Arrhythmias in Adult Congenital Heart Disease Heart Failure.

Heart failure and arrhythmias represent 2 major causes of mortality and morbidity in adults with congenital heart disease. Arrhythmias and heart failure are interdependent, and one may exacerbate the other. Treatment of one also has a positive impact on the other. Management approaches need to be multifaceted, including pharmacotherapy, optimization of hemodynamic status with catheter-based or surgical interventions, and specific management of arrhythmia with device or catheter ablation therapy.

Arrhythmias in Repaired Tetralogy of Fallot: A Scientific Statement From the American Heart Association.

Arrhythmia and sudden cardiac death remain common in repaired tetralogy of Fallot and affect even those with excellent anatomic repairs. Atrial arrhythmia often has mechanisms different from those in acquired heart disease. Ventricular arrhythmia remains a major source of mortality in repaired tetralogy of Fallot. Noninvasive risk stratification is important to identify patients who may benefit from ablation or primary prevention implantable cardioverter defibrillators. Multiple noninvasive risk factors are associated with ventricular arrhythmia, but no universally accepted risk stratification algorithm exists. The mechanism of ventricular arrhythmia is usually attributable to a consistent and discrete set of slowly conducting anatomic isthmuses related to both the native anatomy and the consequences of the surgical repair, which interact with ventricular remodeling to provide arrhythmic substrate. This substrate can be identified during electroanatomic mapping and prophylactically ablated in appropriate patients. This scientific statement discusses the mechanisms and treatment of arrhythmia in repaired tetralogy of Fallot.

Two Cases of a Prenatally Diagnosed Double Aortic Arch with Postnatal Obliteration of the Distal Left Aortic Arch.

We report two cases of prenatally diagnosed double aortic arch with dominant right arch and a left-sided ductus arteriosus, consistent with a complete vascular ring. Postnatal transthoracic echocardiogram and cardiac magnetic resonance imaging demonstrated a spontaneous closure of the ductus arteriosus and obliteration of the left aortic arch distal to the origin of the left subclavian artery in both cases. Spontaneous closure of the ductus arteriosus involving extended ductal tissue in the left aortic arch likely led to obliteration of the distal left arch after birth. One patient presented with recurrent symptoms suggestive of dysphagia and underwent a successful surgical repair of the vascular ring with resolution of symptoms. The other patient has been asymptomatic and is 4 years old at the time of this report.

An Unusual Case of Commotio Cordis Resulting in Ventricular Flutter.

A 16-year-old male developed palpitations immediately following chest impact with a soccer ball. The patient was noted to have ventricular flutter in a delayed presentation that was successfully treated. While ventricular fibrillation is the predominant arrhythmia following commotio cordis, ventricular flutter may occur as well. Ventricular flutter may be better tolerated in a young athletic individual with structurally normal heart and may lead to a delayed presentation.

Epicardial ablation of tachyarrhythmia in children: Experience at two academic centers.

BACKGROUND: Experience with percutaneous epicardial ablation of tachyarrhythmia in pediatrics is limited. This case series addresses the feasibility, safety, and complications of the procedure in children. METHODS: A total of nine patients underwent 10 epicardial ablation procedures from 2002 to 2013 at two academic centers. Activation mapping was performed in all cases, and electroanatomic map was utilized in nine of the 10 procedures. Patients had undergone one to three failed endocardial catheter ablations in addition to medical management, and all had symptoms, a high-risk accessory pathway (AP), aborted cardiac arrest with Wolff-Parkinson-White syndrome (WPW), or ventricular dysfunction. A standard epicardial approach was used for access in all cases, using a 7- or 8- Fr sheath. Epicardial ablation modality was radiofrequency (RF) in seven, cryoablation (CRYO) in one, and CRYO plus RF in one. RESULTS: Median age was 14 (range 8-19) years. INDICATIONS: drug refractory ectopic atrial tachycardia (one), ventricular tachycardia (VT) (five), high-risk AP (two), and aborted cardiac arrest from WPW - (one). Epicardial ablation was not performed in one case despite access due to an inability to maneuver the catheter around a former pericardial scar. VT foci included the right ventricular outflow tract septum, high posterior left ventricle (LV), LV outflow tract, postero-basal LV, and scar from previous rhabdomyoma surgery. WPW foci were in the area of the posterior septum and coronary sinus in all three cases. Overall procedural success was 70% (7/10), with epicardial ablation success in five and endocardial ablation success after epicardial mapping in two. The VT focus was close to the left anterior descending coronary artery in one of the unsuccessful cases in which both RF and CRYO were used. There was one recurrence after a successful epicardial VT ablation, which was managed with a second successful epicardial procedure. There were no other recurrences at more than 1 year of follow-up. Complications were minimal, with one case of inadvertent pleural access requiring no specific therapy. No pericarditis or effusion was seen in any of the patients who underwent epicardial ablation. CONCLUSION: Epicardial ablation in pediatric patients can be performed with low complications and acceptable success. It can be considered for a spectrum of tachycardia mechanisms after failed endocardial ablation attempts and suspected epicardial foci. Success and recurrence may be related to foci in proximity to the epicardial coronaries, pericardial scar, or a distant location from the closest epicardial location. Repeat procedures may be necessary.

Catheter ablation for atrioventricular nodal reentrant tachycardia in patients with congenital heart disease.

