Ira A. Parness

Developmental modulation of myocardial mechanics: age- and growth-related alterations in afterload and contractility.

Somatic growth is associated with alterations in myocardial mechanics in children with heart disease and in most animal models of congenital heart disease. However, the effect of age and body size on myocardial contractility and loading conditions in normal infants and children is not known. Therefore, 256 normal children aged 7 days to 19 years (34% less than 3 years old) were evaluated with noninvasive indexes of left ventricular contractility and loading conditions. Two-dimensional and M-mode echocardiographic recordings of the left ventricle were obtained with a phonocardiogram, indirect pulse tracing and blood pressure recordings. Left ventricular dimensions, wall thickness and pressure measurements obtained from these data were used to calculate peak and end-systolic circumferential and meridional wall stress and mean and integrated meridional wall stress. Velocity of shortening adjusted for heart rate was compared with end-systolic stress to assess contractility independently of loading status. The subjects were stratified for gender and each of the derived variables was related to age and body surface area. Ventricular shape, assessed as the major/minor axis ratio, and the circumferential/meridional stress ratio were found to be invariant with growth. The ratio of posterior wall thickness to minor axis dimension did not change with age, despite the normal age-related increase in blood pressure. The increase in pressure despite unvarying ventricular shape and wall thickness/dimension ratio resulted in a substantial increase in wall stress that was most dramatic during the first few years of life. In association with the increase in afterload, systolic function decreased with age. However, the age-related decrease in the velocity of shortening was greater than that expected from the increase in afterload alone, indicating a higher level of contractility in infants and children during the first years of life than in older subjects. The process of normal growth and development, similar to that in children with heart disease, is associated with a rapid decrease in the trophic response to hemodynamic loads, resulting in an age-associated increase in wall stress. There is a similar but somewhat more rapid decrease in contractility, with the highest values seen in the youngest patients.

Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiologic data.

Although the short-term results of atrial level repair of transposition of the great arteries (TGA) are satisfactory, longer follow-up has disclosed a significant incidence of systemic right ventricular dysfunction and rhythm disturbances. The arterial switch operation (ASO) may represent a major improvement by restoring the left ventricle as the systemic ventricle and avoiding extensive atrial surgery. We have prospectively evaluated 49 consecutive survivors of ASO for TGA with intact ventricular septum (IVS) by clinical examination, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and invasive electrophysiologic studies. The mean length of follow-up has been 29 +/- 14 (SD) months after surgery. All children are currently asymptomatic and on no medications. Severe supravalvular pulmonary stenosis (greater than 60 mm Hg) was present in five children, all of whom have undergone reoperation. No patient has severe supravalvular aortic obstruction. Mild degrees of supravalvular pulmonary or aortic obstruction have not progressed. Seven children (14%) have trivial or mild aortic regurgitation. Two children have proximal occlusion of the left anterior descending coronary artery with adequate retrograde collateral perfusion. One child had an electrocardiographic pattern of inferior myocardial infarction without evidence of ventricular dysfunction. Systemic (left) ventricular function is normal as measured by end-diastolic pressure (mean 7 +/- 6 mm Hg), ejection fraction (mean 68 +/- 6%), end-diastolic volume (mean 101 +/- 22% of predicted normal), and cardiac index (mean 4.7 +/- 1.3 liters/min/m2). Only one patient has sinus node dysfunction. There have been no late deaths. These early results are encouraging. We conclude that the arterial switch operation is currently the procedure of choice for neonates with TGA and IVS.

Use of preformed nitinol snare to improve transcatheter coil delivery in occlusion of patent ductus arteriosus

Abstract Recent studies have reported the efficacy of transcatheter occlusion of the small patent ductus arteriosus (PDA) using a Gianturco Coil1–3 as an alternative to either surgery or Rashkind Umbrella placement.4 This report presents our experience using a preformed nitinol snare, delivered via the venous circulation, to hold and manipulate the coil as it is delivered from the arterial side of the PDA. This modification was designed to aid in the positioning of the coil, and to facilitate coil retrieval in the event of unstable or unfavorable position after delivery.

Infantile dilated cardiomyopathy : relation of outcome to left ventricular mechanics, hemodynamics, and histology at the time of presentation

