Myocardial Injury in Aneurysmal Subarachnoid Haemorrhage: Clinical Correlates and Impact on Mortality in a Single-Centre Australian Intensive Care Unit Cohort

Background Myocardial injury is a recognised complication of aneurysmal subarachnoid haemorrhage (aSAH), arising from catecholamine-mediated neuro-cardiac mechanisms. While international data describe variable incidence and clinical significance, contemporary Australian evidence remains limited. This study aimed to determine the incidence, predictors, and clinical impact of myocardial injury following aSAH in a tertiary Australian intensive care unit (ICU). Methods We performed a retrospective cohort study of adults admitted with aSAH to the Royal Melbourne Hospital ICU between 1 June 2020 and 31 May 2025. Myocardial injury was defined by multimodal criteria: elevated high-sensitivity troponin, new ECG abnormalities, or echocardiographic dysfunction within 72 hours. Outcomes included ICU and hospital mortality, length of stay (LOS), and neurovascular complications. Results Among 300 patients (mean age 56.9 years; 66% female), myocardial injury occurred in 179 (59.7%). Transthoracic echocardiography was performed in 121 patients (40.3%), of whom 74 (24.7%) demonstrated abnormal findings. Elevated troponin was observed in 31.7% (n=95), prolonged QTc in 29% (n=87), and new-onset arrhythmia in 16.7% (n=50). Patients with myocardial injury presented with more severe neurological impairment [mean World Federation of Neurological Societies (WFNS) grade 4 vs. 2; GCS 12 vs. 14] and had higher rates of arrhythmia (36 patients, 20.1% vs. 14 patients, 11.6%), symptomatic vasospasm (73 patients, 40.8% vs. 29 patients, 24.0%), and hydrocephalus (124 patients, 69.3% vs. 64 patients, 52.9%). ICU mortality was significantly higher in the myocardial injury group (44 patients, 24.6% vs. 14 patients, 11.6%; p=0.008), as was hospital mortality (60 patients, 33.5% vs. 16 patients, 13.2%; p=0.0001). Logistic regression identified symptomatic vasospasm as an independent predictor of myocardial injury [odds ratio (OR) 5.1, p<0.001; model accuracy 78.6%, area under the curve (AUC) 0.771]. Conclusions Myocardial injury was frequent in this Australian aSAH cohort and correlated with greater neurological severity, neurovascular complications, and higher mortality.