ECG Interpretation Basics

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Questions and Answers

Which ECG finding is commonly associated with hyperkalaemia?

Shortened QT interval

Flat T waves

Tented T waves (correct)

Absent QRS complex

What is the primary cause of stable angina?

Coronary artery disease (correct)

Valvular heart disease

Hypertension

Coronary artery spasm

In hypokalaemia, which of the following ECG changes is expected?

Elevated ST segment

Shortened PR interval

Absent QRS complex

Long PR interval (correct)

Which class of angina occurs at rest?

Unstable angina Signup and view all the answers

Which artery supplies the sinoatrial node in 60% of individuals?

Right coronary artery Signup and view all the answers

What does a sine wave pattern on an ECG suggest?

Hyperkalaemia Signup and view all the answers

Which class of angina includes symptoms upon mild exertion?

Class III Signup and view all the answers

Which finding is NOT typically associated with hypokalaemia on an ECG?

Tented T waves Signup and view all the answers

What is the expected ST segment change during a vasospastic angina episode?

ST elevation Signup and view all the answers

Which of the following describes the symptoms of Class IV angina?

Symptoms only during rest Signup and view all the answers

Which of the following conditions does NOT typically cause a rise in troponin levels?

Unstable angina Signup and view all the answers

What is the normal range for a PR interval in ECG readings?

0.12-0.20 seconds Signup and view all the answers

Which condition is indicated by a peaked P wave?

Mitral stenosis Signup and view all the answers

What is the recommended time frame for arrival to ECG in suspected acute coronary syndrome?

10 minutes Signup and view all the answers

What does a prolonged QRS complex indicate?

Bundle branch block Signup and view all the answers

What does the 'M' in the treatment ‘MONAC’ stand for?

Morphine Signup and view all the answers

What complication can arise between 3 to 14 days following an acute coronary event?

Ventricular septal rupture Signup and view all the answers

Which of the following is indicative of a left axis deviation?

I positive and II negative Signup and view all the answers

Which of the following is associated with new left bundle branch block (LBBB) in the context of acute coronary syndromes?

Myocardial infarction Signup and view all the answers

Which condition could cause a shortened QT interval?

Hypercalcaemia Signup and view all the answers

What is a common characteristic of atrial fibrillation on an ECG?

Absent P waves Signup and view all the answers

Which statement regarding cardiac complications in the first 24 hours following ACS is correct?

Cardiac arrest due to VF is possible. Signup and view all the answers

A J wave on an ECG typically indicates:

Hypothermia Signup and view all the answers

Which is NOT a common cause of persistent ST elevation on ECG following an ACS?

Severe hypertension Signup and view all the answers

What characteristic of Wolff-Parkinson White syndrome is significant?

Accessory pathway between atria and ventricles Signup and view all the answers

Which drug class is associated with QT interval prolongation?

Antimicrobials Signup and view all the answers

An inverted T wave may indicate which of the following?

Acute myocardial infarction Signup and view all the answers

What should be used for treatment if a patient is hypoxic in acute coronary syndrome?

Oxygen Signup and view all the answers

Which of the following would be considered an irregularly irregular rhythm?

Atrial fibrillation Signup and view all the answers

Which of the following is indicative of high risk in acute coronary syndrome management?

