Implantable cardioverter-defibrillator complication - Revision history

Danbot: Danbot moved page Implantable Cardioverter-Defibrillator complication to Implantable cardioverter-defibrillator complication without leaving a redirect: Naming convention: first word capitalized, subsequent words lowercase

2026-03-22T05:31:33Z

Danbot moved page Implantable Cardioverter-Defibrillator complication to Implantable cardioverter-defibrillator complication without leaving a redirect: Naming convention: first word capitalized, subsequent words lowercase

← Older revision	Revision as of 05:31, 22 March 2026
(No difference)

Blsimpso: /* External Links */

2021-07-02T01:37:24Z

External Links

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	==External Links==		==External Links==
			*[http://www.emdocs.net/ecg-pointers-icds-and-when-they-malfunction/ ECG Pointers: ICDs and when they malfunction]

	==References==		==References==

Bobbycarey: /* Disposition */

2021-03-10T01:32:42Z

Disposition

← Older revision		Revision as of 01:32, 10 March 2021
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	==Disposition==		==Disposition==
	*Consider discharge if:		*Consider discharge if:
	**~~Single shock only~~		**Proven Phantom Shock
	**~~Currently asymptomatic~~		**Resolved Pacemaker Mediated Tachycardia
	**No concerning associated symptoms (e.g. chest pain, dyspnea, syncope)		**Single shock only AND Currently asymptomatic AND No concerning associated symptoms (e.g. chest pain, dyspnea, syncope)
			***Ensure patient has Electrophysiology/Cardiology follow-up
			***Consider Electrophysiology/Cardiology consult
	*Admit all others		*Admit all others

Bobbycarey: /* Management */

2021-03-10T01:28:46Z

Management

← Older revision		Revision as of 01:28, 10 March 2021
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	==Management==		==Management==
			*Reported Shock
			**If unable to prove a phantom shock, electrophysiology or cardiology consult is often needed
			**Interrogation is mandatory, either by an experienced clinician or by device representative
			***Some devices can be remotely interrogated; contact the respective company representative at the above phone numbers to discuss this possibility

			*Repeated Shocks
			**Before placement of a magnet or changing the device parameters, you must determine if the shocks are appropriate (i.e. the patient is in VT storm or having recurrent episodes of VF) or inappropriate
			***If it is determined that the shocks are inappropriate, a magnet will deactivate the shocking function while placed over the device
			**Electrophysiology consult

			*Pacemaker Mediated Tachycardia
			**Break with [[adenosine]] - magnet will not fix PMT in a patient with a defibrillator

	==Disposition==		==Disposition==

Bobbycarey: /* Evaluation */

2021-03-10T01:17:01Z

Evaluation

← Older revision		Revision as of 01:17, 10 March 2021
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	==Evaluation==		==Evaluation==
			===Work-Up===
			*BMP and Mg
			*[[CXR]]
			*[[ECG]]
			*[[Troponin]]
			*Interrogation
			**Each company has on-call representatives who will come interrogate a device 24/7 (phone numbers above)
			**Most cath labs will have machines capable of interrogating each brand

			===Expected ECG Patterns===
			*Absence of pacer artifact indicates intrinsic depolarization
			**With newer pacemakers, pacer spikes may not appear on some or all paced beats, depending on EKG machine
			*Pacing artifacts preceding depolarizations indicate successful pacing and capture
			*Leads in RV apex produce LBBB pattern with appropriate discordance
			*New RBBB pattern may indicate lead in LV
			* Bi-ventricular devices can produce paced QRS complexes that are either narrow or wide and bizarre, depending on device programming
			*Simultaneous depolarization of ventricles produces dominant R wave in V1

			===Plain Film Findings===
			*Obtain PA/Lateral Films to confirm pulse generator, manufacturer, lead placement/number/integrity
			*R atrial lead J shaped(tip medially on AP) entering right atrial appendage
			*RV leads point downward with tip between left spine and cardiac apex--lateral XR shows inferior and anterior
			*Coronary sinus lead- courses posteriorly on lateral XR
			*Extra leads may be appropriately abandoned and capped
			*ICD component appears as thickened shock coil

	==Management==		==Management==

Bobbycarey: /* Differential Diagnosis */

2021-03-10T01:16:00Z

Differential Diagnosis

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	**Most commonly: paced ventricular beat -> retrograde AV node conduction -> intrinsic P wave -> device reacts to intrinsic P wave by looking for intrinsic QRS, but since AV node is now refractory it delivers a paced beat at the programmed P-R interval (typically ~200-250ms), starting the process anew		**Most commonly: paced ventricular beat -> retrograde AV node conduction -> intrinsic P wave -> device reacts to intrinsic P wave by looking for intrinsic QRS, but since AV node is now refractory it delivers a paced beat at the programmed P-R interval (typically ~200-250ms), starting the process anew
	*Tachycardia does not exceed programmed upper limit rate on pacemaker		*Tachycardia does not exceed programmed upper limit rate on pacemaker

