Long QT syndrome: beyond making a diagnosis

Long QT syndrome (LQTS) is an uncommon, but important, cause of ventricular arrhythmias. The diagnosis is straightforward in symptomatic patients with marked QT prolongation on a resting 12-lead electrocardiogram (ECG). However, in many patients, the ECG findings are dynamic, and to make the diagnosis, clinicians need to be aware of suggestive features. The greatest challenge in managing these patients is risk stratification for a sudden arrhythmic event. Beta-blockers have been shown to reduce the risk for ventricular arrhythmias in all genotype-positive patients, regardless of 12-lead ECG findings. For patients in whom beta-blockers are contraindicated, left cardiac sympathetic denervation may be a useful therapy. Implantable cardioverter–defibrillators have a role to play in preventing sudden cardiac death, although their use should be balanced with associated complications and psychological impact. Population screening for LQTS remains controversial. Screening of first-degree relatives in sudden arrhythmic death syndrome is recommended, but population screening is not currently undertaken in the United Kingdom.

Infective endocarditis

A young patient with previously repaired mixed aortic valve disease presented to his local hospital with symptoms and signs consistent with infective endocarditis. Following confirmation of Streptococcus viridans in his blood cultures, he underwent initial antibiotic treatment, followed by surgical resection of his right ventricular outflow tract vegetation. This chapter examines the difficulty in making a diagnosis of infective endocarditis, the devastating nature of its course, and the challenges in managing this condition. Finally, it explores the association of infective endocarditis with poor dental hygiene, the importance of promoting effective oral hygiene, and the evolving evidence in the use of antibiotic prophylaxis.

The spectrum of disease in double outlet right ventricle

Although often used as a diagnosis in its own right, double outlet right ventricle is more accurately merely a description of the ventriculo-arterial connection in a congenitally malformed heart, and use of the term must always be allied with further description of the anatomy. In this chapter we describe a term infant born at 3.4 kg following an antenatal diagnosis of double outlet right ventricle (DORV) with noncommitted ventricular septal defect (VSD), side-by-side great arteries and pulmonary stenosis. There was a duct-dependent pulmonary circulation in the neonatal period, and the infant underwent placement of a Blalock-Taussig shunt. Following multi-modality cardiac imaging, he underwent to complete surgical repair at 16 months of age, with VSD enlargement, tunnelled closure of the VSD to commit the left ventricle to the aorta, and augmentation of the pulmonary outflow tract. Through the chapter, we emphasise the importance of a detailed anatomical description and thorough investigation in this family of defects, in order to allow an understanding of the physiology, clinical behaviour and the management options available for individual patients. Learning points in the chapter include discussion regarding the definitions of DORV, detailed descriptions of the major anatomical groups and a synopsis of the more common surgical options.

Back from the brink: a reversible cardiac cause of fetal hydrops

Fetal hydrops is a form of cardiovascular decompensation unique to fetal physiology, with a wide range of potential causes. In many conditions, it is associated with poor fetal outcome. This chapter explores a challenging case of fetal hydrops, discussing differential diagnoses, methods of echocardiographic assessment, and potential management options. Successful identification and treatment of the underlying cardiac disorder in this case led to complete resolution of hydrops, allowing for full-term delivery, with a good long-term prognosis.

Kawasaki disease

Kawasaki disease is the most common acquired heart disease in children in developed countries. Coronary involvement is reported in 30% of patients with no treatment and decreases to 5% with intravenous immunoglobulin treatment. Given the significant risk for coronary involvement, understanding the long-term prognosis is paramount to guide outpatient follow-up and treatment. This chapter presents the case of a 20-month-old child with Kawasaki disease and giant coronary aneurysms. The chapter reviews the diagnostic criteria and coronary imaging aspects, delves into the treatment options and prognosis, including immunoglobulin treatment.

Coronary artery fistula

This is a case of a 14-year-old boy who attended the emergency department with fever, cough, and arthralgia. Examination revealed hepatomegaly and a continuous murmur. Blood cultures were positive on three separate occasions for meticillin-sensitive Staphylococcus aureus, and a diagnosis of infective endocarditis, with an intra-atrial thrombus complicating a coronary artery fistula, was made. The intracardiac thrombus was functioning as a septic nidus, and the patient had cavitating lung nodules likely representing septic emboli. The patient underwent thrombolytic therapy to eradicate the thrombus and recovered following a prolonged course of intravenous antibiotics and low-molecular weight heparin. Several months later, he electively underwent transcatheter device closure of the coronary artery fistula. This case discusses the definition and types of fistulae; the pathophysiology, presentation, and complications associated with this condition; the investigations and diagnosis; and finally the management options for patients with coronary artery fistulae. The nuances involved in the management of these cases are discussed, including the debate regarding indications for closure.

