S4C35 - Cardiac Pacing

Question 1

Indications for emergency pacing

Answer 1

• symptomatic or hemodynamic unstable bradycarida/AV block
• severe SSS with prolonged asystole (>3s) + syncope
• ventricular standstill due to complete heart block or mobitz type II AV block
• torsades
• recurrent monomorphic ventricular tachycardia
• unstable SVT

Question 2

Transcutaneous Pacing

Answer 2

• capture usually 50-100mA
• then pace at ~1.25x the threshold of initial electrical capture
• synchronous pacing is safer, less chance of sending a signal at a vulnerable period

Question 3

Transvenous Pacing

Answer 3

• set-up for central line
• rate of 80-100beats/min
• use asynchronous mode initially if unstable brady
• complications: perforation of myocardium, cardiac arrhythmias, air embolism, failure of circuit, catheter dislodgement, delayed infxn

Question 4

How far should defib pads be placed from a permanent pacemaker?

Answer 4

10cm

Question 5

Pacemaker Complications

Answer 5

• pacemaker syndrome: occurs when ventricles are paced by atria continue to contract at their own rate so they contract against closed tricuspid/mitral valves resulting in raised jugular and pulmonary venous pressures and progression to CHF
• occurs if sinus node rate exceeds the rate of the PM
• pacemaker malfunction:
• problems with the pocket: check with CXR for lead placement
• problems with the leads
• failure to pace
• failure to sense
• malfunction causing overpacing or runaway pacing

-also order lytes, trops, ECG

Question 6

ICD - implantable cardioverter-defibrillator

Answer 6

• causes for ED visit is usually a pt presenting after being shocked
• approach: determine number of shocks administered, what the pt was doing at time of shock, prodromal symptoms or postshcok trauma, note changes in antiarrhythmic doses, check vital signs, cardiovascular status, generator picket, evidence of trauma
• place pt on monitor
• ST elevation/depression due exclusively to the shock should resolve w/in 15mins
• CXR - may show electrode migration, displacement, #
• do lytes
• can deactivate the ICD by placing a magnet over it

-admit if: unstable, >1 shock in 1 week, dysrhythmia with reversible cause, infxn, mechanical disruption

Question 7

ICD - causes of reversible shock

Answer 7

-false sensing (SVT with rapid ventricular response, muscular activity, extraneous source, sensing T waves as QRS complexes, component failure)