Clinical Focus

  • Pediatric Cardiology
  • Fetal Cardiology
  • Inpatient General Cardiology

Academic Appointments

Professional Education

  • Board Certification: American Board of Pediatrics, Pediatric Cardiology (2018)
  • Fellowship: Lucile Packard Childrens Hospital Advanced Cardiology Fellowships (2018) CA
  • Fellowship: Stanford University Pediatric Cardiology Fellowship (2017) CA
  • Board Certification: American Board of Pediatrics, Pediatrics (2014)
  • Residency: Childrens Hospital Los Angeles Pediatric Residency (2014) CA
  • Medical Education: University of California at Irvine School of Medicine Registrar (2011) CA

Research Interests

  • Data Sciences
  • Technology and Education

All Publications

  • Video-Based Deep Learning for Automated Assessment of Left Ventricular Ejection Fraction in Pediatric Patients. Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography Reddy, C. D., Lopez, L., Ouyang, D., Zou, J. Y., He, B. 2023


    Significant interobserver and interstudy variability occurs for left ventricular functional indices despite standardization of measurement techniques. Artificial intelligence models trained on adult echocardiograms are not likely to be applicable to a pediatric population. We present EchoNet-Peds, a video-based deep learning algorithm, which matches human expert performance of left ventricular (LV) segmentation and ejection fraction (EF).A large pediatric dataset of 4,467 echocardiograms were used to develop EchoNet-Peds. EchoNet-Peds was trained on 80% of the data for segmentation of the left ventricle and estimation of left ventricular EF. The remaining 20% was used to fine tune and validate the algorithm.In both apical 4-chamber (A4C) and parasternal short-axis views (PSAX), EchoNet-Peds segments the left ventricle with a Dice similarity coefficient of 0.89. EchoNet-Peds estimates EF with a mean absolute error of 3.66% and can routinely identify pediatric patients with systolic dysfunction (area under the curve of 0.95). EchoNet-Peds was trained on pediatric echocardiograms and performed significantly better to estimate EF (p < 0.001) than an adult model applied to the same data.Accurate, rapid automation of EF assessment and recognition of systolic dysfunction in a pediatric population are feasible using EchoNet-Peds with the potential for far-reaching clinical impact. In addition, the first large pediatric dataset of annotated echocardiograms is now publicly available for efforts to develop pediatric-specific artificial intelligence algorithms.

    View details for DOI 10.1016/j.echo.2023.01.015

    View details for PubMedID 36754100

  • Artificial intelligence in perinatal diagnosis and management of congenital heart disease. Seminars in perinatology Reddy, C. D., Van den Eynde, J., Kutty, S. 2022: 151588


    Prenatal diagnosis and management of congenital heart disease (CHD) has progressed substantially in the past few decades. Fetal echocardiography can accurately detect and diagnose approximately 85% of cardiac anomalies. The prenatal diagnosis of CHD results in improved care, with improved risk stratification, perioperative status and survival. However, there is much work to be done. A minority of CHD is actually identified prenatally. This seemingly incongruous gap is due, in part, to diminished recognition of an anomaly even when present in the images and the need for increased training to obtain specialized cardiac views. Artificial intelligence (AI) is a field within computer science that focuses on the development of algorithms that "learn, reason, and self-correct" in a human-like fashion. When applied to fetal echocardiography, AI has the potential to improve image acquisition, image optimization, automated measurements, identification of outliers, classification of diagnoses, and prediction of outcomes. Adoption of AI in the field has been thus far limited by a paucity of data, limited resources to implement new technologies, and legal and ethical concerns. Despite these barriers, recognition of the potential benefits will push us to a future in which AI will become a routine part of clinical practice.

