Effect of COVID-19 Pandemic Lockdown on Emergency Medical Service Utilisation, and Percutaneous Coronary Intervention Volume-An Australian Perspective.

BACKGROUND: Acute coronary syndrome (ACS) admissions and percutaneous coronary intervention (PCI) volume declined during periods of COVID-19 lockdown internationally in 2020. The effect of lockdown on emergency medical service (EMS) utilisation, and PCI volume during the initial phase of the pandemic in Australia has not been well described. METHOD: We analysed data from the Victorian Cardiac Outcomes Registry (VCOR), a state-wide PCI registry, linked with the Ambulance Victoria EMS registry. PCI volume, 30-day major adverse cardiovascular and cerebrovascular events (MACCE; composite of mortality, myocardial infarction, stent thrombosis, unplanned revascularisation, and stroke), and EMS utilisation were compared over four time periods: lockdown (26 Mar 2020-12 May 2020); pre-lockdown (26 Feb 2020-25 Mar 2020); post-lockdown (13 May 2020-10 Jul 2020); and the year prior (26 Mar 2019-12 May 2019). Interrupted time series analysis was performed to assess PCI trends within and between consecutive periods. RESULTS: The EMS utilisation for ACS during lockdown was higher compared with other periods: lockdown 39.4% vs pre-lockdown 29.7%; vs post-lockdown 33.6%; vs year prior 27.1%; all p<0.01. Median daily PCI cases were similar: 31 (IQR 10, 38) during lockdown; 39 (15, 49) pre-lockdown; 39.5 (11, 44) post-lockdown; and, 42 (10, 49) the year prior; all p>0.05. Median door-to-procedure time for ACS indication during lockdown was shorter at 3 hours (1.2, 20.6) vs pre-lockdown 3.9 (1.7, 21); vs post-lockdown 3.5 (1.5, 21.26); and, the year prior 3.5 (1.5, 23.7); all p<0.05. Lockdown period was associated with lower odds for 30-day MACCE compared to pre-lockdown (odds ratio [OR] 0.55 [0.33-0.93]; p=0.026); post-lockdown (OR 0.66; [0.40-1.06]; p=0.087); and the year prior (OR 0.55 [0.33-0.93]; p=0.026). CONCLUSIONS: Contrary to international trends, EMS utilisation for ACS increased during lockdown but PCI volumes remained similar throughout the initial stages of the pandemic in Victoria, with no observed adverse effect on 30-day MACCE during lockdown. These data suggest that the public health response in Victoria was not associated with poorer quality cardiovascular care in patients receiving PCI.

Incidence, Predictors, and Outcomes of Nonhome Discharge Following Transcatheter Aortic Valve Implantation: A Multicenter Australian Experience-The NHD TAVI Study.

Patients who undergo transcatheter aortic valve implantation (TAVI) commonly experience nonhome discharge (NHD), a phenomenon associated with increased health care expenditure and possibly poorer outcomes. Despite its clinical relevance in TAVI, the incidence and predictors of NHD and its impact on the quality of life remain poorly characterized. Also unknown is the proportion of patients who undergo TAVI that require long-term residential care after initial NHD. Therefore, we aimed to address these questions using a large, multicenter Australian cohort. A total of 2,229 patients who underwent TAVI from 2010 to 2023 included in the Alfred-Cabrini-Epworth TAVI Registry were analyzed. The median age was 82 (interquartile range 78 to 86) years and 41% were women. A total of 257 patients (12%) were not discharged home after TAVI, with the incidence falling over time (R2 = 0.636, p <0.001). A multivariable logistic regression model for NHD prediction was developed with excellent calibration and discrimination (C-statistic = 0.835). The independent predictors of NHD were postprocedural stroke (adjusted odds ratio [aOR] 11.05), procedure at a private hospital (aOR 3.01), living alone (aOR 2.35), vascular access site complications (aOR 2.09), frailty (aOR 1.89), age >80 years (aOR 1.82), hypoalbuminemia (aOR 1.76), New York Heart Association III to IV (aOR 1.74), and hospital length of stay (aOR 1.13) (all p <0.05). NHD was not associated with mortality at 30 days and <1% of all patients required longer-term residential care. In conclusion, although common after TAVI, NHD does not predict short-term mortality, most patients successfully return home within 30 days, and when used appropriately, NHD may serve as a brief and effective method of optimizing functional status without compromising long-term independence.

