Patent ID: 7389142

Claim:
An implantable heart monitoring device comprising: a control circuit; a first sensor adapted to be disposed in a coronary sinus region of a heart to sense blood oxygen in said coronary sinus region, and supplying a first sensor signal representing a blood oxygen level to the control circuit; at least one further sensor adapted to interact with the heart to sense activity of the heart, said at least one further sensor supplying a further sensor signal representing said activity to the control circuit; and said control circuit, from said further sensor signal, identifying a first portion in a diastolic portion, and a second portion in a systolic portion, of a same heart cycle of the heart, and from said first sensor signal, determining a first value related to said blood oxygen level that occurs during said first portion and identifying said first value as having occurred during said first portion and determining a second value related to said blood oxygen level that occurs during said second portion and identifying said second value as having occurred during said second portion, and said control circuit emitting an output signal indicative of functioning of the heart dependent on a relation between said first value and said second value.