BACKGROUND:The use of cardiac implantable electronic devices (CIEDs) continues to grow. Despite the presence of implanted hardware, patient compliance with in-clinic visits and remote transmissions is poor. We performed a quality improvement (QI) initiative to assess and optimize CIED follow-up in the New England area. METHODS:A regional network of eight pediatric institutions was created. All patients with CIEDs were identified starting in 2016. Noncompliance was defined as: no in-person evaluation within 1 year, or no remote transmission within 6 months. Interventions performed included automated texts/emails, certified letters, and personal phone calls. RESULTS:A total of 612 patients were identified, with the total number of patients increasing over the 5-year QI period as patients had devices implanted and removed. Initial noncompliance with in-person annual follow-up was 29%. If patients were noncompliant, a personal phone call was made, reminding them to return to clinic. If the patient could not be reached for 3 months, a certified letter was sent. The noncompliance rate decreased to 5% over the first year and remained around this level over the QI period (3%-9%). For remote transmissions, 54% of patients were noncompliant. Interventions were performed on subgroups of patients. Automated texts/emails were trialed in 126; after 6 months, 41% of these patients remained noncompliant. Phone calls were then trialed on 87 patients. Over 6 months, noncompliance decreased to 11%. CONCLUSIONS:Patients with CIEDs have poor compliance with regular follow-up. Patients have a limited response to automated measures (texts/emails). Personal phone calls had the greatest impact in improving compliance.

HomeCirculationVol. 149, No. 2Highlights From the Circulation Family of Journals Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBHighlights From the Circulation Family of Journals Originally published8 Jan 2024https://doi.org/10.1161/CIRCULATIONAHA.123.068221Circulation. 2024;149:155–159The November highlights from the Circulation family of journals cover several fascinating topics in cardiology. Among young patients with hypertrophic cardiomyopathy, an association of storage disease and preexcitation is reported in Circulation Arrhythmia and Electrophysiology. The associations of coronary and cerebrovascular microvascular dysfunction, heart failure, and cognitive dysfunction are reported in Circulation: Heart Failure. The incorporation of cost-effectiveness evaluations in clinical cardiology guidelines is reported in Circulation: Cardiovascular Quality and Outcomes. Investigators report an association of pericardial enhancement on cardiac magnetic resonance imaging after cardiac surgery with low-grade inflammation in Circulation: Cardiovascular Imaging. Last, an analysis of cardiac computed tomography characteristics before redo transcatheter aortic valve replacement for the risk of coronary occlusion is reported in Circulation: Cardiovascular Interventions.Circulation: Arrhythmia and ElectrophysiologyHypertrophic Cardiomyopathy and Ventricular Preexcitation in the Young: Cause and Accessory Pathway CharacteristicsRobert Przybylski, MD; Sakethram Saravu Vijayashankar, MD, MRCPCH; Edward T. O’Leary, MD; Robyn J. Hylind, MS, CGC; Jennifer Noon, MSN, CPNP-PC; Audrey Dionne, MD; Elizabeth S. DeWitt, MD; Vassilios J. Bezzerides, MD, PhD; Dominic J. Abrams, MD, MRCP, MBCorrespondence to: Robert Przybylski, MD, Department of Pediatrics, Inova Fairfax Hospital, 3600 Gallows Rd Falls Church, VA. Email robert.przybylski@inova.orgBACKGROUND: The cause of hypertrophic cardiomyopathy (HCM) in the young is highly varied. Ventricular preexcitation (preexcitation) is well recognized, yet little is known about the specificity for any cause and the characteristics of the responsible accessory pathways (AP).METHODS: Retrospective cohort study of patients <21 years of age with HCM/preexcitation from 2000 to 2022. The cause of HCM was defined as isolated HCM, storage disorder, metabolic disease, or genetic syndrome. Atrioventricular AP (true AP) were distinguished from fasciculoventricular fibers (FVF) using standard invasive electrophysiology study criteria. AP were defined as high risk if any of the following were <250 ms: shortest preexcited RR interval in atrial fibrillation, shortest paced preexcited cycle length, or anterograde AP effective refractory period.RESULTS: We identified 345 patients with HCM and 28 (8%) had preexcitation (isolated HCM, 10/220; storage disorder, 8/17; metabolic disease, 5/19; and genetic syndrome, 5/89). Six (21%) patients had clinical atrial fibrillation (1 with shortest preexcited RR interval <250 ms). Twenty-two