Electrocardiographic patterns and clinical outcomes of acute coronary syndrome cardiogenic shock in patients undergoing percutaneous coronary intervention - A propensity score analysis.

OBJECTIVES: To determine the influence of presenting electrocardiographic (ECG) changes on prognosis in acute coronary syndrome cardiogenic shock (ACS-CS) patients undergoing percutaneous coronary angiography (PCI). BACKGROUND: The effect of initial ECG changes such as ST-elevation myocardial infarction (STEMI) versus non-STEMI among patients ACS-CS on prognosis remains unclear. METHODS: We analysed data from consecutive patients with ACS-CS enrolled in the Victorian Cardiac Outcomes registry between 2014 and 2020. Inverse probability of treatment weighting analysis (IPTW) was used to assess the effect of ECG changes on 30-day mortality. RESULTS: Of 1564 patients with ACS-CS who underwent PCI, 161 had non-STEMI and 1403 had STEMI on ECG. The mean age was 66 ± 13 years, and 74 % (1152) were males. Patients with non-STEMI compared to STEMI were older (70 ± 12 vs 65 ± 13 years), had higher rates of diabetes (34 % vs 21 %), prior coronary artery bypass graft surgery (14 % vs 3.3 %), peripheral arterial disease (10.6 % vs 4.1 %, p < 0.01), and lower baseline eGFR (53.8 [37.1, 75.4] vs 65.3 [46.3, 87.8] ml/min/1.73m2), all p ≤ 0.01. Non-STEMI patients were more likely to have a culprit left circumflex artery (29 % vs 20 %) and more often underwent multivessel percutaneous coronary intervention (30 % vs 20 %) but had lower rates of out-of-hospital cardiac arrest (21 % vs 39 %), all p ≤ 0.01. Propensity score analysis with IPTW confirmed that non-STEMI ECG was associated with lower odds for 30-day all-cause mortality (OR 0.47 [0.32, 0.69], p < 0.001), and 30-day major adverse cardiovascular and cerebrovascular events (OR 0.48 [0.33, 0.70]). CONCLUSIONS: In patients undergoing PCI, Non-STEMI as compared to STEMI on index ECG was associated with approximately half the relative risk of both 30-day mortality and 30-day MACCE and could be a useful variable to integrate in ACS-CS risk scores.

Acute Kidney Injury Following Transcatheter Aortic Valve Implantation-A Contemporary Perspective of Incidence, Predictors, and Outcomes.

BACKGROUND: Acute kidney injury (AKI) is a known complication following transcatheter aortic valve implantation (TAVI), associated with increased morbidity and mortality. Most of this data relates to higher-risk patients with early-generation TAVI valves. With TAVI now established as a safe and cost-effective procedure for low-risk patients, there is a distinct need for updated analysis. We aimed to assess the incidence, predictors, and outcomes of AKI in a contemporary cohort of TAVI patients, concurrently examining the role of temporal evolution on AKI. METHOD: A total of 2,564 patients undergoing TAVI from 2008-2023 included in the Alfred-Cabrini-Epworth (ACE) TAVI Registry were analysed. Patients were divided into AKI and no AKI groups. Outcomes were reported according to the Valve Academic Research Consortium-3 (VARC-3) criteria. RESULTS: Of 2,564 patients, median age 83 (78-87) years, 57.4% men and a median Society of Thoracic Surgeons score of 3.6 (2.4-5.5), 163 (6.4%) patients developed AKI with incidence falling from 9.7% between 2008-2014 to 6% between 2015-2023 (p=0.022). On multivariable analysis, independent predictors of AKI were male sex (adjusted odds ratio [aOR] 1.89, p=0.005), congestive cardiac failure (aOR 1.52, p=0.048), estimated glomerular filtration rate 30-59 (aOR: 2.79, p<0.001), estimated glomerular filtration rate <30 (aOR 8.65, p<0.001), non-femoral access (aOR 5.35, p<0.001), contrast volume (aOR 1.01, p<0.001), self-expanding valve (aOR 1.60, p=0.045), and bleeding (aOR 2.88, p=0.005). Acute kidney injury was an independent predictor of 30-day (aOR: 6.07, p<0.001) and 12-month (aOR: 3.01, p=0.002) mortality, an association that remained consistent when excluding TAVIs performed prior to 2015. CONCLUSIONS: Acute kidney injury remains a relatively common complication of TAVI, associated with significant morbidity and mortality even in less comorbid, contemporary practice patients.

