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The pathophysiology of acute right heart failure, determined largely from experimental animal studies, is outlined. The authors also discuss clinical settings in which acute right ventricular failure may occur and methods for assessing right ventricular function. A physiologic approach to the treatment of acute right heart failure in patients is provided.
The surgical treatment of complex congenital malformations of the right heart is described and discussed with regard to the following heart diseases: tetralogy of Fallot (FT), transposition of the great arteries (TGA), tricuspid atresia (TA), single ventricle (SV). The results of the patient material of Goettingen were focused on the right ventricular function. With reference of the FT-correction a residue pulmonary stenosis is considered to be better tolerated than a residual pulmonary insufficiency. The long-term results (observation time from 4 to 17,5 years) proved that the right ventricle (RV)-function can adapt itself to pressure load. Adequate growth to the hypoplastic right ventricle is documented due to right ventricular volume load after operative repair. The Fontan procedure for TA and SV has revealed that the inactivation of the right ventricular pumpunction has not resulted in negative effect on the function of the systemic ventricle, patients clinical conditions and exercise testing have improved.
Calcium-channel antagonists may provide an effective approach to the treatment of pulmonary hypertensive disorders. Biochemical evidence suggests that pulmonary vasoconstriction results from the transmembrane flux of calcium into vascular smooth muscle; accordingly, the pulmonary pressor responses in experimental hypoxic pulmonary hypertension can be attenuated by verapamil and nifedipine. In patients with chronic obstructive lung disease, nifedipine decreases pulmonary artery pressures and pulmonary vascular resistance in proportion to the severity of hypoxemia before treatment. However, little pulmonary vasodilator effect is seen when hypoxemia is corrected by inhalation of oxygen, and systemic arterial oxygen desaturation can occur after nifedipine in patients breathing room air; most importantly, long-term studies in patients with chronic lung disease are lacking. In selected patients with primary pulmonary hypertension and other obliterative diseases of the pulmonary vasculature, nifedipine produces short- and long-term hemodynamic improvement at rest and during exercise, and these benefits are frequently paralleled by amelioration of dyspnea and fatigue. However, in patients in whom right ventricular function has been severely compromised by chronic pressure overload, both verapamil and nifedipine may exert notable depressant effects on right ventricular performance, despite the decrease in right ventricular afterload that would be expected to accompany a decrease in pulmonary vascular resistance. These negative inotropic actions may result in serious deleterious clinical reactions. Although calcium-channel antagonists represent a promising approach to the management of patients with pulmonary hypertension, the long-term efficacy and safety of these drugs in this disorder remain to be established.
In a randomized, controlled trial, ten patients with pulmonary heart disease due to severe chronic airflow obstruction were stratified into two groups: group 1 had clinical features of congestive heart failure during respiratory failure and were regularly receiving diuretics; group 2 had no such clinical features and were not receiving diuretics. In group 1, when placebo was substituted for diuretics, pulmonary edema developed in three patients; exercise performance and ventricular function of the remaining two patients deteriorated. In group 2, there was no difference in exercise tolerance or ventricular function between placebo and diuretic therapy. The clinical deterioration in group 1 was related to abnormal left ventricular function. Thus, diuretics benefit only patients who have clinical features of congestive heart failure. In patients with isolated abnormal right ventricular function, diuretics may be harmful.
Canine studies have shown a correlation between instantaneous segmental lengths in the right ventricular free wall and chamber volume, pressure, and stroke work. To determine whether such correlations exist in intact man, we studied the temporal relationships between chord dynamics in various regions of the right ventricle in 21 heart transplant recipients with apparently normal right ventricular function. Patients were examined by biplane radiography while performing various maneuvers (e.g., Valsalva maneuver). Computer-aided analysis of biplane radiograms of five surgically inserted radiopaque tantalum right ventricular myocardial markers was used to calculate interpoint chord lengths at 33 msec sampling intervals. Two patterns of right ventricular chord asynergy were defined: (1) An akinetic chord had an amplitude of less than 2.0 mm during the course of at least one beat; (2) an out-of-phase chord was more than a quarter period out of phase from the average curve (derived from all concurrently measured marker pairs during each maneuver) for at least one beat. Considering all chords (n = 978), 60 chords (6.1%) were akinetic and nine chords (0.9%) were out of phase. Excluding the outflow tract markers (n = 581), 33 chords (5.7%) were akinetic and five chords (0.9%) showed out-of-phase movement. During some maneuver, at least one akinetic chord occurred in 57% of patients and out-of-phase chords in 33% of patients. Most right ventricular regions were implicated in asynergic motion, including the right ventricular free wall, acute margin, and outflow tract. The frequency and distribution of asynergy in right ventricular chord dynamics observed in this study suggests that changes in a single right ventricular dimension may not accurately reflect global right ventricular events.
