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Biomedical subjects

S D Colan

Publications and source records attributed to S D Colan.

At least 55 records · Page 3Linked to original sources
PubMed1997

Mechanics of left ventricular systolic and diastolic function in physiologic hypertrophy of the athlete's heart.

As a result of a number of factors, there is tremendous diversity in the pattern of cardiac mechanics encountered in athletes. Nevertheless, several trends can be identified, and several conclusions are possible. Hypertrophy of a mild to moderate degree and out of proportion to body size is a common finding. Some athletes experience ventricular dilation with appropriate hypertrophy and preservation of the ventricular mass-to-volume ratio, whereas others manifest concentric hypertrophy with an increased mass-to-volume ratio. The functional changes that are encountered appear to be secondary to the structural alterations, and there is no evidence of altered myocardial systolic or diastolic properties. Some athletes with hypertrophy have reduced wall stress when they are evaluated at rest, and velocity of shortening is augmented because of the reduced afterload. As a result of adaptation to a high-output state, some athletes appear preload reduced when evaluated at rest. Although velocity of shortening is not affected by preload status, fractional shortening is inversely related to preload. The magnitude of systolic shortening is therefore the net result of altered preload and afterload and cannot be understood without assessing both of these parameters. When the various determinants of systolic shortening are included, contractility appears to be normal. There have been several reports of depressed contractility immediately after extreme exertion. Although the mechanism remains uncertain, several intriguing possibilities have been proposed.

Anthropometry↗
PubMed1997

Clinical course and hemodynamic observations after supraannular mitral valve replacement in infants and children.

OBJECTIVES: We report the clinical course and unique hemodynamic findings after placement of a supraannular mitral valve prosthesis. BACKGROUND: Children with symptomatic mitral valve disease whose annulus is too small for the smallest prosthesis are difficult to manage. One option is valve replacement with a prosthesis positioned entirely within the left atrium (LA). METHODS: We reviewed 17 patients (median age 10 months) with symptomatic mitral valve disease who underwent placement of a supraannular valve prosthesis between 1980 and 1994. RESULTS: The actuarial survival rates were 88% at 1 month and 71%, 62% and 53% at 1, 2 and 10 years, respectively. Preoperative hemodynamic data (mean +/- SD)) compared with those after placement of the supraannular mitral prosthesis were as follows: "a" wave to left ventricular end-diastolic pressure gradient 17 +/- 5 versus 4 +/- 4 mm Hg (p = 0.003), mean LA pressure 25 +/- 6 versus 20 +/- 6 mm Hg (p = 0.07), "a" wave 30 +/- 6 versus 19 +/- 5 mm Hg (p = 0.006), "v" wave 28 +/- 5 versus 30 +/- 9 mm Hg (p = 0.31), mean pulmonary artery pressure 54 +/- 19 versus 42 +/- 15 mm Hg (p = 0.07) and left ventricular end-diastolic pressure 14 +/- 5 versus 16 +/- 4 mm Hg (p = 0.12). CONCLUSIONS: Supraannular mitral valve replacement provides relief of mitral stenosis or mitral regurgitation. However, LA to left ventricular early diastolic gradients with large atrial "v" waves contribute to elevated mean LA pressures in the absence of prosthetic valve obstruction or regurgitation. As a result of this unexpected finding, associated left heart obstructive lesions and pulmonary and left ventricular end-diastolic hypertension, the outlook remains poor.

Child, Preschool↗
PubMed1997

Anomalous origin of left coronary artery from pulmonary artery: recovery of left ventricular function after dual coronary repair.

