One year experience with the Chronicle® implantable hemodynamic monitor in patients on the heart transplant waiting list

Aims: The vast majority of heart transplants is performed in patients in HU status. Close monitoring of patients waiting at home is now essential to identify those who deteriorate. Methods: Since October 2005 we implanted a Chronicle® implantable hemodynamic monitor in 10 patients waiting for a heart transplant (all male, 54.7±7.8 years, NYHA 3.3±0.3, LVEF 20.3±7.7%). The device is implanted like a pacemaker and includes a pressure sensor lead which is positioned in the RV outflow tract. This allows the continuous measurement of intracardiac pressure, heart rate and activity. The data are transmitted weekly by the patient with a remote monitor and delivered to the clinician via internet. Results: Weekly transmissions by the patients could be performed in all cases. Medication was adjusted following a pressure increase in 3 patients. Two patients showed episodes of cardiac decompensation, in one the device detected 2 episodes of ventricular tachycardia with a critical decrease of ventricular pressures terminated by an ICD. He was consequently admitted to the hospital and accepted for high urgent listing. By now he and one of the elective patients were successfully transplanted. In 3 other patients the Chronicle® detected cyclic varaiations in heart rate, the typical pattern of sleep apnea syndrome. These patients were referred to ENT for further diagnosis and CPAP treatment. Conclusion: The Chronicle® is easy to implant and appears to be an ideal tool to identify patients waiting at home who are at risk of acute hemodynamic decompensation.