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Biomedical subjects

R Darragh

Publications and source records attributed to R Darragh.

9 recordsLinked to original sources
PubMed2000

Metabolic aspects of myocardial disease and a role for L-carnitine in the treatment of childhood cardiomyopathy.

OBJECTIVES: A multicenter retrospective study was conducted to investigate the possible metabolic causes of pediatric cardiomyopathy and evaluate the outcome of patients treated with L-carnitine. METHODS: Seventy-six patients diagnosed with cardiomyopathy were treated with L-carnitine in addition to conventional cardiac treatment, and 145 patients were treated with conventional treatment only. There were 101 males and 120 females between 1 day and 18 years old. Cardiomyopathy diagnoses included dilated (148 patients), hypertrophic (42 patients), restrictive (16 patients), mixed diagnosis (11 patients), and 4 with an unknown type. Of 76 L-carnitine-treated patients, 29 (38%) had evidence to suggest a disorder of metabolism, and of 145 control patients, 15 (10%) were suspected to have a disorder of metabolism. These metabolic disorders were thought to be the cause for the cardiomyopathy of the patients. The duration of L-carnitine treatment ranged from 2 weeks to >1 year. Information was collected on length of survival (time-to-event), clinical outcome, echocardiogram parameters, and clinical assessments. Data were collected at intervals from baseline to study endpoint, death, transplant, or last known follow-up visit. RESULTS: L-Carnitine-treated patients were younger than control patients and had poorer clinical functioning at baseline, yet they demonstrated lower mortality and a level of clinical functioning and clinical severity comparable to control patients on conventional therapy by the end of the study. An analysis of the interaction between clinical outcome and concomitant medications unexpectedly revealed that the population of patients treated with angiotensin-converting enzyme (ACE) inhibitors (40% of patients) had significantly poorer survival (although their greater likelihood for poor survival may possibly have made them more likely to receive ACE inhibitors). CONCLUSION: Results suggest that L-carnitine provides clinical benefit in treating pediatric cardiomyopathy. There is a need for further exploration of potential explanatory factors for the higher mortality observed in the population of patients treated with ACE inhibitors.

Cardiomyopathies↗
PubMed1994

Cardiac transplantation in infants and children.

Cardiac transplantation has become a more frequently used therapeutic modality for select cardiac pathology in infants and children. Since June 1986, 30 pediatric patients (19 male and 11 female) ranging in age from 4 days to 15 years (11 < or = 1 month old) have undergone orthotopic cardiac transplantation at our institution. Indications included idiopathic cardiomyopathy (n = 8), hypoplastic left heart syndrome (n = 13), and other forms of complex congenital heart disease (n = 9). There have been four operative and three late deaths only in the groups with hypoplastic left heart syndrome and other forms of complex congenital heart disease. Cumulative survival is 77% after a mean follow-up of 30 months (range, 6 to 77 months). Three operative deaths were attributable to pulmonary hypertension, and the other was due to pulmonary hemorrhage. Two late deaths were secondary to allograft rejection, and the third was due to infection. There has been uniform survival in the group with idiopathic cardiomyopathy, and intermediate-term survival rates are 78% and 62% in the groups with complex congenital heart diseases and hypoplastic left heart syndrome, respectively (p = 0.15). Although longer-term results are necessary, orthotopic cardiac transplantation appears to be an acceptable mode of therapy for endstage heart disease in the pediatric age group and technically can be performed despite complex malformations of the great arteries or atria.

Adolescent↗
PubMed1994

Feasibility of generating hemodynamic pressure curves from noninvasive Doppler echocardiographic signals.

OBJECTIVES: This study was designed to determine the feasibility of Doppler generation of accurate, complete right ventricular and pulmonary artery pressure curves in patients with Doppler-measurable tricuspid and pulmonary regurgitation. BACKGROUND: Doppler-derived flow velocities have been used to assess right ventricular systolic pressure; pulmonary artery systolic, diastolic and mean pressures, and left ventricular systolic and diastolic pressures. Instantaneous gradient across any area of discrete narrowing is accurately derived using the simplified Bernoulli equation (4V2). Invasive catheterization is currently the only means of generating intracardiac pressure curves. Noninvasively derived pressure curves using Doppler echocardiography would be a considerable advance in the assessment of normal and pathologic cardiac hemodynamics. METHODS: Right ventricular and pulmonary artery pressure curves were generated in 18 of 22 patients with measurable tricuspid and pulmonary valve regurgitation using superimposition of Doppler-measured tricuspid and pulmonary valve blood flow velocities on an assumed right atrial pressure. Doppler-measured right ventricular and pulmonary artery pressure curves were compared with simultaneous catheterization-measured curves. RESULTS: Doppler-derived pulmonary artery systolic pressure (Doppler PAP) correlated with simultaneous catheter-measured pulmonary artery pressure (Cath PAP) by the equation Doppler PAP = 0.92(Cath PAP) + 4.5, r = 0.98. Other Doppler-derived pressure measurements that correlated at near identity with the catheterization-measured corresponding measurement include Doppler-derived pulmonary artery mean pressure (Doppler mean PAP) [Doppler mean PAP = 0.85(Cath mean PAP) + 2.6, r = 0.97], and Doppler-derived right ventricular pressure (Doppler RVP) [Doppler RVP = 0.84(Cath measured RVP) + 7.9, r = 0.98]. Doppler-derived pulmonary, artery diastolic pressure (Doppler PAP diast) did not correspond as well in this study [Doppler PAP diast = 0.45(Cath PAP diast) + 6.6, r = 0.83]. CONCLUSIONS: Clinically usable right ventricular and pulmonary artery pressure curves can be derived by superimposing Doppler-measured tricuspid and pulmonary valve blood flow velocities in patients with tricuspid and pulmonary valve regurgitation.