OBJECTIVES: We reviewed our institutional experience with anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) after dual coronary repair to assess preoperative variables predictive of outcome, the time course for postoperative recovery of cardiac function, the short- and long-term complications and our experience with left ventricular assist devices (LVAD) in these patients. BACKGROUND: Outcome after surgical repair of ALCAPA remains incompletely defined. METHODS: The surgical records and echocardiograms of 42 patients were reviewed. Left ventricular function was assessed by fractional shortening z-score (FSz) and stress-velocity index. RESULTS: The overall survival rate was 86%. All six patients who died were < 1 year old and died within 3 days of the operation. More severe preoperative mitral regurgitation (MR) was associated with increased mortality, but age, body surface area, preoperative FSz and end-diastolic dimension were not. We used an LVAD for 7 of 28 patients who underwent repair for ALCAPA since its introduction at our institution, with a survival of 5 of 7 patients. The degree of MR improved in 62% of patients and remained unchanged in 38%. Complications included supravalvar pulmonary stenosis (16 of 21 patients) and baffle leaks (11 of 21 patients) with the intrapulmonary baffling technique. Supravalvar pulmonary stenosis developed in 1 of 11 patients after direct coronary reimplantation. Left ventricular function became normalized in all 28 patients with follow-up past 1 year, regardless of preoperative FSz. Of 13 patients who underwent serial postoperative echocardiography, the average time to normalization of function was 2 to 7 months. CONCLUSIONS: The degree of preoperative MR was predictive of outcome, whereas the severity of preoperative cardiac dysfunction and ventricular dilation were not. Mild and moderate MR tended to improve without mitral valvuloplasty. Complete recovery from myocardial dysfunction is expected after dual coronary repair of ALCAPA.

Adolescent↗
PubMed1997

Nutritional status and cardiac mass and function in children infected with the human immunodeficiency virus.

Malnutrition, skeletal muscle wasting, and changes in cardiac muscle mass and function have been described in children infected with the human immunodeficiency virus (HIV). This report analyzes the relation of nutritional status to cardiac muscle mass and function in HIV-infected children. Thirty-six children with symptomatic HIV infection underwent simultaneous anthropometric and echocardiographic evaluations before antiretroviral therapy or supplemental feedings. Nutritional measurements included weight, height, triceps skinfold thickness, and arm muscle circumference. Cardiac measurements included left ventricular mass, contractility, end-diastolic dimension, fractional shortening, blood pressure, and heart rate. In a cross-sectional analysis, children infected with HIV were significantly below age-adjusted standards for height (P = 0.0001), weight (P = 0.0001), triceps skinfold thickness (P = 0.001), and arm muscle circumference (P = 0.04). Left ventricular mass normalized to body surface area was below standard, but contractility was normal. Correlation analyses found an inverse relation between left ventricular mass and weight z score (r = -0.45, P = 0.01), height z score (r = -0.47, P = 0.006), and arm muscle circumference percentile (r = -0.51, P = 0.003). An inverse relation was also found between heart rate and weight z score (r = -0.47, P = 0.007) and arm muscle circumference percentile (r = -0.46, P = 0.007). In malnourished children with HIV infection, a paradoxical relation exists between nutritional status and cardiac muscle mass. The inverse relation between heart rate and nutritional status may suggest altered metabolic rates with possible increased sympathetic tone.

Anthropometry↗
PubMed1997

Multipolar endocardial mapping of the right heart using a basket catheter: acute and chronic animal studies.

