ECG abnormalitys Flashcards
What are the causes of bradycardia
The conduction blocks
Reduced autonomality
What is reduced autonomality
Low metabolic rate (hypothermia or hypothyroidism)
The endurance runners
The increased vagal tone - parasympathetic (so the vasodilation)
What are the forms of conduction (heart) blocks
1st:the elongation of the PR interval
2nd: mobitz 1 - the elongation of the PR interval each beat, this would happenuntil there would be no QRS
Mobitz 2 - no elongated PR but would just have the loss of the QRS
3rd: the beats of the ventricles and the atria would not match,they would each be conducting a different rhythm
How do you measure a normal heart rate
300/n
N being the number of boxes between the next beat
How do you measure a irregular heart rate
The number of beats in the 10s time frame (either the p or the r waves)
Then X6
What is the length and the height of a big box in the ECG
Length: 0.25 seconds
Height: 0.5 volts
What are the reasons for tachycardia
Increased autonomality
Triggered activity
Re-entered currents
What is the cause of the increased autonomality
Sympathetic overstimulation
High metabolic rate
Anxiety or stress
What is the re-entered currents
When would have the scar tissue within the atria, this would be able to conduct some of the impulse
The impulse would then be carried here and would go round in a Circle, so would have the increased stimulation
What is involved in the triggered activity
The EAD (early after depolarisation)
The DAD (delayed after depolarisation)
What is E.A.D
Current would continue from the phase 2 and 3
When the Na+ channels would not be ready
Ventricles would not contact properly
Normally caused by Drugs
What is D.A.D
Would occur at phase 4 of depolarisation
Ca+ channels would not be ready
Ventricles would not pump well
Normally caused by the ischemia
How many small boxes should a P wave be
3 small boxes
How many boxes would the PR interval be
3-5 small boxes
What should the QRS complex look like
Should be upright
Less the 3 small boxes
What should the T-wave look like
Upright and not inverted
Should be half the size of the QRS complex
What does the QT segment look like and what does it show
Should be 9-11 boxes
Would show the depolarisation and repolarisation
What should the ST segment look like
Should be a straight line
What is atrial fibrillation
The irregularly irregular rhythms
Would have the many P waves
Would look like f-waves
What is the main issue with the atrial fibrillation
The formation of the clot in the heart from the pooling of the blood
This would then lead to thrombosis and the scar tissue forming
Clots can form in the brain
What is an eptoic heart beat
Would have the large ventricle beat and depolarisation
So would have the large repolarisation
Would feel as if miss a beat
What is is monomorphic ventricular tachycardia
The QRS complexes would be wide and slow
Would lose the other waves
What is polymorphic ventricle tachycardia
The messed up ventricle contractions
Would not be pumping enough blood
AKA tosades depointes
What would happen in ventricular tachycardia
Would have the heart failure
The ventricles would not be pumping blood out the body
What would happen to the heart rate with the VTs
Low
Still not pumping enough blood out the heart, so the HR can’t increase
What causes the myocardial infarction
The plaques in the coronary artery’s
Would go to the heart and could lead to the damage
Would stop oxygen from getting to a certain area
So would have the necrosis and the infarct form
What is the subendocardial infarction
When would have plaque effect the ventricles tissue
LEADS TO AN INVERTED T WAVE AND ST DEPRESSION
What is a trans mural infarction
When have the whole area effected
THE ST ELEVATION OCCURS and missing T wave
HAVE THE T WAVE INVERSION WHEN HAVE THE INTERVENTION AND REPERFUSION OF THE BLOOD
What does hypokalemia do to the ECG
The depression of the ST interval
small or absent T waves
Slow depolarisation and repolarisation
What does hyperkalemia do to the ECG
The t wave peak, flat P wave, PR prolonged
Quick repolarisation
The depolarisation would take a long time so would have this area prolonged (due to the inactive Na+ channels)
What does myocardial ischaemia normally come with
The hyperkalemia
The graph for them would therefor be similar
What can hypokalemia deteriorate to
The polymorphic ventricle tachycardia (torsades de pointes)
Ventricular tachycardia
Ventricular fibrillation
Why would diabetics get hyperkalemia
Insulin activates the Na+/k+ pump
This would then allow K+ to move into the cells
If not would have the high extracellular K+ levels
