Jay M. Jarmakani

Right Ventricular Volume Determinations in Children Normal Values and Observations with Volume or Pressure Overload

Right ventricular (RV) volumes were calculated from biplane cineangiocardiograms in 46 patients undergoing diagnostic cardiac catheterization. Validation of methodology was performed by comparison of known and calculated volumes of postmortem RV casts as well as by comparison of cineangiocardiographic RV and left ventricular (LV) stroke volumes of patients without shunts or valvular insufficiency. Seven infants, <1 year of age, with normal right hearts as compared with older children showed smaller RV end-diastolic volumes (39 ± 8 vs 70 ± 13 ml/m2, P < 0.001) as well as decreased RV systolic indices (SI) (3.71 ± 0.68 vs 4.66 ± 1.10 liters/min/m2, P < 0.05). There were no differences between normal infants and older children for RV ejection fraction (EF), RVEDV/LVEDV = 1.01, RVSI/LVSI = 0.99, and RVEF/LVEF = 1.04 vs 0.99. In 13 patients with isolated pulmonary stenosis, RVEDV, RVEF, RVSI, RVEDV/LVEDV, and RVSI/LVSI were not different from normal, but RVEF/LVEF averaged 1.13 vs 0.99 in normal infants, P < 0.05. In contrast, 11 patients studied with atrial septal defect or total anomalous pulmonary venous connection had significant increases in RVEDV (128 ml/m2), RVSI (9.34 liters/min/m2), RVEDV/LVEDV (2.36), RVSI/LVSI (2.81), and RVEF/LVEF (1.17), but normal values for RVEF. There was a significant linear relationship between Qp/Qs from oxygen data and RVSI/LVSI. In three patients studied an average of 1 year following atrial septal defect (ASD) repair, RVEDV remained elevated. In volume overload, alterations in RV volume characteristics are apparent and can be useful in shunt estimation; adaptation to an RV pressure overload, however, is not associated with detectable volume alterations.

Left Heart Volume Estimation in Infancy and Childhood: Reevaluation of Methodology and Normal Values

Left ventricular (LV) volume determinations by the area-length method were reevaluated in postmortem studies of left ventricles ranging from 0.5 to 90 cm3 absolute volume. The regression equation relating known and calculated volumes for calculated volumes <15 cm3 (V′ = 0.733V) was found to be significantly different from that for calculated volumes >15 cm3 (V′ = 0.974V - 3.1). From these equations, normal values for cinecardiographic LV end-diastolic volume (LVEDV), LV ejection fraction (LVEF), LV systolic output (LVSO), LV mass (LVM), and left atrial maximal volume (LAMax) were derived from 56 children (19 < 2 years) with normal left ventricles who underwent cardiac catheterization. Values for LVEDV/BSA were significantly less for infants (< 2 years) than for older children (42 ± 10 versus 73 ± 11 cm3/m2, P <0.001). Values for LAMax/BSA were also less for infants than for older children (26 ± 5 versus 38 ± 8 cm3/ m2, P <0.001), and LVEF was significantly increasel for infants (0.68 ± 0.05 versus 0.63 ± 0.05, P <0.01). The values for LVM/BSA (88 ± 12 g/m2) and LVSO/BSA (4.42 ± 0.95 liters/min/m2) were not significantly different for infants and older children. Multiple regression equations were derived for the prediction of normal volume and mass variables from a patients height, weight, and age. The predicted values can be obtained from nomograms, and estimations of normalcy can be made by comparisons of observed and predicted values with the 95% limits as defined.

Partial Fontan: Advantages of an adjustable interatrial communication☆

Systemic venous hypertension after the Fontan procedure is a major cause of mortality and morbidity, accounting for 11 of 16 deaths in our series of 228 Fontan procedures. A partial Fontan with a residual atrial septal defect (ASD) would allow controlled right-to-left shunting to reduce venous pressure and improve cardiac output while maintaining a reduced but acceptable arterial oxygen saturation. This allows complete or graded closure of the ASD after the discontinuation of cardiopulmonary bypass in the operating room or at any time in the postoperative period by exposing the snare under local anesthesia. From 1987 to 1990, 36 patients undergoing the modified Fontan procedure had placement of an adjustable interatrial communication. Indications for placement of an adjustable ASD included increased pulmonary artery pressures, increased pulmonary vascular resistance, reactive airway disease, previously increased or unknown pulmonary vascular resistance, small pulmonary arteries, and borderline ventricular function. Fourteen patients had the adjustable ASD closed at the time of operation, 8 patients underwent narrowing, and 12 underwent closure of the ASD in the postoperative period. Eight patients were discharged with the ASD partially open, and 2 patients underwent delayed closure. The partial Fontan with an adjustable ASD may increase the safety of the Fontan procedure for high-risk groups such as those with increased pulmonary vascular resistance, pulmonary hypertension, and impaired left ventricular function and for infants, who tolerate venous hypertension poorly. The ability to adjust the ASD in stages depending on the hemodynamic response increases flexibility and safety.