The development of catheter-based ablative techniques for primary atrial and ventricular arrhythmias is likely to be assisted by improved techniques for systematic endocardial activation sequence mapping. RA mapping using a multielectrode basket catheter has been shown to be feasible with minimal acute toxicity in a prior study. The objectives of the current study are to investigate: (1) the utility of the basket catheter for mapping RV activation; and (2) the evolution of acute endocardial lesions produced by basket catheter use in both the RA and RV over 4-8 weeks time. A flexible, 5-spoke basket catheter bearing 25 electrode pairs was placed in the RA (n = 9) or the RV (n = 13) in 22 juvenile sheep (22-56 kg). The catheter was deployed for 0.1-4.1 hr (RA) and 0.3-3.9 hr (RV). In 20 of these 22 animals, 32 recordings were made of filtered (30-250 Hz) bipolar electrograms and surface ECG. Electrograms were timed and used to construct activation sequences based on a schematic of catheter geometry. Hearts were examined either acutely (4 RA and 9 RV studies) or 4-8 weeks after the procedure (5 RA and 4 RV studies). One animal undergoing RA placement had an air embolism resulting in cardiac arrest immediately prior to basket placement; all other animals were stable during placement. RA electrograms of sufficient quality to determine activation time were recorded from 82% of pairs in RA maps, and RV electrograms from 89% of pairs in RV maps. Mean activation sequence duration in RV was 16 ms versus 47 ms in RA (P < 0.0001), making construction of RV maps more difficult. Acute postmortem studies of RV placement revealed a silent apical RV puncture in one animal. Superficial abrasion or ecchymosis of RV endocardium and/or tricuspid valve were noted in six animals. Postmortem exams in both RA and RV chronic studies showed healed endocardial lesions, with only superficial scarring. Rapid RV activation mapping using a basket catheter is feasible, but requires precision recording techniques. Endocardial abrasions produced in lambs both by RA and RV placement of the catheter are healed in < 4-8 weeks, with trivial residua. The multielectrode basket catheter may be applicable to the mapping of tachycardias originating in or involving the right ventricle.

Animals↗
PubMed1997

Intra-atrial reentrant tachycardia after palliation of congenital heart disease: characterization of multiple macroreentrant circuits using fluoroscopically based three-dimensional endocardial mapping.

INTRODUCTION: The anatomic substrate of intra-atrial reentrant tachycardia (IART) following congenital heart surgery is poorly understood, but is presumed to be different than common atrial flutter. METHODS AND RESULTS: To study the mechanisms of IART, we used a new technique for high-density endocardial mapping using recordings from a multipolar basket recording catheter (25 bipolar pairs). For each recording, biplane fluorographic reference points were digitized to obtain the spatial locations of electrode pairs, and activation times were calculated using temporal reference points from the surface ECG. Using custom software, data were combined to create three-dimensional atrial activation sequence maps, which were displayed as animated sequences. Using this technique, recordings were made in induced and/or spontaneous IART in 8 patients following congenital heart surgery (5 Fontan, 2 tetralogy of Fallot repair, 1 ventricular septal defect repair), and in 3 patients with normal intracardiac anatomy (1 with type I atrial flutter). Ten discrete IART activation sequences were recorded; 2 patients had 2 sequences each. IART maps were constructed using a median of 108 electrode positions (range 27 to 197) from a median of 6 recordings/sequence (range 3 to 11). Sinus or paced atrial rhythms were also recorded, and maps were created in a similar fashion. Visual analysis of activation sequences of sinus and paced rhythm were anatomically concordant with known mechanisms of atrial activation. IART sequences revealed diverse mechanisms; only 1 IART circuit was similar to that associated with common atrial flutter. Activation wavefront emergence from presumed zones of slow conduction, lines of conduction block, and apparent bystander activation were observed. CONCLUSIONS: High-density atrial activation sequence maps demonstrate that IART following congenital heart surgery utilizes diverse circuits and is distinct from common atrial flutter. The technique used to create these three-dimensional activation sequences may improve understanding of these complex atrial arrhythmias and assist in the development of ablative therapies.

Adolescent↗
PubMed1996

Outcome of patients with ectopia cordis and significant intracardiac defects.

