Nathaniel W. Taggart

Diagnostic Miscues in Congenital Long-QT Syndrome

Background— Long-QT syndrome (LQTS) is a potentially lethal cardiac channelopathy that can be mistaken for palpitations, neurocardiogenic syncope, and epilepsy. Because of increased physician and public awareness of warning signs suggestive of LQTS, there is the potential for LQTS to be overdiagnosed. We sought to determine the agreement between the dismissal diagnosis from an LQTS subspecialty clinic and the original referral diagnosis. Methods and Results— Data from the medical record were compared with data from the outside evaluation for 176 consecutive patients (121 females, median age 16 years, average referral corrected QT interval [QTc] of 481 ms) referred with a diagnosis of LQTS. After evaluation at Mayo Clinic’s LQTS Clinic, patients were categorized as having definite LQTS (D-LQTS), possible LQTS (P-LQTS), or no LQTS (No-LQTS). Seventy-three patients (41%) were categorized as No-LQTS, 56 (32%) as P-LQTS, and only 47 (27%) as D-LQTS. The yield of genetic testing among D-LQTS patients was 78% compared with 34% for P-LQTS and 0% among No-LQTS patients (P<0.0001). The average QTc was greater in either D-LQTS or P-LQTS than in No-LQTS (461 versus 424 ms, P<0.0001). Vasovagal syncope was more common among the No-LQTS subset (28%) than the P-LQTS/D-LQTS group (8%; P=0.04). Determinants for discordance (ie, positive outside diagnosis versus No-LQTS) included overestimation of QTc, diagnosing LQTS on the basis of “borderline” QTc values, and interpretation of a vasovagal fainting episode as an LQTS-precipitated cardiac event. Conclusions— Diagnostic concordance was present for less than one third of the patients who sought a second opinion. Two of every 5 patients referred with the diagnosis of LQTS departed without such a diagnosis. Miscalculation of the QTc, misinterpretation of the normal distribution of QTc values, and misinterpretation of symptoms appear to be responsible for most of the diagnostic miscues.

Late erosion of an Amplatzer septal occluder device 6 years after placement

CLINICAL SUMMARY A 46-year-old man underwent transcatheter closure of a PFO at our institution after a stroke-like event. The stretched diameter of the PFO was 9 to 10 mm. A 14-mm Amplatzer septal occluder device (AGA Medical Corporation, Golden Valley, Minn) was placed. Immediately after placement, a trivial degree of left-to-right shunt was seen through the center of the device by intracardiac echocardiography; agitated saline injection revealed a trivial right-to-left shunt. The procedure was uncomplicated, and the patient was dismissed from the hospital the following day. Predismissal transthoracic echocardiogram (TTE) showed good position and stability of the device with no apparent shunt. Ten days later, the patient returned with intermittent palpitations. Electrocardiogram revealed atrial fibrillation with rapid ventricular response. He was given intravenous diltiazem and promptly returned to sinus rhythm. TTE again documentedgoodposition of the occluder devicewith no recurrent atrial shunt or pericardial effusion. He was observed in the hospital overnight and dismissed on a regimen of oral diltiazem for 1 month. He had no recurrence of atrial fibrillation. Six years later, he came to the emergency department with progressive pleuritic chest pain. He had had similar chest pains 1month prior, which were not extensively investigated, but resolved spontaneously. In the emergency department he was hypotensive with mild jugular venous distention. TTE documented moderate pericardial effusion with tamponade. Pericardiocentesis removed 325 mL of bloody fluid. Transesophageal echocardiography did not show any evidence of shunt around the device. The device was again noted to not straddle the aortic root. Transesophageal echocardiographic

QTc Values Among Children and Adolescents Presenting to the Emergency Department

OBJECTIVE: Long-QT syndrome (LQTS) is both underdiagnosed and overdiagnosed. Many patients are incorrectly diagnosed as having LQTS after presenting to an emergency department (ED) with presyncope/syncope and demonstrating “borderline” QT-interval prolongation (QTc ≥ 440 milliseconds) in a sentinel ED-obtained electrocardiogram (ECG). We sought to evaluate the distribution and clinical significance of QT intervals in the ED. METHODS: We retrospectively reviewed data for all patients 22 years of age or younger (N = 626; 369 females; age, mean ± SD: 17 ± 5 years) who had ECGs obtained in our ED between July 1, 2007, and June 30, 2008. A total of 223 patients were excluded because of known structural heart disease, arrhythmias, electrolyte abnormalities, or exposure to QT-interval–prolonging medications. RESULTS: The average QTc was 428 ± 28 milliseconds (range: 344–566 milliseconds), and approximately one-third of patients had QTc values of ≥440 milliseconds (females: 41%; males: 21%). Overall, 104 patients presented with presyncope/syncope, of whom 14 (13%) had follow-up ECGs. On follow-up, these patients demonstrated significant decreases in QTc values of 33 ± 43 milliseconds (P < .04). Only 8 (31%) of 26 patients with presyncope/syncope with borderline QT values had follow-up ECGs performed, in 5 of which the QTc values were decreased significantly. No patients ultimately received LQTS diagnoses. CONCLUSIONS: In the ED setting, approximately one-third of pediatric patients exhibited QTc values of ≥440 milliseconds and had significant normalization of QTc values in follow-up evaluations. First-time ECGs obtained after a syncopal episode must be interpreted with caution, particularly in the context of so-called borderline QT intervals.