patients underwent electrophysiology study which identified 23 true AP and 16 FVF. Preexcitation was exclusively FVF mediated in 8 (36%) patients. Five (23%) patients had AP with high-risk conduction properties (including ≥1 patient in each etiologic group). Multiple AP were seen in 8 (36%) and AP plus FVF in 10 (45%) patients. Ablation was acutely successful in 13 of 14 patients with recurrence in 3. One procedure was complicated by complete heart block after ablation of a high-risk midseptal AP. There were significant differences in QRS amplitude and delta wave amplitude between groups. There were no surface ECG features that differentiated AP from FVF.CONCLUSIONS: Young patients with HCM and preexcitation have a high likelihood of underlying storage disease or metabolic disease. Nonisolated HCM should be suspected in young patients with large QRS and delta wave amplitudes. Surface ECG is not adequate to discriminate preexcitation from a benign FVF from that secondary to potentially life-threatening AP.Circ Arrhythm Electrophysiol. 2023;16:e012191. doi: 10.1161/CIRCEP.123.012191Circulation: Heart FailureMicrovascular Dysfunction as a Possible Link Between Heart Failure and Cognitive DysfunctionElizabeth Hillier, PhD; Jason Covone, MSc; Kady Fischer, PhD; Hao Yu Chen, PhD; Tarik Hafyane, PhD; Matthias G. Friedrich, MDCorrespondence to: Matthias G. Friedrich, MD, Department of Medicine and Diagnostic Radiology, McGill University, 1001 Decarie Blvd, Montreal, QC H4A 3J1, Canada. Email matthias.friedrich@mcgill.caBACKGROUND: Microvascular function in the brain and heart may play an important role in the course of patients with heart failure (HF), but its relationship with ventricular and cognitive function is not well understood. We hypothesized that microvascular function in HF is closely related to both, cardiac and cognitive function.METHODS: In healthy controls and symptomatic patients with HF (New York Heart Association functional class II or III), we used oxygenation-sensitive magnetic resonance imaging during a standardized breathing maneuver to determine the cerebral oxygenation reserve and the myocardial oxygenation reserve (MORE) as markers for microvascular function. A stepwise multivariable linear regression was performed to determine the variables that best predict changes in cerebral oxygenation reserve and MORE. We also measured cognitive function using the Montreal Cognitive Assessment test.RESULTS: Twenty patients with HF (age 64.4±8.3 years; 50% female sex), and 21 healthy controls (age 55.0±5.1 years; 62% female sex) were included in the analysis. In patients with HF, cerebral oxygenation reserve and MORE were lower than in healthy controls (MORE, −0.1±3.3 versus 5.0±4.2, cerebral oxygenation reserve: 0.43±0.47 versus 1.21±0.60, respectively) as were Montreal Cognitive Assessment score results (HF, 23.9±3.7; healthy, 27.8±1.5; P=0.002). The Montreal Cognitive Assessment score in patients was correlated with cardiac output (r=0.55, P=0.011) and MORE (r=0.46, P=0.040). In addition to the presence of HF, significant predictors of cerebral and myocardial oxygenation reserve were cardiac output and end-diastolic volume, respectively.CONCLUSIONS: Our results indicate that heart failure is an independent predictor of coronary and cerebral microvascular dysfunction as defined by a reduced response to a vasodilatory breathing maneuver. This impaired response was associated with reduced cognitive function.Circ Heart Fail. 2023;16:e010117. doi: 10.1161/CIRCHEARTFAILURE.122.010117Circulation: Cardiovascular Quality and OutcomesEvolution of Value in American College of Cardiology/American Heart Association Clinical Practice GuidelinesAndrea Luviano, MD, MPH; Ankur Pandya, PhDCorrespondence to: Andrea Luviano, MD, MPH, Department of Health Policy, Harvard University, Center for Health Decision Science, Harvard T.H. Chan School of Public Health, 718 Huntington Ave, 2nd Floor, Boston, MA 02115. Email andrealuviano@g.harvard.eduBACKGROUND: In January 2014, the American College of Cardiology/American Heart Association released a policy statement arguing for the inclusion of cost-effectiveness analysis (CEA) and value assessments in clinical practice guidelines. It is unclear whether subsequent guidelines changed how they incorporated such concepts.METHODS: We analyzed guidelines of cardiovascular disease subconditions with a guideline released before and after 2014. We counted the words (total and per page) for 8 selected value- or CEA-related terms and compared counts and rates of terms per page in the guidelines before and after 2014. We counted the number of recommendations with at least 1 reference to a CEA