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function.
Although pectus excavatum (PE) is thought to impair right ventricular (RV) performance, the degree of RV dysfunction, if any, produced by this chest wall deformity remains controversial. To address this issue, we performed 2-dimensional echocardiography and chest wall radiography in 28 subjects with mild-to-severe degrees of PE to assess RV morphology and function in relation to the degree of the chest wall deformity. Measurements of RV anatomy and function obtained in these patients were compared to those of 24 normal control subjects of similar age and sex. In subjects with PE, mean RV outflow tract diameter at the aortic root level was narrower (1.4 +/- 0.3 cm/m2) and end-diastolic (10 +/- 2.3 cm2/m2) and end-systolic (5.8 +/- 1.4 cm2/m2) areas were larger than those in normal controls (1.6 +/- 0.3, 8.6 +/- 1.7, and 4.5 +/- 1.2 cm2/m2, respectively; p < 0.013). The magnitude of these abnormalities was related to the degree of the chest wall deformity evaluated on the chest radiogram (r = 0.54, 0.51, and 0.49, respectively). RV planar emptying fraction, an index of RV systolic function, was reduced in subjects with PE (42 +/- 10%) compared to the normal controls (48 +/- 10%; p = 0.047). No relation could be found, however, between this index and the severity of the chest wall deformity.(ABSTRACT TRUNCATED AT 250 WORDS)
BACKGROUND: Measurement of right ventricular (RV) volumes and right ventricular ejection fraction (RVEF) by three-dimensional echocardiographic (3DE) short-axis disc summation method has been validated in multiple studies. However, in some patients, short-axis images are of insufficient quality for accurate tracing of the RV endocardial border. This study examined the accuracy of long-axis analysis in multiple planes (longitudinal axial plane method) for assessment of RV volumes and RVEF. METHODS: 3DE images were analyzed in 40 subjects with a broad range of RV function. RV end-diastolic (RVEDV) and end-systolic volumes (RVESV) and RVEF were calculated by both short-axis disc summation method and longitudinal axial plane method. RESULTS: Excellent correlation was obtained between the two methods for RVEDV, RVESV, and RVEF (r = 0.99, 0.99, 0.94, respectively; P < 0.0001 for all comparisons). CONCLUSION: 3DE longitudinal-axis analysis is a promising technique for the evaluation of RV function, and may provide an alternative method of assessment in patients with suboptimal short-axis images.
Selected indices of left and right ventricular function and pulmonary circulation have been compared in two groups of patients with constrictive pericarditis: i.e. in 10 patients classified as NYHA functional class II and 13 patients as NYHA class III. The patients with NYHA class III showed higher average values of left ventricular end-diastolic pressure (mean + 19.4 vs 11.4 mm Hg) and right ventricular end-diastolic pressure (mean + 17.3 vs 9.5 mm Hg) as well as pulmonary systolic (mean + 39.5 vs 24.5 mm Hg) and diastolic pressure (mean + 20.6 vs 9.9 mm Hg). Mean total pulmonary resistance and left and right ventricular stiffness indices were slightly higher whereas cardiac index was slightly lower. Complaints of patients with constrictive pericarditis, fatigability and dyspnea are to a large extent determined by the level of end-diastolic pressure in both ventricles and pulmonary hypertension that is by similar direct mechanism as in congestive heart failure.