BACKGROUND: Previous reports suggest a poor prognosis for patients with ectopia cordis and significant congenital heart disease. METHODS AND RESULTS: To determine the outcome of affected patients in a recent medical and surgical era, we reviewed the clinical course, echocardiograms, catheterization data, and operative reports of all patients with ectopia cordis and significant heart disease encountered at Children's Hospital from 1982 to the present. We identified 13 patients with conotruncal defects and either thoracic (TEC, n = 4) or thoracoabdominal (TAEC, n = 9) ectopia cordis. Diagnosis was established in utero in 6, with termination of pregnancy in 2 and death before transfer to Children's Hospital in 1. Of 10 patients postnatally managed at Children's Hospital, 4 of 8 with TAEC and 1 of 2 with TEC survived beyond infancy, with an age at most recent follow-up of 3.5 to 9.8 years. All 5 survivors had procedures as neonates to provide skin coverage over the midline defect and heart, with concomitant repair of a small omphalocele in 4. Three underwent successful surgical repair of the cardiac defect, including ventricular septal defect closure for double-outlet right ventricle (9 months), repair of tetralogy of Fallot with pulmonary atresia (2.6 years), and repair of double-outlet right ventricle, pulmonary stenosis, and total anomalous pulmonary venous connection to the coronary sinus (3.3 years). Two other patients with TAEC, conoventricular defects, and hypoplastic left ventricle underwent single-ventricle palliation. One patient, at 4 years of age underwent a right cavopulmonary anastomosis and intra-atrial coronary sinus-to-right superior vena cava baffle. The second patient had a modified Fontan procedure. None of the 5 survivors had significant extrathoracic defects, whereas all 3 who died by 3 weeks of age had both a large omphalocele and pulmonary hypoplasia. Two infants with pentalogy of Cantrell, 1 with a large omphalocele, died of fungal sepsis by 5 weeks of age, and 1 other died intraoperatively after repair of pulmonary venous confluence obstruction and right Blalock-Taussig shunt placement. CONCLUSIONS: Our experience indicates that patients with TEC and TAEC and significant intracardiac defects, in the absence of significant extracardiac defects, can survive beyond early infancy and undergo successful cardiac repair or more definitive palliation for single-ventricle physiology.

Child↗
PubMed1996

Control mechanisms for physiological hypertrophy of pregnancy.

BACKGROUND: Pregnancy represents an excellent model of acute physiological hypertrophy and atrophy secondary to a transient hemodynamic load. This investigation examined the effects of pregnancy on ventricular mechanics using load-independent indexes of contractility to test the hypothesis that the cardiac trophic response functions as a servomechanism with wall stress as the feedback variable. METHODS AND RESULTS: Serial studies were performed in 33 women at six time periods during and shortly after normal gestation. Changes in ventricular dimension, wall thickness, and left ventricular mass were parallel to changes in body size. Fractional shortening and velocity of shortening progressively diminished during pregnancy, with a nadir at the first postpartum examination, despite a progressive fall in afterload. Cardiac index rose rapidly in early gestation and remained elevated throughout pregnancy. Peak wall stress was elevated in early gestation coincident with the rapid rise in cardiac index due to elevated volume before compensatory rise in mass. With compensatory hypertrophy, peak wall stress normalized by midgestation. The change in left ventricular mass was closely related to peak wall stress but correlated poorly with mean, total, and end-systolic wall stress. CONCLUSIONS: Normal pregnancy is associated with a reversible fall in contractility. Systolic function is preserved throughout most of pregnancy by a fall in afterload but decreases near term and early postpartum because of decreased contractility and diminished preload. Left ventricular hypertrophy and atrophy are temporally related to changes in hemodynamic load. The response is consistent with a tightly coupled servomechanism transduced by peak wall stress with a 1- to 4-week compensatory response time.

Adult↗
PubMed1996

High-density endocardial activation mapping of the right atrium in three dimensions by composition of multielectrode catheter recordings.

The use of radiofrequency ablation for treatment of complex arrhythmia substrates has prompted interest in transcatheter endocardial activation mapping. Technical constraints on catheter fabrication and the intention to use such maps to guide ablation both demand innovative approaches to mapping. A fluoroscopically based endocardial mapping technique is proposed to improve the ability of electrophysiologists to interpret large amounts of data acquired using multielectrode catheter arrays, improving their ability to visualize the data and act on its content. This technique addresses previous limitations imposed by the number of electrodes that can be deployed and by the difficulty in determining their relative spatial locations. It is based on the composition of multiple activation sequence mappings made in a single rhythm, with the spatial locations of recording electrode pairs determined in orthogonal fluoroscopic views referenced to stable intrathoracic markers. Rather than imposing a geometry determined primarily by the measurement apparatus, the spatial locations of only those electrodes in proximity to the endocardial surface, as determined by their ability to record bipolar electrograms, are measured. In this manner, the geometry of the endocardium may be approximated by measurements made of electrode position. Using this approach, the number of endocardial sites that can be sampled in a stable rhythm is theoretically unlimited, resulting in the realization of high-resolution activation maps. Spatiotemporal data may be used to create three-dimensional activation sequence maps, displayed as animated sequences. This technique was used in anatomically normal and diseased human right atria to create activation maps of sinus and paced rhythms, classic atrial flutter, and postoperative intraatrial reentrant tachycardia, using a median of 108 electrode positions (range, 27-197) in 25 maps. The activation sequences represented by these maps were diverse, but qualitatively concordant with known mechanisms of atrial activation. High-density catheter-based activation mapping of the right atrium is feasible and may improve understanding of complex arrhythmias and assist in the development of ablative techniques. Further research is needed on the spatial correlation between cardiac anatomy and fluorography, suppression of spatial artifact, and optimal mapping densities.