    View details for DOI 10.1016/j.semperi.2022.151588

    View details for PubMedID 35396036

  • Criteria for Early Pacemaker Implantation in Patients With Postoperative Heart Block After Congenital Heart Surgery. Circulation. Arrhythmia and electrophysiology Duong, S. Q., Shi, Y., Giacone, H., Navarre, B., Gal, D., Han, B., Sganga, D., Ma, M., Reddy, C. D., Shin, A., Kwiatkowski, D. M., Dubin, A. M., Scheinker, D., Algaze, C. A. 2022: e011145


    Guidelines recommend observation for atrioventricular node recovery until postoperative days (POD) 7 to 10 before permanent pacemaker placement (PPM) in patients with heart block after congenital cardiac surgery. To aid in surgical decision-making for early PPM, we established criteria to identify patients at high risk of requiring PPM.We reviewed all cases of second degree and complete heart block (CHB) on POD 0 from August 2009 through December 2018. A decision tree model was trained to predict the need for PPM amongst patients with persistent CHB and prospectively validated from January 2019 through March 2021. Separate models were developed for all patients on POD 0 and those without recovery by POD 4.Of the 139 patients with postoperative heart block, 68 required PPM. PPM was associated with older age (3.2 versus 1.0 years; P=0.018) and persistent CHB on POD 0 (versus intermittent CHB or second degree heart block; 87% versus 58%; P=0.001). Median days [IQR] to atrioventricular node recovery was 2 [0-5] and PPM was 9 [6-11]. Of the 100 cases of persistent CHB (21 in the validation cohort), 59 (59%) required PPM. A decision tree model identified 4 risk factors for PPM in patients with persistent CHB: (1) aortic valve replacement, subaortic stenosis repair, or Konno procedure; (2) ventricular L-looping; (3) atrioventricular valve replacement; (4) and absence of preoperative antiarrhythmic agent (in POD 0 model only). The POD 4 model specificity was 0.89 [0.67-0.99] and positive predictive value was 0.94 [95% CI 0.81-0.98], which was stable in prospective validation (positive predictive value 1.0).A data-driven analysis led to actionable criteria to identify patients requiring PPM. Patients with left ventricular outflow tract surgery, atrioventricular valve replacement, or ventricular L-Looping could be considered for PPM on POD 4 to reduce risks of temporary pacing and improve care efficiency.

    View details for DOI 10.1161/CIRCEP.122.011145

    View details for PubMedID 36306332

  • Single center blind testing of a US multi-center validated diagnostic algorithm for Kawasaki disease in Taiwan. Frontiers in immunology Kuo, H. C., Hao, S., Jin, B., Chou, C. J., Han, Z., Chang, L. S., Huang, Y. H., Hwa, K., Whitin, J. C., Sylvester, K. G., Reddy, C. D., Chubb, H., Ceresnak, S. R., Kanegaye, J. T., Tremoulet, A. H., Burns, J. C., McElhinney, D., Cohen, H. J., Ling, X. B. 2022; 13: 1031387


    Kawasaki disease (KD) is the leading cause of acquired heart disease in children. The major challenge in KD diagnosis is that it shares clinical signs with other childhood febrile control (FC) subjects. We sought to determine if our algorithmic approach applied to a Taiwan cohort.A single center (Chang Gung Memorial Hospital in Taiwan) cohort of patients suspected with acute KD were prospectively enrolled by local KD specialists for KD analysis. Our previously single-center developed computer-based two-step algorithm was further tested by a five-center validation in US. This first blinded multi-center trial validated our approach, with sufficient sensitivity and positive predictive value, to identify most patients with KD diagnosed at centers across the US. This study involved 418 KDs and 259 FCs from the Chang Gung Memorial Hospital in Taiwan.Our diagnostic algorithm retained sensitivity (379 of 418; 90.7%), specificity (223 of 259; 86.1%), PPV (379 of 409; 92.7%), and NPV (223 of 247; 90.3%) comparable to previous US 2016 single center and US 2020 fiver center results. Only 4.7% (15 of 418) of KD and 2.3% (6 of 259) of FC patients were identified as indeterminate. The algorithm identified 18 of 50 (36%) KD patients who presented 2 or 3 principal criteria. Of 418 KD patients, 157 were infants younger than one year and 89.2% (140 of 157) were classified correctly. Of the 44 patients with KD who had coronary artery abnormalities, our diagnostic algorithm correctly identified 43 (97.7%) including all patients with dilated coronary artery but one who found to resolve in 8 weeks.This work demonstrates the applicability of our algorithmic approach and diagnostic portability in Taiwan.