BACKGROUND: Variability in atrioventricular (AV) node location in congenital heart disease (CHD) can make catheter ablation for atrioventricular nodal reentrant tachycardia (AVNRT) challenging. OBJECTIVE: The purpose of this study was to describe institutional technique and outcomes for slow pathway modification in a cohort with CHD. METHODS: The study consisted of a retrospective review of CHD patients who underwent study from 2001 to 2013 with a diagnosis of AVNRT. Outcomes for slow pathway modification were recorded. In cases in which ablation was deferred, the reasons for this choice were examined. RESULTS: Forty-nine patients (median age 19 years) were included. CHD anatomy involved d-transposition of the great arteries (n = 6), "congenitally corrected" transposition of the great arteries (n = 4), Ebstein anomaly (n = 4), tetralogy of Fallot (n = 5), venous anomalies (n = 8), single ventricle (n = 16), and miscellaneous (n = 6). Ablation was attempted in 39 patients, using radiofrequency energy in 24, cryoablation in 8, and both in 7. Acute success rate was 92% (36/39). One patient had first-degree block in response to cryoablation, but no other complications occurred. At median follow-up 32 months, 1 patient had AVNRT recurrence. Most of the 10 patients in whom ablation was deferred had single-ventricle anatomy with uncertain AV node location. CONCLUSION: Ablation for AVNRT in CHD can be accomplished successfully with attention to underlying anatomy and prior surgery. Patients with single ventricle are a difficult subgroup, and a pharmacologic approach may be indicated in some cases if node localization is ambiguous.

Effect of myocardial dysfunction in cardiac morbidity and all cause mortality in childhood cancer subjects treated with anthracycline therapy.

BACKGROUND: Subacute cardiotoxicity, consisting of acute myocyte damage and associated left ventricular dysfunction, occurs early during anthracycline therapy. We investigated the impact of myocardial dysfunction, defined herein by a shortening fraction (SF) < 29 % at any time during or after anthracycline therapy, on late onset cardiomyopathy and all-cause mortality, among childhood cancer survivors exposed to anthracyclines. In addition, we sought to identify subpopulations of subjects at highest risk for cardiomyopathy and death from all causes. METHODS: Five hundred thirty-one childhood cancer survivors exposed to anthracyclines were enrolled and studied on average 10 (1.4-27.3) years following their initial exposure. The medical records were reviewed to identify known risk factors associated with cardiotoxicity, including cumulative anthracycline dose, length of post-therapy interval, administration of other cardiotoxic medications (vinca alkaloids), previous heart disease, radiation dose to the heart, history of bone marrow transplantation, age at treatment, gender, systolic dysfunction, and history of congestive heart failure during anthracycline therapy. RESULTS: Ninety subjects (16.9 %) developed SF < 29 % and 71 patients (13.4 %) died on average 10 years after initial exposure (range 1.4-27.3 years). Total cumulative dose (OR 3.27, 95 % CI 1.94, 5.49, p < 0.001) and bone marrow transplantation (OR 2.57, 95 % CI 1.24, 5.30, p = 0.01) were found to be statistically significant risk factors for development of myocardial dysfunction. There was a 3-fold increase in the odds of having a SF < 29 % at any point during or following cancer therapy if a subject underwent bone marrow transplantation or had a total cumulative dose anthracycline therapy ≥ 240 mg/m2. The all-cause mortality ratio was almost seven-fold higher (95 % CI, 2.40-fold to 17.81-fold higher) if a subject developed systolic dysfunction, defined by a previous SF < 29 % anytime during or after anthracycline therapy. Nine deaths (12.7 %) were attributed to cardiovascular disease. The risk of dying as a result of cardiac disease also was significantly higher in individuals who had a SF < 29 % at any time during or after therapy. CONCLUSIONS: This study demonstrates an almost seven-fold increase in all cause mortality in pediatric cancer survivors with a history of anthracycline induced myocardial dysfunction defined as SF < 29 %.

Left main coronary artery stenting after cardiac arrest in an infant with William's syndrome.

A 6-month-old female with William's syndrome and biventricular outflow obstruction had a cardiac arrest due to myocardial ischemia soon after induction of anesthesia during cardiac catheterization. The patient was supported with extra corporeal membrane oxygenator (ECMO) and successful stenting of the left main coronary artery was performed as a rescue measure. This intervention allowed successful weaning from ECMO and subsequent discharge from the hospital. Coronary intervention in infants may be successfully performed in dire situations.

The stunned atrial lead: Transient malfunction of a permanent atrial pacer lead following acute myocardial infarction.

Proximal right coronary artery occlusion caused transient loss of sensing and capture of the atrial lead of a permanent dual-chamber pacemaker. Forty-five days after percutaneous revascularization, the atrial lead was discovered to be functioning normally. We hypothesize that ischemia of the right atrium caused stunning of the atrial myocardium at the pacer-lead interface, which gradually improved following percutaneous coronary intervention (PCI), leading to return of lead function over time. So far only one similar case has been described in the literature.

A newborn with cardiomegaly.

An infant with Down's syndrome was noted to have hypoxemia and tachypnea at birth. The clinical examination, electrocardiogram (ECG) and the chest X-ray findings suggested a specific diagnosis that is not usually associated with Down's syndrome. Despite the extremely rare association of Ebstein's anomaly with Down's syndrome, this diagnosis was highly suspected from the initial evaluation. An echocardiogram confirmed the diagnosis of Ebstein's anomaly in this neonate. So far, only about seven cases of Ebstein's anomaly associated with Down's syndrome have been reported in the literature. This case is discussed for its rarity; it also highlights the importance of clinical examination and initial investigations that had suggested the diagnosis well prior to that of the echocardiogram.

A 19-year-old male with palpitations.

A 19-year-old male presented to the emergency department (ED) following intermittent episodes of palpitations. Classical "epsilon waves" noted on his initial electrocardiogram prompted an evaluation for arrhythmogenic right ventricular dysplasia (ARVD). The diagnosis was confirmed with magnetic resonance imaging of the heart and stress test. A prompt recognition and management of this condition in the ED helped prevent significant mortality that may be associated with ARVD.