Two-dimensional echocardiographic assessment of left ventricular volumes and ejection fraction in children.

The ability of two-dimensional echocardiography to masure left ventricular volumes and ejection fraction was evaluated in 25 children with congenital heart disease. Dimensions and planimetered areas were obtained in the short-axis view at the mitral valve and high and low papillary muscle levels and in the apical two- and four-chamber views. Eight algorithms using five geometric models were assessed. Left ventricular end-diastolic volume, end-systolic volume and ejection fraction were compared with data from biplane cineangiocardiograms. The correlation varied with the algorithm used. Algorithms using short-axis views appeared superior to those using only apical long-axis views. Four algorithms estimated left ventricular volumes with equal accuracy (Simpsons rule, assuming the ventricle to be a truncated cone; Simpsons rule, assuming the ventricle to be a truncated ellipse; hemisphere cylinder; and ellipsoid biplane). The single algorithm that best estimated left ventricular ejection fraction was the ellipsoid biplane formula using the short-axis view at the papillary muscle level (r= 0.91, slope = 0.94, SEE = 6.7%). Thus, two-dimensional echocardiography can accurately assess left ventricular volumes and ejection fraction in children with congenital heart disease.

Right and left ventricular volume characteristics in children with pulmonary stenosis and intact ventricular septum.

Right (RV) and left ventricular (LV) volume variables were calculated in 27 patients with pulmonary stenosis (PS) during routine cardiac catheterization. These included 21 patients with isolated PS (group 1) and seven studies in six patients (group II) with PS and right-to-left atrial shunt. Right and left ventricular volumes were calculated according to Simpsons rule and the arealength methods respectively.In group 1, right ventricular end-diastolic volume (RVEDV) was not different from normal, RVEF (0.70 ± 0.02) was significantly higher than normal, and right ventricular stroke index (RVSI) (4.36 L/min/M2 ± 0.23) was normal. The RVEDV/LVEDV ratio was significantly less than normal (P 0.001). Multiple regression analysis indicated that RVEDV (% of normal) decreased with both age and severity of RV outflow obstruction (r = 0.77). In group II, RVEDV and RVSI were both less than normal (P < 0.001), while RVEF was normal. LVEDV in the group was slightly higher than normal (P = 0.026) while LVEF was less than normal (P = 0.027) and resulted in normal LVSI.The data suggest that RV and LV function in children with isolated PS are normal, and that knowledge of the RV volume variables is not essential for the management of these patients. In contrast, hearts of patients with PS and right-to-left interatrial shunt have evidence that suggest depressed ventricular function, and the quantitation of RV volume may be helpful in the management of these patients.

Diagnosis and management of postoperative pulmonary hypertensive crisis.

In this paper we discuss two infants and one child who experienced a previously unreported complication after complete correction of a large, unrestrictive ventricular septal defect. Two patients had documented pulmonary hypertensive crises and severe right-heart failure secondary to hypoxia and pulmonary vasoconstriction. These crises were associated with significantly increased right ventricular (RV) peak systolic and end-diastolic pressures and right-to-left shunting via a foramen ovale which, in turn, exaggerated the hypoxis. The crises were treated successfully with tolazoline in the second and third patients. RV pressure returned to normal values and have remained normal up to 12 months postoperatively in the second patient. Although the RV pressures decreased with tolazoline in the third patient, they never reached normal values. Postoperative monitoring of pulmonary artery and RV pressures in infants with large ventricular septal defects is essential when unexplained complications are encountered. Tolazoline proved to be very effective in the treatment of two patients with pulmonary vasoconstriction secondary to hypoxia.