The preterm patent ductus arteriosus: the controversy of closure

Management of preterm patent ductus arteriosus (PDA) has, and currently is, an issue of much contention. Management strategies have varied between conservative medical management to pragmatic PDA surgical ligation. However, despite the association between the haemodynamically significant ductus arteriosus and many of the morbidities of the preterm neonate, there remains no clear benefit in morbidity and mortality to closure. This case demonstrates the challenges faced by both the neonatal and the cardiology teams and the common trajectory for the preterm infant with the haemodynamically significant patent ductus arteriosus. The case highlights up-to-date developing techniques, clinical tips, and important learning points to aid the management of this common, but controversial, pathology.

Fetal management of hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a major form of congenital heart disease, with universal mortality if left untreated. Even with treatment, survival to eventual palliative univentricular Fontan circulation is in the order of 65% at the age of 5 years. The condition also carries with it a significant load in terms of comorbidities, recurrent interventions, and reduced quality of life. Fetal diagnosis of HLHS is important for accurately counselling the prospective parents on the available options during and after the pregnancy. It is crucial for the adequate planning of, and preparation for, delivery, with evidence emerging that babies delivered with such preparation are in better preoperative condition. Risk stratification is possible with the assessment of restrictive flow at the interatrial septum and the use of magnetic resonance imaging to assess the status of the fetal lungs in this situation. Fetal intervention in cases of a restrictive atrial septum is an emerging and challenging area, with limited evidence for efficacy currently. Due to the high-risk nature of this condition, it is difficult to prove that fetal diagnosis makes any significant impact on mortality.

Challenges in the management of coarctation of the aorta

A postnatally diagnosed child underwent stenting of his native coarctation of the aorta after initial conservative management. After successful treatment of his coarctation, he was followed up regularly and was noted to develop hypertension. Subsequent investigations confirmed that he required further dilatation of his stent in view of somatic growth. Cardiac catheterization revealed an aneurysm at the site of the previous stenting. Given his aberrant right subclavian artery (ARSCA), the procedure was terminated with a view to the best method of treatment. He subsequently underwent re-stenting of his coarctation, with protection of his ARSCA with a balloon over a wire. The chapter explores the challenges in managing this condition using angioplasty, stenting, or surgery, and the common pitfalls that are encountered in the life of patients with this condition.

Solitary indeterminate single ventricle with aortic atresia

A newborn baby weighing 2.3 kg presented to the children’s emergency department with signs of respiratory distress. Initial assessment demonstrated poor peripheral perfusion, weak peripheral pulses and an elevated blood lactate level. Transcutaneous saturations were 85% on air. There was tachycardia, which was out of proportion to tachypnoea. A chest radiograph showed an abnormal cardiac silhouette. After consulting with the regional paediatric cardiology team, the child was commenced on a prostaglandin infusion and a transfer was arranged. Transthoracic echocardiography demonstrated a functionally single ventricle of indeterminate origin with aortic atresia. A decision was made to proceed towards single ventricle palliation. Due to the child’s small size, banding of the branch pulmonary arteries was performed and the child remained on prostin infusion as an interim procedure. A Norwood operation was performed at 2 months of age. A 5-mm Sano conduit was inserted. The child was discharged from hospital at 3.5 months of age. Without an antenatal diagnosis, infants with aortic atresia or severe aortic stenosis and single ventricle physiology present early in the postnatal period with features of cardiogenic shock. Fluid resuscitation and administration of prostaglandin are essential. Unless echocardiography is available locally, the diagnosis may not be confirmed until transfer has been made to a cardiology centre. Usually echocardiography is sufficient to make the diagnosis, although additional imaging modalities, such as computed tomography, cardiac magnetic resonance, or cardiac catheterization, are occasionally required. The Norwood procedure is used as a palliative stepwise strategy. Mortality has improved dramatically in the last 30 years; however, there remains a burden of morbidity. This case explores the diagnosis, strategy, and common pitfalls often encountered in managing children with this new diagnosis.