Miranda, William R.

Background Tachyarrhythmias and bradyarrhythmias affect 20%–50% of adult patients with tetralogy of Fallot (TOF) and some of these patients will require cardiac implantable electronic devices (CIED) such as pacemaker and/or internal cardioverter defibrillator. Methods The Mayo Adult Congenital Heart Disease database was queried for patients with repaired TOF and history of CIED implantation, 1990–2017. The study objectives were: (1) determine the occurrence of device-related complications defined as lead failure, lead recall, device infection and lead thrombus; and (2) determine the occurrence and risk factors for defibrillator shock. Results There were 99 patients (age 46±14 years and 66 (66%) men) with CIED, and the CIEDs were 41 (41%) pacemakers and 73 (73%) defibrillators. Indication for defibrillator implantation was for primary prevention in 28 (38%) and secondary prevention in 45 (62%). Device-related complications occurred in 20 (20%) patients (lead failure 17, lead recall 4, device infection 12 and thrombus 3). Twenty-five per cent of all device infections occurred within 30 days from the time of device generator change. Annualised rates of appropriate and inappropriate shocks were 5.7% and 6.2%, respectively. The use of class III antiarrhythmic drug was protective against defibrillator shock. Conclusion The current study provides useful outcome data to aid patient counselling and clinical decision-making. Further studies are required to explore ways to decrease the risk of postprocedural infection after device generator change, and to determine which patients will benefit from empirical antiarrhythmic therapy as a strategy to decrease incidence of inappropriate defibrillator shock.

Background Nonpulsatile pulmonary blood flow in Fontan circulation results in pulmonary vascular disease, but the potential relationships between pulmonary vascular resistance index (PVRI) and Fontan failure have not been studied. The objective was to determine whether the absence of subpulmonary ventricle in the Fontan circulation would make patients more vulnerable to even low-level elevations in PVRI, and when coupled with low cardiac index, this would identify patients at increased risk of Fontan failure. Methods and Results Two hundred sixty-one adult Fontan patients underwent cardiac catheterization; age 26±3 years, men 146 (56%), atriopulmonary Fontan 144 (55%). Patients were divided into 2 groups: those with high PVRI (>2 WU·m 2 ) and low cardiac index <2.5 L min −1 m −2 (group 1, n=70, 30%), and those with normal PVRI and normal cardiac index (group 2, n=182, 70%). Fontan failure was defined by the composite of all-cause mortality, listing for heart transplantation, or initiation of palliative care. There were 68 (26%) cases of Fontan failure during a mean follow-up of 8.6±2.4 years. When compared with group 2, freedom from Fontan failure was significantly lower in group 1: 66% versus 89% at 5 years. The combination of high PVRI and low cardiac index was an independent risk factor for Fontan failure (hazard ratio, 1.84; 95% confidence interval, 1.09–2.85). Conclusions When coupled with low cardiac index, even mild elevations in PVRI identify patients at high risk of Fontan failure. This suggests that pulmonary vascular disease is a key mechanism underlying Fontan failure and supports further studies to understand the pathophysiology and target treatments to pulmonary vascular tone in this population.

An 88-year-old man with history of bioprosthetic aortic valve replacement was hospitalised with fever, chills, malaise and right lower extremity cellulitis. Laboratory investigations revealed leucocytosis and blood cultures grew Helcococcus kunzii. Although transoesophageal echocardiography was negative for endocarditis, the patient was treated with 4 week of intravenous ceftriaxone. However, he was readmitted 6 weeks later with symptoms of fever, chills and hypoxia in setting of recurrent H. kunzii bacteraemia. A repeat transoesophageal echocardiogram revealed a mobile mass on bioprosthetic aortic valve, severe perivalvular insufficiency with pseudoaneurysm formation, and severe native mitral and tricuspid valve regurgitation. Cardiothoracic surgery was consulted and the patient underwent replacement of aortic valve and aortic root, and tricuspid and mitral valve repairs. Histological examination of excised bioprosthetic aortic valve revealed active endocarditis with cocci identified on silver stain. Patient was successfully treated with 4-week course of intravenous ceftriaxone and was doing well at 2-year follow-up.

Clinical introduction An asymptomatic 29-year-old woman presented for prenatal counselling. She had a history of a heart murmur since childhood and a previous echocardiogram suggesting ‘enlargement of the heart’. Physical exam revealed normal jugular venous pressure and contour. Precordial palpation was unremarkable. Auscultation, however, was abnormal; findings on inspiration and expiration are presented in Figure 1, sound clip. Question Based on the phonocardiogram and online supplementary audio clip, which of the following is correct? An early diastolic filling sound (S3) is heard, indicating increased right ventricular filling pressures. An ejection click without respiratory variation and a systolic ejection murmur are heard, consistent with bicuspid aortic valve stenosis. An ejection click with respiratory variation and a systolic ejection murmur are heard, consistent with pulmonic valve stenosis. A holosystolic murmur with inspiratory augmentation is heard, indicating tricuspid regurgitation.