QRS complex and implantable cardioverter defibrillators (ICDs), cardiac resynchronisation therapy (CRT) with defibrillator (CRT-D) or CRT with pacing (CRT-P) in heart failure

NICE guidance has stated which patients should be considered for the use of implantable cardioverter defibrillators (ICD) include (1):

Implantable cardioverter defibrillators (ICDs) are recommended as options for:

• treating people with previous serious ventricular arrhythmia, that is, people who, without a treatable cause:
  
  
  • have survived a cardiac arrest caused by either ventricular tachycardia (VT) or ventricular fibrillation or
    
    
  • have spontaneous sustained VT causing syncope or significant haemodynamic compromise or
    
    
  • have sustained VT without syncope or cardiac arrest, and also have an associated reduction in left ventricular ejection fraction (LVEF) of 35% or less but their symptoms are no worse than class III of the New York Heart Association (NYHA) functional classification of heart failure
    
    
• treating people who:
  
  
  • have a familial cardiac condition with a high risk of sudden death, such as long QT syndrome, hypertrophic cardiomyopathy, Brugada syndrome or arrhythmogenic right ventricular dysplasia or
    
    
  • have undergone surgical repair of congenital heart disease

Implantable cardioverter defibrillators (ICDs), cardiac resynchronisation therapy (CRT) with defibrillator (CRT-D) or CRT with pacing (CRT-P) are recommended as treatment options for people with heart failure who have left ventricular dysfunction with a left ventricular ejection fraction (LVEF) of 35% or less as specified in table below:

• Treatment options with ICD or CRT for people with heart failure who have left ventricular dysfunction with an LVEF of 35% or less (according to NYHA class, QRS duration and presence of LBBB)

LBBB, left bundle branch block; NYHA, New York Heart Association

The NICE guidance does not cover the use of implantable defibrillators for non-ischaemic dilated cardiomyopathy.

Notes:

• subcutaneous implantable cardioverter defibrillator (2)
  • current evidence on the efficacy of the insertion of a subcutaneous implantable cardioverter defibrillator (ICD) for the prevention of sudden cardiac death in the short and medium term is adequate
    
    
  • an entirely subcutaneous ICD differs from a conventional ICD in that the lead is placed subcutaneously, rather than transvenously
    • the lead comprises 2 sensing electrodes and a shocking coil
    • the ICD senses cardiac signals, but the lead is not directly attached to the heart
    • unlike a conventional ICD, the subcutaneous device is not designed to provide long-term pacing

Reference:

1. NICE (June 2014). Implantable cardioverter defibrillators and cardiac resynchronisation therapy for arrhythmias and heart failure
2. NICE (April 2013). Insertion of a subcutaneous implantable cardioverter defibrillator for prevention of sudden cardiac death.