Melbourne Medical School Collected Works - Research Publications
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ItemNo Preview AvailableClinical Utility of Echocardiographic Strain and Strain Rate Measurements(SPRINGER, 2021-03)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.
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ItemLeft atrial, pulmonary vein, and left atrial appendage anatomy in Indigenous individuals: Implications for atrial fibrillation(ELSEVIER IRELAND LTD, 2021-06)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.
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ItemHandheld ultrasound to reduce requests for inappropriate echocardiogram (HURRIE)(BIOSCIENTIFICA LTD, 2019-12)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%.