Krypton-81m equilibrium ventriculography was used to study right ventricular function in 23 healthy male volunteers. Technetium-99m lung perfusion scintigraphy was employed to subtract radionuclide activity within lung during image analysis thereby enhancing image quality. The imaging technique was used to generate a time-activity curve for the right ventricle allowing the definition of indices of normal systolic and diastolic function for the right ventricle. At rest, indices of systolic ejection and diastolic filling were comparable to those previously reported for the left ventricle. Using the imaging technique, movement artifact during exercise reduces image quality and limits accurate measurement of these indices to resting studies.
Cardiovascular function was studied in a model of intestinal vascular obstruction in cats. To measure right ventricular end diastolic pressure and maximal dP/dt, a tip transducer catheter was placed into the right ventricle. The intestinal vascular obstruction resulted in shock with decreases of blood pressure, cardiac output, and external cardiac work. Small intestinal mucosal lesions were found in all shocked cats. At an increased preload to the heart, right ventricular function was depressed in shocked cats. The model corresponds to one used earlier in the rat, where cardioinhibitory activity in venous blood was found in vitro. In this corresponding model of intestinal shock in the cat a depressed function of the right ventricle of the heart was found in vivo.
OBJECTIVE: Assessment of ventricular function in the fetus has been limited for many reasons, including relative cardiac size and atypical orientation of fetal cardiac structures. A myocardial performance index (MPI) has been described in adult and pediatric populations as an echocardiographic measure of global (systolic and diastolic) ventricular performance. Because the MPI is a Doppler index, it is independent of ventricular geometry and can be applied to both left and right ventricular function. This study attempts to define the MPI in a group of normal fetuses and compare these data to other published studies of this index. STUDY DESIGN: The right ventricular (RV) and left ventricular (LV) MPI were measured in 125 normal fetuses (20--40 weeks gestation, mean age 28 weeks). These fetuses were divided into five gestational age groups for comparison. These data were compared to 152 normal children (age 3--18 years, mean age 9.3 years). RESULTS: In normal fetuses, the LV MPI was 0.36 +/- 0.06 and the RV MPI was 0.35 +/- 0.05. This was not statistically different from the group of normal children in whom the LV MPI was 0.35 +/- 0.03 and the RV MPI was 0.32 +/- 0.03. In addition, no significant change in the fetal MPI was seen with advancing gestational age. CONCLUSION: This study demonstrates that fetal ventricular function can be quantitatively measured with the MPI. The MPI provides an easily obtainable and reproducible measure of fetal ventricular performance that can be readily incorporated into all fetal echocardiographic examinations.
The Leboyer birth method requires that the newborn infant is placed on the mothers abdomen and the cord is clamped when it stops pulsating. Since late cord-clamping may result in marked hypervolemia and polycythemia of the neonate, we studied right and left ventricular systolic time intervals by means of pulsed-Doppler echocardiography. Left and right ventricular preejection periods (LPEP, RPEP), right time peak velocity (RTPV), left and right ventricular ejection times (LVET, RVET), and ratio of RTPV/RVET(c) corrected for heart rate were studied in 15 fullterm neonates with early (< 10s) cord clamping and in 15 fullterm neonates delivered according to Leboyer (cord clamping after 3 min) on day 1 (2-4 h after birth) and day 5. After Leboyer birth hematocrit was significantly increased on day 1 (0.61 +/- 0.06 vs. 0.53 +/- 0.07) and on day 5 (0.57 +/- 0.02 vs. 0.50 +/- 0.07). Blood pressure was similar in both groups and increased by about 10% from day 1 to day 5. LVET and RVET were not affected by the mode of placental transfusion, thereby suggesting normal left and right ventricular function after Leboyer birth. The LPEP/LVET (0.36 +/- 0.09 vs. 0.30 +/- 0.08) and RPEP/RVET ratio (0.41 +/- 0.11 vs. 0.33 +/- 0.08) were significantly higher in the Leboyer group (p < 0.05) compared to the early cord clamped group suggesting higher systemic and pulmonary resistance. RPEP decreased significantly by 17% in the control group from day 1 to day 5 (p < 0.05), but did not change in the Leboyer group. In the Leboyer group RPEP/RVET ratio decreased significantly from day 1 to day 5, whereas the control values did not change during the first five days. RTPV:RVET(c) is inversely related to pulmonary artery pressure. A normal ratio is > 0.35, or greater. Mean ratio of RTPV : RVET(c) was significantly lower in the Leboyer group (0.31 +/- 0.08) on day 1 compared to the control group (0.41 +/- 0.09; p < 0.05), but did not differ on day 5. The results suggest that Leboyer delivery was associated with transiently increased pulmonary and systemic resistance, whereas right and left ventricular functions were not affected. This may be explained by increased blood viscosity due to increased hematocrit.
