Left atrial, pulmonary vein, and left atrial appendage anatomy in Indigenous individuals: Implications for atrial fibrillation.

BACKGROUND: Indigenous Australians experience a greater burden of AF. Whether this is in-part due to differences in arrhythmogenic structures that appear to contribute to AF differences amongst other ethnicities is not known. METHODS: We studied forty individuals matched for ethnicity and other AF risk factors. Computed tomography imaging was used to characterise left atrial (LA), pulmonary vein (PV), and left atrial appendage (LAA) anatomy. RESULTS: There were no significant differences in LA diameters or volumes between Indigenous and non-Indigenous Australians. Similarly, we could not detect any consistent differences in PV number, morphology, diameters, or ostial characteristics according to ethnicity. LAA analyses suggested that Indigenous Australians may have a greater proportion of non chickenwing LAA type, and a tendency for eccentric, oval-shaped LAA ostia; however, there were no other differences seen with regards to LAA volume or depth. Indexed values for LA, PV and LAA anatomy corrected for body size were broadly similar. CONCLUSIONS: In a cohort of individuals matched for AF risk factors, we could find no strong evidence of ethnic differences in LA, PV, and LAA characteristics that may explain a predisposition of Indigenous Australians for atrial arrhythmogenesis. These findings, in conjunction with our previous data showing highly prevalent cardiometabolic risk factors in Indigenous Australians with AF, suggest that it is these conditions that are more likely responsible for the AF substrate in these individuals. Continued efforts should therefore be directed towards risk factor management in an attempt to prevent and minimise the effects of AF in Indigenous Australians.

Management and Outcomes of Prosthetic Valve Thrombosis. An Australian Case Series From the Northern Territory.

BACKGROUND: Prosthetic valve thrombosis (PVT) is an uncommon but serious cause of morbidity and mortality after cardiac valve implantation. The most common cause leading to PVT is inadequate anticoagulation. Royal Darwin Hospital is a major referral centre for the Top End of Australia and is unique in having a high burden of rheumatic heart disease (RHD) requiring valve surgery, issues with adherence with oral anticoagulants, and the absence of onsite cardiothoracic facility. METHODS: We report clinical characteristics and outcomes of consecutive patients presenting with PVT to a single centre without on-site cardiothoracic surgery. RESULTS: Thirty-two (32) episodes involving 21 patients were retrospectively identified between 2000 and 2017. Our cohort had an average age of 37 years. Nineteen (19) patients were of Aboriginal or Torres Strait Islander descent. All valves were mechanical, except for one bioprosthetic mitral valve, with average time from implantation to initial PVT 5.1 years. The majority of patients were in New York Heart Association (NYHA) class III and IV (6%, and 66%, respectively). Anti-coagulation was sub-therapeutic in 88% of presentations. Eleven (11) (34%) presentations were recurrent PVT involving eight patients. Twenty-six (26) (82%) episodes were treated with thrombolytic therapy which achieved complete success in 65% and partial success in 19%. Five (5) patients received a second dose of the lytic agent. Of the four patients not responding to thrombolytic therapy, two died and two were urgently transferred to a facility with on-site cardiothoracic surgery. Five (5) out of 32 episodes resulted in death (16%) with overall mortality 24% for the cohort over the entire time period. Thrombolytic therapy was associated with five major bleeding episodes (16%) including two fatal bleeds. CONCLUSIONS: Prosthetic valve thrombosis is a rare but life-threatening complication of prosthetic valves, with the vast majority of patients found to be inadequately anticoagulated. Despite differences in thrombolytic agents these were successful in the majority of patients.

Takotsubo Cardiomyopathy Associated With Work-Place Bullying.

Background: Takotsubo cardiomyopathy (TC) is a condition of transient left ventricular dysfunction precipitated by acute physical or emotional stress. The pathogenesis of TC is not well understood, but it is known to predominantly affect postmenopausal women in the context of physical or emotional triggers. Aims: To describe a case of TC with an association to a never previously described work place stressor of bullying. Case Report: A 48-year-old female lawyer developed acute chest pain after experiencing significant emotional distress at a workplace meeting. She had experienced 18 months of increasing work-related mental stress in a new managerial role. She was initially thought to have a non-ST-elevation myocardial infarction (NSTEMI) with widespread T wave inversion on electrocardiogram and elevated serial troponin. However, a diagnosis of TC was subsequently made given the characteristic apical ballooning morphology of the left ventricle found on echocardiogram, normal coronary arteries on angiography and a normal echocardiogram 3 weeks later. This case report describes TC in a younger demographic and a link with workplace bullying. Conclusions: Chronic workplace bullying has the potential for serious physical harm by precipitating Takotsubo cardiomyopathy.