Patient Prioritisation for the S-ICD

A majority of ICD indicated patients are suitable for S-ICD, as demonstrated by clinical data and EU and US guidelines. 

The arrow indicates the patient prioritisation for the S-ICD based on guidelines and clinical literature(1 2 3), in increasing order.

Click on the titles to explore the indications


Bradycardia Pacing

Among patients with no pacing indication at the time of ICD implant, the development of RVP is uncommon within the first 2 years after implantation15.

No significant increased risk of pacing need until age 8015.

Occurrence of new pacing need was low in real-world S-ICD registries:

Extraction for new pacing requirement: No. of patients 
EFFORTLESS mid-term follow-up6 1 / 985 (0.1%)
Dutch 6 year follow-up16 1 / 118 (0.8%)
Austrian Registry17 2 / 336 (0.8%)

Need for ATP at implant

ATP has been shown to be effective for termination of fast monomorphic VT (>188 bpm).

Who needs ATP:

From SCDHeFT, recurrent mVT occurred in only 7% of patients18, with 0.5 – 2% reoccurence/year19
The impact of device programming:
Contemporary programming significantly reduces therapy delivered, suggesting that given sufficient time, a majority of mVT episodes will self-terminate23, 24, 25.

Rate of appropriate shock delivery

Multiple studies have shown similar rates of appropriate shocks despite reductions in ATP delivered:

1 year rate of Appropriate Therapy

Multiple studies have shown similar rates of appropriate shocks despite reductions in ATP delivered.
1 year Kaplan Meier incidence shown for S-ICD, PainFREE SST and ADVANCE III. 1 year rate for MADIT-RIT annualised at an average follow-up of 1.4 years. MADIT-RI, PainFREE SST and ADVANCE III did not include S-ICD devices.

Future need for ATP

Benefit of ATP:

In studies of long detection programming, 97-98.4% of patients received no benefit from ATP23, 26.

Shocks avoided by ATP in major clinical trials

Risk of VT acceleration:

ATP has been shown to accelerate arrhythmias in up to 8.5% of cases. Placing the patient at greater risk of degeneration of the
rhythm to a faster, unstable, and poorly tolerated rhythm24, 27, 28, 29.

What is the role of an ICD: SCD prevention or VT management?

Catheter ablation is recommended (ESC Class I indication)11 in patients with:

  • Scar-related heart disease presenting with incessant VTs
  • Ischemic heart disease and recurrent ICD shocks due to sustained VTs

Real world SICD data show very low rate of change out to TV-ICD due to need for ATP:

Extraction for new pacing requirements: No. of patients 
EFFORTLESS mid-term follow-up6 5 / 985 (0.5%)
Austrian Registry17 1 / 236 (0.4%)

“Typical” ICD Patients

ICD benefit in low EF/CHF patients

  • 34% reduction in SCD risk by ICD in MADIT II population30
  • 23% reduction in SCD risk by shockonly ICD at five years among (ischemic and non ischemic) CHF patients18

Proportion of low EF patients implanted with an SICD has increased over time:2, 6, 31

Proportion of low EF patients implanted with an SICD has increased over time

Risk factors:

High proportion of patients at high risk of infection among low EF/CHF patients:

  • 31-33% of patients with diabetes in SCDHeFT and MADIT II18, 32
  • 25% of patients with renal disfunction in CHF population18, 32

S-ICD is the preferred therapy for patients who are at high risk of infections (AHA/ACC/HRS guidelines, Class I recommendation)1.

S-ICD: Class IIa recommendation for ALL ICD indicated patients without need for pacing1, 11.


Older ICD Patients

AHA/ACC/HRS guidelines: class IIa recommendation for patients >75 years old with at least 1 year of life expectancy1

S-ICD performs better than TV-ICD in discrimination of SVT37, 38.

Inappropriate shocks due to SVT in patients implanted with TV-ICD

Appropriate ICD therapy delivered in up to 23% of older patients (with EF>25%)39.



High Risk Patients

Inadequate venous access:
As many as 61% of patients may have venous stenosis following initial device implantation34.

Predictors of device infection33,34,40:

  • Diabetes
  • Heart Failure
  • Kidney disease
  • Previous device infection