Dr. Ojas Mehta performs device implantation and electrophysiology studies and procedures for a range of complex cardiac rhythm disorders. Below are some of the procedures that he offers.

Cardiac Device Implantation

Implantable loop recorders

• These are small devices that are implanted within the subcutaneous / fat layer on the chest wall or below the breast. A very small incision < 1cm is required. This procedure can be done under local anaesthesia.

Pacemakers - transvenous and leadless

• These are devices that are designed to stimulate your heart in the absence of your own electrical signals. These systems are very sophisticated and can be programmed / modified to suit your needs.

• Transvenous devices rest in the shoulder region, often the left side, with wires that connect to the heart via the large central veins.

• Leadless devices avoid the wires that travel through the veins but lack the same functionality as traditional transvenous systems. These are implanted via the vein in the groin.

Conduction system pacing

• Conduction system pacing is a novel technique of implantation to enable capture of the patient’s natural wiring system. This involves deploying the lead tip in a precise location in the interventricular septum to enable stimulation of the electrical pathways in the heart, rather than just the muscle. It is likely that this technique will reduce the incidence of pacemaker induced cardiomyopathy, which can be caused when there is a high burden of cardiac pacing.

Defibrillators - transvenous and subcutaneous

• These are devices that are designed to detect fast and potentially dangerous cardiac rhythms that originate from the ventricles of the heart.

• Transvenous devices rest in the shoulder region, often the left side, with wires that connect to the heart via the large central veins.

• Subcutaneous devices avoid the wires that travel through the veins and rest in the left chest wall region with a wire that sits adjacent to the sternum. Given the absence of wires that travel in the blood stream, there is less chance that any infection of the system would affect the heart. However, there is lesser functionality of these devices at this stage in time.

Electrophysiology Studies and Procedures

Electrical Cardioversion

• This is a procedure done with the aid of anaesthesia. Pads are placed on the chest wall and a strong electrical current or ‘shock’ is delivered to a heart at a synchronised time point in order to stimulate a large portion of the heart muscle and enable resetting of the heart rhythms. This is done to restore normal sinus rhythm.

Electrophysiology Study

• This is a procedure done with delicate catheters that sit in the heart chambers and collect electrical signals. Specific electrical signals are delivered to stimulate the heart in a precise manner to enable documentation of the behaviours of various part of the electrical conduction system and also to evoke and study abnormal arrhythmias. If there is something treatable, a catheter ablation would often be performed.

Catheter Ablation

• Ablation is a technique of damage cardiac tissue in a deliberate fashion to prevent the generation or propagation of abnormal heart rhythms

• The technology is highly sophisticated and catheters that are placed in the body can be visualised in real time using magnetic and electrical sensors that are placed on the tips of these catheters. This allows proceduralists to know the position of the catheter with respect to the heart and together with the electrical signals picked up by these catheters, a map of the heart can be created from within.

• There are multiple modalities by which we can deliver energy to tissue and this is often selected on an individual basis. The traditional ablation technology is radiofrequency (heating tissue) and cryoablation (freezing tissue) which are thermal modalities. A relatively new technology is pulsed-field ablation which delivers strong electrical currents to irreversibly damage tissue. At this stage, these modalities all have equivalent efficacy with slight variation in safety profiles.

Resources

Below are links to animations to better understand certain concepts (external website)

• Electrophysiology study

• 3-D mapping

• Supraventricular tachycardia

• Focal atrial tachycardia

• Atrial Flutter

• Catheter ablation for Atrial Fibrillation

• Idiopathic Ventricular Tachycardia

• Ischemic Ventricular Tachycardia

• Pacemaker implantation

• Cardiac Resynchronisation Therapy

• Implantable Cardiac Defibrillator