Body Surface Potential Mapping↗
PubMed1996

Sevoflurane depresses myocardial contractility less than halothane during induction of anesthesia in children.

BACKGROUND: Cardiovascular stability is an important prerequisite for any new volatile anesthetic. We compared echocardiographically derived indices of myocardial contractility during inhalation induction with sevoflurane and halothane in children. METHODS: Twenty children were randomized to receive either halothane or sevoflurane for inhalation induction of anesthesia. No preoperative medications were given. Myocardial contractility was evaluated at baseline and at sevoflurane and halothane end-tidal concentrations of 1.0 minimum alveolar concentration (MAC) and 1.5 MAC. RESULTS: There were no differences between groups in patient age, sex, physical status, weight, or height. Equilibration times and MAC multiples of sevoflurane and halothane were comparable. Vital signs remained stable throughout the study. Left ventricular end-systolic meridional wall stress increased with halothane but remained unchanged with sevoflurane. Systemic vascular resistance decreased from baseline to 1 MAC and 1.5 MAC with sevoflurane. Halothane depressed contractility as assessed by the stress-velocity index and stress-shortening index, whereas contractility remained within normal limits with sevoflurane. Total minute stress and normalized total mechanical energy expenditure, measures of myocardial oxygen consumption, did not change with either agent. CONCLUSIONS: Myocardial contractility was decreased less during inhalation induction of anesthesia with sevoflurane compared with halothane in children. Although the induction of anesthesia with sevoflurane or halothane was equally well tolerated, the preservation of myocardial contractility with sevoflurane makes it an attractive alternative for inducing anesthesia in children.

Anesthesia, Inhalation↗
PubMed1996

Myocardial mechanics before and after ablation of chronic tachycardia.

Chronic tachycardia has been shown to cause a congestive cardiomyopathy; however, previous methods of evaluating ventricular function are highly dependent on cardiac loading conditions. Mean velocity of fiber shortening and its relation to end-systolic wall stress (ESS) is a preload independent index of contractility that incorporates afterload. We reviewed 33 patients (aged 5 months to 20 years; mean 9.7 years) with ectopic atrial tachycardia (EAT) (n = 19), permanent junctional reciprocating tachycardia (PJRT) (n = 12), or ventricular tachycardia (n = 2), who underwent nonpharmacological elimination of tachycardia ; 28 by radiofrequency ablation and 5 surgically. Ventricular function was evaluated by echocardiographic measurements of shortening fraction, mean velocity shortening corrected for heart rate (VcFc), and afterload as ESS. Contractility, expressed as the stress-velocity index, was determined by comparing the Ess/VcFc relation to the predicted normal VcFc for the measured ESS. Myocardial dysfunction was seen in 21 patients: 13 with EAT; 7 with PJRT; and 1 with ventricular tachycardia. In patients with EAT, the mean heart rate in tachycardia was significantly faster in those with dysfunction than in those without dysfunction (176.8 +/- 23.2 vs 136.7 +/- 28.2; P < 0.02). Of the 21 patients with dysfunction, full recovery was seen in 17 of 18 patients restudied after intervention (mean 17.5 +/- 17.6 weeks), and the remaining patient improved markedly, but did not normalize entirely. Dysfunction, seen in 64% of young patients with chronic tachycardia, was due to depressed myocardial contractility, and is generally reversible within 3 months of definitive therapy.

