William Chan

Ventricular tachycardia and sudden death in myotonic dystrophy: clinical, electrophysiologic and pathologic features.

A 37 year old man who presented with a cardiomyopathy, conduction defects and atrial and ventricular arrhythmias was found to have the neuromuscular manifestations of myotonic dystrophy. Despite implantation of a permanent cardiac pacemaker, antiarrhythmic drug therapy and antiarrhythmic surgery, sudden death occurred. The results of electrophysiologic studies, coronary arteriography and pathologic findings are described. This case confirms previous observations that ventricular arrhythmias, in addition to atrial arrhythmias and conduction disturbances, are cardiac manifestations of myotonic dystrophy and can lead to sudden death.

Prospective evaluation of aortic stenosis in end-stage kidney disease: a more fulminant process?

BACKGROUNDnWe have previously demonstrated an increased rate of progression of aortic stenosis (AS) in patients with end-stage kidney disease (CKD 5D) compared to controls. We sought to follow prospectively a CKD 5D cohort with AS and determine major event-free survival. Follow-up was terminated once all CKD 5D subjects had undergone aortic valve replacement (AVR) or died. Our aim was to determine whether the increased rate of progression resulted in shorter major event-free (AVR or death) survival as compared to controls.nnnMETHODSnWe re-matched our original CKD 5D cohort (n = 27) to a control cohort (n = 27) based on aortic valve area (AVA) at completion of the prior study. This was done as CKD 5D and AVA were the only statistically significant variables with respect to rate of progression.nnnRESULTSnAll the CKD 5D patients (100%) underwent surgery or died during the follow-up period. In contrast, 17 (63%) of the controls underwent surgery or died. Of the remaining 10 controls, nine remain alive and free of AVR and one was lost to follow-up.nnnCONCLUSIONnThe controls displayed greater major event-free survival (P = 0.001), suggesting a need to consider patients with CKD 5D and AS for early AVR once echocardiographic evidence of moderate to severe AS is present, regardless of symptoms.

The Echocardiographic Features of an Aneurysm of the Inter-Atrial Septum

The echocardiographic features of a surgically confirmed case of an aneurysm of the inter-atrial septum presenting as a persistent right atrial lesion were described. The lesion appeared cystic and could be differentiated from solid tumours. In contrast to other reported cases of smaller aneurysms, the lesion in this patient remained in the right atrium and did not show any phasic variation during the respiratory cycle because of its larger size. A review of the reported echocardiographic features of intra-cavitary right atrial tumours and pseudotumours was made. This highlighted distinguishing features that could be used in the differential diagnosis of space-occupying lesion within the right atrium.

Does the subtype of acute coronary syndrome treated by percutaneous coronary intervention predict long-term clinical outcomes?

AimsnThe prognosis of patients undergoing percutaneous coronary intervention (PCI) for different subtypes of acute coronary syndromes (ACS) remains unclear. We compared short- and long-term mortality in patients undergoing PCI for unstable angina (UA), non-ST-elevation myocardial infarction (NSTEMI), and ST-elevation myocardial infarction (STEMI).nnnMethods and resultsnThis was a retrospective cohort study of 13xa0184 patients (5966 STEMI, 5307 NSTEMI, and 1911 UA) undergoing PCI between 1 January 2005 and 30 November 2013 in a multi-centre registry. Clinical and procedural characteristics, as well as outcomes, were compared by ACS subtype. Long-term all-cause mortality data were obtained via linkage to the National Death Index (NDI). Patients with STEMI compared with NSTEMI and UA were younger (62.9 ± 12.8 vs. 64.7 ± 12.5 vs. 65.5 ± 11.8 years; P < 0.01), had fewer comorbidities including diabetes, heart failure, and previous myocardial infarction (all P < 0.01). Procedural success was similar across all groups (P = 0.54). In-hospital, 30-day and 1-year all-cause mortality increased significantly from UA to NSTEMI to STEMI patients (1-year mortality 2.5% vs. 4.5% vs. 8.7%; P < 0.01). Kaplan-Meier survival estimates showed increased early mortality in the STEMI group (log-rank P < 0.01). However, after approximately 8.2 years, survival was similar across all groups. In a proportional-odds model using flexible parametric survival modelling, ACS subtype was not an independent predictor of NDI-linked mortality [UA: odds ratio (OR) 0.85, 95% CI 0.71-1.02; STEMI: OR 1.01, 95% confidence interval (CI) 0.88-1.16; NSTEMI as reference category].nnnConclusionnDespite disparate baseline characteristics and differences in short-term mortality, long-term mortality was similar across the spectrum of ACS treated by PCI and contemporary medical therapy.

The challenge of staphylococcal pacemaker endocarditis in a patient with transposition of the great arteries endocarditis in congenital heart disease

Staphylococcus aureus is a leading cause of septicaemia and infective endocarditis. The overall incidence of staphylococcal bacteraemia is increasing, contributing to 16% of all hospital-acquired bacteraemias. The use of cardiac pacemakers has revolutionized the management of rhythm disturbances, yet this has also resulted in a group of patients at risk of pacemaker lead endocarditis and seeding in the range of 1% to 7%. We describe a 26-year-old man with transposition of the great arteries who had a pacemaker implanted and presented with S. aureus septicaemia 2 years postpacemaker implantation and went on to develop pacemaker lead endocarditis. This report illustrates the risk of endocarditis in the population with congenital heart disease and an intracardiac device.