ECG 2 Flashcards
location V5-V6
anterolateral wall
location 2, 3 Avf
inferior wall
location of I, aVL
high lateral wall
prolonged QT interval if the
QT interval is more than half the RR interval
Causes of prolonged QT interval
- Hypocalcemia
- hypokalemia
- hypomagnesemia
- Class 1A or 3 anti-arrhythmic drugs
- Hypothermia
- Congenital Long QT syndrome
hypercalcemia effect on QT interval
shortened
hypocalcemia effect on QT interval
prolonged
in hypokalemia
- prolonged QT interval
- T wave merges with the U wave
- u waves frequent
- T wave may be inverted
in mild hyperkalemia
- Tall T waves
2. Peaked & Symmetrical
in moderate hyperkalemia
- P &R waves flatten,
- QRS & T broaden,
- Big S waves develop
in severe hyperkalemia
- P & R waves gone,
2. S and T waves broaden in a “sine wave” pattern
abnormalities in the QT interval and the T wave due to drugs, abnormal electrolytes or other causes predispose to ____
arrhythmias usually though alterations in repokarization
There are ___ large boxes (heavy lines) between the R waves and ___ small boxes (thin lines) between the R waves.
6
30
T wave is inverted, a sign of ____
ischemia
ST elevation is a sign of ______.
transmural injury in an acute coronary syndrome, usually with a clot due to platelet aggregation obstructing a coronary artery.
Most commonly the injury is associated with an acute MI.
But, if the obstructed artery is quickly opened with angioplasty or a thrombolytic agent the ST elevation may partially or entirely reverse and much, or rarely all, injury avoided.
very small Q waves
- may not be pathological
2. But sizable Q wave is usually due to transmural necrosis.
sizable means
at least one small box wide (≥0.04 seconds).
When Q waves develop in leads which would normally be positive they give information on ___
localization of the infarct.
Infarcts usually involve only the
left ventricle.
Q waves in inferior leads (II,III, aVF) are due to_____.
inferior infarcts
Q waves in leads V1-V4 are due to _____.
anterior wall infarcts
Leads I, aVL and the anterolateral leads (V5,V6) are associated with ____
lateral wall infarcts.
a transmural acute MI typically:
evolves over time
acute MI early stage
- rarely seen
- lasts only a few minutes i
- giant, upright “hyperacute” T waves.
- T wave inverts (“ischemia”)
- ST segments then rise (“current of injury”).
In acute MI,____ are usually the last ECG findings to develop
Q waves
in acute MI, sometimes, the ST elevation ___
precedes or occurs simultaneously with the T inversion. .
When the QT interval is altered susceptibilities to __ increase.
arrhythmias
This is especially likely with QT prolongation.
commonly QT prolongation is acquired due to ____
electrolyte abnormalities or drugs.
Hypokalemia: common causes
- overuse of diuretics
- vomiting
- diarrhea
- Alkalosis
- potassium losing nephropathies
- excess aldosterone