Cardiomyopathy, Dilated↗
PubMed1995

Immunoglobulins and left ventricular structure and function in pediatric HIV infection.

BACKGROUND: Progressive left ventricular (LV) dilation is common in children infected with HIV-1 and may be a harbinger of congestive heart failure (CHF). In many HIV-infected children, dilation is associated with inadequate LV hypertrophy, elevated afterload, and reduced LV function. Because CHF has been observed empirically to improve after treatment with intravenous immunoglobulin (IVIG) in other conditions and because LV dysfunction in pediatric HIV may be immunologically mediated, we examined retrospectively the relation between immunoglobulins and LV structure and function in 49 HIV-infected infants and children without CHF. METHODS AND RESULTS: A total of 106 echocardiograms were performed in these children within 30 days of serum immunoglobulin (IgG, IgA, and IgM) measurements; this includes 12 children treated with IVIG therapy. All echocardiographic parameters, blood pressures, and immunoglobulins were adjusted for age or body surface area and subjected to repeated-measures regression. Regression models were adjusted simultaneously for endogenous IgA, IgG, IgM, IVIG therapy, zidovudine therapy, age, HIV disease stage, and weight. Higher endogenous serum IgG levels and IVIG treatment were associated with significantly greater wall thickness and lower peak wall stress. Higher endogenous serum IgA levels were associated with more normal LV wall thickness and LV thickness-to-dimension ratios. LV contractility, fractional shortening, end-systolic wall stress, and thickness-to-dimension ratio all showed a trend toward more normal values with higher endogenous immunoglobulin values or during IVIG treatment. CONCLUSIONS: LV structure and function appear to be more normal in HIV-infected children who receive IVIG treatment and in those with higher endogenous IgG levels. These results suggest that both the impaired myocardial growth and the LV dysfunction observed may be immunologically mediated and responsive to immunomodulatory therapy.

Case-Control Studies↗
PubMed1995

Left heart obstructive lesions and left ventricular growth in the midtrimester fetus. A longitudinal study.

BACKGROUND: Isolated case reports that suggest the potential for development of left heart hypoplasia late in gestation provide the only information about the in utero natural history of left heart obstructive lesions. METHODS AND RESULTS: We reviewed the prenatal and postnatal echocardiograms of 21 fetuses with left heart obstructive lesions, including 15 with serial antenatal study, to elucidate the antenatal natural history of this spectrum of disease and to identify features indicative of postnatal disease severity. Ventricular, atrioventricular valve, and great artery dimensions were measured and growth curves were developed with comparisons to data from 47 normal fetuses. Fetuses were divided into groups according to whether postnatally the left heart was capable (group 1, n = 10) or incapable (group 2, n = 7) of supporting the systemic circulation in the presence of a patent aortic valve. Group 3 (n = 4) included fetuses with aortic atresia. At the initial examination (21.7 +/- 3.4 weeks' gestation), left heart dimensions were normal or reduced, with the most diminutive measurements in group 3. Three fetuses in group 2 and most in group 1 had normal initial left heart dimensions. Subsequent growth of left heart structures either paralleled normal growth or was reduced, the latter resulting in the development or progression of left heart hypoplasia. All left heart dimensions grew more slowly in group 2 and group 3 than in group 1 (P < .05). Other prenatal features observed only in groups 2 and 3 included reversed (n = 10) or bidirectional (n = 1) foramen ovale flow and retrograde distal arch flow (n = 9). Initial midtrimester mitral valve and ascending aorta z scores and the growth rates of all left heart structures correlated strongly with postnatal left ventricular end-diastolic dimension (P = .0007 to .03, r = .57 to .82) and could be additional indicators of postnatal disease severity. One group 1 fetus developed severe aortic stenosis late in gestation. CONCLUSIONS: The potential for the in utero development or progression in severity of left heart obstruction and hypoplasia in left heart obstructive lesions necessitates serial prenatal study in affected fetuses carried to term.