    View details for DOI 10.3389/fimmu.2022.1031387

    View details for PubMedID 36263040

    View details for PubMedCentralID PMC9575935

  • Intraoperative epicardial echocardiography or transoesophageal echocardiography in CHD: how much does it matter? Cardiology in the young Stauffer, K. J., Brabender, J., Reddy, C. D., Selamet Tierney, E. S., Lopez, L., Maeda, K., Navaratnam, M., Punn, R. 2022: 1-8


    BACKGROUND: Intraoperative imaging determines the integrity of surgical repairs. Transoesophageal echocardiography represents standard care for intraoperative imaging in CHD. However, some conditions preclude its use, and epicardial echocardiography is used alternatively. Minimal literature exists on the impact of epicardial echocardiography versus transoesophageal echocardiography. We aimed to evaluate accuracy between the two modalities and hypothesised higher imaging error rates for epicardial echocardiography.METHODS: We retrospectively reviewed all epicardial echocardiograms performed over 16 years and compared them to an age- and procedure-matched, randomly selected transoesophageal echocardiography cohort. We detected un- or misidentified cardiac lesions during the intraoperative imaging and evaluated patient outcomes. Data are presented as a median with a range, or a number with percentages, with comparisons by Wilcoxon two-sample test and Fisher's exact test.RESULTS: Totally, 413 patients comprised the epicardial echocardiography group with 295 transoesophageal echocardiography matches. Rates of imaging discrepancies, re-operation, and incision infection were similar. About 13% of epicardial echocardiography patients had imaging discrepancies versus 16% for transoesophageal (p = 0.2352), the former also had smaller body sizes (p < 0.0001) and more genetic abnormalities (33% versus 19%, p < 0.0001). Death/mechanical support occurred more frequently in epicardial echocardiography patients (16% versus 6%, p < 0.0001), while hospitalisations were longer (25 versus 19 days, p = 0.0003).CONCLUSIONS: Diagnostic accuracy was similar between patients undergoing epicardial echocardiography and transoesophageal echocardiography, while rates of death and mechanical support were increased in this inherently higher risk patient population. Epicardial echocardiography provides a reasonable alternative when transoesophageal echocardiography is not feasible.

    View details for DOI 10.1017/S1047951122001536

    View details for PubMedID 35747949

  • "Echo pause" for postoperative transthoracic echocardiographic surveillance. Echocardiography (Mount Kisco, N.Y.) Cox, K., Arunamata, A., Krawczeski, C. D., Reddy, C., Kipps, A. K., Long, J., Roth, S. J., Axelrod, D. M., Hanley, F., Shin, A., Selamet Tierney, E. S. 2019


    BACKGROUND: No guidelines exist for inpatient postoperative transthoracic echocardiographic (TTE) surveillance in congenital heart disease. We prospectively evaluated indications for postoperative TTEs in patients with congenital heart disease to identify areas to improve upon (Phase 1) and then assessed the impact of a simple pilot intervention (Phase 2).METHODS: We included patients with RACHS-1 (Risk Adjustment for Congenital Heart Surgery) scores of 2 and 3 to keep the cohort homogenous. During Phase 1, we collected data prospectively to identify postoperative TTEs for which there were no new findings and no associated clinical management decisions ("potentially redundant" TTEs). During Phase 2, prior to placement of a TTE order, an "Echo Pause" was performed during rounds to prompt review of prior TTE results and indication for the current order. The number of "potentially redundant" TTEs during Phase 1 vs. Phase 2 was compared.RESULTS: During Phase 1, 98 postoperative TTEs were performed on 51 patients. Potentially "redundant" TTEs were identified in two main areas: (a) TTEs ordered to evaluate pericardial effusion and (b) TTEs ordered with the indication of "postoperative," "follow-up," or "discharge" in the setting of a prior complete postoperative TTE and no apparent change in clinical status. During Phase 2, 101 TTEs were performed on 63 patients. The number of "potentially redundant" TTEs decreased from 14/98 (14%) to 5/101 (5%) (P=.026).CONCLUSION: Our results suggest that the number of "potentially redundant" TTEs during inpatient postoperative surveillance of patients with congenital heart disease can be decreased by a simple intervention during rounds such as an "Echo Pause."

