Cardiac Arryhythmias Flashcards
Cardiac Arrhythmias
They are deviations from normal cardiac rate and rhythm
causes of cardiac arrhythmias
damage to the heart’s conduction system or systemic causes such as electrolyte imbalance
fever, hypoxia, stress, infection or drug toxicity
_____________ reduce the efficiency of the heart’s pumping cycle
Dysrhythmias
Bradycardia
refers to a regular but slow heart rate (less than 60 beats/min). It often results from parasympathetic stimulation
Tachycardia
is a regular rapid heart rate (greater than 100-160 beats/min). This may be a normal response to sympathetic stimulation
Sick sinus syndrome
is a heart condition marked by alternating bradycardia and tachycardia, often requiring a mechanical pacemaker
____________________ are the most common dysrrhythmias
• Atrial conduction abnormalities
__________________________ are extra contractions of the atria
• Premature atrial contractions/beats (PAC/PAB)
cause of Premature atrial contractions/beats (PAC/PAB)
PACs occur when another region of the atria depolarizes before the sinoatrial node and thus triggers a premature heartbeat
Atrial Flutter
refers to atrial rate of 160-350 beats/min (less filling time so less output)
• Atrial Fibrillation
is a rate over 350 beats/min
____________ causes pooling of blood in the atria and is treated with anticoagulant medications to prevent clotting and stroke (no filling)
• Fibrillation
What causes heart blocks
• Atrioventricular node abnormalities cause heart blocks
AV conduction is prolonged.
There is a slight delay in getting the electrical signal from SA to AV node, but heart functions normally
It is recognized on the electrocardiogram by a prolonged P-R interval.
First degree heart block
First degree heart block
• A heart block in which the conduction of impulses through the atrioventricular node is delayed but all atrial beats are followed by ventricular beats.
Second degree heart block (Mobitz type I)
the PR intervals become progressively longer until a QRS complex is dropped every 2nd or 3rd or 4th beat
treatment for second degree heart block
Treatment is a cardiac pacemaker implantation
ventricular rhythm is irregular
Atrial rhythm is regular
Second degree AV block
Third Degree Heart Block
no impulse sent from the atria to the ventricles
The ventricles spontaneously contracts independent of the atria contraction (which is normal)
Third Degree Heart Block
Bundle branch block
interference with conduction in one of the bundle branches (right or left)
How does a Bundle branch block appear on the ECG
wide QRS wave
Ventricular tachycardia
a fast heart rhythm (greater than 100 beats/min), that originates in one of the ventricles of the heart
Ventricular fibrillation
muscle fibers contract independently and rapidly (uncoordinated quivering) and therefore are ineffective in ejecting blood