Coronary angiography likely needed Signup and view all the answers

Study Notes

ECG

Rate: Number of large squares between consecutive R waves
Rhythm: Regular or irregular. Sinus arrhythmia, atrial flutter or fibrillation, 2nd degree heart block.
Axis: I positive, II positive is normal. I positive and II negative is left axis deviation. I negative, III (± II) positive is returning.
P wave: Precedes QRS complex, upright in II, III, and aVF, inverted in aVR. Absent in atrial fibrillation, present in hyperkalemia.
PR interval: 3-5 small squares (0.12-0.2s). Shortened with faster AV conduction (Wolff-Parkinson-White syndrome) and prolonged with slower AV conduction (1st degree heart block, hypokalemia).
QRS complex: < 3 small squares (<0.2s). Shortened with supraventricular origin, prolonged with ventricular origin or aberrant conduction of supraventricular complexes (bundle branch block, hyperkalemia).
Pathological Q waves: Within few days of MI.
QT interval: Shortened with hypercalcemia, prolonged with hypokalemia, hypocalcemia, hypothermia, and anti-arrhythmics.
ST segment: Isoelectric. Elevated (normal variant, high take-off), STEMI, vasospastic/variant/Prinzmetal angina, acute pericarditis (saddle-shaped). Depressed (normal variant, upward sloping), NSTEMI, posterior MI (V1-V3), unstable angina, digoxin effect.
T wave: Inverted in aVR, sometimes aVL, III, V1, V2, V3. Abnormal if inverted in I, II, aVF, V4-6. Peaked with hyperkalemia, TCA overdose, or within hours of MI. Flattened with hypokalemia, hypocalcemia, or within hours of MI.
Other waves: J wave with hypothermia, U wave with hypokalemia. Delta wave in WPW syndrome.
Hyperkalemia: Tall, tented T waves, prolonged QRS complex, absent P waves.
Hypokalaemia: "In hypokalaemia U have no Pot and no Tea, but a long PR and a long QT”.

Other

SAN: Sinoatrial node (RCA 60%, circumflex 40%)
AVN: Atrioventricular node (RCA 80%, circumflex 20%)
Angina: Constrictive chest discomfort, insufficient blood supply to the heart, relieved by rest or GTN. Stable angina occurs with exertion/stress. Unstable angina occurs at rest, or abruptly deteriorates.
Vasospastic angina: Spasm.
Acute Coronary Syndromes (ACS): STEMI and NSTEMI have troponin rise due to myocardial cell death. Unstable angina does not.
ST elevation, T wave inversion: Classically hyperacute T waves; then ST elevation, T wave inversion, then pathological Q waves.
NSTEMI and unstable angina: GRACE score. If low risk, fondaparinux. If high risk, glycoprotein IIb/IIIa and UH.
Complications of ACS: Cardiac arrest, AV block, acute heart failure, cardiogenic shock, pericarditis.
Tachycardia: Stable and Irregular. Regular narrow complex tachycardia (sinus tachycardia, AVRT, Wolf-Parkinson White). Irregular narrow complex tachycardia (sinus arrhythmia, atrial fibrillation, atrial flutter).
Bradycardia: Sinus, 1st, 2nd degree (Mobitz I and II), 3rd degree AV block.
Heart Failure: Left sided or Right sided with NYHA functional classification (I, II, III. IV).
Valvular Heart Disease: Mitral regurgitation, mitral stenosis (rheumatic fever), aortic stenosis, aortic regurgitation.
Congenital Heart Disease: Atrial septal defect (ASD), Ventricular septal defect (VSD), Patent ductus arteriosus (PDA), Tetralogy of Fallot (TOF), Transposition of the great arteries.
Pericarditis: Sharp chest pain (worse lying flat, better sitting), fever, pericardial rub. Diagnosed by ECG.
Infective Endocarditis: Fever + new murmur = infective endocarditis until proven otherwise.
Rheumatic fever: Strep pyogenes, acute pharyngitis. (Jones Criteria).
Hypertrophic obstructive cardiomyopathy: LV hypertrophy, leads to decreased compliance and decreased CO.
Pacemakers: Transcutaneous (temporary) or Transvenous (permanent) pacing. Defibrillation.
Antiarrhythmics
Antiplatelets
Thrombolytics

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Description

This quiz covers essential concepts in ECG interpretation, including heart rate calculation, rhythm abnormalities, and normal axis alignment. It also explores the significance of various components of the ECG trace, such as P waves, PR intervals, and QRS complexes. Understand key pathological indicators for improved clinical assessment.