Numerous clinical and experimental studies have suggested that adequate pulmonary blood flow and normal central venous pressure may be maintained without significant contribution of right ventricular function. These data induced experimental and clinical research in the quest for complete bypass of the right heart. More than 40 different operations have been designed to bypass the right ventricle. Partial right ventricular bypass was achieved in 1949 by anastomosing the superior vena cava to the pulmonary artery in animal experiments. In 1950 such as operation was successfully performed clinically for the first time. Complete bypass of the right heart was accomplished for the first time experimentally in 1954 by performing a superior vena cava-to-right pulmonary artery anastomosis and implanting the inferior vena cava into the left atrium. Successful clinical bypass of the right heart was carried out later by implanting both vena cavae into the pulmonary circulation. Until the cavopulmonary shunt conclusively proved the validity of the concept that compensated circulation is possible without participation of the right ventricle, surgeons did not fully understand its possible relevance in clinical situations. The development of partial and complete right heart bypass procedures, both experimental and clinical, not only presented us with viable alternatives to aortopulmonary shunts like the Blalock-Taussig or Potts anastomosis, but it also opened the way to development of new operations such as the Fontan procedure which are based on the principle of low pressure pulmonary flow and right ventricular bypass.
Changes in right-ventricular function were investigated after surgical correction of the mitral-tricuspid valvular defect and congenital heart diseases, such as the interventricular septum defect and Fallot's tetrad. In patients with acquired valvular defects, the analysis of intraventricular pressure curves showed reduced hyperfunction and better relaxation of the right ventricle. The assessment of the effects of different surgical accesses used in radical correction of the interventricular septum defect and Fallot's tetrad demonstrated the advantage of sparing surgery achieved through the right atrium.
The relative ease of acquisition and safety of two-dimensional echocardiography has established it as the mainstay for routine cardiac imaging. Translation of imaging data into useful quantitative information, however, requires fitting the ventricle to a specific geometric model. Because of its complex shape and anterior position, many attempts at right ventricular quantitation by two-dimensional echocardiography have been criticized as impractical and not reproducible. A simple method incorporating subcostal and apical imaging was introduced in 1984. This approach appeared to combine accuracy and practicability but was never validated in a clinical setting because of the difficulties of subcostal imaging in adults. This study assessed the feasibility and accuracy of this technique in the pediatric population. Results of volume comparison to values derived by magnetic resonance imaging were r = 0.96, standard error of the estimate (SEE) = 19.3 ml, and mean difference = 15 +/- 19.4 ml and r = 0.97, SEE = 12.3 ml, and bias = 5 +/- 11.8 ml for diastolic and systolic volumes, respectively. Comparison of estimates of ejection fraction with magnetic resonance imaging demonstrated r = 0.90, SEE = 5.9%, and bias = 3% +/- 5.7%. Interobserver and intraobserver variability was 9.9% and 8.2%, respectively, for systolic volumes and 11.5% and 8.9%, respectively, for diastolic volumes. Evaluation of right ventricular size and function by this approach is comparable to determinations by magnetic resonance imaging and may be clinically useful in the management of pediatric patients.