or a CEA-related article to compare the ratios of such recommendations to all recommendations before and after 2014. We looked for the inclusion of the value assessment system recommended by the writing committee of the American College of Cardiology/American Heart Association policy statement of 2014.RESULTS: We analyzed 20 guidelines of 10 different cardiovascular disease subconditions. Seven of the 10 cardiovascular disease subconditions had guidelines with a greater term per page rate after 2014 than before 2014. Across all 20 guidelines, the proportion of recommendations with at least 1 reference to a CEA changed from 0.44% to 1.99% (P<0.01). The proportion of recommendations with at least 1 reference to a CEA-related article changed from 1.02% to 3.34% (P<0.01). Only 3 guidelines used a value assessment system.CONCLUSIONS: The proportion of recommendations with at least 1 reference to a CEA or CEA-related article was low before and after 2014 for most of the subconditions, however, with substantial variation in this finding across the guidelines included in our analysis. There is a need to organize existing CEA information better and produce more policy-relevant CEAs so guideline writers can more easily make recommendations that incentivize high-value care and caution against using low-value care.Circ Cardiovasc Qual Outcomes. 2023;16:e010086. doi: 10.1161/CIRCOUTCOMES.123.010086Circulation: Cardiovascular ImagingPrevalence of Pericardial Late Gadolinium Enhancement in Patients After Cardiac Surgery: Clinical and Histological CorrelationsAnna Giulia Pavon, MD; Ruben Martinez Fernandez, MS; Dimitri Arangalage, MD, PhD; Luca Bergamaschi, MD; Niccolò Maurizi, MD; Sebastien Colombier, MD; Samuel Rotman, MD; Anna Nowacka, MD; Judith Bouchardy, MD; Juerg Schwitter, MD; Matthias Kirsch, MD; Pierre Monney, MD; Tobias Rutz, MDCorrespondence to: Anna Giulia Pavon, MD, Division of Cardiology, Cardiocentro Ticino Institute, Ente Ospedaliero Cantonale, Via Tesserete, 48, 6900 Lugano, Switzerland. Email annagiulia.pavon@eoc.chBACKGROUND: Pericardial late gadolinium enhancement (LGE) is usually associated with active pericarditis, but it is not infrequently found in patients after cardiac surgery even a long time after the intervention. The clinical relevance of this finding and its histological correlates are unknown. We sought to determine the prevalence of chronic pericardial LGE in patients after cardiac surgery.METHODS: All consecutive patients with previous cardiac surgery, who were referred to cardiovascular magnetic resonance between January 2017 and December 2021 were enrolled in the study. Cardiovascular magnetic resonance examination protocol was adapted to clinical indication but always included standard LGE acquisitions. Two independent observers blinded to clinical data assessed the presence of pericardial enhancement on LGE sequences. Fifteen patients underwent cardiac reintervention and pericardial biopsies were obtained. The primary study end point was to assess the prevalence of pericardial enhancement after cardiac surgery and identify possible determinants. The secondary end point was to correlate pericardial enhancement with clinical symptoms and histopathology.RESULTS: Two hundred four patients were included in the study. The median time between surgery and cardiovascular magnetic resonance was 160 months (35–226 months). Pericardial LGE was observed in 90 patients (44%). All patients were asymptomatic, and no specific treatment for pericarditis was started. All patients remained asymptomatic at a 1-year clinical follow-up. Pericardial LGE was significantly correlated with the number of previous surgeries (P=0.03). Pericardial fibrosis was detected in all 15 pericardial biopsy specimens; pericardial LGE was present in 7 patients (47%) who underwent biopsy. Histological signs of low-grade inflammation were detected in 6 patients (40%) with severe, circumferential pericardial LGE but in no patient without pericardial enhancement.CONCLUSIONS: Pericardial LGE is a frequent finding even several years after cardiac surgery. Its histological correlate is a chronic subclinical post–pericardiotomy inflammation.Circ Cardiovasc Imaging. 