	~~==Differential Diagnosis==~~


	==Evaluation==		==Evaluation==

Bobbycarey: /* Shocks (i.e. Defibrillation) */

2021-03-10T01:13:56Z

Shocks (i.e. Defibrillation)

@@ Line 73: / Line 73: @@
 **Unipolar Cautery - can cause sensing and pacing malfunction as well as reprogramming
-==Shocks (i.e. Defibrillation)==
+==Complications==
 *Approximately 1/3 - 1/2 of ICD patients receive a shock within one year of placement<ref>Sears SF Jr., Shea JB, Conti JB. Cardiology patient page. How to respond to an implantable cardioverter-defibrillator shock. Circulation. 2005;111:e380–e382</ref>
 **Generally described by patients as a powerful "kick to the chest"
@@ Line 90: / Line 91: @@
 **More common in patients who have never had an actual shock
 **Occurs in 9% of patients each year<ref>Berg SK et al. Phantom shocks in patients with implantable cardioverter defibrillator: results from a randomized rehabilitation trial (COPE-ICD). Europace. 2013 Oct;15(10):1463-7. Epub 2013 Apr 18.</ref>
 ==Differential Diagnosis==

Bobbycarey: /* Clinical Features */

2021-03-10T01:09:57Z

Clinical Features

@@ Line 73: / Line 73: @@
 **Unipolar Cautery - can cause sensing and pacing malfunction as well as reprogramming
-==Clinical Features==
+==Shocks (i.e. Defibrillation)==
 ==Differential Diagnosis==

Bobbycarey: /* Functions */

2021-03-10T00:53:37Z

Functions

← Older revision		Revision as of 00:53, 10 March 2021
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	*Defibrillation		*Defibrillation
	**Delivery of a large electrical shock (up to 42 joules) from one electrode to the other in response to VT or VF		**Delivery of a large electrical shock (up to 42 joules) from one electrode to the other in response to VT or VF
	**Approximately 1/3 - 1/2 of ICD patients receive a shock within one year of placement<ref>Sears SF Jr., Shea JB, Conti JB. Cardiology patient page. How to respond to an implantable cardioverter-defibrillator shock. Circulation. 2005;111:e380–e382</ref>
	**Generally described by patients as a powerful "kick to the chest"
	**Can be very distressing and a source of anxiety for patients
	*Magnet Mode		*Magnet Mode
	**Placement of a magnet over the generator will deactivate anti-tachycardia pacing and defibrillation modes as long as the magnet is in place.		**Placement of a magnet over the generator will deactivate anti-tachycardia pacing and defibrillation modes as long as the magnet is in place.

Bobbycarey: /* Indications for ICD implantation */

2021-03-10T00:51:47Z

Indications for ICD implantation

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	*Secondary Prevention<ref>Al-Khatib SM et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2018;72(14):e91. Epub 2018 Aug 16.</ref>		*Secondary Prevention<ref>Al-Khatib SM et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2018;72(14):e91. Epub 2018 Aug 16.</ref>
	**Previous episode of unstable VT or VF		**Previous episode of unstable VT or VF
	***'''Not indicated''' if VT/VF occurs <48 hours after [[~~myocardial_infarction~~]]		***'''Not indicated''' if VT/VF occurs <48 hours after [[myocardial infarction]]
	**Sustained VT in setting of cardiomyopathy or channelopathy		**Sustained VT in setting of cardiomyopathy or channelopathy
	*Primary Prevention<ref>Al-Khatib SM et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2018;72(14):e91. Epub 2018 Aug 16.</ref>		*Primary Prevention<ref>Al-Khatib SM et al. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2018;72(14):e91. Epub 2018 Aug 16.</ref>
	**[[~~Myocardial_infarction~~]] >40 days ago with LVEF <30%		**[[Myocardial infarction]] >40 days ago with LVEF <30%
	**[[Cardiomyopathy]] + NYHA Functional Class II or III, and LVEF <35%		**[[Cardiomyopathy]] + NYHA Functional Class II or III, and LVEF <35%
	***Controversy exists over applying the above criteria to non-ischemic cardiomyopathy		***Controversy exists over applying the above criteria to non-ischemic cardiomyopathy
	**Patients with underlying disorders placing them at high risk for unstable VT or VF		**Patients with underlying disorders placing them at high risk for unstable VT or VF
	***Congenital [[~~long_QT_syndrome~~]]		***Congenital [[long QT syndrome]]
	***High-risk [[HOCM]]		***High-risk [[HOCM]]
	***[[~~Brugada_syndrome~~]]		***[[Brugada syndrome]]
	***[[ARVD]]		***[[ARVD]]
	***Other channelopathies		***Other channelopathies