Definition
• PM: Intracardiac device used for significant AV block &/or sinus node dysfxn
• AICD: Intracardiac device for the termination of VF/VT, & prevention of sudden cardiac death → for pts s/p VF/unstable VT arrest, persistent EF ≤30–35%, Brugada, or long QT syndrome (Circulation2007;115:1170; NEJM1997;337:1576)
• Biventricular pacing (cardiac resynchronization therapy): RA, RV, & coronary sinus leads → synchronize RV & LV function → ↓ CHF sxs & hospitalization, ↑ survival (NEJM 2004;350:2140; NEJM2005;352:1539)
Approach
• Obtain an ECG & rhythm strip immediately
• Obtain the make & model of the device (most pts have a card, o/w obtain AP CXR → magnify device to obtain model number → internet search for type)
• Common PM codes: DDD (dual chamber paced, sensed, & response to sensed beat) & VVI (dual chamber paced, sensed, & inhibitory response to sensed beat)
Evaluation
• Magnet placed over device
• PM: Inhibits sensing, paces at fixed rate regardless of intrinsic cardiac activity
• AICD: Inhibits further firing, though not bradycardic pacing
History
• Lightheadedness, palpitations, syncope
Findings
• ↑, ↓, &/or irregular HR, ↓ BP
Evaluation
• ECG, CXR (to visualize device & leads)
Treatment
• Transcutaneous pacing: For unstable pt
• MAGNET: FOR PM-mediated tachycardia: Magnet over the PM → paces @ 80 bpm OR OVERSENSING
Disposition
• Consult EP or device rep. for interrogation & reprogramming; to cath lab for lead/battery replacement
History
• AICD firing: Sudden jolt of pain
• Premonitory sxs: Palpitations, LH, dyspnea, CP
• Precipitants: Exercise, illness, noncompliance w/ antiarrhythmics, new meds
Evaluation
• ECG (ischemia, ↑ QT), CBC, Chem 7, cardiac markers, CXR
Treatment
• Treat 1°-illness, follow ACLS protocol for arrhythmia
Disposition
• Consult EP or device rep. for interrogation & reprogramming
• No firing (nl interrogation despite sxs): Look for other cause of sxs → d/c home
• Inappropriate firing (based on interrogation): Treat underlying condition; reprogram if necessary
• Appropriate firing (based on interrogation): Admit to Tele unit or CCU
• Look for precipitants: VT, abnl electrolytes, ↑ QT, ischemia, medication noncompliance or abuse
Pearl
• If make/model # of device unknown, magnification of PA CXR will reveal device-sp code in small print