Cardiac rhythm monitors & equipment 2 Flashcards
The heart depolarizes from the
base–> apex and the endocardium to epicardium
The heart repolarizes from the
apex–> base and epicardium–> endocardium
Which leads monitor the septum?
V1 & V2
The mean electrical vector tends to point: (select 2)
a. towards areas of hypertrophy
b. towards areas of myocardial infarction
c. away from areas of myocardial infarction
d. away from areas of hypertrophy
a. towards areas of hypertrophy
c. away from areas of myocardial infarction
The easiest way to determine axis deviation is to examine
lead I & aVF
Normal axis shows lead 1 & aVF as
both positive
Left axis deviation shows lead 1 & aVF as
lead 1= +
lead aVF= -
Right axis deviation shows lead 1 & aVF as
lead 1= -
lead aVF= +
Extreme right axis deviation shows lead 1 & aVF as
both negative
Right axis deviation is typically caused by things that
affect the right heart
COPD
acute bronchospasm
cor pulmonale
pulmonary embolus
Left axis deviation is typically caused by things that
affect the left heart
chronic HTN
left bundle branch block
aortic stenosis
aortic insufficiency
mitral regurgitation
Normal axis is between
-30 and +90 degrees
Left axis deviation is more
negative than -30 degrees
Right axis deviation is more
positive than 90 degrees
All of the following are effective for the treatment of atrial fibrillation EXCEPT:
a. verapamil
b. digoxin
c. metoprolol
d. adenosine
d. adenosine
Sinus bradycardia is defined as
HR <60 bpm
Sinus bradycardia is usually due to
increased vagal tone
The first-line treatment for sinus bradycardia is
atropine
Other treatments of sinus bradycardia include
external pacing or glucagon (useful for beta-blocker or CCB overdose)
Sinus arrhythmia is usually the result of
SA node’s pacing rate varying with respiration
Sinus tachycardia is defined as
HR >100 bpm
Tachycardia reduces ___________ while increasing _________________
myocardial oxygen supply while increasing oxygen demand
Causes of sinus tachycardia includes
SNS stimulation
hypovolemia
hypoxemia
infection
pain
thyrotoxicosis
malignant hyperthermia
Treatment for sinus tachycardia includes
addressing the underlying cause and providing rate control with beta-blockers or calcium channel blockers
Atrial fibrillation is the result of
chaotic electrical activity in the atrium conducted to the ventricle at a varied and irregular rate
Atrial fibrillation results in _________________ which can reduce cardiac output in patients with poor ventricular compliance
loss of atrial kick
Acute onset a-fib is treted with
cardioversion (start at 100 joules)
If the onset of a-fib is >48 hours, then ___________ must be performed prior to cardioversion.
cardiac ultrasound such as TEE to rule out atrial thrombus
Atrial flutter is an
organized supraventricular rhythm characterized by a “saw tooth” pattern
Patients with atrial fibrillation are at risk for
atrial thrombus formation and stroke
Treatment for atrial flutter includes
rate control medications and cardioversion
Premature ventricular contractions originate from
foci below the AV node
A PVC that lands on the second half of the T wave (during the relative refractory period) can precipitate
the R on T phenomenon
Symptomatic PVCs can be treated with
lidocaine
Treatment for PVCs includes the
reversal of hypoxia/hypercarbia, correction of electrolyte imbalances, discontinuation of QT-prolonging drugs, and repositioning a central line that’s tickling the right atrium
The initial dose of glucagon to treat sinus bradycardia is __________- followed by__________
50-70 mcg/kg q3-5 min
followed by an infusion at 2-10 mg/hr.
____________ is the most common postoperative tachydysrhythmia usually occurring between post-op day 2 and 4.
atrial fibrillation
Junctional rhythm occurs when the
AV node functions as the dominant pacemaker
Junctional rhythm can be caused by
SA node depression (volatile anesthetics), SA node block, or prolonged conduction at the AV ode
Treatment for junctional rhythm includes
Atropine if hemodynamics are impacted by the slow rate
Development of PVCs can include many things including
SNS stimulation
myocardial ischemia and/or infarction
valvular heart disease
cardiomyopathy
prolonged QT interval
hypokalemia
hypomagnesemia
digitalis toxicity
caffeine
cocaine
alcohol
mechanical irritation (central line insertion)
PVCs should be treated when
they are frequent (>6/min), polymorphic, or when they occur in runs of 3 or more
The most common cause of sudden cardiac death is
ventricular fibrillation
Treatment for ventricular fibrillation is
CPR with defibrillation
Brugada syndrome is a
sodium ion channelopathy in the heart
Brugada syndrome is the most common cause of
sudden nocturnal death due to ventricular tachycardia or fibrillation
Diagnostic EKG findings of Brugada syndrome includes
a right bundle branch block and ST-segment elevation in the precordial leads (V1-V3)
Patients with brugada syndrome may require
ICD or pad placement during surgery
During sinus arrhythmia, heart rate increases during:
inhalation–> decreased intrathoracic pressure–> increased venous return–> increased heart rate
What reflex may initiate sinus arrhythmia?
Bainbridge reflex