Use of Clinical and Echocardiographic Evaluation to Assess the Risk of Heart Failure.

BACKGROUND: Clinical and echocardiographic features predict incident heart failure (HF), but the optimal strategy for combining them is unclear. OBJECTIVES: This study sought to define an effective means of using echocardiography in HF risk evaluation. METHODS: The same clinical and echocardiographic evaluation was obtained in 2 groups with HF risk factors: a training group (n = 926, followed to 7 years) and a validation group (n = 355, followed to 10 years). Clinical risk was categorized as low, intermediate, and high using 4-year ARIC (Atherosclerosis Risk In Communities) HF risk score cutpoints of 9% and 33%. A risk stratification algorithm based on clinical risk and echocardiographic markers of stage B HF (SBHF) (abnormal global longitudinal strain [GLS], diastolic dysfunction, or left ventricular hypertrophy) was developed using a classification and regression tree analysis and was validated. RESULTS: HF developed in 12% of the training group, including 9%, 18%, and 73% of low-, intermediate-, and high-risk patients. HF occurred in 8.6% of stage A HF and 19.4% of SBHF (P < 0.001), but stage A HF with clinical risk of ≥9% had similar outcome to SBHF. Abnormal GLS (HR: 2.92 [95% CI: 1.95-4.37]; P < 0.001) was the strongest independent predictor of HF. Normal GLS and diastolic function reclassified 61% of the intermediate-risk group into the low-risk group (HF incidence: 12%). In the validation group, 11% developed HF over 4.5 years; 4%, 17%, and 39% of low-, intermediate-, and high-risk groups. Similar results were obtained after exclusion of patients with known coronary artery disease. The echocardiographic parameters also provided significant incremental value to the ARIC score in predicting new HF admission (C-statistic: 0.78 [95% CI: 0.71-0.84] vs 0.83 [95% CI: 0.77-0.88]; P = 0.027). CONCLUSIONS: Clinical risk assessment is adequate to classify low and high HF risk. Echocardiographic evaluation reclassifies 61% of intermediate-risk patients.

Clinical Features and Outcomes Among Patients With Refractory Out-of-Hospital Cardiac Arrest and an Initial Shockable Rhythm.

BACKGROUND: Clinical features among patients with refractory out-of-hospital cardiac arrest (OHCA) and initial shockable rhythms of ventricular fibrillation/pulseless ventricular tachycardia are not well-characterized. METHODS: We compared clinical characteristics and coronary angiographic findings between patients with refractory OHCA (incessant ventricular fibrillation/pulseless ventricular tachycardia after ≥3 direct-current shocks) and those without refractory OHCA. RESULTS: Between 2014 and 2018, a total of 204 patients with ventricular fibrillation/pulseless ventricular tachycardia OHCA (median age 62; males 78%) were divided into groups with (36%, 74/204) and without refractory arrest (64%, 130/204). Refractory OHCA patients had longer cardiopulmonary resuscitation (23 versus 15 minutes), more frequently required ≥450 mg amiodarone (34% versus 3.8%), and had cardiogenic shock (80% versus 55%) necessitating higher adrenaline dose (4.0 versus 1.0 mg) and higher rates of mechanical ventilation (92% versus 74%; all P<0.01). Of 167 patients (82%) selected for coronary angiography, 33% (n=55) had refractory OHCA (P=0.035). Significant coronary artery disease (≥1 major vessel with >70% stenosis) was present in >70% of patients. Refractory OHCA patients frequently had acute coronary occlusion (64% versus 47%), especially left circumflex (20% versus 6.4%) and graft vessel (7.3% versus 0.9%; all P<0.05) compared with those without refractory OHCA. Refractory OHCA group had higher in-hospital mortality (45% versus 30%, P=0.036) and greater new requirement for dialysis (18% versus 6.3%, P=0.011). After adjustment, refractory OHCA was associated with over 2-fold higher odds of in-hospital mortality (odds ratio, 2.28 [95% CI, 1.06-4.89]; P=0.034). CONCLUSIONS: Refractory ventricular fibrillation/pulseless ventricular tachycardia OHCA was associated with more intensive resuscitation, higher rates of acute coronary occlusion, and poorer in-hospital outcomes, underscoring the need for future studies in this extreme-risk subgroup.