Echocardiography↗
PubMed1995

Female sex and higher drug dose as risk factors for late cardiotoxic effects of doxorubicin therapy for childhood cancer.

BACKGROUND: Late cardiotoxic effects of doxorubicin are increasingly a problem for patients who survive childhood cancer. Cardiotoxicity is often progressive, and some patients have disabling symptoms. Our objective was to identify risk factors for late cardiotoxicity. METHODS: We examined echocardiograms from 120 children and adults who had received cumulative doses of 244 to 550 mg of doxorubicin per square meter of body-surface area for the treatment of acute lymphoblastic leukemia or osteogenic sarcoma in childhood, a mean of 8.1 years earlier. Measurements of blood pressure and left ventricular function, contractility (measured as the stress-velocity index), end-diastolic posterior-wall thickness, end-diastolic dimension, mass, and afterload (measured as end-systolic wall stress) were compared with sex-specific values from a cohort of 296 normal subjects. RESULTS: All echocardiographic measurements were abnormal at follow-up a minimum of two years after the end of therapy, with more frequent and severe abnormalities in female patients. In a multivariate analysis, female sex and a higher cumulative dose of doxorubicin were associated with depressed contractility (P < or = 0.001), and there was an interaction between these two variables. Independent and significant associations were found between a higher rate of administration of doxorubicin and increased afterload (P < or = 0.001), left ventricular dilatation, and depressed left ventricular function; between a higher cumulative dose and depressed left ventricular function (P < or = 0.001); between a younger age at diagnosis and reduced left-ventricular-wall thickness and mass and increased afterload; and between a longer time since the completion of doxorubicin therapy and reduced left-ventricular-wall thickness and increased afterload (P < or = 0.001). CONCLUSIONS: Female sex and a higher rate of administration of doxorubicin were independent risk factors for cardiac abnormalities after treatment with doxorubicin for childhood cancer; the prevalence and severity of abnormalities increased with longer follow-up.

Adolescent↗
PubMed1995

In utero pulmonary artery and aortic growth and potential for progression of pulmonary outflow tract obstruction in tetralogy of Fallot.

OBJECTIVES: This study was designed to define patterns of pulmonary artery and aortic growth in fetuses with tetralogy of Fallot and to determine the potential for in utero progression of right ventricular outflow tract obstruction. BACKGROUND: Despite an abundance of reports documenting the prenatal diagnosis of tetralogy of Fallot, there is little information about its course in utero. METHODS: Pulmonary artery and ascending aortic diameters were measured from prenatal and postnatal echocardiograms of 16 fetuses with tetralogy of Fallot, initially studied at 23.6 +/- 6.0 (mean +/- SD) weeks of gestation. Fetuses were classified retrospectively as having mild and severe tetralogy of Fallot according to whether the pulmonary artery circulation was (severe, n = 5) or was not (mild, n = 11) ductus arteriosus dependent at birth. RESULTS: Initial main pulmonary artery diameter was small for gestational age in 9 fetuses, large in 2 and normal in 5 compared with data from 57 gestational age-adjusted normal fetal studies; it was significantly smaller in the group with severe tetralogy of Fallot (p = 0.05). The initial main pulmonary artery/aortic diameter ratio was also smaller for the group with severe tetralogy of Fallot (0.50 +/- 0.15 vs. 0.73 +/- 0.14 in the group with mild tetralogy of Fallot, p = 0.01). Initial aortic and branch pulmonary artery diameters tended to be normal or near normal for age. In eight fetuses serially studied, main and branch pulmonary artery growth was normal or reduced during prenatal follow-up. Pulmonary artery growth was most reduced in two fetuses in the group with severe tetralogy of Fallot, resulting in pulmonary artery hypoplasia at birth. Two fetuses with valvular pulmonary atresia at birth had previously shown anterograde pulmonary outflow in midgestation, suggesting progression of pulmonary outflow obstruction. CONCLUSIONS: The postnatal spectrum of pulmonary artery size in tetralogy of Fallot can be attributed to variable patterns of growth in utero. Main pulmonary artery size, main pulmonary artery/aortic diameter ratio and pattern of pulmonary artery growth may be predictive of the severity of postnatal pulmonary outflow obstruction. Pulmonary atresia can develop in utero in some fetuses with tetralogy of Fallot.

