Salim F Idriss

Duke University, Durham, North Carolina, United States

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Publications (54)193.94 Total impact

  • Journal of the American College of Cardiology 03/2015; 65(10):A494. DOI:10.1016/S0735-1097(15)60494-6 · 15.34 Impact Factor
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    ABSTRACT: -The Pediatric Heart Network's (PHN) Single Ventricle Reconstruction Trial (SVR) randomized infants with single right ventricles (RV) undergoing a Norwood procedure to a modified Blalock-Taussig or RV-to-pulmonary artery shunt. This report compares RV parameters in the two groups using 3-dimensional echocardiography (3DE). -3DE studies were obtained at 10/15 SVR centers. Of the 549 subjects, 314 underwent 3DE studies at one to four time points (pre-Norwood, post-Norwood, pre-stage II, and 14 months) for a total of 757 3DEs. Of these, 565 (75%) were acceptable for analysis. RV volume, mass, mass:volume ratio, ejection fraction (EF), and severity of tricuspid regurgitation did not differ by shunt type. RV volumes and mass did not change after the Norwood, but increased from pre-Norwood to pre-stage II (end-diastolic volume [EDV, ml]/body surface area [BSA](1.3), end-systolic volume [ESV, ml]/BSA(1.3) and mass[g]/BSA(1.3) mean difference [95% confidence interval] = 25.0 [8.7, 41.3], 19.3 [8.3, 30.4], and 17.9 [7.3, 28.5], then decreased by 14 months (EDV/BSA(1.3), ESV/BSA(1.3) and mass/BSA(1.3) mean difference [95% confidence interval] = -24.4 [-35.0, -13.7], -9.8 [-17.9, -1.7], and -15.3 [-22.0, -8.6]. EF decreased from pre-Norwood to pre-stage II (mean difference [95% confidence interval] = -3.7% [-6.9%, -0.5%]), but did not decrease further by 14 months. -We found no statistically significant differences between study groups in 3DE measures of RV size and function, or magnitude of tricuspid regurgitation. Volume unloading was seen after stage II, as expected, but EF did not improve. This study provides insights into the remodeling of the operated univentricular RV in infancy. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00115934.
    Circulation Cardiovascular Imaging 10/2013; 6(6). DOI:10.1161/CIRCIMAGING.113.000304 · 6.75 Impact Factor
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    ABSTRACT: OBJECTIVE.: Although many Fontan patients undergo pacemaker placement, there are few studies characterizing this population. Our purpose was to compare clinical characteristics, functional status and measures of ventricular performance in Fontan patients with and without a pacemaker. PATIENTS AND DESIGN.: The National Heart, Lung, and Blood Institute funded Pediatric Heart Network Fontan Cross-Sectional Study characterized 546 Fontan survivors. Clinical characteristics, medical history and study outcomes (Child Health Questionnaire [CHQ]), echocardiographic evaluation of ventricular function, and exercise testing) were compared between subjects with and without pacemakers. RESULTS.: Of 71 subjects with pacemakers (13%), 43/71 (61%) were in a paced rhythm at the time of study enrollment (age 11.9 ± 3.4 years). Pacemaker subjects were older at study enrollment, more likely to have single left ventricles, and taking more medications. There were no differences in age at Fontan or Fontan type between the pacemaker and no pacemaker groups. There were no differences in exercise performance between groups. CHQ physical summary scores were lower in the pacemaker subjects (39.7 ± 14.3 vs. 46.1 ± 11.2, P =.001). Ventricular ejection fraction z-score was also lower (-1.4 ± 1.9 vs. -0.8 ± 2.0, P =.05) in pacemaker subjects. CONCLUSIONS.: In our cohort of Fontan survivors, those with a pacemaker have poorer functional status and evidence of decreased ventricular systolic function compared to Fontan survivors without a pacemaker.