Left Ventricular End-Diastolic Pressure for the Prediction of Contrast-Induced Nephropathy and Clinical Outcomes in Patients With ST-Elevation Myocardial Infarction Who Underwent Primary Percutaneous Intervention (the ELEVATE Study).

Contrast-induced nephropathy (CIN) is an important complication of percutaneous coronary intervention (PCI). We investigated whether left ventricular end-diastolic pressure (LVEDP) in patients who underwent PCI might be additive to current risk stratification of CIN. Data from consecutive patients who underwent primary PCI for ST-elevation myocardial infarction between 2013 and 2018 at Western Health in Victoria, Australia were analyzed. CIN was defined as a 25% increase in serum creatinine from baseline or 44 µmol/L increase in absolute value within 48 hours of contrast administration. Compared with patients without CIN (n = 455, 93%), those who developed CIN (n = 35, 7%) were older (64 vs 58 years, p = 0.006), and had higher peak creatine kinase (2,862 [1,258 to 3,952] vs 1,341 U/L [641 to 2,613], p = 0.02). The CIN group had higher median LVEDP (30 [21-33] vs 25 mm Hg [20-30], p = 0.013) and higher median Mehran risk score (MRS) (5 [2-8] vs 2 [1-5], p <0.001). Patients with CIN had more in-hospital major adverse cardiovascular and cerebrovascular events (composite end point of death, new or recurrent myocardial infarction or stent thrombosis, target vessel revascularization or stroke) (23% vs 8.6%, p = 0.01), but similar 30-day major adverse cardiovascular and cerebrovascular events (20% vs 15%, p = 0.46). An LVEDP >30 mm Hg independently predicted CIN (odds ratio 3.4, 95% confidence interval 1.46 to 8.03, p = 0.005). The addition of LVEDP ≥30 mm Hg to MRS marginally improved risk prediction for CIN compared with MRS alone (area-under-curve, c-statistic = 0.71 vs c-statistic = 0.63, p = 0.08). In conclusion, elevated LVEDP ≥30 mm Hg during primary PCI was an independent predictor of CIN in patients treated for ST-elevation myocardial infarction. The addition of LVEDP to the MRS may improve risk prediction for CIN.

Sex differences among patients presenting to hospital with out-of-hospital cardiac arrest and shockable rhythm.