Aorta↗
PubMed1995

Echocardiographic predictors of candidacy for successful transcatheter atrial septal defect closure.

We reviewed pre-closure echocardiograms on all patients undergoing transcatheter atrial septal defect (ASD) closure with the Bard double-umbrella occluder device aided by simultaneous transesophageal echocardiography to determine precatheterization predictors of outcome. Transesophageal echocardiograms were performed on 28 of 132 patients (22%) undergoing device closure (age = 3-72 years, mean = 14 years; weight = 15-68 kg, mean = 35 kg). Three devices were removed because of unstable position. Of the remaining 25 patients, 21 had effective closure (residual flow diameter < or = 3 mm) and 18 had favorable arm position (device arm on proper side of the septum and not in contact with an atrioventricular valve leaflet). Only ASD size predicted effective closure. All patients with a maximum defect size of < 13 mm had effective closure. Among the 17 patients with defects > or = 13 mm, 10 had effective closure, 4 had significant residual flow, and 3 had devices removed for unstable position. Atrial dimensions and rim size did not predict effective closure. There were no pre-closure predictors of favorable arm position which was associated only with the size of the device implanted.

Adolescent↗
PubMed1995

Arrhythmias and intracardiac conduction after the arterial switch operation.

UNLABELLED: Intraatrial baffling procedures such as the Mustard or Senning repair of transposition of the great arteries have been associated with a high incidence of cardiac arrhythmias. These abnormalities are thought to arise from trauma to the sinus node and atrial muscle during the procedure. In the arterial switch operation, there is little intraatrial manipulation other than the repair of the atrial septal defect. In theory, rhythm disturbances after the arterial switch operation should be less prevalent. From January 1, 1983, to December 31, 1990, 390 patients (230 with intact ventricular septum and 160 with a coexisting ventricular septal defect) underwent an arterial switch operation. Electrocardiograms and 24-hour Holter monitor studies were obtained in the 364 survivors at hospital discharge and during follow-up. Limited intracardiac electrophysiologic studies were performed 6 to 12 months after the operation. RESULTS: Atrioventricular node function was preserved in most patients; seven patients (2%) had first-degree, two (0.7%) second-degree, and five (1.7%) had complete atrioventricular block (all with coexisting ventricular septal defect). All five patients with complete heart block received a permanent pacemaker. In those patients not having a permanent pacemaker, sinus rhythm was present in 96% on the surface electrocardiogram and 99% during 24-hour Holter monitor studies (1 month to 8.5 years, mean 2.1 years after the operation). Intracardiac electrophysiologic studies (n = 158) demonstrated normal corrected sinus node recovery times and AH intervals in 97% of patients. Atrial ectopy was present in 152 of 172 (81%) patients, with the majority (64%) of patients having only occasional premature beats without repetitive forms. Ventricular ectopy was a frequent finding during 24-hour monitoring. At hospital discharge 70% had ventricular ectopy; these values fell to 57% (in patients with intact ventricular septum) and 30% (in patients with a coexisting ventricular septal defect) at follow-up. In the early postoperative period, there were 25 episodes of supraventricular tachycardia (14 of which required therapy), 6 episodes of junctional ectopic tachycardia, and 9 episodes of ventricular tachycardia. The incidence of supraventricular tachycardia had fallen to 5% at follow-up, with no atrial flutter or fibrillation noted. Three patients had ventricular tachycardia on follow-up Holter studies. In summary, our results confirm the theoretical advantages of anatomic correction over atrial level correction of transposition of the great arteries with respect to preservation of sinus node function and low incidence of clinically significant tachyarrhythmias.

Arrhythmias, Cardiac↗