Left Heart Function in Children with Tetralogy of Fallot before and after Palliative or Corrective Surgery

Left heart volume and left ventricular mass (LV mass) were calculated from biplane cineangiocardiograms in 58 tetralogy of Fallot (TF) patients preoperatively, in 31 patients after shunt procedure, and in 24 patients after complete correction. Preoperatively, the LV end-diastolic volume and left atrial maximal volume (LAmax) were normal in cyanotic infants less than 2.0 years old and in acyanotic patients more than 2.0 years old. These variables, however, were less than normal in cyanotic children > 2.0 years old. Left ventricular ejection fraction (LVEF) and LV systolic index (LVSI) were both less than normal in all groups preoperatively. LV mass was normal preoperatively. After successful shunt procedure, there was a significant increase (P < 0.01) in LVEDV, LVSI, LAmax, and LV mass. The LVEF, however, remained less than normal. After successful corrective surgery, the total group showed a significant increase (P < 0.01) in LVEDV, LVSI, LAmax,and LV mass as compared with preoperative values. Furthermore, the LVEDV was slightly but significantly higher than normal and the LV ejection fraction remained significantly depressed from normal. There was an inverse correlation between LVEDV or LVSI, expressed as a percent of normal, and hemoglobin concentration but not with the net left-to-right shunt or aortic saturation.The decreased LV ejection fraction in cyanotic tetralogy patients in the presence of decreased peak LV pressure (decreased afterload) as well as the decreased LVEF after shunt procedure or complete correction (increased preload) suggests that LV function is depressed in tetralogy patients and remains depressed despite corrective surgery.

Factors influencing survival in patients undergoing the bidirectional Glenn anastomosis

The bidirectional Glenn anastomosis (BGA) has long been used as a surgical intervention for patients with single ventricle physiology. Initially, this procedure was the final stage in palliation and was performed in older children. Eventually, as the Fontan procedure came to be used as a method to separate circulations, the Glenn procedure was performed as an intermediate step. Over time, the BGA was performed as an alternative for patients who were considered to be at high risk with the Fontan procedure. Between January 1, 1988, and January 1, 1994, 129 patients underwent BGA at the University of California-Los Angeles. These patients were reviewed retrospectively, including clinic visits, catheterization, and echocardiographic information. The overall survival rate was 87% (112 of 129 patients). The average length of follow-up was 27 months. This information was then analyzed by univariate and multivariate analysis. Several factors were related to failure in patients who underwent BGA including pulmonary artery pressure, systemic right ventricle, and presence of anomolous pulmonary venous drainage and heterotaxy syndrome.

Two-dimensional echocardiographic assessment of right ventricular volume in children with congenital heart disease

The ability of 2-dimensional echocardiography to measure right ventricular (RV) volume and ejection fraction was assessed in 22 children with congenital heart disease. From the apical 4 chambers 2-dimensional echocardiographic image, the long-axis length of the right ventricle was measured and the area planimetered. On the anteroposterior and lateral cineangiocardiographic planes, the right ventricle was separated into 2 parts: RV sinus and outflow tract. The longest length, inflow tract length, and area of the sinus were measured from biplane cineangiographic views. The echographic long-axis length correlated well with the longest length of the RV sinus measured from both anteroposterior and lateral cineangiographic views at both end-systole and end-diastole. Moreover, the echographic area correlated well with the sinus area obtained from both cineangiographic views. From these regression analyses, the echographic long axis length and area were corrected to the angiographic longest length and area of the sinus. The new corrected echographic longest length and area were applied to 3 formulas (2 biplane and 1 uniplane) to calculate the sinus volume of the right ventricle. Total RV volume was then derived from the sinus volume. RV volumes and ejection fraction determined by 2-dimensional echocardiography were compared with those obtained from biplane cineangiography using Simpsons rule method. All formulas tested predicted RV volumes and ejection fraction with equal accuracy. Thus, 2-dimensional echocardiography can assess RV volume and ejection fraction in children with congenital heart disease.

Left Heart Volume Characteristics with a Right Ventricular Volume Overload Total Anomalous Pulmonary Venous Connection and Large Atrial Septal Defect

Left heart volume characteristics were evaluated by using biplane cineangiocardiography in 18 studies in 15 patients with total anomalous pulmonary venous connection (TAPVC) and in 37 studies on 35 patients with large secundum or sinus venosus atrial septal defects (ASD). Left ventricular end-diastolic volume (LVEDV) was decreased to less than 67% of normal in five of 15 preoperative TAPVC patients, but the average value for the entire group was not significantly different from normal. In ASD patients, the average LVEDV was 87% of normal which was significantly decreased (P < 0.001). The ejection fraction was decreased from normal in patients with TAPVC and ASD who were less than 2 years of age (0.62 vs. 0.68, P < 0.01), but was normal in older patients. Left ventricular systolic output was significantly decreased from normal in both TAPVC (75% of normal, P < 0.001) and ASD patients (81% of normal, P < 0.001). Left atrial maximal volume was significantly decreased from normal in TAPVC patients averaging only 55% of normal (P < 0.001), but was normal in eight ASD patients. All volume variables increased following corrective surgery in two TAPVC patients and two ASD patients. These studies document that left heart volumes and outputs in infants and children with TAPVC and large isolated atrial defects can be diminished preoperatively.