This experimental study was designed to assess the influence of failure of the right side of the heart or pulmonary hypertension, or both, on the performance of a novel miniaturized left ventricular assist device. In small-sized dogs (n = 50) ischemic global left ventricular failure was induced and support was provided by the HIA-VAD displacement pump (stroke volume 10 or 25 ml) installed as a left ventricular assist device. In three groups of animals (n = 10 each) pulmonary hypertension was created before induction of global left ventricular failure. During left ventricular assist device support temporary ischemic failure of the right side of the heart was induced in four groups of animals (n = 10 each). In the group subjected to left ventricular failure, support with the left ventricular assist device, and right ventricular failure during left ventricular assist, left atrial pressure and cardiac index were significantly lower than in the group subjected to left ventricular failure and left ventricular assist alone (2 +/- 6 versus 11 +/- 6 mm Hg and 1.6 +/- 0.4 versus 1.0 +/- 0.4 L/(min/m2), respectively, p < 0.05). In the group subjected to pulmonary hypertension, left ventricular failure, and left ventricular support, left atrial pressure dropped to values near zero but cardiac index remained unaltered as compared with results with the same regimen without pulmonary hypertension. However, when right ventricular failure was added (that is, pulmonary hypertension, left ventricular failure, left ventricular support, and right ventricular failure during support with the left ventricular assist device) left atrial pressure dropped to negative values (p < 0.05) and cardiac index progressively deteriorated. When, in an additional group of dogs, biventricular support was installed in the latter regimen, circulation was initially well supported but oxygenation deteriorated in 60% of cases. We conclude that (1) adequate right ventricular function was indispensable during support with the left ventricular assist device, (2) the combination of pulmonary hypertension and right ventricular failure led to the "low left ventricular assist device output syndrome," and (3) biventricular mechanical support in the presence of pulmonary hypertension may be complicated by the alveolar leakage syndrome.
OBJECTIVE: Neonates with profound heart failure resulting from Ebstein anomaly have historically had poor outcomes. We report our institutional experience with the surgical management of Ebstein anomaly in severely symptomatic neonates. METHODS: A retrospective review of all patients (n = 16) undergoing neonatal intervention for Ebstein anomaly between 1992 and 2005 has been carried out. The indications for operation were overt heart failure, cyanosis, and acidosis associated with tricuspid regurgitation, depressed right ventricular function, and severe cardiomegaly. The magnitude of cardiac enlargement was assessed by cardiothoracic ratio and Great Ormond Street ratio (area of right atrium + atrialized right ventricle/area of functional left atrium + left ventricle). The operative strategy was first to assess for the possibility of tricuspid valve repair with or without right ventricular outflow tract reconstruction. If this was not feasible, then right ventricular exclusion was performed by oversewing the tricuspid valve with a pericardial patch. A reduction atrioplasty was done and, depending on the extent of the atrialized portion of the right ventricle, plication was performed. A modified Blalock-Taussig shunt provided pulmonary blood flow. This univentricular approach (Starnes procedure) evolved to include a fenestration in the tricuspid valve patch to allow for right ventricular decompression. Analysis included overall and group-specific survival as well as the testing of perioperative clinical, morphologic, and surgical variables for correlation with mortality and morbidity. RESULTS: Mean age and weight at operation were 8 +/-10 days and 3.1 +/- 0.4 kg. Tricuspid valve repair was undertaken in 3 patients with 1 requiring conversion to right ventricular exclusion 3 months after the initial operation. In those with right ventricular exclusion, the tricuspid valve patch was fenestrated in 10 and nonfenestrated in 3. One patient had heart transplant as the initial procedure. There were 5 hospital deaths (31%) and no late deaths among the survivors. Survival in the cohort with a fenestrated tricuspid valve patch was 80% (8/10) versus 33% (1/3) for the nonfenestrated group. This difference did not reach statistical significance, although the trend seems clinically important. There was no difference in the cardiothoracic ratio (0.82 fenestrated vs 0.84 nonfenestrated: P = .802) or the Great Ormond Street ratio (1.2 fenestrated vs 1.02 nonfenestrated: P = .477) between the two groups. Among the 9 survivors of right ventricular exclusion, 3 have had completion of their Fontan, and all 9 have undergone a bidirectional Glenn procedure. All operations including homograft placement in the right ventricular outflow tract, whether during repair or during right ventricular exclusion, ended in death. CONCLUSION: Right ventricular exclusion with a fenestrated tricuspid valve patch combined with right atrioplasty and right ventriculoplasty and a Blalock-Taussig shunt (Starnes procedure) has provided effective palliation for neonates presenting with critical Ebstein anomaly and a tricuspid valve that cannot be repaired.