    View details for DOI 10.1111/echo.14505

    View details for PubMedID 31628768

  • Bridge to success: A better method of cryoablation for atrioventricular nodal reentrant tachycardia in children HEART RHYTHM Reddy, C. D., Ceresnak, S. R., Motonaga, K. S., Avasarala, K., Feller, C., Trela, A., Hanisch, D., Dubin, A. M. 2017; 14 (11): 1649–54


    Cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) is associated with higher recurrence rates than radiofrequency ablation (RFA). Junctional tachycardia marks procedural success with RFA, but no such indicator exists for cryoablation.The purpose of this study as to determine the impact of voltage mapping plus longer ablation lesions on midterm success of cryoablation for children with AVNRT.We performed a single-center retrospective analysis of pediatric patients with AVNRT who underwent cryoablation from 2011 to 2015. Patients ablated using a standard electroanatomic approach (control) were compared with patients ablated using voltage mapping (voltage group). In the voltage group, EnSite NavX navigation and visualization technology (St Jude Medical, St Paul, MN) was used to develop a "bridge" of lower voltage gradients (0.3-0.8 mV) of the posteroseptal right atrium to guide cryoablation. Kaplan-Meier analysis was used to determine freedom from recurrence of supraventricular tachycardia.In all, 122 patients were included (71 voltage, 51 control). There was no difference between groups regarding age, sex, or catheter-tip size. Short-term success was similar in both groups (98.5% voltage vs 92% control; P = .159), but recurrence rates were lower in the voltage group (0% vs 11%, P = .006). Follow-up time was shorter in the voltage group (15 ± 7 months vs 22 ± 17 months, P < .05). The 1-year freedom from recurrence was lower in the voltage group (100% vs 91.5%, P <.05). Ablation times were longer in the voltage group (43.7 ± 20.9 minutes vs 34.3 ± 20.5 minutes, P = .01), but overall procedure times were shorter in the voltage group (157 ± 40 minutes vs 198 ± 133 minutes; P = .018). No significant complication was seen in either group.Voltage gradient mapping and longer lesion time can decrease recurrence rates in pediatric patients with AVNRT.

    View details for PubMedID 28716699

  • A Comparison of AV Nodal Reentrant Tachycardia in Young Children and Adolescents: Electrophysiology, Ablation, and Outcomes. Pacing and clinical electrophysiology : PACE Reddy, C. D., Silka, M. J., Bar-Cohen, Y. 2015; 38 (11): 1325-32


    Atrioventricular nodal reentrant tachycardia (AVNRT) typically occurs in adolescents and adults with limited data regarding AVNRT in young children.All patients with AVNRT who underwent electrophysiology study and ablation between 2005 and 2012 were retrospectively studied. Patients were stratified by age <10 years (young AVNRT) or ≥10 years (older AVNRT). Young AVNRT patients were also compared to age-matched patients with orthodromic reentrant tachycardia (ORT).A total of 275 studies in 272 patients were evaluated including 38 young AVNRT patients (7.7 ± 1.5 years) and 202 older AVNRT patients (14.9 ± 2.1 years). An atrial-His jump ≥50 ms was demonstrated in 56% of young and 64% of older patients. Slow pathway modification was attempted in all but one older patient with acute ablation success achieved in all. RF ablation was the primary ablation modality with cryoablation used in 10 patients (three young and seven older). Recurrences were rare (zero young and three older patients) despite residual AVNRT echo beats postablation in 34% of young and 40% of older patients. One older AVNRT patient (0.5%) required a pacemaker for heart block while no complications occurred in the young patients. Electrophysiologic parameters were comparable to the 35 age-matched young ORT group (7.7 ±1.7 years) in whom supraventricular tachycardia was more inducible.Slow pathway modification for AVNRT in children resulted in high success and low complication rates, regardless of age. Recurrence of tachycardia was infrequent despite persistence of AVNRT echo beats in 34-40% of patients following slow pathway modification.