    Congenital Heart Disease 07/2012; 8(1). DOI:10.1111/j.1747-0803.2012.00692.x · 1.20 Impact Factor
  • Salim Idriss · Ronald J Kanter
    Journal of Cardiovascular Electrophysiology 03/2012; 23(5):486-8. DOI:10.1111/j.1540-8167.2011.02261.x · 2.88 Impact Factor
  • Ashish N Doshi · Salim F Idriss
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    ABSTRACT: Structural inhomogeneities in cardiac tissue have been associated with increased cellular repolarization alternans in animal experiments and increased T-wave alternans (TWA) in clinical studies. However, the effect of structural inhomogeneities on the relationship between cellular alternans and TWA has not been thoroughly investigated. We created 1-dimensional multicellular fiber models with and without a resistive barrier in various fiber regions and paced each model to induce cellular alternans. The models demonstrate that a resistive barrier in one fiber region substantially alters cellular repolarization alternans throughout the fiber. A midmyocardial or subepicardial barrier increase both TWA amplitude and maximum cellular alternans magnitude, relative to a fiber without a barrier. In addition, a direct relationship exists between TWA amplitude and maximum cellular alternans magnitude, which was highly dependent on barrier location. These results suggest that the position of a structural inhomogeneity within the myocardium may have substantial effects on dynamic repolarization instability and arrhythmogenicity.
    Journal of electrocardiology 11/2010; 43(6):566-71. DOI:10.1016/j.jelectrocard.2010.07.019 · 1.36 Impact Factor
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    ABSTRACT: Our aim was to examine the prevalence of arrhythmias and identify independent associations of time to arrhythmia development. Since introduction of the Fontan operation in 1971, long-term results have steadily improved with newer modifications. However, atrial arrhythmias are frequent and contribute to ongoing morbidity and mortality. Data are lacking regarding the prevalence of arrhythmias and risk factors for their development in the current era. The Pediatric Heart Network Fontan Cross-Sectional study evaluated data from 7 centers, with 520 patients age 6 to 18 years (mean 8.6 +/- 3.4 years after the Fontan operation), including echocardiograms, electrocardiograms, exercise testing, parent-reported Child Health Questionnaire (CHQ) results, and medical history. Supraventricular tachycardias were present in 9.4% of patients. Intra-atrial re-entrant tachycardia (IART) was present in 7.3% (32 of 520). The hazard of IART decreased until 4 to 6 years post-Fontan, and then increased with age thereafter. Cardiac anatomy and resting heart rate (including marked bradycardia) were not associated with IART. We identified 3 independent associations of time to occurrence of IART: lower CHQ physical summary score (p < 0.001); predominant rhythm (p = 0.002; highest risk with paced rhythm), and type of Fontan operation (p = 0.037; highest risk with atriopulmonary connection). Time to IART did not differ between patients with lateral tunnel and extracardiac conduit types of Fontan repair. Ventricular tachycardia was noted in 3.5% of patients. Overall prevalence of IART was lower in this cohort (7.3%) than previously reported. Lower functional status, an atriopulmonary connection, and paced rhythm were determined to be independently associated with development of IART after Fontan. (Relationship Between Functional Health Status and Ventricular Performance After Fontan-Pediatric Heart Network; NCT00132782).
    Journal of the American College of Cardiology 09/2010; 56(11):890-6. DOI:10.1016/j.jacc.2010.03.079 · 15.34 Impact Factor
  • Journal of Cardiovascular Electrophysiology 05/2010; 21(5):585-7. DOI:10.1111/j.1540-8167.2009.01676.x · 2.88 Impact Factor
  • Nina Hakacova · Galen S Wagner · Salim F Idriss
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    ABSTRACT: The objective of this study was to test the hypothesis that patients with primum atrioventricular septal defect (AVSD) have an imbalance in the positions of the left ventricular papillary muscles compared with healthy subjects, and that this anatomic imbalance correlates with left deviation of the QRS axis. The function and contraction pattern of the heart is best predicted when cardiac anatomy is considered together with its electrical activation sequence. Understanding the electroanatomic relationships is essential for discovering the developmental relationships between the conduction system and heart structures. Left deviation of the QRS axis is typically present in patients with primum AVSD. However, the pathophysiology of this phenomenon is not understood. Thirty-five patients with primum AVSD and 35 healthy subjects were included in the study. Echocardiographic images were used to determine the papillary muscle positions. A 12-lead electrocardiogram was used to determine the QRS axis in the frontal plane in both patients and healthy subjects. An imbalance between papillary muscle positions in primum AVSD patients was defined as the position of the anterior papillary muscle closer to the septum and/or the position of the posterior papillary muscle further from the septum compared with the position of the papillary muscles in healthy subjects. In primum AVSD patients compared with control subjects, there was significant imbalance in the positions of the papillary muscles (p = 0.0007). The imbalance of papillary muscles correlated with deviation of the QRS (r = 0.5, p = 0.0019). Abnormality in the position of the papillary muscles changes continuously with the abnormality of the QRS axis. Understanding the electroanatomic relationships provides important insight into developmental relationships between the conduction system and the trabecular structures in primum AVSD patients. These results may provide insights in understanding the continuity of primum AVSD abnormality, in estimating the best surgical approach, and predicting the prognosis of primum AVSD patients.
