Defibrillator Technology is Developing Fast

Defibrillators are crucial to any healthcare facility because they increase the chances of survival from a sudden cardiac arrest (SCA). Defibrillators and the treatment of SCA have come a long way in recent years! From great big bulky devices that were on trolleys in hospitals and only used by authorized doctors, to now being located in many public places wherever people are likely to be.

Public access defibrillators (PADs) or automated external defibrillators (AEDs) are compact, lightweight, and easy to locate and store just about anywhere. They are designed for the public who may not even have any training to apply and use them when required. All PADs/AEDs today talk through the SCA, prompting one to do the next step and monitoring the progress. One cannot go wrong with modern day units.

There is now an evolution of defibrillator devices from using transvenous leads to subcutaneous leads, and from transvenous to leadless. The device landscape has transformed from mostly pacemakers to mostly defibrillators. According to Technavio, the rising prevalence of cardiovascular diseases (CVD) and advances in technology will be the primary growth drivers for the global defibrillator market that will grow at a CAGR of more than 7 percent from 2018 to 2022. The rising prevalence of SCA will continue to boost the adoption of defibrillators.

Technological Advances
Twenty years ago is approximately when the first dual-chamber defibrillators were available for use. Up to that point, defibrillators had undergone some advances, including anti-tachycardia pacing, biphasic shock waveforms, and using the implantable cardioverter defibrillator as an electrode, but only provided ventricular backup pacing from a single ventricular lead. These were not very good at preventing the heart from going too slow, so sometimes it was needed to insert a separate pacemaker and defibrillator in the same patient. Since that time, there have been huge developments. For instance, combining a dual-chamber pacemaker with an ICD, which is crucial in some patients, is a big advance over the single-chamber pacemaker/ICD combination.

Leadless therapy. Transvenous pacemakers and ICDs are effective treatment modalities for cardiac bradyarrhythmias and tachyarrhythmias. However, these systems are associated with device-related complications, mostly related to the transvenous leads, which result in morbidity and mortality. Transvenous pace and shock leads have shown high failure rates during long-term clinical follow-up. Device infections (sometimes involving the pocket but more so when systemic) are associated with a high risk of mortality.

To reduce complications related to transvenous leads, both the leadless pacemaker and the subcutaneous implantable cardioverter-defibrillators (S-ICDs) were introduced and have shown clinical efficacy and safety. To date, these systems are only available for patients either requiring single-chamber right ventricular pacing or shock-only defibrillation therapy. Combined use of both devices could bring the benefits of leadless therapy to a larger patient population by providing both bradycardia pacing and defibrillation therapy.

Wearable cardiac defibrillator. A wearable cardiac defibrillator (WCD) is an external vest-like device that is intended to perform the same functions as an ICD without requiring an invasive procedure. This device is used to monitor and treat abnormal heart rhythms in people at risk. The vest includes an electrode belt that contains the cardiac monitoring electrodes and the therapy electrodes that deliver an electrical shock if a life-threatening ventricular arrhythmia is detected. The WCD is programmable and communicates with the patient through voice and display messages, tones, or alarms and vibration against the skin.

When an arrhythmia is detected, the device instructs the patient to stop the impending shock by pressing a response button to avoid receiving a shock while conscious. The WCD is designed to deliver an electric shock within 60 seconds of the onset of ventricular tachycardia or ventricular fibrillation unless a conscious patient presses the response button. The patient can also connect the WCD to an external modem and send the data it has collected over the phone to a physician’s computer for review.

MRI compatibility. In the past, individuals with ICDs were limited in terms of full body magnetic resonance imaging (MRI) and were often prevented from undergoing chest scans. Fortunately, recent advancements have allowed for the creation of MRI-compatible ICDs and patients with the new MRI-compatible ICDs can undergo this important diagnostic imaging without fear of complications. Leading manufacturers have released devices that allow individuals to undergo full body scans, even after implantation.

Following the FDA approval in late 2015 of the first ICD system for use during MRI scans, last 2 years saw the expansion of additional FDA-approved MRI-conditional CIEDs and lead systems, including CRT-D systems and additional pacing systems. MRI capability is now approved for some systems for total body use without exclusion of chest MRI, and in some systems for up to 3T scans.

Remote monitoring. Another major change over time is in the way physicians follow their patients. They can perform remote monitoring of patients to augment in-person checks. Remote monitoring also affords the chance to adjust clinical care after detecting a change in the patient’s clinical condition or device malfunction, which may improve major clinical outcomes such as death and hospitalization. The device telemetry could only travel a few inches, but now it transmits several yards.

Most recently, the devices use Bluetooth for telemetry. The ICD uplinks to the bedside monitor, which uses cellular technology to link to central databases and uses the Internet to send the information to the physicians. The patient does not have to do anything but sleep. This has revolutionized the way physicians follow the devices and the patients. The patients can travel all over the world and can still be in touch with what is going on with them. The devices themselves now alert both the physician and the patient when there is a problem.

Other advances. The latest advance includes, but is not limited to, having a more consistent shock with a higher confidence level. Another advancement is the ability to deliver more current. These are important because it is a matter of life and death and these devices need to be reliable. Many of the newest defibrillators now have a wireless capability. This is used for recording events during codes and can be used to create reports of the actions taken during a code event. These models have the capability to transmit ECG via Wi-Fi or cellular connection to the healthcare facility before the patient arrives.

Most of the recent defibrillators can also do automatic internal diagnostics usually once a day to ensure the defibrillator is working properly. They also test the battery and report the status back to a central computer. Some of the modern models also include improved CPR coaching and/or real-time feedback. CPR feedback is a new advancement that most manufacturers are adopting and SpCO (carbon monoxide) measurement for pre-hospital models is also becoming popular.

Outlook
Physicians highly recommend ICD for patients with arrhythmias as this device is used as a continuous monitoring device. This may help in reducing the delivery time of an AED, leading to increased chances of survival with faster treatment. Most defibrillators are now configured with ECG, most have external pacing capability, pulse oximetry, and even CO2 monitoring. When defibrillators are integrated with other technologies like pacemakers, the functioning of these devices is further enhanced. The continual purchase volume of ICD devices and continuous technological advancements and product innovations will positively influence the heart defibrillator market over the years.

The rising demand for advanced defibrillators will further lead to innovation and improvement in implantable as well as external defibrillators with reduced inappropriate shocks, longer battery life, less invasive installation, and quadripolar leads. With modern technology and the investment in R&D for defibrillators, it will not be too long before a defibrillator will be something one can carry in a pocket. No doubt they will soon be the size of a mobile device!