2023;16:e015606. doi: 10.1161/CIRCIMAGING.123.015606Circulation: Cardiovascular InterventionsFeasibility of Redo-transcatheter Aortic Valve Replacement in Sapien Valves Based on In-vivo Computed Tomography AssessmentMiho Fukui, MD, PhD; Atsushi Okada, MD, PhD; Kiahltone R. Thao, BA; Marcus R. Burns, DNP; Hideki Koike, MD, PhD; Cheng Wang, MD; Asa Phichaphop, MD; John R. Lesser, MD; Paul Sorajja, MD; João L. Cavalcante, MD; Vinayak N. Bapat, MDCorrespondence to: Vinayak N. Bapat, MD, Minneapolis Heart Institute at Abbott Northwestern Hospital, 800 E 28th St, Ste 300, Minneapolis, MN 55407. Email vnbapat@yahoo.comBACKGROUND: Our aim was to assess the feasibility of repeat transcatheter aortic valve (TAV) replacement for degenerated Sapien3 (S3) prostheses by simulating subsequent implantation of S3 or Evolut, using in vivo computed tomography–based sizing and the impact on coronary and patient-prosthesis mismatch risks.METHODS: Computed tomography scans from 356 patients with prior S3 TAV replacement implantation were analyzed. The in vivo sizing for second TAV based on averaged area of 3 levels of outflow, mid (narrowest) and inflow, was compared with in vitro recommendations, that is, same size as index S3 for second S3 and 1 size larger for Evolut. Risks of coronary obstruction and patient-prosthesis mismatch were determined by valve-to-aorta distance and estimated effective orifice area, respectively.RESULTS: Overall, the majority of patients (n=328; 92.1%) had underexpanded index S3 with an expansion area of 94% (91%–97%), leading to significant differences in size selection of the second TAV between in vivo and in vitro sizing strategies. Expansion area <89% served as a threshold, resulting in 1 size smaller than the in vitro recommendations were selected in 45 patients (13%) for S3-in-S3 and 13 (4%) for Evolut-in-S3, while the remaining patients followed in vitro recommendations (P<0.01, in vivo versus in vitro sizing). Overall, 57% of total patients for S3-in-S3 simulation and 60% for Evolut-in-S3 were considered low risk for coronary complications. Deep index S3 implantation (odds ratio, 0.76 [interquartile range, 0.67–0.87]; P<0.001) and selecting Evolut as the second TAV (11% risk reduction in intermediate- or high-risk patients) reduced coronary risk. Estimated moderate or severe patient-prosthesis mismatch risk was 21% for S3-in-S3 and 1% for Evolut-in-S3, assuming optimal expansion of the second TAV.CONCLUSIONS: Redo-TAV replacement with S3-in-S3 and Evolut-in-S3 could be feasible with low risk to coronaries in ≈60% of patients, while the remaining 40% will be at intermediate or high risk. The feasibility of redo-TAV replacement is influenced by sizing strategy, type of second TAV, native annular anatomy, and implant depth.Circ Cardiovasc Interv. 2023;16:e013497. doi: 10.1161/CIRCINTERVENTIONS.123.013497FootnotesCirculation is available at www.ahajournals.org/journal/circ eLetters(0) eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate. Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page. Sign In to Submit a Response to This Article Previous Back to top Next FiguresReferencesRelatedDetails January 9, 2024Vol 149, Issue 2 Advertisement Article Information Metrics © 2024 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.123.068221PMID: 38190450 Originally publishedJanuary 8, 2024 PDF download Advertisement

OBJECTIVE:The need for permanent pacemaker (PPM) for iatrogenic atrioventricular block (AVB) after congenital heart surgery is approximately 1%. We aimed to evaluate the long-term outcomes of patients with PPM for iatrogenic AVB and compare them with patients with an optimal repair (trivial/no residual) Residual Lesion Score (RLS) Class 1 repair without PPM need. METHODS:We reviewed 183 patients discharged with PPM for iatrogenic AVB from 2011 to 2022. Patients who survived to discharge with >30 days of follow-up were matched 1:1 with a cohort of patients categorized as RLS Class 1 on the basis of fundamental diagnosis and primary procedure. RESULTS:Median age at PPM placement was 1.4 years (interquartile range, 4.3 months to 3.9 years). The cumulative incidence of moderate or greater ventricular dysfunction at 1 year and 5 years was 11% and 18% in patients with PPM, respectively, compared with 3% and 7% in patients categorized as RLS Class 1 (subdistribution hazard ratio, 2.6; 95% confidence interval, 1.2-6.1; P = .022). Independently, patients with PPM with hypoplastic left heart syndrome (P = .027) and who had undergone Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Category 5 procedures (P = .033) were at greater risk of ventricular dysfunction. Transplant-free survival at 1 year and 5 years was 94% and 89% in patients with PPM, respectively, compared with 98% and 97% in patients categorized as RLS Class 1 (P = .044). In addition, patients with PPM with palliated circulation had significantly lower transplant-free survival (P < .001). CONCLUSIONS:Compared with patients with an optimal repair without PPM, patients with PPM for iatrogenic AVB are at greater risk of developing moderate or greater ventricular dysfunction and have lower transplant-free survival.

BACKGROUND:Postoperative arrhythmias are most often transient and medically treated, but some patients may require electrophysiology study (EPS) and ablation. OBJECTIVE:The purpose of this study was to describe the efficacy and safety of early postoperative ablation. METHODS:This study presents a retrospective series of patients who underwent EPS within 12 months of surgery for congenital heart disease between 2000 and 2021. The procedural outcome included complete or partial success, empirical ablation or failure, and complications. The long-term outcome included arrhythmia recurrence and burden according to a 12-point clinical arrhythmia severity score (documented arrhythmia, arrhythmia severity, cardioversion, and antiarrhythmic medication). RESULTS:Among 28,902 operations during the study period, 24 patients (0.1%) underwent EPS within 3 months of surgery and 26 (0.1%) 3-12 months after surgery. Most patients had great (n = 27 [50%]) or moderate (n = 21 [42%]) congenital heart disease complexity. Mechanisms of arrhythmias included intra-atrial reentrant tachycardia (n = 23 [46%]), ectopic atrial tachycardia (n = 13 [26%]), accessory pathway (n = 6 [12%]), atrioventricular nodal reentrant tachycardia (n = 7 [14%]), twin atrioventricular node (n = 1 [2%]), atrial fibrillation (n = 1 [2%]), junctional ectopic tachycardia (n = 1 [2%]), and ventricular tachycardia (n = 2 [4%]). The procedure was acutely successful in 41 patients (82%), empirical in 5 (10%), and unsuccessful in 4 (8%). Complications occurred in 4 (8%) patients (major in 1, moderate in 1, and minor in 2). The recurrence of arrhythmia was documented in 27 patients (54%), although the burden of arrhythmia was significantly reduced. CONCLUSION:A minority of patients require early postoperative EPS and ablation. For those, the procedure can be performed with reasonable acute success and manageable morbidity even in critically ill patients with complex surgical anatomy.

Catheter-based slow pathway modification (SPM) for atrioventricular nodal reentrant tachycardia (AVNRT) is traditionally performed at empiric sites using anatomical landmarks and test ablation feedback within the triangle of Koch (TK). While studies have described more tailored techniques such as bipolar low voltage bridge (LVB) and wavefront collision identification, few have systematically compared the diagnostic yields of each and none have investigated whether omnipolar mapping technology provides incremental benefit. The objective of this study was to compare the utility of omnipolar and bipolar-derived qualitative and quantitative measurements in identifying and localizing dual AVN substrate in patients with versus without AVNRT. A retrospective case-control study of consecutive patients with paroxysmal supraventricular tachycardia undergoing electrophysiology study with both omnipolar and bipolar mapping from 2022-2023. Thirteen AVNRT cases (median age 16.1 years, 512 TK points) were compared to nine non-AVNRT controls (median age 15.7 years, 332 TK points). Among qualitative variables, an omnipolar activation vector pivot, defined as a ≥45 degree change in activation direction within the TK, had the highest positive (81

Objectives Although conduction location can be reliably predicted in double inlet ventricle, ventricular septation continues to carry a significant risk of complete heart block. This study describes our experience using intraoperative conduction mapping during ventricular septation. Methods Patients undergoing ventricular septation from 2017 to 2023 were identified. Conduction mapping was performed on the open, decompressed, beating heart to identify the His bundle. Mapped His bundle locations were compared with those predicted from magnetic resonance imaging diagnoses by a senior pediatric cardiac electrophysiologist blinded to mapping results. Results Ventricular septation was performed in 31 patients, 25 with hypoplastic right ventricles and 6 with hypoplastic left ventricles. Two-stage septation was performed in 25 patients, and single-stage septation was performed in 6 patients. Mapped conduction location was performed in the last 25 consecutive patients. Mapped conduction location was concordant with expected location in 21 of 22 patients with predictions. Complete heart block requiring a permanent pacemaker occurred in 4 patients despite successful mapping, whereas 10 patients required other reoperations, most commonly to address residual atrioventricular valve regurgitation or subpulmonary obstruction from the ventricular septal defect patch. There has been no perioperative mortality, need for single-ventricle palliation, or heart transplantation. All 13 patients who have progressed to complete septation and 18 patients with interstage circulation have acceptable hemodynamics, preserved ventricular function, and no heart failure symptoms at latest follow-up. Conclusions Ventricular septation represents an alternative to the Fontan that can be performed safely in a subset of patients with acceptable early outcomes. Conduction mapping is an adjunct strategy that may add precision to well-established rules for reliably predicting conduction location.

