Clinical Usefulness and Efficacy of Intrathoracic Impedance Monitoring Using the OptiVol Patient Alert(TM)

Clinical Usefulness and Efficacy of Intrathoracic Impedance Monitoring Using the OptiVol Patient Alert(TM) in Medtronic(R) ICD's for Early Detection of Decompensated Heart Failure

In this study we investigate the clinical value and efficacy of OptiVol (TM) impedance measurements by Medtronic (R) ICD's. We aim to determine sensitivity and positive predictive value for detecting heart failure. We also investigate if left ventricular filling pattern measured by echocardiography and/or brain natriuretic peptide (BNP) level can be used to improve the positive predictive value of the Optivol alert

Patients who have a Medtronic (R) ICD equipped with the Optivol (TM) impedance monitoring will be included in your study after informed consent. The OptiVol (TM) feature will be activated and at baseline data is collected (blood sample including BNP, electrocardiography, echocardiography, chest X-ray and ICD check-up). During follow-up patients will be re-assessed in case of an OptiVol alert or in case of heart failure.

Inclusion Criteria:

• chronic heart failure of any cause
• implanted Medtronic ICD with OptiVol impedance monitoring

Exclusion Criteria:

• inability to receive informed consent