrosis are clearer with respect to the pre-a. The PI necroses show no correlation. Graphs of left ventricular function as well as an analysis of the various other parameters show that the DS, the AL, and to a lesser extent the PI are associated with the grossest depression of left ventricular function. A study of the amplitude of the "a" wave also shows that the effect of infacts of the free wall of the left ventricule on the compliance is greater. A study of right ventricular function as well as the correlations between the pulmonary and right atrial pressures confirms the presence of right ventricular disfunction in DS and PI necroses. Impaired left ventricular function, impaired right ventricular function, and disorders of compliance seem to be the determining factors in changing the haemodynamics in the various ECG sites of infarction.

Acute Disease↗
PubMed1996

Right ventricular diastolic function in children with pulmonary regurgitation after repair of tetralogy of Fallot: volumetric evaluation by magnetic resonance velocity mapping.

OBJECTIVES: We sought to assess right ventricular diastolic function in young patients with corrected tetralogy of Fallot and pulmonary regurgitation. BACKGROUND: Pulmonary regurgitation is an important problem in repair of tetralogy of Fallot. Its effects on right ventricular diastolic function in children are unknown. METHODS: Nineteen children with repair of tetralogy of Fallot (mean age [+/- SD] 12 +/- 3 years, mean age at operation 1.5 +/- 1) and 12 healthy children were studied. Summation of magnetic resonance velocity mapping pulmonary and tricuspid volume flow curves provided right ventricular time-volume curves. Ventricular size was assessed with tomographic magnetic resonance imaging (MRI). Graded exercise testing was performed. RESULTS: Systematic and random differences (mean +/- SD) of velocity mapping and Doppler tricuspid time to peak velocities (peak E: 1 +/- 26 ms, r = 0.43; peak A: 2 +/- 11 ms, r = 0.76), E/A ratio (0.04 +/- 0.5, r = 0.63) and duration of pulmonary regurgitation (20 +/- 35 ms, r = 0.74) were satisfactory. In 6 patients (group I), late diastolic forward pulmonary artery flow was absent; in 13 patients (group II), this flow contributed 1% to 14% to right ventricular stroke volume. Significant differences were increased deceleration time (315 +/- 91 vs. 168 +/- 28 ms, p < 0.001), decreased filling fraction (44 +/- 11 vs. 55 +/- 16%, p = 0.02) and increased peak early filling rate (378 +/- 124 vs. 286 +/- 112 ml/s, p = 0.018) between control subjects and group I, and increased deceleration time (230 +/- 40, p = 0.03) between control subjects and group II. Pulmonary regurgitation, ventricular size and ejection fraction did not differ significantly between patient groups. Exercise function was diminished with restrictive right ventricular physiology (p < 0.001, group II vs. control subjects). CONCLUSIONS: Impaired relaxation and restriction to filling affect right ventricular function in children with repair of tetralogy of Fallot and pulmonary regurgitation. Restrictive right ventricular physiology is associated with decreased exercise function.

Adolescent↗
PubMed2004

Intraaortic balloon pumping improves hemodynamics and right ventricular efficiency in acute ischemic right ventricular failure.

BACKGROUND: Left ventricular unloading has a potentially deleterious effect in right ventricular failure as a result of altered septal interplay. However, a positive effect of an intraaortic balloon pump during right ventricular failure has been suggested. We investigated the impact of intraaortic balloon pumping on hemodynamics and both left and right ventricular function in an experimental model of isolated right ventricular failure. METHODS: Sixteen anesthetized pigs (25 to 34 kg) were used in an in vivo model. Pressure-conductance catheters assessed right and left ventricular pressure-volume relationships. Acute right ventricular failure was induced by right coronary microembolization, and led to severely impaired right ventricular function, reduced cardiac output and arterial pressure, and an increased pulmonary vascular resistance and pulmonary arterial elastance. Animals were then randomized to balloon pump or control groups and evaluated with respect to hemodynamics and ventricular function after 1 hour. RESULTS: Intraaortic balloon pumping did not alter right or left ventricular contractility. However, balloon pump-treated animals had significantly improved cardiac output (+18% +/- 18% versus -6% +/- 7%; p = 0.003) and mean arterial pressure (+36% +/- 30% versus -7% +/- 14%; p = 0.004) compared with controls. Animals in the balloon pump group had lower pulmonary vascular resistance (795 +/- 63 versus 912 +/- 259 dynes . sec . cm(-5); p < 0.01) and pulmonary arterial elastance (1.14 +/- 0.20 versus 1.69 +/- 0.65 mm Hg/mL; p < 0.01), and increased stroke volume (22.3 +/- 4.7 versus 17.9 +/- 4.7 mL; p = 0.016). Right ventricular efficiency was also improved in the balloon pump group (stroke work per pressure-volume area = 0.60 +/- 0.14 versus 0.41 +/- 0.12; p < 0.01). CONCLUSIONS: Intraaortic balloon pump support does not alter right or left ventricular function in acute right ventricular failure. However, arterial pressure, cardiac output, and right ventricular efficiency are improved, possibly because of a balloon pump-induced reduction in pulmonary arterial resistance.

Acute Disease↗
PubMed1998

Evaluation of regional differences in right ventricular systolic function by acoustic quantification echocardiography and cine magnetic resonance imaging.

BACKGROUND: Accurate quantitative evaluation of right ventricular (RV) function has been limited by its complex structural geometry. Although embryological and anatomic observations suggest that the RV is composed of 2 distinct components, the RV sinus and infundibulum, most studies on RV dimensions and function viewed it as a single chamber. This study was designed to determine the volumes, relative contribution to global systolic function, and temporal course of contraction and relaxation of the RV sinus and infundibulum. METHODS AND RESULTS: Thirty-one individuals without heart disease (aged 1 month to 17 years, 16 boys and 15 girls) participated in this study. Instantaneous area over time, its derivatives, and the temporal course of contraction and relaxation were studied by acoustic quantification echocardiography and phonocardiography in 20 individuals. Global and regional RV volumes and ejection fraction were determined by cine MRI in 11 individuals. The RV sinus made up 81+/-6% of the combined RV end-diastolic volume and 87+/-4% of the combined stroke volume. The infundibulum accounted for the remaining 19+/-6% and 13+/-4%, respectively (P<0.0001). Compared with the infundibulum, the extent of RV sinus fiber shortening was significantly greater: for ejection fraction (56+/-11% versus 38+/-13%, P<0.001), fractional area change (42+/-14% versus 28+/-9%, P<0.0001), and dA/dt (27+/-17% versus 13+/-6%, P<0.0001). Analysis of temporal course of contraction and relaxation (expressed as percentage of the cardiac cycle to adjust for differences in heart rate) showed that the infundibulum follows the RV sinus: onset of contraction 53%+/-14 versus 19+/-11% of systole, time to peak systole 115+/-16% versus 97+/-19% (P< or =0.01), indicating a peristalsis-like pattern of contraction and relaxation. CONCLUSIONS: The results of this study demonstrate significant regional differences between the sinus and infundibulum components of the RV with regard to contribution to stroke volume, extent of fiber shortening, and sequence of mechanical activation. These data from normal individuals can be used in future research on RV function in pathological conditions.

Adolescent↗