The association between cardiorespiratory fitness (CRF) and mortality risk is based mostly on 1 CRF assessment. The impact of CRF change on mortality risk is not well-defined.This study sought to evaluate changes in CRF and all-cause mortality.We assessed 93,060 participants aged 30-95 years (mean 61.3 ± 9.8 years). All completed 2 symptom-limited exercise treadmill tests, 1 or more years apart (mean 5.8 ± 3.7 years) with no evidence of overt cardiovascular disease. Participants were assigned to age-specific fitness quartiles based on peak METS achieved on the baseline exercise treadmill test. Additionally, each CRF quartile was stratified based on CRF changes (increase, decrease, no change) observed on the final exercise treadmill test. Multivariable Cox models were used to estimate HRs and 95% CIs for all-cause mortality.During a median follow-up of 6.3 years (IQR: 3.7-9.9 years), 18,302 participants died with an average yearly mortality rate of 27.6 events per 1,000 person-years. In general, changes in CRF ≥1.0 MET were associated with inverse and proportionate changes in mortality risk regardless of baseline CRF status. For example, a decline in CRF of >2.0 METS was associated with a 74% increase in risk (HR: 1.74; 95% CI: 1.59-1.91) for low-fit individuals with CVD, and 69% increase (HR: 1.69; 95% CI: 1.45-1.96) for those without CVD.Changes in CRF reflected inverse and proportional changes in mortality risk for those with and without CVD. The impact of relatively small CRF changes on mortality risk has considerable clinical and public health significance.

Background: Abnormal repolarization in long QT syndrome type 1 (LQT1) is characterized by QT prolongation and abnormal T-waves. In the absence of familial disease, LQT1 is easily missed in infants as the QTc is often normal, exposing children to life-threatening arrhythmia. Hypothesis: T-wave morphology metrics are superior to QTc for diagnosis of LQT1. Aim: Compare quantifiable aspects of T-wave morphology and QTc to differentiate infants with and without LQT1. Methods: Infants aged 0.5-6 months with a pathogenic/likely pathogenic KCNQ1 variant were compared to age/sex-matched controls in a 1:2 ratio. Measurements were made in leads II/V5. T-wave morphology was assessed by J-point to T-wave peak (J-Tp) and Tp to T-wave end (Tp-Te). Bazett’s formula was used to correct for heart rate and Te defined using the tangent method. Results: We identified 34 LQT1 infants and 68 controls. The median (IQR) QTc was 457 (430-476) ms for LQT1 cases and 402 (392-420) ms for controls (p<0.001). The 98%tile QTc for controls was 448 ms and 13/34 (38%) LQT1 cases were below this value. In lead II, LQT1 cases had a significantly longer rate corrected J-Tp compared to controls, 294 (272-312) ms v. 222 (211-234) ms (p <0.001) and shorter Tp-Te, 71 (60-80) ms v. 85 (75-95) ms (p<0.001). The J-Tp/Tp-Te ratio was 0.25 in LQT1 cases and 0.39 in controls (p<0.001). Findings were similar in V5. V5 rate corrected J-Tp best discriminated between LQT1 cases and controls (ROC AUC 0.99, optimal cut point ≥256ms) and outperformed QTc (AUC 0.92). This remained true in those with QTc <98%tile (AUC 0.98). Measurements in a subset of 30 infants made by 3 ECG readers showed superior reliability for J-Tp in leads II and V5 (ICC coefficient 0.92) compared to QTc (0.88). Conclusions: Nearly 40% of infants with LQT1 have a normal a QTc, yet a significantly abnormal and quantifiable T-wave morphology. J-Tp and Tp-Te are reliable and reproducible measurements and should be included in the assessment of potential infantile LQT1.

