Diagnostic features of EKG - disorders Flashcards
(35 cards)
EKG findings of LV hypertrophy
- Bigger R waves in Left-sided Leads (due to larger muscle mass)
→ I, aVL, V5, V6 - T wave can be inverted
EKG findings of Right Ventricular Hypertrophy
Big R waves in Right-sided Leads
→ V1,V2
EKG findings of Myocardial ischemia
ST depression
T wave inversion - sometimes
EKG findings of ischemia during acute coronary syndrome
T wave inversion
What is transmural injury and what are the
EKG findings of transmural injury
ST elevation
Note: Transmural injury: death of myocardial tissue that extends from the endocardium to the epicardium as a result of a myocardial infarction.
Coronary artery most responsible for MI seen in inferior Leads
inferior Leads are II, III, av1
RCA
Coronary artery most responsible for MI seen in anteroseptal leads
anteroseptal: V1-V2
LAD
Coronary artery most responsible for MI seen in anteroapical leads
V3-V4
LAD (distal)
Coronary artery most responsible for MI seen in anterolateral leads?
V5, V6, I, aVl
CFX
Coronary artery most responsible for MI seen in posterior leads
V1-V2
RCA
(note: V1-V2 is also anteroseptal and responsible for LAD)
EKG findings of myocardial injury/infarction
Pathological/sizable Q waves
(>1 small box)
- Q waves in inferior leads (II,III, aVF) are due to inferior infarcts.
- Q waves in anterior leads (V1-V4) are due to anterior wall infarcts.
Can Q waves differentiate between acute MI and one that happened years ago?
No, but ST elevation along with Q wave can
ST elevation can.
- Acute: see ST elevation
- Hours: see ST elevation AND ↓ R wave and Q deeper waves
- Weeks: normal ST and persistent Q waves
(note: Q waves are usually the last ECG findings to develop)
What the the giant upright t waves called that are rarely seen in MI?
Hyperacute/peaked T waves
- lasts only a few minutes and rarely caught bc usually people dont have an MI while they are hooked up to an EKG
ECG findings in MI in:
Transmural MI
Subendocardial MI
transmural:
- ST elevation
- With Q waves
Subendocardial:
- ST depression (lasting 2/3 days)
- no Q waves
(note: ST depression may reflect transient ischemia w/o necrosis)
Difference between Stenosis and regurge sounds:
Stenosis: hear the sound before the closing of valves
Regurge: hear the sound after closing of the valves
How can you tell if you have a prolonged QT interval? Why is this important?
If you look peak to peak, divide in half = if you don’t see the T wave, you have a prolonged QT interval
- When the QT interval is altered susceptibilities to arrhythmias increase - especially likely with QT prolongation.
Causes of prolonged QT interval
hypocalcemia hypokalemai hypomagnesemia hypothermia Class 1A or 3 anti-arrythmic drugs Congenital Long QT syndrome
How do calcium levels affect the QT intervals?
Hypercalcemia shortens the QT interval.
§ The commonest cause is hyperparathyroidism.
Hypocalcemia lengthens the QT interval (is more common)
§ Has many causes (life threatening ventricular arrhythmias)
EKG findings of hypokalemia
- what can this cause?
Prolonged QT
T wave merging with U wave
- Hypokalemia is a common cause of arrhythmias.
Common causes of hypokalemia?
overuse of diuretics and vomiting or diarrhea
EKG findings in: mild hyperkalemia (5.5-7.5)
increased T wave voltages with a distinctive peaked, symmetrical appearance.
EKG findings in: highish hyperkalemia (7.5-9.0)
P waves may flatten and the QRS & T waves widen.
A broad S wave often appears.
EKG findings in: highhh hyperkalemia (>9.0)
sinusoidal pattern appears without P or R waves.
most common cause of hyperkalemia?
renal failure
If unrecognized hyperkalemia often causes fatal arrhythmias (and cardiac arrests)
