Pacemaker / Defibrillator

Pacemakers are typically implanted for slow heartbeats. Defibrillators are recommended for patients who have had malignant ventricular arrhythmias such as ventricular tachycardia or ventricular fibrillation causing sudden cardiac death or patients at risk for these events.

The defibrillator shocks the heart out of these life threatening arrhythmias. These devices typically take an hour to an hour and a half to implant. Patients are generally kept in the hospital overnight but in some instances can even be sent home on the same day.

These devices are placed transvenously with wires running into the heart. In general these devices do not limit a patient's activities or the lifestyle. In fact, the newer generations of these devices are even compatible with MRI scanning.

These devices can now be followed remotely from home, with data transmitted to the physician’s office. Variations include subcutaneous defibrillators, HIS Bundle Pacing, cardiac resynchronization therapy, as well as remote monitoring of implantable devices.

Below: A defibrillator implant procedure. (A pacemaker implant is performed in the same way.)

Subcutaneous (SQ) AICD Implantation

This automatic implantable defibrillator from Boston Scientific Corp. was recently approved to treat sudden cardiac death. Conventional implanted defibrillators require leads be placed through veins and placed directly into the heart. This novel device avoids placing any leads into the heart. Placing leads through blood vessels to the inside of the heart can cause acute problems during the implant of a defibrillator, including cardiac perforation or a collapsed lung. In the longer term, endocardial leads have been shown, especially over time, to ultimately fail to function. They can also cause vessel obstruction, valve malfunction, or become infected. This newer device avoids these complications.

The lead used with this device runs subcutaneously, under the skin over the front of the chest. Again, there is no "hardware" placed in the blood vessels or heart. The shock waveform is delivered between the lead and the device itself.

Notice there is no lead in the heart or blood vessels:

Here is a conventional AICD, where there is lead in both the heart and blood vessels:

The SQ AICD is not recommended for those who need pacing for bradycardia or cardiac resychronization.

This device may be ideal for young patients especially, so they can avoid the long term problems associated with endocardial/endovascular leads.

When Bluetooth Meets Pacemaker

Dr. Steven Zweibel, director of electrophysiology at Hartford Hospital on the Bluetooth-enabled Azure pacemaker:

Q: Describe how does this technology works.
A: For decades, we used technology to have a pacemaker communicate with a special monitor so that we can remotely track the function of a pacemaker device. Studies have shown that this remote monitoring helps reduce mortality. Twenty-first century advancements allow for these new devices to make use of Bluetooth technology coupled with a smartphone app to allow monitoring via their mobile device.  The same information that we receive via the bedside monitor can now be sent via their mobile device. This can give us more timely information about arrhythmias or issues with the device.  Since the app on the patient’s mobile device is a piece of software, there is the ability to upgrade the app to provide new functionality. An example of an advance that I can envision in the future would be the ability for the device to detect when a patient has fallen and contact a family member or healthcare provider automatically.

Q: How secure is the transfer of patient data?
A: The data between the patient’s pacemaker and mobile device is fully encrypted, as is the data going from the mobile device to (device manufacturer) Medtronic and then to our device clinic.  It is very important to note that the patient’s pacemaker works completely independently from their mobile device and that no changes to the programming of the pacemaker can be done via the patient’s mobile device.

Q: This new pacemaker is unique in another way: It’s compatible with MRI imaging.
A:  Most devices that we implant at Hartford Hospital, including pacemakers and defibrillators, are now MRI compatible, and have been for a few years. This new pacemaker is no exception.  This has been a great advance for our patients to allow them to have the option of having an MRI scan, when previously this was not possible.

Q:  Describe more of the benefits of pacemaker technology today.
A: Device companies have been working very hard on battery and circuitry technology to make these devices last as long as possible.  I used to tell patients that their pacemaker would last 7 to 10 years. Now I can safely tell them that they should expect to get at least 12 to 14 years from their pacemaker battery. This will lead to fewer operations to replace their device when the battery becomes depleted.

Our Pacemaker and Defibrillator Locations: