The S-ICD may be the only choice for patients who require an ICD but for whom a transvenous ICD is not practical.

1. The concern is expressed for the pediatric or GUCH (Grown-Up Congenital Heart disease) population who lack venous access as a result of congenital abnormalities.
2. Factors favoring S-ICD in children with intact venous access because of the impact of growing on endocardial leads and the potential to protect venous vasculature
3.  Acquired stenosis or occlusion of central veins could make it difficult or impossible to put a lead; these venous anomalies can be discovered in 7% of instances during pre-implant contrast venography.
4. A history of endocarditis or device infections: In these situations, there is a very significant risk of relapse, which could have disastrous effects. 
5. Cancer patients who require a long-term indwelling catheter for drug infusion, dialysis, immunodeficiencies, and dialysis are other conditions that carry a very high risk of endovascular lead infection.
6. To prevent endovascular fibrosis, which could make surgical lead extraction difficult at the time of transplantation, an S-ICD should be taken into consideration in patients who are anticipating cardiac transplantation.
7. Young patients with an active lifestyle and a long life expectancy seem to benefit from an S-ICD. This is especially true for inherited genetic arrhythmogenic syndromes (Brugada, Long and Short QT, Early Repolarization), in which the most common clinical arrhythmias are polymorphic VT or VF (not treated with ATP), and the likelihood of bradycardia and monomorphic VT is extremely low.
8. Due to the high complication rate of typical transvenous ICD, S-ICD would also be a beneficial alternative in hypertrophic cardiomyopathy.
9. Patients with prosthetic heart valves (infection risk) and women, particularly for cosmetic reasons, are other potential applications for this innovative device.
10. Regarding primary prevention in patients with dilated ischemic or non-ischemic coronary arteries

Patients for secondary prevention who have survived an out-of-hospital VF episode may be given consideration for an S-ICD (with no evidence of monomorphic VT as index arrhythmia).

ICDs are usually used in people who have heart conditions such as:

• Ventricular tachycardia.
• Ventricular fibrillation.
• Previous sudden cardiac arrest.

In those who:

• Are susceptible to infections or have already experienced ICD infections, an S-ICD may be the best ICD alternative.
•  Have difficult-to-access heart anatomy.
•  Lead extremely active lives.
• Are more likely to live longer than transvenous ICDs do on average and are younger.

            

What happens exactly before the subcutaneous implantable cardioverter defibrillator procedure?

Before the S-ICD operation, your healthcare practitioner will present you with detailed instructions. • Stop using specific medications, like blood thinners, a few days prior to the treatment.

• On the day of the surgery, avoid eating and drinking.
• Make plans for transportation home after the surgery.

Anatomical areas for incisions and gadget installation may be marked by a healthcare professional just before the procedure.

• Clean and shave the region where the gadget will be inserted by your surgeon.
• Place an IV line in your arm to receive fluids and drugs.
• Give antibiotics to patients to avoid infections.
• Use an anaesthetic to numb the pain.
• Hold your arms in place with a comfortable strap to keep them from contacting the sterile area.

What happens during this procedure?

The procedure to implant an S-ICD generally takes a couple of hours. It needs inserting two parts: a generator and a defibrillation lead.

Most people get conscious sedation and are awake but relaxed during the procedure. You must not feel any pain, so tell your healthcare provider if you do.

During the procedure, your healthcare provider or the doctor continuously monitors your vital signs and the progress of the procedure, often using:

• Arm cuff to measure blood pressure.
• Electrocardiogram (also called EKG) to track the electrical impulses travelling through your heart.
• Fluoroscopy, uses X-rays to help your healthcare provider see the leads during this procedure.
• Oximeter monitor to check blood oxygen levels.

The left side of your chest or under your left arm will both have two or three incisions from a surgeon. They place the generator inside your fat, next to your ribcage, and under your skin. The lead is then tunnelled beneath your skin, up into your neck, and then to the middle of your chest, close to your breastbone.

The system is tested before the treatment is complete by causing an irregular heart rhythm and allowing the device to shock you to show that it is functioning as intended. (Your medical staff will provide medications to keep you sedated so that you won't experience any discomfort.) The incisions are then stitched shut.

What happens after S-ICD surgery?

You proceed to the recovery room following the surgery. The medical staff there keeps an eye on you as the anaesthetic wears off. An X-ray may be requested by your doctor to confirm the components of the device are in the right place.

On the day of the procedure, most patients return home. You'll need a driver to take you home because of the anaesthetic.