Cardioverter-Defibrillator Implantation

Updated: Apr 01, 2014
  • Author: Adam S Budzikowski, MD, PhD, FHRS; Chief Editor: Richard A Lange, MD, MBA  more...
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Overview

Background

Techniques and indications for implantable cardioverter-defibrillator (ICD) placement have changed tremendously since the inception of this therapy in 1980. [1] Initially, most of the patients who received ICD therapy either showed evidence of sustained ventricular tachycardia (VT) or were survivors of sudden cardiac arrest. [2, 3] At that time, thoracotomy was required for placement of epicardial defibrillation patches, and the large device size limited implantation sites to the upper abdomen.

Development of transvenous systems and miniaturization of the device allowed for pectoral placement of the defibrillator generator with a very low risk of complications. Most ICD placements now occur for primary prevention of sudden cardiac death (SCD). [4, 5]

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Practice Essentials

The implantable cardioverter-defibrillator (ICD) is first-line treatment and prophylaxis for patients at risk for ventricular tachycardia (VT) or ventricular fibrillation (VF). Current devices offer tiered therapy with programmable antitachycardia pacing schemes, as well as low-energy and high-energy shocks in multiple tachycardia zones.

Dual-chamber, rate-responsive bradycardia pacing is now available in all ICDs, and sophisticated discrimination algorithms minimize shocks for atrial fibrillation, sinus tachycardia, and other non–life-threatening supraventricular tachyarrhythmias. Diagnostic functions, including stored electrograms, allow for verification of shock appropriateness.

Equipment

Equipment used in the placement of an ICD includes the following:

  • Fluoroscope
  • Surgical tray
  • Peelable hemostatic sheath(s)
  • External defibrillator
  • ICD generator and lead(s)
  • Pacing cable(s)
  • Analyzer

See Periprocedural Care for more detail.

Technique

Incision

The skin incision is usually made in the right or left subclavicular area, depending on the patient’s handedness. It is generally preferred that the ICD be inserted on the side opposite the patient’s dominant hand.

Creation of subcutaneous pocket

  • An incision 5-7 cm in length is made and carried down to the subcutaneous tissue; the dissection is extended to the prepectoral fascia with electrocauterization, blunt dissection, or both
  • Once the incision is carried down to the prepectoral fascia, electrocautery is used to create a new plane in the inferior part of the incision with the help of an Army-Navy retractor
  • The pocket that will accommodate the ICD is then created with a combination of electrodissection and blunt dissection with the fingers
  • Once the pocket has been created and hemostasis achieved, attention is turned toward obtaining vascular access

Creation of subpectoral pocket

  • For a subpectoral pocket, the author prefers, if possible, to use cephalic vein access for placement of leads
  • The incision is carried down to the prepectoral fascia and down to the deltopectoral groove, usually first with the cautery and subsequently with blunt dissection to avoid injury to the cephalic vein
  • The cephalic vein is then isolated and secured
  • The lateral edge of the deltopectoral muscle is subsequently lifted and gently separated from the pectoralis minor by using blunt dissection with Metzenbaum scissors; blunt dissection with fingers may also be used at this point
  • Once the subpectoral pocket has been created, attention is turned toward obtaining vascular access

ICD and leads

For the majority of patients, a single-chamber ICD (with only a ventricular lead) is preferred unless sinoatrial (SA) node (ie, sinus node) dysfunction is seen or significant atrioventricular (AV) conduction abnormalities are present.

The defibrillation leads may have 2 defibrillation coils, with the distal coil placed in the right ventricle and the more proximal coil typically extending from the junction of the right atria to the superior vena cava, or it may have only a single distal defibrillation coil.

Insertion of generator

It is important to place the lead(s) in the bottom of the pocket and then to position the ICD in such a way that it covers the leads. This protects the lead(s) during any future generator change.

The round part of the device should face the lateral aspect of the patient, and the part where the lead connection is made should face the middle of the chest. In patients who require a subpectoral pocket, an Army-Navy retractor may be necessary to lift the pectoralis initially so as to facilitate device placement.

Defibrillator threshold testing

After the lead is secured and connected to the defibrillator and the defibrillator placed in the pocket, defibrillation threshold (DFT) testing should be done in most patients. After this is completed, the pocket can be closed.

See Technique for more detail.

Medication

Appropriate pain medication is necessary after the implantation procedure. Patients in whom the device was placed subpectorally experience significantly more pain than do those in whom the device was placed subcutaneously.

The evidence for postprocedural antibiotic administration is inconclusive and, for the most part, not based on randomized trials. Nevertheless, most practitioners prescribe oral antibiotics for a short period.

See Medication for more detail.

