STEPUP Cardiovascular System: Bradyarrhythmias Flashcards
What is the sinus rate for bradycardia? When is this clinically significant?
1) Sinus rate < 60bpm
2) Clinically significant when rate is persistently < 45bpm
What are causes of sinus bradycardia?
1) Ischemia
2) Increased vagal tone
3) Antiarrhythmic drugs
4) May be a normal finding in trained athletes
Is sinus bradycardia symptomatic? What are some common symptoms?
1) Yes, but can be asymptomatic
2) Patients may complain of fatigue, inability to exercise, angina, or syncope
What can be used to elevate the sinus rate by blocking vagal stimulation to the sinoatrial node? What else may be required if bradycardia persists?
1) Atropine
2) A cardiac pacemaker
What is sick sinus syndrome? What age are patients, usually? What are symptoms? What may be required?
1) Sinus node dysfunction characterized by a persistent spontaneous sinus bradycardia
2) Patients usually elderly
3) Symptoms include dizziness, confusion, syncope, fatigue, and CHF
4) Pacemaker implantation may be required
What is first degree AV block? Does a QRS complex follows each P wave? Where is the delay usually? Does it require treatment?
1) PR interval is prolonged (>0.20 seconds)
2) Yes
3) Delay is usually in the AV node
4) Benign condition that does not require treatment
What is second-degree AV block Mobitz type I (wenckebach)? Where is the site of block? Does it require treatment?
1) Characterized by progressive prolongation of PR interval until a P wave fails to conduct
2) Site of block is usually within AV node
3) Benign condition that does not require treatment
What is a second-degree AV block Mobitz type II? What does it often progress to? Where is the site of the block? What is absolutely necessary for treatment?
1) P wave fails to conduct suddenly, without a preceding PR interval prolongation; therefore, the QRS drops suddenly
2) Often progresses to complete heart block
3) Site of block is within the His-Purkinje system
4) Pacemaker implantation is necessary
What is third-degree (complete) AV block? What is the ventricular rate? What is AV block characterized by? What is absolutely necessary for treatment?
1) Absence of conduction of atrial impulses to the ventricles; no correspondence between P wave and QRS complexes
2) A ventricular pacemaker (escape rhythm) maintains a ventricular rate of 25 to 40 bpm
a) Characterized by AV dissociation
b) Pacemaker implantation is necessary
What two types of heart block require pacemaker implantation?
1) Second-degree Mobitz type II
2) Third-degree AV blocks
What is a cardiac pacemaker? What are three types?
1) Device that delivers direct electrical stimulation to the heart when the heart’s natural pacemaker is unable to do so
2) a) Permanent implantable system for long-term treatment
b) Temporary systems - either transcutaneous (with electrode pads over chest) or transvenous - both use an external pulse generator that patient can secure to waist with straps
On ECG, what is cardiac pacing noted by?
The presence of a “spike”
What are 4 indications for a cardiac pacemaker implantation?
1) Sinus node dysfunction is most common indication
2) Symptomatic heart block - Mobitz II second-degree block and complete heart block (even if asymptomatic)
3) Symptomatic bradyarrhythmias
4) Tachyarrhythmias to interrupt rapid rhythm disturbances