    View details for DOI 10.1111/pace.12699

    View details for PubMedID 26234164

  • 50 is the new 70: Short ventriculoatrial times are common in children with atrioventricular reciprocating tachycardia. Heart rhythm Ceresnak, S. R., Doan, L. N., Motonaga, K. S., Avasarala, K., Trela, A. V., Reddy, C. D., Dubin, A. M. 2015; 12 (7): 1541-1547


    One of the basic electrophysiological principles of atrioventricular reciprocating tachycardia (AVRT) is that ventriculoatrial (VA) times during tachycardia are >70 ms. We hypothesized, however, that children may commonly have VA times <70 ms in AVRT.This study sought to determine the incidence and characteristics associated with short-VA AVRT in children.A retrospective single-center review of children with AVRT from 2000 to 2014 was performed. All patients ≤18 years of age with AVRT at electrophysiology study were included. Patients with persistent junctional reciprocating tachycardia, atrioventricular nodal reentry tachycardia, and tachycardia not unequivocally proven to be AVRT were excluded. VA time was defined as the time between earliest ventricular activation and earliest atrial activation in any lead and was confirmed by 2 electrophysiologists. Patients with VA times <70 ms (SHORT-VA) and those with standard VA times ≥70 ms (STD-VA) were compared. Logistic regression analysis identified characteristics of SHORT-VA patients.A total of 495 patients with AVRT were included (mean age 11.7 ± 4.1 years). There were 265 patients (54%) with concealed accessory pathways (APs) and 230 (46%) with Wolff-Parkinson-White syndrome. AP location was left-sided in 301 patients (61%) and right-sided in 194 (39%). The mean VA time in AVRT was 100 ± 33 ms. A total of 63 patients (13%) had VA times <70 ms (SHORT-VA). The shortest VA time during AVRT was 50 ms. There was no difference in age, AV nodal block cycle, or body surface area between SHORT-VA and STD-VA patients, but SHORT-VA patients had lower weight (43 ± 17 vs 51 ± 23 kg, P = .02), lower AV nodal effective refractory period (AVNERP; 269 ± 50 vs 245 ± 52 ms, P < .01), and more left-sided APs (50 [79%] vs 251 [58%]; P < .01]. On multivariate logistic regression, factors associated with SHORT-VA included left-sided AP (odds ratio [OR] 5.79, confidence interval [95% CI] 2.21-15.1, P < .01), shorter AVNERP (OR 0.99, CI 0.98-0.99, P < .01), and lower weight (OR 0.97, CI 0.95-0.99, P < .01).Children with AVRT can frequently have VA times <70 ms, with 50 ms being the shortest VA time. This finding debunks the classic electrophysiology principle that VA times in AVRT must be >70 ms. SHORT-VA AVRT was more common in children with left-sided APs.

    View details for DOI 10.1016/j.hrthm.2015.03.047

    View details for PubMedID 25828598

  • Testosterone concentrations in early pregnancy: relation to method of conception in an infertile population REPRODUCTIVE BIOMEDICINE ONLINE Lathi, R. B., Moayeri, S. E., Reddy, C. D., Gebhardt, J., Behr, B., Westphal, L. M. 2012; 24 (3): 360-363


    This prospective cohort study of infertility patients compared testosterone concentrations in early pregnancy in infertility patients who conceived naturally or after treatment. Although all groups demonstrated some increase in pregnancy testosterone from baseline concentrations, subjects who conceived following ovulation induction showed a significantly increased rise in testosterone as compared with controls (P<0.01).

    View details for DOI 10.1016/j.rbmo.2011.11.018

    View details for PubMedID 22285241