What are the 7 steps in ECG interpretation?
- Is there electrical activity with a pulse? 2. What is the ventricular (QRS) rate? 3. Is the QRS rhythm regular or irregular? 4. Is the QRS width narrow or wide? 5. Is atrial activity present (e.g., P waves)? 6. How is atrial activity related to ventricular activity? 7. Are there any ST or T wave abnormalities?
What are two key ECG changes that suggest cardiac ischaemia?
ST-segment depression and T-wave inversion.
What distinguishes stable, unstable, and Prinzmetal angina?
Stable: Triggered by exertion, relieved by rest/GTN. Unstable: Occurs at rest, not relieved by GTN. Prinzmetal: Caused by vasospasm, ST elevation on ECG, unpredictable.
What’s the difference between STEMI and NSTEMI?
STEMI: ST elevation, full occlusion, confirmed on ECG. NSTEMI: No ST elevation, confirmed by troponin elevation.
Why is troponin important in diagnosing AMI?
Elevation >3x normal or a change of +0.3 ng/mL in 2 hours has a high likelihood ratio (LR 58.92).
What symptoms strongly suggest ACS?
ST depression, radiating pain to both arms, typical ischemic pain, past similar AMI pain.
What are the types of AV blocks?
1st Degree: PR prolongation, all impulses conducted. 2nd Degree Type I (Wenckebach): Progressive PR lengthening → dropped beat. 2nd Degree Type II: Sudden dropped beats without PR change. 3rd Degree: Complete dissociation between atria and ventricles.
What does the HEART acronym stand for?
History, ECG, Age, Risk factors, Troponin.
What determines blood pressure (BP)?
BP = Peripheral Vascular Resistance (PVR) × Cardiac Output (CO); and CO = Heart Rate (HR) × Stroke Volume (SV).
What are the components of stroke volume?
SV = End Diastolic Volume (EDV) - End Systolic Volume (ESV).
What causes an increase in cardiac output?
Increased HR, increased contractility, increased preload, or decreased afterload.
What is the significance of the J-point on an ECG?
The J-point is where the QRS complex transitions into the ST segment; elevation or depression here can indicate ischaemia or infarction.
What are the five main types of ACS?
Stable angina, Prinzmetal angina, Unstable angina, STEMI, NSTEMI.
What differentiates unstable angina from NSTEMI?
NSTEMI causes troponin elevation; unstable angina does not.
What are signs of cardiac ischaemia on ECG?
ST-segment depression and T-wave inversion.
What are common descriptors of cardiac chest pain?
Heaviness, tightness, pressure, radiating to jaw or arms, not relieved by rest or GTN in unstable angina.
How do you identify ventricular tachycardia (VT)?
Wide, fast QRS complexes; often monomorphic or polymorphic; no visible P waves.
What is ventricular bigeminy?
Every second beat is a premature ventricular contraction (PVC).
Why should cardiac ischaemia be presumed in chest pain?
ACS can present subtly; better to treat as cardiac unless another cause is obvious.
What are key red flag differentials for chest pain?
Aortic dissection, Pulmonary embolism, Pneumothorax, Pericarditis, Chest infection.
What are the main drug classes used in AMI?
Antiplatelets (aspirin), nitrates (GTN), anticoagulants (heparin), thrombolytics, beta-blockers.
What are two main reperfusion therapies?
Percutaneous Coronary Intervention (PCI) and thrombolysis.
What is the indication for thrombolysis?
STEMI when PCI is not immediately available, and no contraindications exist.
What is the implication of ‘time = muscle’?
The longer myocardium is ischaemic, the more tissue dies — early reperfusion saves heart muscle.
