What to do for Inappropriate AICD Firing

Dr. Grock presents today’s Morning Report!

The Case:

65 M h/o HTN, CHF w/ EF 25% with AICD presents s/p 3 shocks. Appears well. ECG: LBBB unchanged without any other scariness.

What do you do? (IV/O2,Cards for device interrogation, Check lytes (ca, k, mag), (cbc?/Trop?))

Cards interrogates: three runs of v tach.

An Aside on Magnets with AICD/PM
Magnets inhibit sensing of AICD and pacemaker.

A PM is designed to sense for a heart beat; and if it doesn’t sense one within a programmed time frame, it will pace the patient. If you turn off sensing what will happen? (The pacemaker will pace)
An AICD is programmed to detect tachycardia above a certain rate. If you put a magnet over it to turn of the sensing what happens? (It won’t defibrillate)

Diagnosis:
Electrical storm/arrhythmic storm/V Tach storm

Definition: 3 or more appropriate shocks in 24 hours.
Pathophys: severe underlying structural heart disease. Most inciting factor never discovered. Could be drug tox, lytes, MI, chf decompensation, prolonged qtc, brugada
Stats: 10-20% of patients with AICD. Associated with high mortality (7.4x risk of death)

Management:

If unstable: cardiovert electrically
If stable: amio (150 mg push then 60mg/hr for 6 hours) + beta blockers +/- Propofol for sedation/intubation.
Per uptodate: metoprolol (PO or IV – 2.5-5 mg over 5 minutes, repeat prn to 15mg in 15 min)
Per other review: propanolol

Treatment in special cases: Quinidine for brugada, PCI if related to ischemia

If above unsuccessful: ep study for ablation (meta analysis of 472 pts show decreased recurrence rate and low procedural mortality, other studies show that it is less likely helpful in polymorphic VT and VF), lvad/intra-aortic balloon pump, ecmo, cardiac transplant, cardiac sympathetic denervation, renal artery denervation (4 pts), re-programming aicd (anti-tachycardia pacing, only shocking after longer periods of VT).

References

Uptodate (http://www.uptodate.com/contents/electrical-storm-and-incessant-ventricular-tachycardia?source=search_result&search=electrical+storm&selectedTitle=1~19)

Principles of Critical Care, 3^rd edition

Hurst’s The Heart, 13^th edition

Pourdjabbar A, Maze R, Hibbert B, Ruel M, Haddad H. Left ventricular assist device in the management of refractory electrical storm. Perfusion. 2014 Aug 8. pii: 0267659114546033.

Eifling M, Razavi M, Massumi A. The evaluation and management of electrical storm. Tex Heart Inst J. 2011;38(2):111-21.

DeSouza I., Martindale, J. Managing Pacemaker-Related Complications and Malfunctions in the Emergency Department. EBMedicine.net. Sept 2014, Vol 16, N. 9.