BackgroundFor patients with acute dilated cardiomyopathy, definition of prognosis and of clinical features predictive of outcome is particularly important due to the availability of cardiac transplantation and other innovative treatment strategies. Methods and ResultsWe reviewed our experience with 24 children under 2 years of age with dilated congestive cardiomyopathy to determine outcome and potential predictive variables. Clinical, serological, ECG, echocardiographic, hemodynamic, and histological findings were analyzed. Idiopathic cardiomyopathy or myocarditis constituted 29% of the patients presenting with congestive heart failure without structural heart disease. Among these patients, 45% recovered completely, 25% survived with persistent left ventricular dysfunction, and 30% died. All except one of the deaths occurred during the first 2 months after presentation. Poorer outcome and higher mortality were associated with a more severely depressed left ventricular ejection fraction and/or a more spherical left ventricular shape at presentation. Histological evidence of myocardial inflammation was a favorable prognostic indicator, whereas histological evidence of endocardial fibroelastosis was associated with a poor outcome. During the recovery phase, diastolic volume fell rapidly. Ventricular mass was elevated from the earliest observations and fell more slowly, with persistent elevation of the mass-to-volume ratio up to 2 years. Function and contractility improved over the first several months in most patients who recovered, although in occasional patients continued improvement was seen for as long as 2 years after presentation. ConclusionsHistological and echocardiographic features can be used to identify patients at particularly high risk for death. To have any impact on outcome, decisions about cardiac transplantation must be reached rapidly, since almost all deaths occurred within the first 2 months after presentation. Recovery of function is often rapid, but continued improvement may be seen for as long as 2 years.

Left ventricular contractility and function in Kawasaki syndrome. Effect of intravenous gamma-globulin.

To investigate the effect of Kawasaki syndrome on myocardial function, as well as the influence of high-dose intravenous gamma-globulin therapy on resolution of functional abnormalities, we studied 98 patients with Kawasaki syndrome during five time intervals from onset of illness: 1) 10 days or less, 2) 11-31 days, 3) 1-3 months, 4) 3-12 months, and 5) 1-3 years. Normal controls included 48 children under age 8 years, without known cardiovascular disease. Using two-dimensional directed M-mode echocardiograms, we obtained chamber dimensions, fractional shortening, rate-corrected velocity of shortening (Vcfc) adjusted for end-systolic wall stress, and early diastolic function parameters that included adjusted peak rates of left ventricular dimension change, wall thinning, and their respective timing. Left ventricular systolic and diastolic dimensions were larger (both p less than 0.01) in patients than in normal subjects in period 1. Stress-adjusted Vcfc was much lower in patients in the 3 months after disease onset; by period 5, contractility was comparable in patients and normal subjects. Adjusted indexes of early diastolic function did not differ significantly between patients and normal subjects. To investigate the effect of gamma-globulin, we analyzed data on 47 patients prospectively randomized to therapy with aspirin alone (n = 19, 40%) or to aspirin plus gamma-globulin, 400 mg/kg/day for 4 consecutive days (n = 28, 60%). In period 1, before treatment, the two groups had mean fractional shortening and stress-adjusted Vcfc comparable to each other but much lower than those of normal subjects (p less than or equal to 0.001). Patients treated with aspirin alone continued to have diminished fractional shortening and Vcfc compared with normal subjects in periods 2, 3, and 4 (all p less than or equal to 0.05). In contrast, fractional shortening and Vcfc in gamma-globulin-treated patients in these periods were comparable to those of normal subjects. By period 5, no difference was detected in systolic function or contractility between either treatment group and normal subjects. We conclude that early abnormalities of left ventricular contractility and myocardial function, as assessed by echocardiography, generally resolve by 1-3 years after disease onset and that recovery is accelerated by administration of IVGG in the acute phase.

Natural history and patterns of recovery of contractile function in single left ventricle after Fontan operation.

BackgroundBefore the era of the Fontan procedure, the typical course of patients with single left ventricle (LV) consisted of heart failure and death during the second or third decade of life. Despite the advent of effective palliative therapy, ventricular dysfunction remains a significant clinical problem for these patients. Methods and ResultsTo investigate the causes of ventricular dysfunction in these patients and to determine whether Fontan-type repair reverses deterioration of LV function, the ventricular dimensions, volume, shape, wall stress, and systolic function were determined by echocardiography in 84 patients 0.2–35 years old with double-inlet single LV or tricuspid atresia. Measurements were obtained in 67 patients after palliation (arterial shunt or pulmonary artery band) and in 47 patients a median of 4.4 years after a Glenn (n=9) or a Fontan operation (n=38). Before a Fontan procedure, ventricular volumes were 2 to 3 times normal. Ventricular afterload, assessed as circumferential and meridional end-systolic wall stress, became abnormal after 2 years of age. With age, LV shape changed progressively from ellipsoidal to spherical, as indicated by the decrease in long axis: short axis ratio from normal (1.9) toward unity. Concomitantly, the ratio of circumferential to meridional end-systolic wall stress fell from 1.3 to unity, the ratio of a sphere at equilibrium. This age-related change in shape and load occurred in concert with progressive deterioration of LV systolic function and contractility. Aortic oxygen saturation, an indicator of pulmonary blood flow and therefore volume work in single-ventricle physiology, was inversely and independently correlated with contractility. In the group of patients in whom a Glenn or a Fontan operation was performed at < 10 years of age, ventricular dimensions, volumes, and wall stress diminished and LV function and contractility improved after surgery (p < 0.001). In patients undergoing surgery after 10 years of age, few had improvement of LV function after surgery. Postoperative ventricular function and contractility were inversely related to age at surgery and to aortic oxygen saturation measured before surgery. ConclusionsAlthough Fontan-type repair of single ventricle early in life is associated with reversal of the abnormal contractile mechanics associated with age and volume load, this capacity for recovery diminishes with age at surgery.

