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Hypertroponinaemia. Michael Stewart CT1 ACCS. Case 1. 64 year old male Known history of IHD – 2x NSTEMI, UA Two hours of central chest pain, identical to previous MI ECG: Lateral ST depression Trop T 0.07. Case 2. 72 year old male
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Hypertroponinaemia Michael Stewart CT1 ACCS
Case 1 • 64 year old male • Known history of IHD – 2x NSTEMI, UA • Two hours of central chest pain, identical to previous MI • ECG: Lateral ST depression • Trop T 0.07
Case 2 • 72 year old male • Presents with three hours central chest pain, onset during dancing • Nausea, mildly dyspnoeic • Ex-smoker; hypertensive • Not diabetic, no FH of IHD
Case 2 • ECG shows dynamic inferior ST depression • Pain eased after IV GTN and morphine with resolution of ECG changes • Troponin 0.56
Case 3 • 62 year old female • Onset of palpitations and dyspnoea on waking • GP found irregular pulse, rate ~160
Case 3 • Hypertensive; no other significant co-morbidity • ECG: Fast AF, rate ~170 • BP 100/60 • Pale, clammy, drowsy • DC Cardioversion – SR restored • Troponin 0.13
Troponin • Component of cardiac and striated muscle • Calcium binding initiates conformational change to permit myosin to bind to actin filament • Myosin conformational cycling on actin acts as ‘molecular motor’ for muscle contraction • Cardiac Troponins are specific for cardiac myocyte damage • Troponin is NOT specific for myocardial infarction
PICI/SICI/NICI • Primary Ischaemic Cardiac Injury • Secondary Ischaemic Cardiac Injury • Non-Ischaemic Cardiac Injury
PICI • Coronary artery occlusion/stenosis by thrombotic disease • STEMI/NSTEMI
NSTEMI • Any two of: • Typical chest pain • Typical ECG changes • Rise in cardiac enzymes New definition!
2007 Universal Definition Troponin > 99th centile of reference range • (Locally agreed at Trop T > 0.1) PLUS: • Ischaemic symptoms • ECG changes • Regional wall motion abnormality • Loss of viable myocardium on imaging
SICI • Secondary cause of coronary artery obstruction • Embolic disease; during PCI; during CABG • Coronary vasospasm or inflammation • Primary; vasculitides; SLE • Increased myocardial oxygen demand • Tachyarrythmias; prolonged exercise; sympathomimetic drugs; heart failure; PE
NICI • Direct trauma • Penetrating; blunt; surgical • Myocarditis • Infectious; auto-immune; drug/alcohol; inflammatory • Metabolic • Renal failure; multiple organ failure; sepsis
Cases • Case 1: Typical chest pain, Trop T 0.07 • PICI, not criteria for NSTEMI • Case 2: Typical chest pain, Trop T 0.56 • NSTEMI • Case 3: Fast AF, no pain, Trop T 0.13 • SICI ( + NICI )
Summary • Troponins are a sensitive marker of cardiac myocyte damage • Not all cardiac myocyte damage represents acute myocardial infarction • Primary, secondary, and non-ischaemic causes exist
References • Thygesen, Kristian, Alpert, Joseph S., White, Harvey D., on behalf of the Joint ESC/ACCF/AHA/WHF Task Force for the Redefinition of Myocardial Infarction, Universal Definition of Myocardial Infarction J Am Coll Cardiol 2007 50: 2173-2195 • Collinson, P O, Stubbs, P JAre troponins confusing?Heart 2003 89: 1285-1287 • http://www.trauma.org