    JACC. Cardiovascular imaging 12/2009; 2(12):1357-65. DOI:10.1016/j.jcmg.2009.08.009 · 6.99 Impact Factor
  • Ashish N Doshi · Salim F Idriss
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    ABSTRACT: T-wave alternans (TWA) is a useful marker of cardiac instability, but not much is known about the factors that affect its measurement, such as electrode placement. We used a 1-dimensional myocardial fiber computer model of alternans to investigate the effect of electrode position on TWA measurement. Results demonstrated that TWA amplitude and T-wave amplitude change proportionally if both recording electrodes are symmetrically moved toward or away from the tissue. However, TWA amplitude and T-wave amplitude change out of proportion to one another when one electrode is moved while the other electrode remains stationary. These disproportionate changes result from beatwise alternation in the asymmetric potential field around the tissue. In summary, nonlinear changes in tissue repolarization during alternans result in nonlinear changes in T-wave amplitude and TWA amplitude.
    Journal of electrocardiology 08/2009; 42(6):549-54. DOI:10.1016/j.jelectrocard.2009.06.012 · 1.36 Impact Factor
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    ABSTRACT: Determination of mitral papillary muscle positions is of increasing interest in wide spectrum of clinical cardiology fields. Particularly, relative positioning of the papillary muscles between the inter-ventricular septum and the left ventricular free wall is of interest. A reproducible method for determination of papillary muscle positions has not been established. In this study a new 'septal-to-free wall arc ratio' (SFAR) method for measuring papillary muscle positions is presented. The reproducibility of the SFAR method between echocardiographic (ECHO) and magnetic resonance (MRI) modalities and between observers is tested. Twenty subjects with structurally normal hearts in whom both MRI and ECHO were performed in 2007 were included in the study. Papillary muscle positions were determined using the SFAR method. Inter-modality (ECHO and MRI) and inter-observer reproducibility of the methods was assessed by calculating correlation coefficients and the mean difference from agreement. The inter-modality correlation of the SFAR method was 0.80 (P < 0.0001) for both papillary muscles. The mean difference of measurements from agreement was 4% for the superior and 2% for the inferior papillary muscle. The inter-observer correlation was 0.93 (P < 0.0001) for superior and 0.90 (P = 0.0002) for inferior papillary muscle. The mean inter-observer difference from agreement was 2% for superior and 3% for inferior papillary muscle. The SFAR method may be applied in wide range of both scientific and clinical medical fields as a reproducible method for determination of papillary muscle positions with the benefit of estimation of relative papillary muscle positions both from the septum and the free wall.
