Implantable Devices

Question 1

Implantable devices

Answer 1

This patient has had syncope.

Please examine his cardiovascular system.

Question 2

Clinical signs of Implantable Device

Answer 2

1. Incisional scar in the infraclavicular position (may be abdominal)
2. Palpation demonstrates a pacemaker
3. Signs of heart failure: raised JVP, bibasal crackles and pedal oedema
4. Medic alert bracelet
5. Local infection: red/hot/tender/fluctuant/erosion

Question 3

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

Answer 3

1- Treating people with previous serious ventricular arrhythmia, that is without a treatable cause in people who have:
–> Survived a cardiac arrest caused by either VT or VF or
–> Spontaneous sustained VT causing syncope or significant haemodynamic compromise or
–> Sustained VT without syncope or cardiac arrest, and with LVEF of 35% or less but their Sx are no worse than NYHA class III
2- Treating people who have:
–> Familial cardiac condition with a high risk of sudden death, such as LQTS, HOCM, Brugada syndrome or arrhythmogenic right ventricular dysplasia or
–> Undergone surgical repair of congenital heart disease.

Question 4

Implantable cardioverter defibrillators (ICDs)
Cardiac resynchronisation therapy (CRT) with defibrillator (CRT D) or
CRT with pacing (CRT P)
are recommended as treatment options for: ??

Answer 4

Heart failure Pt who have left ventricular dysfunction with a LVEF of 35% or less according to QRS duration, NYHA class and presence of LBBB 
1- QRS interval <120 milliseconds 
==> NYHA class I, II, III : ICD if there is a high risk of SCD
==> NYHA class IV: ICD and CRT not clinically indicated 
2- QRS interval 120–149 milliseconds without LBBB 
==> NYHA class I, II, III : ICD 
==> NYHA class IV: CRT-P 
3- QRS interval 120–149 milliseconds with LBBB: 
==> NYHA class I: ICD 
==> NYHA class II: CRT-D 
==> NYHA class III: CRT-P or CRT-D 
==> NYHA class V: CRT-P 
4- QRS interval ≥150 milliseconds with or without LBBB: 
==> NYHA class I &amp; II: CRT-D  
==> NYHA class III: CRT-P or CRT-D 
==> NYHA class V: CRT-P 
NB: Cardiac resynchronization therapy (CRT ) = biventricular pacemakers (BiV)

Question 5

Implantable cardiac defibrillators (ICD)

Answer 5

‘Shock box’ also delivers anti‐tachycardia pacing (ATP) – improves mortality

Question 6

Indications of ICD as a Primary prevention

Answer 6

1. MI > 4 weeks ago (NYHA no worse than class III)
   ⚬⚬ LVEF < 35% and non‐sustained VT and positive EP study or
   ⚬⚬ LVEF < 30% and QRSd ≥ 120 milliseconds
2. Familial condition with high‐risk SCD ⚬⚬ LQTS, ARVD, Brugada, HCM, complex congenital heart disease

Question 7

Secondary prevention (without other treatable cause)

Answer 7

1. cardiac arrest due to VT or VF or
2. Haemodynamically compromising VT or
3. VT with LVEF < 35% (not NYHA IV)

Question 8

Cardiac resynchronization therapy (CRT ) – biventricular pacemakers (BiV)

Answer 8

Extra LV pacemaker lead via the coronary sinus – improves mortality/symptoms May be considered if:

1. LVEF < 35%
2. NYHA II–IV on optimal medical therapy
3. Sinus rhythm and QRSd > 150 milliseconds (if LBBB morphology may be >120 milliseconds)

Question 9

New York Heart Association (NYHA) functional classification of heart failure.

Answer 9

I = Cardiac disease, but no symptoms and no limitation in ordinary physical activity, e.g. no shortness of breath when walking > 300 m, climbing stairs etc.

II = Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity 100-300 m.

III = Marked limitation in activity due to symptoms, even during less-than-ordinary activity, e.g. walking short distances (20–100 m). Comfortable only at rest.

IV = Severe limitations. Experiences symptoms even while at rest. Mostly bed-bound patients.