Lung Impedance Monitoring In Treatment of Chronic Heart Failure
Lung Impedance Monitoring In Treatment of Chronic Heart Failure
Heart failure is a major clinical problem that is increasing in magnitude and the cost of
 management of heart failure is escalating. A significant part of this cost is related to
 unplanned acute presentation to emergency departments and hospitalisation with worsening
 shortness of breath due to increased fluid content in the lungs.

 Many heart failure patients are already fitted with defibrillators to protect them from the
 risk of fast heart rhythms and sudden death and are followed up in both the heart failure
 clinics and defibrillator clinics. Recently some of the defibrillators fitted have been
 equipped with an extra function that can detect and warn of changes in the fluid content of
 the lungs very early even before the patient starts to complain of any shortness of breath
 and before any signs of fluid overload are seen clinically. However, it is not known how to
 deal with these warnings if they occur very early and it is not known whether a medical
 intervention at his stage is beneficial to prevent progression and eventual hospital
 admission. In the majority of cases, early warnings of this kind are ignored or this function
 is disabled at implantation of the device.

 The current study will involve patients who have already been fitted with a device with the
 above capability. The investigators will use the new function to guide management of these
 patients and compare their outcome with similar patients who are fitted with devices without
 it. The investigators will attempt to manage early warnings by a predetermined increase in
 medications in a group of patients and compare their clinical course to a similar group in
 whom no action is taken.
Inclusion Criteria:

 -  Previously fitted with an ICD or a CRT-D device for primary or secondary prevention
 (for at least 34 days) with a Medtronic Optivol capable Device

 -  Previous hospital admission for decompensated heart failure

 -  Left ventricular systolic dysfunction (EF <50%)

 -  Currently compensated heart failure with a functional class of III or better

 -  All patients will be on optimal medical treatment including a beta blocker, an ACEI
 (or ARB) and spironolactone unless contraindicated or not tolerated

 Exclusion Criteria:

 -  Decompensated patients who have NYHA class IV or clinical signs of lung congestion at
 time of evaluation (these patients may be included later if/when their NYHA class
 improves)

 -  Patients with a high Optivol fluid index at time of evaluation (these patients may be
 included later when the Optivol fluid index comes down)

 -  Patients with advanced renal failure ± dialysis (Chronic Kidney Disease class 4 or 5
 with an estimated GFR of <30 ml/min)