Outpatient closure of the patent ductus arteriosus.

We have modified and applied to selected outpatients the transvenous approach to correction of patent ductus arteriosus (PDA) with the Rashkind PDA Occluder. Modifications included establishing the diagnosis and PDA anatomy before catheterization with echocardiography. The sedation/anesthetic regimen was altered to meet the needs with respect to transcatheter PDA closure rather than diagnostic cardiac catheterization. Anticoagulation was avoided. A strategy for management of pin entrapment in the foam was devised. Residual trans-PDA flow after umbrella placement was temporarily occluded with balloon-tipped catheters. These modifications were used in 23 consecutive patients with uncomplicated PDA. Closure was successful in each child. Nineteen of 23 patients were discharged on the day of the procedure. No serious complications were encountered.

Bulboventricular foramen size in infants with double-inlet left ventricle or tricuspid atresia with transposed great arteries: influence on initial palliative operation and rate of growth.

Bulboventricular foramen obstruction may complicate the management of patients with single left ventricle. Bulboventricular foramen size was measured in 28 neonates and infants greater than 5 months old and followed up for 2 to 5 years in those patients whose only systemic outflow was through the foramen. The bulboventricular foramen was measured in two planes by two-dimensional echocardiography, its area calculated and indexed to body surface area. One patient died before surgical treatment. The mean initial bulboventricular foramen area index was 0.94 cm2/m2 in 12 patients (Group A) in whom the foramen was bypassed as the first procedure in early infancy. The remaining 15 patients underwent other palliative operations but the bulboventricular foramen continued to serve as the systemic outflow tract. There was one surgical death. Six (Group B) of the 14 survivors developed bulboventricular foramen obstruction during follow-up (mean initial bulboventricular foramen area index 1.75 cm2/m2). The remaining eight patients (Group C) did not develop obstruction during follow-up and had an initial bulboventricular foramen larger than that in the other two groups (mean initial bulboventricular foramen area index 3.95 cm2/m2). All patients with an initial bulboventricular foramen area index less than 2 cm2/m2 who did not undergo early bulboventricular foramen bypass developed late obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcatheter closure of a large patent ductus arteriosus with the clamshell septal umbrella.

In 14 patients undergoing transcatheter closure of a large (greater than 4 mm diameter) patent ductus arteriosus, occlusion was attempted with use of the Bard Clamshell septal umbrella. Patient age ranged from 0.7 to 30.4 years. Isolated patent ductus arteriosus was present in 11 patients; 3 had additional congenital heart lesions. Moderate or severe pulmonary hypertension was present in four patients. The diameter of the patent ductus arteriosus ranged from 4.5 to 14 mm, as determined by contrast injection through an 11F sheath or by balloon sizing; it appeared larger by this method than by the standard angiographic method. All 14 patent ductus arteriosi were successfully closed. Prior embolization of a Rashkind umbrella was the reason for using a Clamshell device in three patients; one additional embolization of a Clamshell device occurred. All errant devices were retrieved at cardiac catheterization, without associated hemodynamic instability. No other complications occurred. Among the 14 patients, 11 had complete ductal closure by Doppler color flow mapping at last follow-up and 3 had trivial residual flow. All four patients having associated complex lesions or pulmonary hypertension, or both, had symptomatic improvement after the procedure, although one child (with Shones anomaly) died 3 months later. The Clamshell device provides stable and effective closure of a large patent ductus arteriosus, and allows transcatheter closure to be offered to some patients who were previously considered unsuitable for this procedure.

Abnormal myocardial mechanics in Kawasaki disease: Rapid response to γ-globulin☆

Abstract Background The time course and rate of recovery of myocardial dysfunction in association with Kawasaki disease in response to intravenous γ-globulin is unknown and may provide mechanistic clues. Methods and Results The acute changes in myocardial contractility in 25 patients with Kawasaki disease were evaluated by noninvasive stress-shortening and stress-velocity analysis. Echocardiograms were performed before and then daily for 4 days during which the patients received γ-globulin 1.6 to 2 g/kg. Before treatment, contractility was abnormally low Conclusions More than half the patients with Kawasaki disease have abnormal contractility at presentation. Myocardial response to globulin therapy is associated with rapid improvement in myocardial mechanics, with a high concordance between the clinical and myocardial response to therapy. The speed of recovery suggests that depressed contractility in patients with Kawasaki disease is caused by a rapidly reversible process such as circulating toxins or activated cytokines. Long-term outcome is good even in those patients with slow recovery of myocardial function.