4. Cardiac causes of cardiac arrest Flashcards
types of ACS?
STEMI
NSTE ACS (NSTEMI, unstable angina)
ACS in most cases results from ___ ___ disease, and is initiated by the rupture of erosion of an ____ ____ within a coronary artery
coronary artery
atherosclerotic plaque
describe the sequentia of events that leads to ACS then an atherosclerotic plaque within a coronary artery erodes/ ruptures?
1) acute thrombosis within the vessel lumen
2) contraction of smooth muscle cells in the artery wall resulting in vasoconstriction that reduces the lumen of the artery
3) associated partial or complete obstruction of the lumen, often with embolism of thrombus into the distal part of the vessel
all leads to sudden and critical reduction in blood flow to the myocardium
T/F: you may see ECG changes in unstable angina
true- may be evidence of acute myocardial ischaemia (usually ST-segment depression) or show non-specific abnormalities (e.g. T wave inversion)
all pts with unstable angina should have their risk assessed with an established risk calculator e.g.
GRACE
what ECG findings are suggestive of STEMI?
ST segment elevation or new LBBB
T/F: the amount of troponin released reflects the amount of myocardium damaged
true
left untreated, a STEMI will lead to the development of __ waves on the ECG
Q
T/F: confirmation of elevated troponin is required to make the initial diagnosis of STEMI
False
clinical signs on examination of aortic dissection?
hypotension, loss of peripheral pulse, R-R delay, aortic regurgitation, signs of stroke from carotid artery involvement
treatment of STEMI?
reperfusion therapy
ideally PCI
if that can’t be achieved within 120 minutes of onset of CP, fibrinolytic therapy should be considered
anteroseptal infarction - which ECG leads and which coronary artery?
V1-4 (extension to V5-6, I and aVL indicates anterolateral)
LAD
an ANTERIOR/LATERAL/INFERIOR infarct has a worse prognosis
anterior
inferior infarction - which ECG leads and which coronary artery?
II, III and aVF
Right coronary or, less commonly, the circumflex artery
lateral infarction - which ECG leads and which coronary artery?
V5-6, and/ or I/ aVL
Circumflex artery or diagnoal branch of the LAD
posterior infarction - which ECG leads and which coronary artery?
reciprocal ST-segment depression in the anterior leads
Most often right coronary artery but can also be a dominant circumflex artery
what ECG changes reflect posterior Q wave development?
development of a dominant R wave in V1-V2 (reflects posterior Q wave development
suspicion of posterior ECG can be confirmed by repeating the ECG with what change?
addition of posterior leads (V7-10)
Right ventricular infarction may be present in up to one third of patients with ____ and ____ STEMI
inferior and posterior
a diagnosis of extensive RV infarction is suggested by what clinical signs?
fluid responsive hypotension and signs of high systemic venous pressure (e.g. jugular venous distension) without pulmonary congestion
extensive RV infarction may be seen on an ECG when ST-segment elevation in what lead accompanies an inferior or posterior STEMI?
V1
the ECGs of people with SAH or TBI can show ECG changes including…
ST segment depression or elevation, or T-wave inversion
what ECG changes can happen in people with major PE?
T wave inversion in leads V1-4
T/F: the greater the troponin, the greater the risk of a further event or death
true
what other life threatening conditions presenting with chest pain can have elevated troponins?
including PE, aortic dissection and myocarditis