OBJECTIVE: Sex differences in patients presenting with out-of-hospital cardiac arrest (OHCA) and shockable rhythm might be associated with disparities in clinical outcomes. METHODS: We conducted a retrospective cohort study and compared characteristics and short-term outcomes between male and female adult patients who presented with OHCA and shockable rhythm at two large metropolitan health services in Melbourne, Australia between the period of 2014-2018. Logistic regression was used to assess the effect of sex on clinical outcomes. RESULTS: Of 212 patients, 166 (78%) were males and 46 (22%) were females. Both males and females presented with similar rates of ST-elevation myocardial infarction (44% vs 36%, P = 0.29), although males were more likely to have a history of coronary artery disease (32% vs 13%) and a final diagnosis of a cardiac cause for their OHCA (89% vs 72%), both P = 0.01. Rates of coronary angiography (81% vs 71%, P = 0.23) and percutaneous coronary intervention (51% vs 42%, P = 0.37) were comparable among males and females. No differences in rates of in-hospital mortality (38% vs 37%, P = 0.90) and 30-day major adverse cardiac and cerebrovascular events (composite of all-cause mortality, myocardial infarction, coronary revascularization and nonfatal stroke) (39% vs 41%, P = 0.79) were observed between males and females, respectively. Female sex was not associated with worse in-hospital mortality when adjusted for other variables (odds ratio 0.66, 95% confidence interval 0.28-1.60, P = 0.36). CONCLUSION: Among patients presenting with OHCA and a shockable rhythm, baseline sex and sex differences were not associated with disparities in short-term outcomes in contemporary systems of care.

Evaluation of factors associated with selection for coronary angiography and in-hospital mortality among patients presenting with out-of-hospital cardiac arrest without ST-segment elevation.

BACKGROUND: Clinical factors favouring coronary angiography (CA) selection and variables associated with in-hospital mortality among patients presenting with out-of-hospital cardiac arrest (OHCA) without ST-segment elevation (STE) remain unclear. METHODS: We evaluated clinical characteristics associated with CA selection and in-hospital mortality in patients with OHCA, shockable rhythm and no STE. RESULTS: Between 2014 and 2018, 118 patients with OHCA and shockable rhythm without STE (mean age 59; males 75%) were stratified by whether CA was performed. Of 86 (73%) patients undergoing CA, 30 (35%) received percutaneous coronary intervention (PCI). CA patients had shorter return of spontaneous circulation (ROSC) time (17 vs. 25 min) and were more frequently between 50 and 60 years (29% vs. 6.5%), with initial Glasgow Coma Scale (GCS) score >8 (24% vs. 6%) (all p < 0.05). In-hospital mortality was 33% (n = 39) for overall cohort (CA 27% vs. no-CA 50%, p = 0.02). Compared to late CA, early CA ( ≤ 2 h) was not associated with lower in-hospital mortality (32% vs. 34%, p = 0.82). Predictors of in-hospital mortality included longer defibrillation time (odds ratio 3.07, 95% confidence interval 1.44-6.53 per 5-min increase), lower pH (2.02, 1.33-3.09 per 0.1 decrease), hypoalbuminemia (2.02, 1.03-3.95 per 5 g/L decrease), and baseline renal dysfunction (1.33, 1.02-1.72 per 10 ml/min/1.73 m2 decrease), while PCI to lesion (0.11, 0.01-0.79) and bystander defibrillation (0.06, 0.004-0.80) were protective factors (all p < 0.05). CONCLUSIONS: Among patients with OHCA and shockable rhythm without STE, younger age, shorter time to ROSC and GCS >8 were associated with CA selection, while less effective resuscitation, greater burden of comorbidities and absence of treatable coronary lesion were key adverse prognostic predictors.

Adverse Impact of Peri-Procedural Stroke in Patients Who Underwent Percutaneous Coronary Intervention.

