Multiple technological advances in the ICD have resulted in smaller size, easier implantation and improved detection, therapy, and stored diagnostic information.
The technology and science behind defibrillators has advanced tremendously over the past 10 years. Today, defibrillators require only a 2 to 2┬╜ inch incision to insert. Best of all, most patients can leave the same or the next day. Even more incredible than their small size and effectiveness is the fact that these devices can be programmed, monitored, and adjusted through wireless technology that can communicate the status with a patient's physician. With defibrillators becoming more prevalent in communities, and with the greater public awareness of their value, the number of deaths each year from sudden cardiac arrest can be dramatically reduced.
Along with the advances in wearable devices, defibrillation has centered around adding more capabilities to existing AEDs, including storing information about a patient's heart rate to pass on to medical professionals, and regulations around where defibrillators must be present. Most businesses now recognize the importance of having these devices available.
Several new implantable cardioverter defibrillators (ICDs) offer pacing functions and many vendors provide wireless remote monitoring/interrogation of the device data with bedside sending units so patients do not need to come in for regular office visits. New-generation ICD with bi-functional capability of preventing cardiac arrest along with performing the role of a pacemaker are enhancing the sales volume. The cost-effectiveness of ICD therapy appears favorable, given the marked survival benefit seen in randomized trials relative to antiarrhythmic drug treatment. The growing number of ICD recipients necessitates an understanding of the specialized features of the modern ICD and the role of device therapy in clinical practice. These products are witnessing high demand due to cost-effectiveness and technological upgradation such as wireless and cloud-based patient-monitoring software. Manufacturers are employing innovative technology with quadripolar lead devices that allow for higher programming and reporting at home, decreasing the frequent visits to the hospitals.
While the use of implantable defibrillators has been a tremendous advance in patients at risk for ventricular tachyarrhythmias, the use of automatic external defibrillators (AEDs) and wearable defibrillators is also a remarkable advancement that allows for potential sudden cardiac death (SCD) prevention in more patients. Nonetheless, the area of medical genetics is an evolving discipline; ongoing research and refined methods of risk-stratification may continue to delineate groups with survival benefit from ICDs.
Public access defibrillators (PADs). AEDs or PADs are very compact today and are easy to locate and store just about anywhere. With modern technology and the investment in R&D for defibrillators, it will not be too long before defibrillator will be something one can carry in their pocket. No doubt they will soon be the size of a mobile phone.
Implantable cardioverter-defibrillators. Although conventional implantable cardioverter-defibrillators (ICDs) have proved effective in the prevention of SCD, they still appear to be limited by non-trivial acute and long-term complications. The recent advent of an entirely subcutaneous ICD (S-ICD) represents a further step in the evolution of defibrillation technology toward a less-invasive approach. Multiple technological advances in the implantable cardioverter defibrillator (ICD) have resulted in smaller size, easier implantation and improved detection, therapy, and stored diagnostic information. Advanced dual-chamber ICDs are currently available that allow dual-chamber rate-responsive pacing with mode switching, enhanced detection algorithms, antitachycardia pacing, low-energy cardioversion, high-energy shocks, and extensive diagnostics. Based on improvements in lead systems and improved energy waveforms, almost all devices are being implanted with non-thoracotomy leads in the pectoralis area. The results of recent clinical trials have expanded indications for the ICD for primary and secondary prevention of sudden cardiac death.
Quadripolar lead devices. One of the biggest innovations has been the introduction of quadripolar lead devices. Quadripolar leads could enhance response to cardiac resynchronization therapy (CRT), offering four pacing locations along the distal end of the lead. Several quadripolar leads are available, all with different shapes and electrode spacing. Electrodes can be positioned in an ideal pacing location, determined by delayed mechanical or electrical activation, and away from phrenic nerve stimulation, high-pacing thresholds, and fibrosis. Implantation is safe, with comparable or even lower complication rates compared with standard bipolar leads.
Battery life. Battery longevity has long been an issue with ICDs. As patients live longer, they may need to undergo surgical procedures every few years for regular battery replacements. Increased device longevity can reduce the risk of infection and other complications due to repeat replacement procedures and help minimize out-of-pocket patient expenses for avoidable replacement procedures.
Reducing shocks. Patients' quality of life and faith in their ICDs can be significantly decreased if their ICD shocks the patient needlessly. Some vendors now include technology to help reduce inappropriate shocks. Advanced technologies are offering advanced sensing options designed to reduce the incidence of inappropriate shocks. The algorithm provides advanced alerts as well as more proactively lowering the risk of lead-related complications through its ability to automatically withhold tachycardia therapy in the presence of lead noise (over-sensing of electrical signals). Specific programming distinguishes between rhythms that require defibrillation therapy and those that do not, such as benign arrhythmias.
Challenges and Opportunities
Development of technologically advanced defibrillator, rapid growth in aging population with high risk of target diseases, rising incidences of cardiovascular disease, growing focus of public and private organizations and key market players toward public access defibrillator, and increasing number of training and awareness programs are propelling the growth of the market.
However, lack of awareness about sudden cardiac arrest, issues related to the use of defibrillator devices (external and implantable), and unfavorable healthcare reforms are restraining the growth of this market. In addition to this, the increasing pricing pressure on market players and frequent product recalls are the key challenges faced by market players.
Future advances in technology are motivated by the demographics of an aging population and by the success of various medical interventions in improving the survival of cardiac patients prone to SCD. A goal of newer-generation ICD devices will be to provide intervention prior to arrhythmia onset, avoiding discomforting cardioversion or defibrillation therapy.
ECG or physiologic parameters known to increase ventricular arrhythmia risk, including long-short R-R intervals, T-wave alternans, heart rate variability, or hemodynamic instability, may be intervened on by novel ICD therapies. Such programmable therapies may include pacing to avoid long-short coupling, intermittent antiarrhythmic drug infusion, or multisite pacing to improve hemodynamics.
Further advances in device technology could undoubtedly expand the role of the ICD in the primary and secondary prevention of SCD. The recently developed generation of S-ICD demonstrates favorable features including a smaller device, longer longevity, and remote-monitoring compatibility. Further innovations in the S-ICD system and potential integration with leadless pacing may play an important role in defibrillation therapy and prevention of SCD in the near future.
With advances in capacitor and battery technology coupled with improved lead systems and waveform resulting in lower defibrillation thresholds, it is likely that lower-output, smaller devices will be developed. Future advances in devices may likely lead to improved arrhythmia classification, more advanced automated features, and additional features including more sophisticated sensors and biventricular pacing systems.