Flashcards in ECG Quiz Answers Deck (29)
Which leads show anterior view of the heart?
ECG features of complete heart block?
P waves and QRS complexes are completely unrelated
- indicates no co-ordinated electrical communication between the atria and ventricles
Lead I, II, III deflections in right axis deviation?
Lead III most positive
Lead I negative
Lead I, II, III deflections in normal cardiac axis?
Lead II most positive
Lead I, II, III deflections in left axis deviation?
Lead I most positive
Leads II, III negative
Heart rate calculation on ECG?
- count number of large squares within one R-R interval
- divide 300 by this number to calculate heart rate
e.g. 4 large squares between R waves. HR = 300/4 = 75bpm
Normal length of PR interval?
0.12-0.20 seconds (120-200 milliseconds or 3-5 small squares on ECG paper)
What are short PR intervals associated with?
Pre-excitation syndromes e.g. Wolff-Parkinson-White syndrome
What are prolonged PR intervals associated with?
AV blocks e.g. 1st-degree AV block/heart block
How is first-degree heart block represented on ECG?
Fixed prolonged PR interval (>200ms)
Common causes of first-degree heart block?
AV nodal disease
Enhanced vagal tone (e.g. athletes)
Acute MI (esp acute inferior MI)
Drugs that commonly cause first-degree heart block?
Cardiac glycosides (digoxin)
Features of Mobitz Type 1 second-degree heart block on ECG?
Slowly increasing PR interval with a regularly dropped QRS complex
Inferior MI ECG features + corresponding coronary artery?
ST elevation in II, III, aVF
- most commonly right coronary artery
Anterior/Septal MI ECG features + corresponding coronary artery?
ST elevation in V3, V4 (anterior) or V1, V2 (septal)
- left anterior descending artery
High lateral MI ECG findings + corresponding coronary artery?
ST elevation in I, aVL
- left anterior descending artery branch
Low lateral MI ECG findings + corresponding coronary artery?
ST elevation in V5, V6
- circumflex artery branch
Occlusion of right ventricular branch of right coronary artery can give rise to?
Isolated ST elevation in V1, V2
Occlusion of circumflex artery can also present with?
Posterior ST elevation (V7-V9) and anterior ST depression in V2-V4
Earliest sign of MI?
Tall T-waves (rarely seen as is during the hyperacute period)
- ST elevation more commonly noted
Tall tented T waves = ?
Mobitz Type 2 second-degree heart block ECG findings?
PR interval but there are dropped beats (will be clarified by frequency of dropped beats)
- type 1 has prolonging PR interval
Atrial fibrillation ECG features?
Irregularly irregular + absence of clear P waves
Normal QRS complex duration?
~0.12 seconds or slightly less (3 small squares)
What is a QRS complex described as if it lasts longer than 0.12 seconds and what is it a sign of?
- sign of inefficient conduction of the ventricles, such as in bundle branch block
Method of calculating HR from ECG when pulse is irregular?
Count number of complexes on the rhythm strip (10 seconds long)
Multiply the number of complexes by 6 (average no. of complexes in 1 minute)
What condition is a Delta wave associated with?
What does diagnosis of WPW syndrome require?
Evidence of tachyarrhythmias AND a delta wave