Peri-procedural stroke (PPS) is an important complication in patients who underwent percutaneous coronary intervention (PCI). The extent to which PPS impacts mortality and outcomes remains to be defined. Consecutive patients who underwent PCI enrolled in the Victorian Cardiac Outcomes Registry (2014 to 2018) were categorized into PPS and no PPS groups. The primary outcome was 30-day major adverse cardiovascular events (MACEs) (composite of mortality, myocardial infarction, stent thrombosis, and unplanned revascularization). Of 50,300 patients, PPS occurred in 0.26% patients (n = 133) (71% ischemic, and 29% hemorrhagic etiology). Patients who developed PPS were older (69 vs 66 years) compared with patients with no PPS, and more likely to have pre-existing heart failure (59% vs 29%), chronic kidney disease (33% vs 20%), and previous cerebrovascular disease (13% vs 3.6%), p <0.01. Among those with PPS, there was a higher frequency of presentation with ST-elevation myocardial infarction (49% vs 18%) and out-of-hospital cardiac arrest (14% vs 2.2%), PCI by way of femoral access (59% vs 46%), and adjunctive thrombus aspiration (12% vs 3.6%), all p = <0.001. PPS was associated with incident 30-day MACE (odds ratio [OR] 2.97, 95% confidence intervals [CIs] 1.86 to 4.74, p <0.001) after multivariable adjustment. Utilizing inverse probability of treatment weighting analysis, PPS remained predictive of 30-day MACE (OR 1.91, 95% CI 1.31 to 2.80, p = 0.001) driven by higher 30-day mortality (OR 2.0, 95% CI 1.35 to 2.96, p = 0.001). In conclusion, in this large, multi-center registry, the incidence of PPS was low; however, its clinical sequelae were significant, with a twofold increased risk of 30-day MACE and all-cause death.

Improving the Characterization of Stage A and B Heart Failure by Adding Global Longitudinal Strain.

BACKGROUND: Current guidelines distinguish stage B heart failure (SBHF) (asymptomatic left ventricular [LV] dysfunction) from stage A heart failure (SAHF) (asymptomatic with heart failure [HF] risk factors) on the basis of myocardial infarction, LV remodeling (hypertrophy or reduced ejection fraction [EF]) or valvular disease. However, subclinical HF with preserved EF may not be identified with these criteria. OBJECTIVES: The purpose of this study was to assess the prediction of incident HF with global longitudinal strain (GLS) in patients with SAHF and SBHF. METHODS: The authors analyzed echocardiograms (including GLS) in 447 patients (age 65 ± 11 years; 77% male) enrolled in a prospective study of HF in individuals at risk of incident HF, with normal or mildly impaired EF (≥40%). Long-term follow-up was obtained via data linkage. Analysis was performed using a competing risks model. RESULTS: After a median of 9 years of follow-up, 50 (10%) of the 447 patients had new HF admissions, and 87 (18%) died. In multivariable analysis, all imaging variables were independent predictors of HF admissions, including left ventricular ejection fraction (LVEF) (HR: 0.97 [95% CI: 0.94-0.99]), LV mass index (HR: 1.01 [95% CI: 1.00-1.02]), left atrial volume index (HR: 1.02 [95% CI: 1.00-1.05]), and E/e' (HR: 1.05 [95% CI: 1.01-1.24]), incremental to clinical variables (age and Charlson comorbidity score). However, the addition of GLS provided value incremental to both clinical and other echocardiographic parameters (P = 0.004). Impaired GLS (<18%) (HR: 4.09 [95% CI: 1.87-8.92]) was independent and incremental to all clinical and other echocardiographic variables in predicting HF, and impaired LVEF, left ventricular hypertrophy, left atrial enlargement, high E/e', or SBHF were not predictive. CONCLUSIONS: The inclusion of GLS as a criterion for SBHF would add independent and incremental information to standard markers of SBHF for the prediction of subsequent HF admissions.

Incremental Value of Global Longitudinal Strain in the Long-Term Prediction of Heart Failure among Patients with Coronary Artery Disease.