    Clinical Physiology and Functional Imaging 05/2009; 29(3):181-6. DOI:10.1111/j.1475-097X.2008.00853.x · 1.33 Impact Factor
  • Caroline L Ring · Salim F Idriss · Wanda Krassowska Neu
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    ABSTRACT: Long QT Syndrome (LQTS) is a congenital disorder associated with life-threatening arrhythmias. LQT1, a type of LQTS affecting the slow delayed rectifier potassium current, shows a higher incidence of arrhythmia associated with sympathetic stimulation than other types of LQTS. LQT1 patients show increased variability of repolarization with epinephrine infusion, as measured from the 12-lead ECG. We investigate the variability of repolarization measured as action potential duration (APD) in the rabbit left ventricle: how APD variability is affected by pacing rate, transmural location, LQT1 induced by chromanol 293b, and epinephrine infusion. Chromanol preferentially changes APD variability in the midwall. Infusing epinephrine returns the variability to near-control levels. These results differ substantially from clinical studies and show the need for further study.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2009; 2009:4520-2. DOI:10.1109/IEMBS.2009.5334105
  • IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 01/2009; 56(1):c1-c2. DOI:10.1109/TUFFC.2009.993 · 1.50 Impact Factor
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    ABSTRACT: The presence of a single left superior vena cava in the absence of complex congenital heart disease is uncommon, and, in the absence of hemodynamic consequences, it would not be expected to result in cardiovascular signs or symptoms. Single case reports and our anecdotal experience suggested to us that this anomaly is highly associated with cardiac arrhythmias. We sought to describe the clinically important arrhythmias in a population of young patients having this anomaly. A retrospective chart review was performed from all patients <20 years old and who were determined by echocardiography over an 11-year-period to have a single left superior vena cava and minor or no coexisting congenital heart defects. The prevalence of nonsinus pacemaker, age-corrected sinus rate percentile, and prevalence of brady- or tachyarrhythmias was compared with a control group of patients having bilateral superior vena cavae. Eight patients having a single left and 55 patients having bilateral superior vena cava(e) were identified. The existence of this anomaly tended to be associated with a lower age-corrected sinus rate percentile (17.5% vs 75%, P = 0.09), and was associated with a higher prevalence of arrhythmias (50% vs 7%, P = 0.014) compared with the control group. In the study group, one patient each had clinically relevant sinus node dysfunction, third-degree AV block, Wolff-Parkinson-White syndrome and atrial fibrillation, and AV nodal reentrant tachycardia. Even in the absence of symptoms, patients found to have a single left superior vena cava should be monitored long-term for clinically important arrhythmias.
    Journal of Cardiovascular Electrophysiology 10/2008; 20(2):182-6. DOI:10.1111/j.1540-8167.2008.01307.x · 2.88 Impact Factor
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    Salim F Idriss · Jamie A Bell
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    ABSTRACT: Long QT syndrome is a disease characterized by abnormal lengthening of the QT interval and by sudden cardiac death. It is a disease of development, with the incidence of a sudden event increasing during childhood. Repolarization instability during postnatal development could make the substrate susceptible to a fatal arrhythmia. Dynamic changes in repolarization that occur on a beat-to-beat basis, known as alternans, are a hallmark of electrical instability. T-wave alternans (TWA) in the electrocardiogram correlates with arrhythmia risk and long-term survival in adults. We determined TWA properties longitudinally in vivo in 7 propofol-sedated New Zealand white rabbits using transesophageal pacing weekly from 2 to 10 weeks of age. Furthermore, TWA induction after the onset of rapid pacing was characterized in vitro in 6 infant (2 weeks) and 6 adolescent (7 weeks) isolated, arterially perfused rabbit hearts. In vivo, TWA amplitude was maximum at 2 weeks and declined with age. Isoproterenol increased TWA at 8 weeks (adolescence). In vitro, large-amplitude TWA was induced with rapid pacing in both infant and adolescents but decreased to low, steady-state levels in infants. We conclude that TWA properties are age dependent in rabbit. Significant TWA is induced in rabbit at the onset of rapid pacing.
