Meds/Management/Interventions Flashcards
A-fib
Control ventricular rate via blocking AV node to increase filling time and CO
Convert A-fib or A-flutter to NSR
BBs/CCBAs/digoxin ==> rate control
Amiodarone ==> NSR
Ventricular arrhythmias
Treat underlying conditions
Prevent V-fib
PVCs - reduce vs. risk of premature death
BBs/amiodarone/flecanide/quinidine/procainamide
Pacemaker indications
Slow HR Absent HR: Sick sinus syndrome (SA node not firing well) Symptomatic bradycardia Tachy-brady syndrome A-fib c slow ventricular response 3rd degree heart block Chronotropic incompetence Paroxysmal A-fib (comes and goes c NSR)
Areas of insertion for PM
Subclavian v. Axillary v. Cephalic v. RA RV
External PM use
Short-term or in emergencies
Temporary use after cardiac surgery - implanted during surgery and usually out s/p day 1
Endocardial PM
Can be used in children
How does a PM work?
Electrical stimulation of myocardium to depolarize it
Can you tell if someone has a PM by their telemetry strip?
Yes - it appears as a vertical line - vertical deflection before the complex it is trying to pace
If the PM is pacing the atria…
The black line appears before the P wave
If the PM is pacing a ventricle…
The black line appears before the QRS complex
Types of PMs
Fixed rate
Demand - sense depolarization and normal electrical activity (can change c activity) - if depolarization is absent or delayed, it fires at a present rate
Single chamber PM…
Paces either the ventricles or atria
Dual chamber PM…
Paces both the atria and the ventricles
AV synchronous chamber PM…
Paces the atria and ventricles simultaneously and restores normal timing
How are PMs classified?
According to:
Chambers paced
Chambers sensed
Response to sensed impulse
1st letter PM code…
PACED chamber (A; V; D - both)
2nd letter PM code…
SENSED chamber (A; V; D - both) *senses intrinsic electrical activity*
3rd letter PM code…
RESPONSE TO SENSED SIGNAL
I - inhibited by activity (PM withholds or inhibits response - doesn’t give a pace - if electrical activity sensed)
T - triggered by activity
D - dual - inhibited or triggered
4th letter PM code…
PROGRAMMABILITY
P - simple programmability
M - multi-programmable (rate, sensing, output, refractory period)
C - communicating (telemetry)
R - rate response (can respond to physical activity, but doesn’t tell which type of sensory - RR vs. activity sensor)
5th letter PM code…
ANTI-TACHYCARDIA FEATURES
O - no anti-tachy arrhythmia function
P - can pace the Pt. Out of tachy episode
Which type of PM can be used c A-fib?
VVI
V - paces ventricles
V - senses ventricles
I - inhibited by sensed ventricular depolarization (PM will not pace if ventricle is depolarizing)
PM ex: DDI
Paces both A/V
Senses both A/V
Inhibits PM output if normal electrical activity occurring in either/both chambers
PM ex: AAT
Paces atria
Senses atria
Each sensed event triggers the pacer to fire within the P wave
How does a VVI PM work c A-fib?
It tries to maximize communication between A/Vs
It waits for the ventricle to contract
Telemetry: PM spike, then QRS (wide) bc pacing ventricles and bc impulse from PM, not AV node
there is not great synchrony between A/Vs
PM ex: DDD
Optimal, fully automatic, universal, physiologic
Both chambers paced and sensed
Sensed atrial signal causes PM to INHIBIT atrial output - timer starts that causes a triggered ventricular output after certain interval
If QRS occurs naturally, PM inhibits ventricular output
Intrinsic P wave and intrinsic QRS can inhibit pacing
Intrinsic P wave can trigger a paced QRS
Which type of PM is the most common?
DDD
Rate modulation - PM 4th code
Physiologically-based (minute ventilation - increases c activity ==> RR x TV)
requires a longer warm-up bc there is a slight delay to activity - need to extend warm-up and cool-down c exercise
If there are no depolarization complexes on ECG c PM…
The PM fires normally but fails to capture
PM failure to sense
Fails to sense underlying rhythm and fires in complete disregard for Pt.’s own rhythm - may compete c heart for control
PM under- or over-sensing
PM can over-sense by misinterpreting muscle movement as depolarization
Sx when PM isn’t meeting demands (CO sx if not keeping up c activity)…
SOB Syncope Angina CHF sx (if decreased ventricular contraction) Fatigue Vertigo Confusion Dizziness
If PM used for tachy-dysrhythmia, NOTE CUT-OFF RATE…
10 beats BELOW cut-off rate is MAX HR IN KARVONEN - otherwise PM will fire when not necessary
If PM ATRIAL RATE IS FIXED, ventricular rate is affected
BLUNTED HR response to exercise ==> need prolonged warm-up/cool-down
PM PT considerations
No lifting x 6 wks. (Fibrosis needs to occur over PM)
No overhead exercise until MD clears
Avoid contact sports (low-intensity competitive sports allowed if approved by MD)
ICD (implantable cardiac defibrillator)
Monitors heart RHYTHM (PM ==> RATE) ==> prevents SCD
Delivers electrical shock if dangerous rhythm detected:
V-tach
V-fib
ICD considered for…
Previous cardiac arrest (V-tach or V-fib)
I controlled dysrhythmia c meds
Cardiomyopathy c dysrhythmia (or at risk)
CAD, low LVEF, and episode of V-tach
Digoxin toxicity can cause which types of heart problems?
Sinus dysrhythmia A-fib Junctional rhythm 2nd degree AV block, Type II (Mobitz II) 3rd degree (complete) heart block V-tach V-fib
Intervention for symptomatic sinus bradycardia
PM
Atropine (need adequate resting CO)
Intervention for A-flutter
BBs
Cardioversion to reset electrical system
Controlled A-fib
HR < 100 (V rate) ==> little impact on CO
Uncontrolled A-fib
HR > 100 (V rate) ==> impacts CO - MONITOR VITALS
Interventions for A-fib
Antiarrhyhmic meds
Cardioversion
Interventions for junctional rhythm
Atropine to increase HR
PM
Interventions for 3rd degree (complete) heart block
Permanent PM
Atropine
Interventions for V-tach
Cardioversion; defibrillation
Meds to normalize rhythm
Interventions for V-fib
Defibrillation
CPR
O2
Cardiac meds