BACKGROUND: Heart failure (HF) remains a common complication for patients with coronary artery disease (CAD), especially after acute myocardial infarction. Although left ventricular ejection fraction (LVEF) is conventionally used to assess cardiac function for risk stratification, it has been shown in other settings to underestimate the risk of HF compared with global longitudinal strain (GLS). Moreover, most evidence pertains to early-onset HF. We sought the clinical and myocardial predictors for late-onset HF in patients with CAD. METHODS: We analyzed echocardiograms (including GLS) in 334 patients with CAD (ages 65 ± 11 years, 77% male) who were enrolled in the Nurse-Led Intervention for Less Chronic Heart Failure trial, a prospective, randomized controlled trial that compared standard care with nurse-led intervention to prevent HF in individuals at risk of incident HF. Long-term (9 years) follow-up was obtained via data linkage. Analysis was performed using a competing-risk model. RESULTS: Baseline LVEF values were normal or mildly impaired (LVEF ≥ 40%) in all subjects. After a median of 9 years of follow-up, 50 (15%) of the 334 patients had new HF admissions, and 68 (20%) died. In a competing-risk model, HF was associated with GLS (hazard ratio = 1.15 [1.05-1.25], P = .001), independent of estimated glomerular filtration rate (hazard ratio = 0.98 [0.97-0.99], P = .045), Charlson comorbidity score (hazard ratio = 1.64 [1.25-2.15], P < .001), or E/e' (hazard ratio = 1.08 [1.02-1.14], P = .01). Global longitudinal strain-but not conventional echocardiographic measures-added incremental value to a clinical model based on age, gender, and Charlson score (area under the curve, 0.78-0.83, P = .01). Global longitudinal strain was still associated with HF development in patients taking baseline angiotensin convertase enzyme inhibitors (hazard ratio = 1.21 [1.11-1.31], P < .01) and baseline beta-blockers (1.17 [1.09, 1.26]; P < .01). Mortality was associated with older men, risk factors (hypertension or diabetes), and comorbidities (AF and chronic kidney disease). CONCLUSIONS: Global longitudinal strain is independently associated with risk of incident HF in patients admitted with CAD and provides incremental prognostic value to standard markers. Identifying an at-risk subgroup using GLS may be the focus of future randomized controlled trails to enable targeted therapeutic intervention.

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.

Clinical Utility of Echocardiographic Strain and Strain Rate Measurements.

PURPOSE OF REVIEW: Assessment of left ventricular function is pivotal in many decisions, but ejection fraction has fundamental limitations for assessment of mild dysfunction, and especially for repeated assessments. Myocardial deformation imaging using speckle-tracking is widely available on modern echocardiography systems, and is now feasible as a clinical, rather than purely a research tool. Strain can be measured in all cardiac chambers, most commonly as a systolic parameter, although it can be measured in diastole. Generally, speckle tracking is more effective at measuring strain than strain-rate, which requires a higher temporal resolution. The purpose of this review is to help clinicians understand the main situations where strain provides incremental value to standard echocardiographic measurements. RECENT FINDINGS: The normal range of LV global longitudinal strain (GLS) has now been defined as -18% and lower (ie more negative), abnormal as -16% or higher (ie less negative), with -16 to -18% being borderline. The variation between different vendors is now small for global parameters, but regional strain measurement remains unreliable - and therefore its use for stress echocardiography remains problematic. The most valuable indications for measuring strain are subclinical LV dysfunction (eg., GLS in HFpEF, stage B heart failure, aortic stenosis, mitral regurgitation), RV dysfunction (RV strain in pulmonary hypertension), atrial fibrillation (LA strain) and sequential follow-up (cardiotoxicity). Strain measurements have clinical utility in a number of settings and should be considered as part of the standard echocardiogram.

Handheld ultrasound to reduce requests for inappropriate echocardiogram (HURRIE).

BACKGROUND: Handheld ultrasound could provide sufficient information to satisfy the clinical questions underlying 'rarely appropriate' echo requests, but there are limited data about its use as a gatekeeper to standard echocardiography. We sought to determine whether the use of handheld ultrasound could improve the appropriate use of echocardiography. METHOD: A prospective study comparing handheld ultrasound strategy to standard echocardiography for studies deemed rarely appropriate, using a questionnaire based on appropriate use criteria was conducted across two hospitals, from October 2017 to April 2018. RESULTS: Groups undergoing Handheld ultrasound (n = 76, 58 (46.5-72.5) years, 53 males, 78% outpatients) and standard echocardiography (n = 72, 61 (49.0-71.5) years, 42 males, 76% outpatients) were comparable. There was a significant decrease in the time to scan from just over 1 month in standard group to a median of 12 days in handheld ultrasound group (P < 0.001). This difference was small for inpatients (from 1 day to a median of 10 min in handheld ultrasound, P = 0.014), but prominent in outpatients (from 1.5 months in the standard group to median of 2 weeks in the handheld ultrasound group, P < 0.001). There was no increase in the need for follow-up scan within 6 months and no significant differences in length of hospital stay for inpatients. CONCLUSION: Handheld ultrasound can be an effective gatekeeper to standard echocardiography for requests deemed rarely appropriate, reducing time to echocardiography significantly and potentially decreasing the need for standard echocardiography by up to 20%.

