Implantable Sensor Monitors Heart Failure Patients Remotely

An implantable wireless device remotely monitors pulmonary artery (PA) pressure and heart rate in heart failure patients.

The CardioMEMS HF System is a permanently implantable, battery-free wireless system intended to provide PA pressure measurements, including systolic, diastolic, and mean pressures, which can be displayed as an 18 second PA waveform or as a pressure trend data waveform; heart rate is also displayed. The PA and heart rate data can then be reviewed by physicians, who can make decisions regarding the status of the patient and, if necessary, initiate changes in medical therapy, with the goal of reducing hospitalization due to heart failure.

The system consists of three parts - a sensor/monitor implanted permanently in the PA that is powered by radiofrequency (RF) energy; a transvenous catheter delivery system that deploys the sensor within a branch of the left or right distal PA; and the CardioMEMS hospital and patient electronics system. During the RF pulse, the sensor accumulates energy, and after excitation stops, the energy is re-radiated by the sensor and received by the electronics unit. The PA pressure data is encoded in the frequency of the sensor transmit signal, processed, and transferred to a secure database.

The sensor itself is a resonant circuit consisting of a capacitor and an inductor. The capacitance of the sensor is a function of the pressure in the sensor's environment, and the resonant frequency is a function of the capacitance, measured by the electronics unit. Due to presence of the inductor coil, the sensor can be electromagnetically coupled and the resonant frequency of the circuit can be measured remotely. This allows for wireless communication with the sensor and eliminates the need for a battery. The CardioMEMS HF System is a product of CardioMEMS (Atlanta, GA, USA), and has been approved by the US Food and Drug Administration (FDA).

“Hospitalizations are very traumatic for heart failure patients and costly to the health care system,” said Jay Yadav, MD, Founder and CEO of CardioMEMS. “With the availability of the CardioMEMS heart failure monitoring system, doctors and nurses can now deliver improved and more efficient care to their patients and produce meaningful reductions in their patients’ heart failure related hospitalizations.”

In September 2010, St. Jude Medical (SJM; St. Paul, MN, USA) invested USD 60 million for 19% ownership of CardioMEMS, with an exclusive option to purchase the remaining 81% of the company for USD 375 million. SJM intends to immediately exercise its exclusive option to acquire CardioMEMS.

Related Links:
CardioMEMS
St. Jude Medical