ch 26 caring for clients with cardiac dysrhythmias

Normal Sinus Rhythm
• Heart rate is between 60 and 100 beats/minute.
• SA node initiates the impulse.
• Impulse travels to the AV node in 0.12 to 0.2 second.
• Ventricles depolarize in 0.12 second or less.
• Impulse occurs regularly.
– Atrial dysrhythmias originating in the sinus node:
sinus bradycardia, sinus tachycardia
– Atrial dysrhythmias developing in sites outside the
sinus node: premature atrial contractions,
supraventricular tachycardia, atrial flutter, atrial
• most common cause of dysrhythimas is ischemic heart disease
• cardiac dysrhythmias can originate in the atria, atrioventricule node (AV), or ventricles

pharmacologic considerations
– a dose of 0.5-1.0 mg of atripine sulfate may be given every 1-2 hours to increase the HR
– max of 2.0 mg is given IV
– isoproterenol (isuprel), a beta adrenergic blocker,vis also used to treat severe bradycardiac
– when either drug is administered, closely monitor the pulse rate for drug response

Cardiac Dysrhythmias: Atrial:
Sinus Bradycardia
Sinus Bradycardia
• Dysrhythmia that proceeds normally through the
conduction pathway but at a slower than usual rate
(?60 beats/minute)
– Causes: healthy athletes, heart disorders,
increased intracranial pressure, hypothyroidism,
digitalis toxicity; danger is that the slow rate may
be insufficient to maintain cardiac output
– Medical Management
• Atropine sulfate: a cholinergic blocking agent is
given IV to increase a dangerously slow HR