    Journal of electrocardiology 10/2008; 41(6):474-9. DOI:10.1016/j.jelectrocard.2008.07.026 · 1.36 Impact Factor
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    ABSTRACT: Ultrasound image guidance of interventional devices during minimally invasive surgery provides the clinician with improved soft tissue contrast while reducing ionizing radiation exposure. One problem with ultrasound image guidance is poor visualization of the device tip during the clinical procedure. We have described previously guidance of several interventional devices using a real-time 3-D (RT3-D) ultrasound system with 3-D color Doppler combined with the ColorMark technology. We then developed an analytical model for a vibrating needle to maximize the tip vibrations and improve the reliability and sensitivity of our technique. In this paper, we use the analytical model and improved radiofrequency (RF) and color Doppler filters to detect two different vibrating devices in water tank experiments as well as in an in vivo canine experiment. We performed water tank experiments with four different 3- D transducers: a 5 MHz transesophageal (TEE) probe, a 5 MHz transthoracic (TTE) probe, a 5 MHz intracardiac catheter (ICE) transducer, and a 2.5 MHz commercial TTE probe. Each transducer was used to scan an aortic graft suspended in the water tank. An atrial septal puncture needle and an endomyocardial biopsy forceps, each vibrating at 1.3 kHz, were inserted into the vascular graft and were tracked using 3-D color Doppler. Improved RF and wall filters increased the detected color Doppler sensitivity by 14 dB. In three simultaneous planes from the in vivo 3-D scan, we identified both the septal puncture needle and the biopsy forceps within the right atrium using the 2.5 MHz probe. A new display filter was used to suppress the unwanted flash artifact associated with physiological motion.
    IEEE transactions on ultrasonics, ferroelectrics, and frequency control 02/2008; 55(6):1355-62. DOI:10.1109/TUFFC.2008.798 · 1.50 Impact Factor
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    Eric C Pua · Salim F Idriss · Patrick D Wolf · S W Smith
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    ABSTRACT: At present, there are limited methods of acquiring three-dimensional visualization of cardiac structure and function in real-time during interventional electrophysiology procedures. Images acquired for integration of computerized tomography and magnetic resonance imaging with electroanatomic mapping systems are static and are obtained earlier in time. The purpose of this study was to test the feasibility of real-time three-dimensional transesophageal echocardiography for the guidance of interventional electrophysiological studies. A matrix array transducer with 504 channels operating at 5 MHz in a 1 cm diameter steerable esophageal probe was used in conjunction with a scanner capable of real-time 3D scanning of pyramidal volumes from 65 degrees to 120 degrees at rates up to 30 volumes per second. This device has a spatial resolution of approximately 3 mm at 5 cm depth. The authors acquired real-time three-dimensional images of anatomic landmarks of value for electrophysiological procedures in five closed chest canines. Real-time, three-dimensional ultrasound imaging was also used for visualization and guidance of interventional catheter devices within the canine heart. Real-time three-dimensional images of the atria, pulmonary veins, and coronary sinus were acquired. Real-time 3-D color flow Doppler was employed to confirm patency. Multiple image planes of image volumes and rendered views were used to track catheter position and orientation. Images of left veno-atrial junctions have been confirmed by dissection. This study has demonstrated the feasiblity of using real-time three-dimensional transesophageal echocardiography for guiding interventional electrophysiology. The technology has the potential to fill a niche as an adjunct modality for cost-effective real-time interventional guidance and assessment, providing catheter and pacing lead visualization simultaneously with functional volumetric cardiac imaging.
    Ultrasonic Imaging 08/2007; 29(3):182-94. DOI:10.1177/016173460702900304 · 1.16 Impact Factor
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    Ann M Pitruzzello · Wanda Krassowska · Salim F Idriss
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    ABSTRACT: Spatial heterogeneity of repolarization can provide a substrate for reentry to occur in myocardium. This heterogeneity may result from spatial differences in action potential duration (APD) restitution. The restitution portrait (RP) measures many aspects of rate-dependent restitution: the dynamic restitution curve (RC), S1-S2 RC, and short-term memory response. We used the RP to characterize epicardial patterns of spatial heterogeneity of restitution that were repeatable across animals. New Zealand White rabbit ventricles were paced from the epicardial apex, midventricle, or base, and optical action potentials were recorded from the same three regions. A perturbed downsweep pacing protocol was applied that measured the RP over a range of cycle lengths from 1,000 to 140 ms. The time constant of short-term memory measured close to the stimulus was dependent on location. In the midventricle the mean time constant was 19.1 +/- 1.1 s, but it was 39% longer at the apex (P < 0.01) and 23% longer at the base (P = 0.03). The S1-S2 RC slope was dependent on pacing site (P = 0.015), with steeper slope when pacing from the apex than from the base. There were no significant repeatable spatial patterns in steady-state APD at all cycle lengths or in dynamic RC slope. These results indicate that transient patterns of epicardial heterogeneity of APD may occur after a change in pacing rate. Thus it may affect cardiac electrical stability at the onset of a tachycardia or during a series of ectopic beats. Differences in restitution with respect to pacing site suggest that vulnerability may be affected by the location of reentry or ectopic foci.