Premature ventricular contractions (PVCs) are common in children and are often perceived as benign. However, frequent PVCs can lead to left ventricular (LV) dysfunction. Risk factors for PVC-mediated LV dysfunction are not well defined in children.

INTRODUCTION:The use of flecainide and propafenone for medical cardioversion of atrial fibrillation (AF) and atrial flutter/intra-atrial reentrant tachycardia (IART) is well-described in adults without congenital heart disease (CHD). Data are sparse regarding their use for the same purpose in adults with CHD and in adolescent patients with anatomically normal hearts and we sought to describe the use of class IC drugs in this population and identify factors associated with decreased likelihood of success. METHODS:Single center retrospective cohort study of patients who received oral flecainide or propafenone for medical cardioversion of AF or IART from 2000 to 2022. The unit of analysis was each episode of AF/IART. We performed a time-to-sinus rhythm analysis using a Cox proportional hazards model clustering on the patient to identify factors associated with increased likelihood of success. RESULTS:We identified 45 episodes involving 41 patients. As only episodes of AF were successfully cardioverted with medical therapy, episodes of IART were excluded from our analyses. Use of flecainide was the only factor associated with increased likelihood of success. There was a statistically insignificant trend toward decreased likelihood of success in patients with CHD. CONCLUSIONS:Flecainide was more effective than propafenone. We did not detect a difference in rate of conversion to sinus rhythm between patients with and without CHD and were likely underpowered to do so, however, there was a trend toward decreased likelihood of success in patients with CHD. That said, medical therapy was effective in >50% of patients with CHD with AF.

While operational efficiency has been evaluated in adult interventional and surgical specialties, limited data exist regarding the prediction of case complexity in the pediatric and congenital electrophysiology (EP) laboratory.

BACKGROUND: The cause of hypertrophic cardiomyopathy (HCM) in the young is highly varied. Ventricular preexcitation (preexcitation) is well recognized, yet little is known about the specificity for any cause and the characteristics of the responsible accessory pathways (AP). METHODS: Retrospective cohort study of patients <21 years of age with HCM/preexcitation from 2000 to 2022. The cause of HCM was defined as isolated HCM, storage disorder, metabolic disease, or genetic syndrome. Atrioventricular AP (true AP) were distinguished from fasciculoventricular fibers (FVF) using standard invasive electrophysiology study criteria. AP were defined as high risk if any of the following were <250 ms: shortest preexcited RR interval in atrial fibrillation, shortest paced preexcited cycle length, or anterograde AP effective refractory period. RESULTS: We identified 345 patients with HCM and 28 (8%) had preexcitation (isolated HCM, 10/220; storage disorder, 8/17; metabolic disease, 5/19; and genetic syndrome, 5/89). Six (21%) patients had clinical atrial fibrillation (1 with shortest preexcited RR interval <250 ms). Twenty-two patients underwent electrophysiology study which identified 23 true AP and 16 FVF. Preexcitation was exclusively FVF mediated in 8 (36%) patients. Five (23%) patients had AP with high-risk conduction properties (including ≥1 patient in each etiologic group). Multiple AP were seen in 8 (36%) and AP plus FVF in 10 (45%) patients. Ablation was acutely successful in 13 of 14 patients with recurrence in 3. One procedure was complicated by complete heart block after ablation of a high-risk midseptal AP. There were significant differences in QRS amplitude and delta wave amplitude between groups. There were no surface ECG features that differentiated AP from FVF. CONCLUSIONS: Young patients with HCM and preexcitation have a high likelihood of underlying storage disease or metabolic disease. Nonisolated HCM should be suspected in young patients with large QRS and delta wave amplitudes. Surface ECG is not adequate to discriminate preexcitation from a benign FVF from that secondary to potentially life-threatening AP.