Percutaneous Pulmonary Valve Implantation in a Native Outflow Tract: 3-Dimensional DynaCT Rotational Angiographic Reconstruction and 3-Dimensional Printed Model

A 15-year-old girl with D-transposition of the great arteries presented with combined neo-pulmonary stenosis and regurgitation following arterial switch operation as a neonate and neo-pulmonary valvectomy at 6 years of age. Echocardiography revealed right ventricular enlargement and severe neo-

Immediate Outcomes of Covered Stent Placement for Treatment or Prevention of Aortic Wall Injury Associated With Coarctation of the Aorta (COAST II).

OBJECTIVES This study aimed to describe the safety and short-term efficacy of the Covered Cheatham-Platinum stent (CCPS) in treating or preventing aortic wall injury (AWI) in patients with coarctation of the aorta (CoA). BACKGROUND The COAST II trial (Covered Cheatham-Platinum Stents for Prevention or Treatment of Aortic Wall Injury Associated with Coarctation of the Aorta Trial) is a multicenter, single-arm trial using the CCPS for the treatment and/or prevention of AWI in patients with CoA and pre-existing AWI or increased risk of AWI. METHODS Patients were enrolled if they had a history of CoA with pre-existing AWI (Treatment group) or with increased risk of AWI (Prevention group). Pre/post-implant hemodynamics and angiography were reported. A core laboratory performed standardized review of all angiograms. One-month follow-up was reported. RESULTS A total of 158 patients (male = 65%; median age 19 years) underwent placement of CCPS. Eighty-three patients had pre-existing AWI. The average ascending-to-descending aorta systolic gradient improved from 27 ± 20 mm Hg to 4 ± 6 mm Hg. Complete coverage of pre-existing AWI was achieved in 66 of 71 patients (93%) with AWI who received a single CCPS. Ultimately, complete coverage of AWI was achieved in 76 of 83 patients (92%); 7 patients had minor endoleaks that did not require repeat intervention. Four patients experienced important access site vascular injury. There were no acute AWI, repeat interventions, or deaths. CONCLUSIONS The CCPS can effectively treat and potentially prevent AWI associated with CoA. Access site arterial injury is the most common important complication. Longer-term follow-up is necessary to define mid- and late-term outcomes.

Prevalence and outcome of thrombotic and embolic complications in adults after Fontan operation

Background There are limited studies of thrombotic and embolic complications (TEC) in the adult Fontan population. The purpose of the study was to determine the prevalence, risk factors, and outcomes of TECs in this population. Methods Retrospective review of adults with a previous Fontan operation, with follow‐up at Mayo Clinic, 1994‐2014. Systemic TEC was defined as intracardiac thrombus, ischemic stroke, or systemic arterial embolus. Nonsystemic TEC was defined as Fontan conduit/right atrial thrombus or pulmonary embolus. Results We identified 387 patients with a mean (SD) age of 28 (7) years and a mean follow‐up of 8 (2) years. An atriopulmonary connection (APC) was done for 286 patients (74%). Atrial arrhythmias were present in 278 (72%). There were 121 TECs (systemic n = 36, nonsystemic n = 85) in 98 patients (25%). Risk factors for systemic TEC were atrial arrhythmia (hazard ratio 2.28, P = .001) and APC (hazard ratio 1.98, P = .02); nonsystemic TEC also had similar risk factors. All 98 patients received warfarin. Warfarin was discontinued in 10 of 98 because of bleeding, and 8 of these 10 subsequently had a second TEC. Among the 82 patients who had follow‐up imaging, 16 (20%) had resolution of thrombus. In total, 24 of 98 patients had a second TEC, most of whom had inadequate anticoagulation. Conclusions Thrombotic and embolic complication was not uncommon; risk factors for TEC were APC and atrial arrhythmias. Most patients were treated successfully with warfarin alone. A second TEC occurred in most patients whose anticoagulation was discontinued because of bleeding events.

Transcatheter closure of postmyocardial infarction, iatrogenic, and postoperative ventricular septal defects: The Mayo Clinic experience.

To determine event‐free survival after transcatheter closure of ventricular septal defect (VSD), and to identify predictors of adverse events (AE) in post myocardial infarction VSD (post‐MI VSD) subgroup.

Radiation reduction in pediatric and adult congenital patients during cardiac catheterization.

Our objective was to determine if technical changes combined with radiation safety initiatives reduced the radiation dose delivered to patients during congenital catheterization.

Transseptal puncture to facilitate device closure of “long‐tunnel” patent foramen ovale

Patent foramen ovale (PFO) is common and may predispose to paradoxical embolism. Transcatheter device closure of PFO can be challenging in certain cases of “long‐tunnel” PFO morphology. We report our experience with device closure of long‐tunnel PFO using transseptal puncture.

A stepwise model for delivering medical humanitarian aid requiring complex interventions

OBJECTIVES Cardiothoracic surgeons and practitioners of cardiovascular medicine have a long history of humanitarian aid. Although this is worthwhile at multiple levels and occasionally described in some detail, few efforts have a proven algorithm with demonstrable outcomes that suggest effective educational methodology or clinical results approaching accepted standards in developed countries. METHODS Our report provides a stepwise approach to developing highly successful self-sustainable, replicable, and scalable humanitarian congenital cardiac surgical programs, and provides data to allow insight into the efficacy of our model. RESULTS This program model has evolved over 25 years, during which it has been replicated several times and scaled throughout a vast and populous country. Since 1989, Russia has undergone considerable social, political, and economic changes. Our program model proved successful throughout this time despite dynamic social, political, and medical landscapes. CONCLUSIONS The positive results of our program model indicate that these methodologies may be helpful to others attempting to address the worldwide shortage of cardiovascular care and particularly the complex interventions required in the management of congenital cardiovascular disease.