Platypnea-orthodeoxia syndrome after right lower lobectomy for lung cancer.

Platypnea-orthodeoxia syndrome (POS) is a rare condition characterized by dyspnoea and deoxygenation in an upright position that is relieved by supine positioning. There are only five published accounts of it occurring post-lobectomy. We present the case of a 72-year-old male with 3 months of supposedly unexplained dyspnoea after right lower lobectomy for lung cancer who was confirmed to have POS. We highlight the importance of recognition and management as well as provide a brief summary of the pathophysiology.

Pulmonary Hypertension in Central Australia: A Community-Based Cohort Study.

BACKGROUND: The burden of pulmonary hypertension (PHT) in Central Australia has not been previously studied. Our aim is to characterise the prevalence, clinical classification, and long-term survival of individuals with PHT in Central Australia. METHODS: A community-based cohort study of all individuals diagnosed with PHT in Central Australia between 2005 and 2016 was undertaken. We estimated PHT prevalence using population data, describe clinical PHT classification, and characterised long-term survival using Kaplan-Meier approaches. RESULTS: A total of 183 patients were identified (mean age 52±16years, 63% female). Of these individuals, 149 (81.4%) were of Aboriginal and Torres Strait Islander (ATSI) descent. The prevalence per 100,000 of any PHT was significantly higher In ATSI (723 [95% CI 608-839] compared to non-ATSI individuals (126 [95% CI 84-168], p<0.001). Furthermore, ATSI individuals were diagnosed at younger ages compared to non-ATSI individuals (49±15 vs 64±16years, p<0.001). Median estimated pulmonary artery systolic pressure (ePASP) was higher in patients with pulmonary arterial hypertension (PAH) compared to other causes (62 [IQR 54-69] vs 50 [IQR 44-58] mmHg, p<0.01). The median survival rate from diagnosis was 9 years (IQR 7.2-13.2). Age and ePASP were significant predictors of mortality (HR 1.05 [95% CI 1.02-1.07] and HR 1.56 [95% 1.00-2.42] respectively). CONCLUSIONS: In this community based study, we found a high burden of PHT in Central Australia. The prevalence of PHT is greater in ATSI individuals and is diagnosed at younger ages compared to non-ATSI individuals. Together with other cardiovascular diseases, PHT may be in-part contributing to the gap in life expectancy between ATSI and non-ATSI individuals.

Radiological characteristics of atrial myxoma in Cardiac Computed Tomography.

BACKGROUND: Although the primary role of Cardiac Computed Tomography (CCT) is assessment of the coronary arteries, the technique also allows detailed examination of cardiac structures and other cardiac pathologies including cardiac myxoma. However, limited data exists regarding the CCT characteristics of cardiac myxoma. OBJECTIVE: To describe the radiological characteristics of a series of cardiac myxomas in CCT. METHODS: We retrospectively identified all patients at our tertiary urban referral centre with cardiac myxoma on CCT over a seven-year period between July 2008 and July 2015. We describe the CCT characteristics of eight cases. Seven of them had histologically documented myxoma after surgical removal, while one patient had a lesion suggestive of myxoma on echocardiography and CCT. RESULTS: Eight patients were diagnosed with cardiac myxoma, comprising five females and three males. Seven of eight myxomas were located in the left atrium and one in the right atrium. Seven myxomas were polypoid in shape and one myxoma was villous. The average size was 22 × 26 mm. Calcification was present in half of the myxomas and average attenuation was 74 ± 46 Hounsfield Units. CONCLUSION: CCT has an important role in assessment of cardiac structures. This series highlights the radiological characteristics of cardiac myxoma.