Blood Flow Velocity↗
PubMed1989

Estimation of the ratio of pulmonary to systemic pressures by pulsed-wave Doppler echocardiography for assessment of pulmonary arterial pressures.

This study describes a method for estimation of the ratio of pulmonary to systemic pressures by pulsed-wave Doppler echocardiography. Sixty-eight patients ages 1 day to 68 years who underwent cardiac catheterization had Doppler studies of the right and left ventricular outflows. Preejection period (PEP), ejection time (ET) and mean acceleration to peak velocity (ACCm) were measured on each waveform. The expression: F = (PEP x ACCm)/ET was calculated for right and left ventricular outflows as an index of the effects that the interaction between ventricular contraction and afterload has on the shape of the Doppler waveforms generated in each outflow. The quotient of (F for the right outflow)/(F for the left outflow), or waveform contour ratio, was used to express the degree of pressure-dependent variability between each subject's right and left ventricular outflow tracings. The waveform contour ratio was strikingly similar to the ratio of systolic pulmonary to systemic pressures and also closely correlated to the ratio of mean pressures. The product of waveform contour ratio and arm systolic pressure gave a consistently accurate estimate of systolic pulmonary pressures. It is concluded that the present method can be used successfully for the noninvasive assessment of pulmonary arterial pressures.

Adolescent↗
PubMedDate not supplied

Dynamic three-dimensional echocardiographic reconstruction of congenital cardiac septation defects.

Dynamic three-dimensional echocardiographic reconstructions of 27 cardiac septation defects were performed in 19 sedated infants and children. Using a subxiphoid rotational scanning approach, complete visualization of the entire shape and breadth of the defect was attained in 11 of 16 ventricular septal defects and 9 of 11 atrial septal defects. This technique enabled the operator to cut slices from the three-dimensional block of echocardiographic data in order to present septation defects in a region- or lesion-oriented fashion. Poor baseline two-dimensional image quality and certain small septation defects that were readily obscured by nearby structures led to inadequate three-dimensional reconstructions. The application of dynamic three-dimensional echocardiography for assessment of cardiac septation defects uniquely provided (1) the ability to present en face views of atrial and ventricular septal defects; and (2) a means by which intracardiac anatomy can be displayed in a region- and lesion-oriented fashion for interventional and surgical planning purposes.

Adolescent↗
PubMedDate not supplied

Echocardiographic analysis of rejection in the infant heart transplant recipient.

Eleven children who received transplants at less than 2 years of age underwent 59 echocardiograms at the time of endomyocardial biopsy for the assessment of the ability of echocardiography to predict acute rejection in the infant heart transplant recipient. Two patients died of acute rejection and autopsy findings were compared with premortum echocardiograms. Biopsy specimens were graded as no rejection (n = 46), mild rejection (cellular infiltrate, n = 5), or moderate-severe rejection (myocyte necrosis/edema, n = 8). Echocardiographic indexes measured included the following: left ventricular mass, left ventricular volume, ejection fraction, heart rate, and peak rate of posterior wall thinning. Compared with controls, patients during mild rejection had slower posterior wall diastolic thinning (p < 0.01). No significant change was noted in left ventricular mass until endomyocardial biopsy specimens showed severe rejection. No significant changes were noted in heart rate or ejection fraction in any of the groups. In conclusion, decrease in the peak rate of posterior wall diastolic thinning may be a sensitive indicator of acute rejection in the infant heart transplant recipient.

Acute Disease↗
PubMedDate not supplied

Triple-drug immunosuppression for heart transplantation in infants and children.

Triple-drug immunosuppression with OKT3 induction is effective rejection prophylaxis in pediatric cardiac allograft recipients. The concerns regarding prevalent lymphoproliferative disease, growth retardation, cytomegalovirus, and other opportunistic infections have not been realized. Since June 1986, 34 pediatric patients, 23 males and 11 females, (age 4 days to 15 years) have undergone orthotopic heart transplantation at our institution. Fifteen patients were less than 6 months old and 13 had type I or II hypoplastic left heart syndrome. There have been four (12%) operative and four (12%) late deaths and a survival rate of 76% after a mean follow-up of 33 months (range, 1 to 82 months). The only deaths attributed to allograft rejection occurred in two newborn recipients (2 and 10 months after surgery) who neither received maintenance steroids nor underwent routine biopsy. The only death from infection (pneumococcus) occurred 6 months after surgery in a 4-year-old patient who was not known to be asplenic. Of the 27 long-term (> 1 year) survivors, 17 (68%) had an average of two rejection episodes during the follow-up period, 10 patients (32%) have been free of graft rejection, and 26 patients (96%) have not experienced a cytomegalovirus infection despite OKT3 induction therapy. Two patients developed lymphoproliferative disease, one of whom was successfully treated by transient reduction of immunosuppression. The other patient died 13 months after transplantation of a lymphoma of the central nervous system. All survivors have demonstrated satisfactory increases in mean height and weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