ECG Flashcards
J point
Junction between the QRS complex and beginning of the ST segment
1 heavy box is ___ seconds
0.2 seconds
PR interval in first degree AV block
Greater than 1 heavy box (longer than 0.2 seconds)
RBBB- which leads to check
QRS greater than 0.12 seconds. 2 R waves present in V1 and V2. Also, the last QRS deflection should be pointing upward.
LBBB- which leads to check
QRS greater than 0.12 seconds. Two R waves present in V5 and V6. The last QRS deflection pointing downward.
What can you NOT diagnose when BBB present?
Infarct pattern, axis, or ventricular hypertrophy
Lead I and lead AVF in Right axis deviation
Lead I negative, lead AVF positive
Lead I and lead AVF in extreme right axis deviation
Both Lead I and AVF negative
Lead I and lead AVF in left axis deviation
Lead I is positive, lead AVF negative
Lead I is positive, and lead AVF is negative. What is your next step
Check lead II. If negative, confirm LAD. If positive, axis is normal.
What axis deviation might you find in healthy children or really tall thin adults?
RAD
Patient with occlusion of Left anterior descending artery and left circumflex a. Which way does the axis deviate?
LAD artery occlusion- infarction of left ventricular anterior areas. Left circumflex occlusion causes necrosis of lateral left ventricle. causes RAD.
Patient with WPW syndrome. Axis deviation…
If right sided accessory pathway- causes LAD. If left sided accessory pathway- causes RAD
Patient with pulmonary stenosis (due to pulmonary embolism), causing increased afterload. RVH results- what finding do you look for in ECG?
Look at Lead V1- usually small R and large S. In RVH, LARGE R present. (but don’t confuse with posterior infarction)
70 year old man with aortic stenosis due to calcification of valve. Increased afterload, causing LVH. What finding do you look for in ECG?
Large S wave in V1, and large R wave in V5. Each peak should be greater than 35 mm. (35 small squares)
Ischemia on ECG signified by
Symmetric T wave inversions
Transmural ischemia vs. subendocardial ischemia
transmural- st elevation, subendocardial ischemia- st depression.
What should you not confuse with ST elevation?
J point elevation- concave up T wave in leads V2-V5
When is a Q wave pathologic?
Greater than 0.04 seconds (1 small square), if depth is at least 1/3 the height of the R wave, and is present in two or more contiguous leads
Anterior wall infarction involves leads
V1-V4
Inferior wall infarction involves leads
II, III, AVF
Lateral wall infarction involves leads..
V5 and V6
Posterior wall infarction signified by..
Large R wave and ST depression in V1 and V2
4 key properties of myocardial cells
automaticity, excitability, conductivity, and contractility
Normal P wave height and duration
0.5-2.5 mm, and 0.06-0.10 seconds in duration
Most common cause of atrial tachycardia
digitalis toxicity
What rhythm is COPD often associated with?
Multifocal Atrial tachycardia
WPW Tx
Ablation. antiarrhythmics
What consequence may occur if atrial fibrillation sustains for more than 2 days?
Emboli formation in arteries
What is holiday heart syndrome associated with, and what rhythm might result?
Binge drinking- atrial fibrillation
HR of junctional arrhythmia
40-60 bpm
HR of accelerated junctional arrhythmia
60-100 bpm
HR of junctional tachycardia
100-190 bpm
Most common cause of ventricular dysrhythmia
ischemia
Idioventricular rhythm HR
20-40 bpm
Accelerated idioventricular HR
between 40-100 bpm
Ventricular tachycardia HR
more than 100 bpm
Why should you be very concerned with ventricular tachycardia?
can turn into ventricular fibrillation
example of polymorphic VT
torsades de pointes
Tx for congenital prolonged QT syndrome
beta blockers with pacemakers
Acquired causes of prologed QT syndrome
drugs- antiarrhythmic agents, antidepressants, electrolyte imbalances, myocardial ischemia, significant bradycardia