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Indications

Indications for ICD implantation are established and classified on the basis of the guidelines developed by the American College of Cardiology (ACC), the American Heart Association (AHA), and the Heart Rhythm Society (HRS). [6]

Class I indications are as follows:

  • ICD therapy is indicated in patients who are survivors of cardiac arrest due to ventricular fibrillation (VF) or hemodynamically unstable sustained VT after evaluation to define the cause of the event and to exclude any completely reversible causes
  • ICD therapy is indicated in patients with structural heart disease and spontaneous sustained VT, whether hemodynamically stable or unstable
  • ICD therapy is indicated in patients with syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced at electrophysiologic study
  • ICD therapy is indicated in patients with nonsustained VT due to prior myocardial infarction (MI), left ventricular ejection fraction (LVEF) less than 40%, and inducible VF or sustained VT at electrophysiologic study
  • ICD therapy is indicated in patients with LVEF less than or equal to 35% due to prior MI who are at least 40 days post-MI and are in New York Heart Association (NYHA) functional class II or III
  • ICD therapy is indicated in patients with nonischemic dilated cardiomyopathy who have an LVEF less than or equal to 35% and who are in NYHA functional class II or III
  • ICD therapy is indicated in patients with left ventricular dysfunction due to prior MI who are at least 40 days post-MI, have an LVEF less than 30%, and are in NYHA functional class I

Class IIa indications are as follows:

  • ICD implantation is reasonable for patients with unexplained syncope, significant left ventricular dysfunction, and nonischemic dilated cardiomyopathy
  • ICD implantation is reasonable for patients with sustained VT and normal or near-normal ventricular function
  • ICD implantation is reasonable for patients with hypertrophic cardiomyopathy who have 1 or more major risk factor for SCD
  • ICD implantation is reasonable for the prevention of SCD in patients with arrhythmogenic right ventricular dysplasia or cardiomyopathy who have 1 or more risk factors for SCD
  • ICD implantation is reasonable to reduce SCD in patients with long-QT syndrome who are experiencing syncope or VT while receiving beta blockers
  • ICD implantation is reasonable for nonhospitalized patients awaiting transplantation
  • ICD implantation is reasonable for patients with Brugada syndrome who have had syncope
  • ICD implantation is reasonable for patients with Brugada syndrome who have documented VT that has not resulted in cardiac arrest
  • ICD implantation is reasonable for patients with catecholaminergic polymorphic VT who have syncope or documented sustained VT while receiving beta blockers
  • ICD implantation is reasonable for patients with cardiac sarcoidosis, giant cell myocarditis, or Chagas disease

Class IIb indications are as follows:

  • ICD therapy may be considered in patients with nonischemic heart disease who have an LVEF of less than or equal to 35% and who are in NYHA functional class I
  • ICD therapy may be considered for patients with long-QT syndrome and risk factors for SCD
  • ICD therapy may be considered in patients with syncope and advanced structural heart disease in whom thorough invasive and noninvasive investigations have failed to define a cause
  • ICD therapy may be considered in patients with a familial cardiomyopathy associated with sudden death
  • ICD therapy may be considered in patients with left ventricular noncompaction

Class III indications are as follows:

  • ICD therapy is not indicated for patients who do not have a reasonable expectation of survival with an acceptable functional status for at least 1 year, even if they meet ICD implantation criteria specified in the class I, IIa, and IIb recommendations above
  • ICD therapy is not indicated for patients with incessant VT or VF
  • ICD therapy is not indicated in patients with significant psychiatric illnesses that may be aggravated by device implantation or that may preclude systematic follow-up
  • ICD therapy is not indicated for NYHA class IV patients with drug-refractory congestive heart failure (CHF) who are not candidates for cardiac transplantation or implantation of a cardiac resynchronization therapy (CRT) device that incorporates both pacing and defibrillation capabilities
  • ICD therapy is not indicated for syncope of undetermined cause in a patient without inducible ventricular tachyarrhythmias and without structural heart disease
  • ICD therapy is not indicated when VF or VT is amenable to surgical or catheter ablation (eg, atrial arrhythmias associated with Wolff-Parkinson-White [WPW] syndrome, right ventricular or left ventricular outflow tract VT, idiopathic VT, or fascicular VT in the absence of structural heart disease)
  • ICD therapy is not indicated for patients with ventricular tachyarrhythmias due to a completely reversible disorder in the absence of structural heart disease (eg, electrolyte imbalance, drugs, or trauma)

Available evidence suggest that new device implantation can be safely accomplished in patients who are anticoagulated with warfarin with a therapeutic international normalized ratio (INR) in the range of 2 to 3. [7]

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