Implantable Devices Flashcards
signs of SA node dysfunction
sinus bradycardia <60 bpm
sinus arrest
PSVT - atrial fibrillation/flutter
pacemaker types
temporary or permanent
both have implanted pulse generator and lead wire leading into the heart with an electrode
temporary pacemaker types
transcutaneous: electrodes on chest wall, painful
transatrial: electrodes on atria, uncommon
transvenous: electrodes on ventricle from the femoral artery pathway
indications for temporary pacemaker
acute MI
post cardiac surgery
drug toxicity
bridge to permanent pacemaker
permanent pacemaker indications
SA node dysfunction
2nd degree AV block, bradycardia
3rd degree AV block w bradycardia, CHF, atrial fibrillation/flutter, asystole periods
acute anterior MI w AV block
severe bundle branch blocks
conditions warranting a pacemaker
syncope
dizziness
CHF
mental confusion
palpatations
dyspnea
exercise intolerance
heart chamber pacing: atrial
electrode in R atrium, increase atrial contribution to ventricular filling, increase CO by stimulating SA/AV node
heart chamber pacing: ventricular
electrode placed in R ventricle
increased ventricular rate when there is a heart block/bradycardia
heart chamber pacing: dual chamber
electrodes in both R atrium and ventricle
maintain timing between the two chambers to increase CO
Modes of pacing
pacemaker
fixed: preset firing rate
demand: fires only when HR falls below certain rate
rate-responsive: fires depending on pt activity level, increases pace with increased CO
mechanisms of demand pacemakers
sensing mechanism: determine intrinsic rate and whether it’s adequate
pacing mechanism: triggered when no intrinsic complex occurs in set time
ICD indications
implantable cardioverter defibrillator
for life threatening arrhythmias
ICD mechanism
shocks heart to cardiovert when fatal arrhythmia detected
quick and painful, can cause pt to collapse
CRT - cardiac resynchronization device used to pace both ventricles at once
PT implications for pacemakers/ICDs
do not pull out leads/disconnect
don’t tension wires when transferring
patient education to: avoid electrical devices with magnetic field
post op instructions: bedrest, L arm sling 24 hrs, L UE avoid shoulder flexion/abduction, no lifting > 5 lbs, no driving until pacemaker cleared to be working
Holter monitor
portable device to continuously monitor heart electrical activity 24+ hours
observe occasional cardiac arrhythmias
LVAD mechanism
L ventricular assist device
mechanical pump assuming function of damaged ventricle to restore CO
for pts with advanced heart failure
LVAD types
pulsatile: noisy
Axial: continuous flow, modern, quiet
VAD indications
bridge to transplant: heart transplant candidate
destination therapy: long term, perm implant for class 3-4 HF
5-10 years survival
criteria for VAD implant
2 hospital admissions
not improving on medications
hyponatremia
hypovolemic
ionotrope dependent (meds)
EF < 35%
VAD functions
restore CO, BP
reduce L ventricle work, avoid more damage
reduce pulmonary pressure
improve body perfusion
+++ pump flow
normal for larger pts due to larger CO
could also indicate clot formation in pump
— pump flow
normal for smaller pts
or pt is hypovolemic and needs fluid bolus
vitals for VAD pts
may not have pulse due to pump
get MAP w doppler, HR w telemetry
O2 sats hard to get
impella
mechanical circulatory assist device
endovascular
mini VAD pumps blood from L ventricle to aorta
indications for impella
pts w MI and cardiogenic shock needing support
complicated PTCA
severe uncompensated HF
myocarditis
rest needed for ventricle to reduce O2 demand
off pump CABG
approved for used 6hrs-14 days+~
PT precautions after VAD placement
arousal level
anticoagulants
vasopressors/ionotropes
O2 support
arrhythmias
pulmonary a. cath
arterial lines
CVP line
chest tube
sternal precautinos
balloon pump removal
EKG picks up native heart contraction
contraindications to PT after VAD
VAD malfunction
intra aortic balloon pump
open chest
active bleeding
hemodynamic instability like BP fluctuation
full ventilator support
symptoms appear: angina, EKG changes, dyspnea 5+, O2 sats drop, systolic BP drop
PT goals after VAD
function
strict! sternal precautions
pulmonary care
reduce kyphotic posture
abdominal binder
pt education on battery life
heart rate blunted by beta blockers
RPE11-13