    AJP Heart and Circulatory Physiology 03/2007; 292(3):H1568-78. DOI:10.1152/ajpheart.00619.2006 · 4.01 Impact Factor
  • M.P. Fronheiser · S.F. Idriss · P.D. Wolf · S.W. Smith
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    ABSTRACT: We have previously described guidance of several interventional devices using a real time 3D (RT3D) ultrasound system with 3D color Doppler combined with the ColorMark technology. We then developed an analytical model for a vibrating needle to maximize the tip vibrations and improve the reliability and sensitivity of our technique. In this work, we use the analytical model and improved radiofrequency (RF) and color Doppler filters to detect two different vibrating devices in water tank experiments as well as in an in vivo canine experiment. An atrial septal puncture needle and an endomyocardial biopsy forceps, each vibrating at 1.3 kHz, were inserted into the vascular graft and were tracked using 3D color Doppler. Improved RF and wall filters increased the detected color Doppler sensitivity by 14 dB. In three simultaneous planes from the in vivo 3D scan, we identified both the septal puncture needle and the biopsy forceps within the right atrium using the 2.5 MHz probe. A display filter was used to suppress the unwanted flash artifact associated with physiological motion.
    Ultrasonics Symposium, 2007. IEEE; 01/2007
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    ABSTRACT: Endomyocardial biopsy is the gold standard survey for cardiac graft rejection. Signal-averaged electrocardiography (SAECG) identifies slowly conducting, diseased myocardium. We sought to determine whether SAECG is a sensitive, noninvasive transplant surveillance method in the young.Ninety-four SAECGs recorded prior to biopsy in 20 young transplant (OHT) patients and those from 15 healthy age-matched controls (CTL) were analyzed. In the OHT group, 56 no-rejection (NOREJ) (ISHLT grades 0 or 1 A) and 37 acute rejection (REJ) (ISHLT grades IB, 2, and 3A) SAECGs were compared, SAECGs were filtered at 40-255 Hz. Total QRS duration (QRSd), duration of terminal low amplitude of QRS under 40 microV (LAS), and root mean square amplitude of terminal 40 msec of QRS (RMS40) were compared.SAECGs were significantly different in CTL vs NOREJ but not in NOREJ vs REJ: QRSd, 81.7 +/- 8, 107.2 +/- 18.4, and 112.3 +/- 21.6 msec, respectively; LAS, (18 +/- 5.8, 23.6 +/- 10.7, and 27 +/- 14.8 msec, respectively; and RMS40, (169.3 +/- 100.4, 68 +/- 48.8, and 57.5 +/- 45.6 microV, respectively. Children following OHT exhibited significant differences in the SAECG compared to controls. Differences between the NOREJ and REJ groups were negligible. Therefore, SAECG may not be effective in detecting OHT rejection in the young.
    Pediatric Cardiology 10/2006; 27(5):589-93. DOI:10.1007/s00246-005-1155-5 · 1.55 Impact Factor

Publication Stats

677 Citations
193.94 Total Impact Points

Institutions

  • 1992–2013
    • Duke University
      • Department of Biomedical Engineering (BME)
      Durham, North Carolina, United States
  • 1995–2012
    • Duke University Medical Center
      • • Department of Pediatrics
      • • Division of Cardiology
      • • Department of Medicine
      Durham, North Carolina, United States
  • 2002
    • Case Western Reserve University
      • Rainbow Babies and Children's Hospital
      Cleveland, Ohio, United States