Defibrillation, Synchronized Cardioversion and Automatic Internal Cardiac Defibrillators

• creates the energy needed to pass through skin, lungs and tissue 
• you will transmit the energy through the chest wall
• Single shocks need higher voltage 
• Repeated shocks can use lower voltage
• Myocardial cells rupture (elevated Troponin levels) with each shock and with higher voltage (Newer defibrillators are preset to lower voltage levels by giving multiple discharges/shock)

• Biphasic energy passes through both directions. This lowers the transthoracic resistance
• require less energy to be used, salvage myocardial cells and convert rhythms at lower doses of joules

• Vtac--> defib will depolarize all cells at once and hopefully fastest (SA) node will take over. 
• V-Fib. This would be a good one too. 
• *Neither one is producing any cardiac output.

• Dispenses shock when cells capable of transmission of current during ventricular repolarization 
• Can use lower doses/voltage
• Can be elective or emergent
• Can use for atrial fibrillation/flutter (elective), or stable VT (has pulse and awake)
• *need to have an R wave.

• NPO 
• Anticoagulate- may be thrombogenic
• Informed Consent
• IV access/ sedation if awake
• Monitor HR, BP, RR. remove oxygen just prior to cardioversion
• Known K+, Mg+ lab values

• Paddles require at least 25 # of pressure
• Pads must seal to the chest (if not, shock can arch to NC and burn nose), AP (Anterior/Posterior) placement preferred to just anterior pad placement
• Call “Stand Clear” prior to shock
• Repeat assessment and VS after procedure
• Use ACLS trained professionals

• Used for sudden death due to heart attach (as opposed to trauma). (spontaneous ventricular tachycardia)
• ? Used for pacing
• ? Used for re-synchronization in Heart failure (4 chamber pacing) 
• Can be reprogrammed via phone call. Freaky.

• Senses fast rhythms by...
• ? Measures QRS width for wide tachycardia
• ? Monitors for high voltage (VT is usually very tall in amplitude)
• ? watches for sustained rhythm (not salvos or NSVT)
• ?  charges the defib with low voltage
• ?  Discharges the defib

• Monophasic Defibrillation: 200, 300, 360
• ? Biphasic Defibrillation: 120, 200, 240
• ? Synchronized cardioversion: 50, 120, 150
• ? AICD: 15 for six attempts then 25

• Do not defibrillate over pacer
• ? Patient will feel shock
• ? Others may/may not feel shock
• ? Rhythms can be downloaded and examined
• ? Frequent shocks require further medical work up and rhythm suppression
• ? Prevent SVT at rates >150- they may be shocked because sometimes the PM cannot tell the difference.

• What might you include in discharge instructions?
• ?  Can a patient die with an AICD? Of course. They are not immortal. 
• ?  What about airport metal detectors? microwave ovens? Metal detectors will be activated. Microwaves shouldn't be a problem, unless they're in one. 
• ?  Will they pass out with an activated AICD? No. The V-tac causes pt to pass out.
• ?  Are the patients electrically sensitive? No.

Will stimulate "pace making" (usually in the ventricle) cells of heart in the absence of heart cell conductivity in the vicinity of the pacemaker electrode.

• PM is silent on auscultation.

• If electrode goes bad, it stays in place and another is simply inserted somewhere else.

• Capture: heart tissue picks up pacer electrical activity and carries it
• Sense: Pacer Maker detects heart's own rhythm and does not fire.

• Look for capture
• Want it "scarred in." 
• ECG complex will never look normal