Impact of adherence to surgical and non-surgical components of infective endocarditis guidelines and recommendations.

BACKGROUND: Infective endocarditis (IE) is associated with significant morbidity and mortality. Non-adherence to IE guidelines and recommendations is frequent, and may adversely impact patient outcomes. AIM: To assess the impact of non-adherence to components of existing IE guidelines and recommendations on a composite outcome consisting of any of the following: mortality, unplanned cardiac surgery, embolic event or relapse of positive blood culture within six months of diagnosis. METHODS: A single centre, retrospective cohort study. RESULTS: Amongst 157 patients, there was inconsistent adherence to: initial diagnosis of an infective condition (87%), timely administration of antimicrobial therapy (82%), appropriateness of predominant antimicrobial regime (94%), appropriate management of the portal of entry (86%), multidisciplinary input (75%), end of antimicrobial therapy repeat echocardiography (60%) and adherence to indications for surgery (76%). Inpatient mortality was 12.1% (n = 19) and the composite adverse outcome occurred in 36 (22.9%) patients. In multivariate logistic regression analysis, infection of prosthetic device (adjusted odds ratio [95% confidence interval]; 2.43 [1.07-5.50]) and non-adherence to surgical guidelines (aOR 3.67 [1.60-8.47]) were significantly associated with an adverse outcome. CONCLUSIONS: Our data suggests that adherence to differing components of IE management guidelines and recommendations varies and that non-adherence to surgical aspects of guidelines has the biggest impact in determining outcomes.

The Index of Microcirculatory Resistance Postpercutaneous Coronary Intervention Predicts Left Ventricular Recovery in Patients With Thrombolyzed ST-Segment Elevation Myocardial Infarction.

BACKGROUND: The index of microcirculatory resistance (IMR), an invasive measure of microvascular function, has been shown to correlate with clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study is to evaluate the predictive value of IMR on left ventricular recovery in patients undergoing a pharmacoinvasive strategy for STEMI. METHODS: The index of microcirculatory resistance was assessed following percutaneous coronary intervention (PCI) in 31 patients with STEMI who were initially managed with thrombolysis. Other markers of microvascular function such as coronary flow reserve (CFR), TIMI flow grade, corrected TIMI frame count (cTFC), and ST-segment resolution were also recorded. All indices were evaluated against measures of left ventricular function and recovery 3 months postindex event. RESULTS: The IMR correlated with left ventricular function, as assessed by wall motion score and ejection fraction at 3-month follow-up (r = 0.652, P = 0.005; r = -0.452, P = 0.011, respectively). The traditional methods of assessing microvascular function, such as CFR, TIMI flow grade, cTFC, and ST-segment resolution did not correlate with wall motion score and ejection fraction at 3 months. Post-PCI IMR was significantly lower in those patients with left ventricular recovery at 3 months (18 U vs 39 U, P < 0.001). The optimal cut-off value for post-PCI IMR and left ventricular recovery was 32 U. In patients in whom the IMR was greater than 32 U, the percent change in ejection fraction was significantly lower than in those patients in whom the IMR was less than 32 U (2 ± 11 vs 12 ± 8, P = 0.012). CONCLUSIONS: In patients presenting with STEMI initially managed with thrombolysis and subsequently undergoing PCI, IMR correlates with measures of left ventricular function and has the potential to predict left ventricular recovery at 3 months.

Renal sympathetic nerve denervation for the treatment of resistant hypertension.

Improvements in BP control with pharmacotherapy undoubtedly translate into significant individual and population health benefits. RDN results in impressive reductions in BP, which are likely to be associated with further improvements in clinical outcomes. With more clinical trials and concurrent development of new devices, we hope that RDN holds up to its current accolades.

Early Australian experience with intravascular lithotripsy treatment of severe calcific coronary stenosis: IVL in acute/chronic coronary syndromes.

Aims: Calcified coronary stenoses are a serious impediment to optimal stent expansion and can lead to stent failure and catastrophic adverse outcomes. We hereby present early Australian experience with intravascular lithotripsy for the treatment of calcific lesions in acute and chronic coronary syndromes. Methods and results: This was a single-centre retrospective study of all patients treated with intravascular lithotripsy (IVL) between October 2019 and June 2021. Patient demographics, procedural variables, and treatment safety/efficacy outcomes were evaluated. During this period, there were 40 patients and 41 coronary lesions with IVL-assisted percutaneous coronary intervention (PCI) (70% male; mean age 72.8±9.5 years). Indications for PCI were acute coronary syndromes in 25 patients (62.5%), and stable angina in 15 patients (37.5%). Upfront IVL usage occurred in 5% of cases with the rest being bailout procedures due to suboptimal initial balloon predilatation or stent underexpansion. Angiographic success (<20% residual stenosis) occurred in 37 cases (92.5%), with mean residual stenosis of 8.25%±8.5%. Two patients experienced procedural complications (5%). Conclusions: IVL appears to be a safe and effective modality in modifying coronary calcium to achieve optimal stent expansion in real-world practice. This device obviates the need for more complex lesion preparation strategies such as rotational or orbital atherectomy.

