ECG's Flashcards
Nail them for the exam!!
Sinus rhythm is denoted by
Upright P waves in Lead II, before each QRS complex
Time interval for a large and small square?
How do you calculate the rate?
Small square - 0.04ms
Large square - 0.2ms
Rate: 300/number of large squares
Draw the graph used to determine isoelectric axis
Normal QT values for Male and Female?
How do you calculate the QTc?
Male 440
Female 460
QTc= QT/√R-R Bazett
R-R interval is 60/HR
Causes of a prolonged QT?
Drugs: Amiodarone, flecanide, citalopram, macrolides, methadone
El’s: Hypo Ca/K/Mg/TFT’s
In contrast to a short QT: digitalis and hyper K
What does a LBBB look like on an ECG?
Wide QRS > 0.12msec
RSR in V5 +/- V6
Dominant S wave in V1
Loss of Q waves V5-V6
ST segment depression
Note concordance or lack of - Sgarbossa
(25% depth of the preceeding S wave, disconcordant)
What does an RBBB look like on an ECG?
V1: RSR’ pattern in V1, with (appropriate) discordant T wave changes
V6: Widened, slurred S wave in V6
QRS: >0.12msec
TWi V1-V3
LAFB - what are the components?
You are looking only at left hand side of ecg:
Prolonged QRS
LAD
qR complexes in leads I, aVL (QRS +ve, no S wave bit)
rS complexes in leads II, III, aVF (Negative complex)
Prolonged R wave peak time in aVL > 45ms
The most common causes are age-related fibrotic changes, ischaemic heart disease, hypertension, cardiomyopathies, infiltration from systemic disease, cardiac surgery or trauma, and, for RBBB, pulmonary embolism or cor pulmonale.
What are the features of a LPFB?
Right axis deviation (RAD) (> +90 degrees)
rS complexes in leads I and aVL
qR complexes in leads II, III and aVF
Prolonged R wave peak time in aVF
(note complexes are opposite to LAFB)
What are the features of a bi-fascicular block?
Always a RBBB plus either:
LAD (essentially an LAFB)
RAD (essentially a LPFB)
Tri-fascicular block is the addition of PR prolongation (first or second degree)
Significance is progression to heart block within a year (1-4%)
Features of LVH?
Sokolov-Lyon criteria: S wave depth in V1 + tallest R wave height in V5-V6 > 35 mm
Voltage criteria must be accompanied by non-voltage criteria to be considered diagnostic of LVH
Non-volatage: ST segment depression and T wave inversion in the left-sided leads: AKA the left ventricular ‘strain’ pattern (seen in leads I,aVL, V4-V6)
Features of RVH?
All the R’s:
RAD
RAE
RV Strain (ST depression / T wave inversion in the right precordial (V1-4) and inferior (II, III, aVF) leads.)
Twi V1-V2
RSR in V1
Features of HOCM?
Left ventricular hypertrophy with increased precordial voltages and non-specific ST segment and T-wave abnormalities
Deep, narrow (“dagger-like”) Q waves in lateral (I, aVL, V5-6) +/- inferior (II, III, aVF) leads (your left strain leads)
May also have atrial enlargement, WPW features, arrythmias, and giant precordial TWi in apical HOCM
