Cardiac Output

Lower-dose heparin during extracorporeal membrane oxygenation meets the RATE trial's non-inferiority threshold for a composite of bleeding, thromboembolism and mortality. This does not establish superior safety or survival, and separate indications for full anticoagulation remain important.

Dilated, hypertrophic and restrictive cardiomyopathies require different haemodynamic approaches. Echocardiography helps distinguish impaired contraction, dynamic outflow obstruction and poor ventricular filling, preventing treatments that might worsen obstruction and helping differentiate myocardial restriction from pericardial constriction.

Cardiac output monitoring should complement rather than replace bedside assessment of perfusion. Thermodilution, pulse contour analysis, Doppler and echocardiography each have assumptions and limitations, while normal blood pressure or a reassuring displayed value can coexist with inadequate flow.

Cardioplegia protects the myocardium during aortic cross-clamping through arrest, cooling, unloading, substrate and buffering; delivery route, ventricular distension, returning electrical activity and systemic electrolyte changes can all signal inadequate or problematic myocardial protection.

Postoperative atrial fibrillation reflects both atrial substrate and reversible physiological triggers; stable patients need correction of pain, hypovolaemia, hypoxia, anaemia and electrolyte disturbance before drug treatment, while adverse features call for synchronised cardioversion

Perioperative transoesophageal echocardiography supports ventricular assessment, recognition of systolic anterior motion and troubleshooting of mechanical support, while imaging can identify cannula, cardioplegia and guidewire problems that may otherwise be difficult to explain in theatre.

Five core transthoracic echocardiography views help identify hypovolaemia, vasoplegia, right ventricular failure, tamponade, dynamic outflow obstruction and aortic dissection, while ventricular findings, vena caval measurements, lung ultrasound and clinical context should be interpreted together.

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GLIMPSE finds an unadjusted association between GLP-1 receptor agonist use and perioperative regurgitation or aspiration, but confounding, observer awareness and few pulmonary aspirations limit causal conclusions; medication checks and deliberate emergence planning remain practical priorities.

Transoesophageal echocardiography helps assess balloon-pump suitability and positioning, choose appropriate extracorporeal membrane oxygenation support and identify complications including recirculation, left ventricular distension, intracardiac stasis and postoperative tamponade.

Transoesophageal echocardiography guides ventricular assist device implantation and troubleshooting, using ventricular filling, septal position, valve function and cannula flow to identify inadequate unloading, suction, right ventricular failure, obstruction and incorrect Impella positioning.