A pacemaker is a small, implantable device that monitors the heart for rhythm problems. If a problem arises, the device can deliver a tiny electrical pulse that stimulates the heart into correcting its abnormal rate. There are several kinds of pacemaker, each designed to handle different types of heart problem:
Standard pacemaker – which delivers corrections to one, two or three chambers in the heart
Cardiac resynchronisation therapy (CRT) device – a heart failure pacemaker that enables the chambers to beat in time with each other (heart failure is when the heart doesn’t pump as efficiently as it should)
Implantable cardioverter defibrillators (ICD) – a heart failure pacemaker that can deliver a small shock or faster pacing impulse to reset the heart rhythm
CRT-ICD (or CRT-D) devices – a pacemaker that combines both CRT and ICD functions in one small unit
A CRT-ICD device, also known as a CRT-D pacemaker, combines two types of heart failure treatment in one: Cardiac resynchronisation therapy (CRT) and Implantable cardioverter defibrillation (ICD). It’s helpful to know a little about how these two treatments work. To summarise:
CRT paces the heart to correct delayed electrical signals, which can prevent the lower chambers (the ventricles) from working together efficiently; the CRT device paces the heart to “resynchronise” the ventricles and make them contract together normally.
ICD is like a miniature, internal defibrillator machine for the heart: if it detects a dangerous rhythm problem, it delivers tiny electrical shocks that correct the issue
As well as monitoring the heart for rhythm problems, CRT-ICDs can deliver a stronger pulse of electrical energy than a regular pacemaker; this burst of energy resets the heartbeat and helps prevent further complications, such as sudden cardiac death.
For more detail on CRT, see What is a CRT pacemaker? in the Heart Failure Pacemakers section of our website. You may also find this news article helpful: CRT for heart failure? A major trial offers new hope for patients. For more on ICDs in general, head to the Internal Defibrillators section.
CRT-ICDs are often recommended for people who have heart failure (where the heart doesn’t pump as well as it should), but who also need an additional layer of protection from other rhythm-related problems; for instance:
- You have previously suffered from, or are at risk of suffering, a serious heart rhythm
condition called ventricular tachycardia (VT)
- You have previously suffered from, or are at risk of suffering, a serious heart rhythm condition called ventricular fibrillation (VF)
- You’ve suffered a heart attack that has damaged your heart’s electrical pathways and / or its ability to pump efficiently
Ultimately, the CRT-ICD device can help to prevent the heart from developing a life-threatening problem like sudden cardiac death, where the heart stops beating altogether.
Pacemakers work by running a series of tiny leads (also known as wires) into the chambers within the heart; once connected, they allow the device to continuously monitor electrical activity and deliver corrective pulses if necessary. CRT-ICDs are fitted using “transvenous implantation”: this means we’ll insert the leads through one of your veins. To do this, we make a small incision (roughly 5cm wide) underneath your collarbone, usually on the left side of the chest. An x-ray image enables us to guide the leads down the vein to your heart. Once in place, we’ll connect these leads to your new device. The device itself will be placed just underneath your skin. Your device will also be tested to make sure it’s working properly. Although CRT-ICD fittings are usually done with a local anaesthetic, under certain circumstances some can be done under general anaesthetic. If you’re having one under local anaesthetic, we may also offer you a sedative to help you relax and feel comfortable during the procedure.
When you arrive at the clinic, the hospital team will assess you and run through your details. We’ll then take you through to the theatre, where you’ll be given a sedative to help you relax (or a general anaesthetic, if you’re having one). Before the procedure begins, we carefully prepare the area with an antiseptic solution, and we’ll give you a small injection of local anaesthetic to numb the skin. We then make the incision and insert the leads that will connect to your pacemaker device (you won’t feel any pain as the leads are inserted). The CRT-ICD itself will sit within a tiny pocket underneath the skin on your chest. Before completing the procedure, we test your device to make sure it’s functioning well. Finally, we close the wound with medical dissolvable stitches. The whole procedure usually takes around 90 minutes.
There are several other things you should know if you’re set to have a CRT-ICD, or are thinking about having the device. One is that you will receive an ID card with your device, before you leave the hospital – these are issued for all pacemakers, and you’ll need to carry yours with you at all times. ID cards detail the make and model of your device; this gives doctors essential information about your pacemaker if you need treatment in the future. In some patients, heart failure pacemakers also have implications for things like car insurance, future operations, and for use with certain household devices, such as mobile phones and magnetic equipment. For more detail, see What else do I need to be aware of? In the Pacemakers section of our website. (For more about driving, see Will I be able to drive after my pacemaker fitting?).
It’s also important to understand that, since internal defibrillation devices are designed to protect you by reacting to potentially dangerous rhythm changes, they can sometimes discharge unnecessarily. However, this type of occurrence is relatively rare – it’s estimated that around one or two ICD patients in every 100 will receive a shock from their device that they didn’t need. Before you leave the hospital after your fitting, we’ll give you comprehensive information about how to look after your device.
Yes. We will usually ask you to come back in for a follow-up appointment around six weeks after the fitting. At this appointment, we’ll check that your CRT-ICD is working well and review the information that’s recorded on it. After that, you’ll also need to return to the clinic for regular checks on your device. These usually need to happen once a year, but could potentially be more frequent than that. These checks allow us to review your heart failure pacemaker’s settings and battery life, and test the condition of the leads. We can make adjustments if we need to. We will also monitor your heart rhythm and save all the data from your tests to your medical records.
As with all electrical devices, pacemaker batteries don’t last forever – but we’ll make sure you have plenty of notice before your CRT-ICD battery needs to be renewed. The battery life for most pacemakers is at least six years, and in some cases up to 12. We’ll test your battery when you come in for a check-up so we know how much power it has left. To change the battery on your device, you’ll need to come into clinic for a new fitting. This procedure is similar to the initial fitting, but generally much quicker because in most cases we won’t be inserting new leads into your heart.