Transfer learning artificial intelligence for automated detection of atrial fibrillation in patients undergoing evaluation for suspected obstructive sleep apnoea: a feasibility study.

BACKGROUND: Individuals with obstructive sleep apnoea (OSA) experience a higher burden of atrial fibrillation (AF) than the general population, and many cases of AF remain undetected. We tested the feasibility of an artificial intelligence (AI) approach to opportunistic detection of AF from single-lead electrocardiograms (ECGs) which are routinely recorded during in-laboratory polysomnographic sleep studies. METHODS: Using transfer learning, an existing ECG AI model was applied to 1839 single-lead ECG traces recorded during in-laboratory sleep studies without any training of the algorithm. Manual review of all traces was performed by two trained clinicians who were blinded to each other's review. Discrepancies between the two investigators were resolved by two cardiologists who were also unaware of each other's scoring. The diagnostic accuracy of the AI algorithm was calculated against the results of the manual ECG review which were considered gold standard. RESULTS: Manual review identified AF in 144 of the 1839 single-lead ECGs (7.8%). The AI detected all cases of manually confirmed AF (sensitivity = 100%, 95% CI: 97.5-100.0). The AI model misclassified many ECGs with artefacts as AF, resulting in a specificity of 76.0 (95% CI: 73.9-78.0), and an overall diagnostic accuracy of 77.9% (95% CI: 75.9%-97.8%). CONCLUSION: Transfer learning AI, without additional training, can be successfully applied to disparate ECG signals, with excellent negative predictive values, and can exclude AF among patients undergoing evaluation for suspected OSA. Further signal-specific training is likely to improve the AI's specificity and decrease the need for manual verification.

Advances in screening for undiagnosed atrial fibrillation for stroke prevention and implications for patients with obstructive sleep apnoea: a literature review and research agenda.

Atrial fibrillation (AF) is the most common type of sustained cardiac arrhythmia encountered in clinical practice, and its burden is expected to increase in most developed countries over the next few decades. Because AF can be silent, it is often not diagnosed until an AF-related complication occurs, such as stroke. AF is also associated with increased risk of heart failure, lower quality of life, and death. Anticoagulation has been shown to dramatically decrease embolic risk in the setting of atrial fibrillation, resulting in growing interest in early detection of previously undiagnosed AF. Newly developed monitoring devices have improved the detection of AF and have been recommended in guidelines for screening of AF in individuals aged 65 years and over. While screening is currently targeted to these older individuals, younger patients with obstructive sleep apnoea (OSA) are at higher risk of AF and stroke than the general population, indicating a need for targeted early detection of AF in this group. Compared to individuals without OSA, those with OSA are four times more likely to develop AF, and the risk of AF is strongly associated with OSA severity. The overall prevalence of AF among individuals with OSA remains unknown because of limitations related to study design and to the conventional methods previously used for AF detection. Recent and emerging technological advances may improve the detection of undiagnosed AF in high-risk population groups, such as those with OSA. In this clinical review, we discuss the methods of screening for AF and the applications of newer technologies for AF detection in patients with OSA. We conclude the review with a brief description of our research agenda in this area.

Measurement of microvascular function in patients presenting with thrombolysis for ST elevation myocardial infarction, and PCI for non-ST elevation myocardial infarction.

BACKGROUND: In this prospective study, we compared the invasive measures of microvascular function in two subsets: patients with pharmacoinvasive thrombolysis for STEMI, and patients undergoing percutaneous coronary intervention (PCI) for NSTEMI. METHODS: The study consisted of 17 patients with STEMI referred for cardiac catheterisation post thrombolysis, and 20 patients with NSTEMI. Coronary physiological indexes were measured in each patient before and after PCI. RESULTS: The median pre-PCI index of microcirculatory function (IMR) at baseline was significantly higher in the STEMI group than the NSTEMI group (26 units vs. 15 units, p = 0.02). Following PCI, IMR decreased in both groups (STEMI 20 units vs. NSTEMI 14 units, p = 0.10). There was an inverse correlation between post PCI IMR and left ventricular ejection fraction (LVEF) (r = -0.52, p = 0.001). Furthermore, post PCI IMR was an independent predictor of index admission LVEF in the total population (ß = -0.388, p = 0.02). CONCLUSION: Invasive measures of microvascular function are inferior in a pharmacoinvasive STEMI group compared to a clinically stable NSTEMI group. In the STEMI population, the IMR following coronary intervention appears to predict LVEF.