Method for the detection of subcutanous cardiac signals and a cardiac device for use in detecting subcutaneous cardiac signals

A cardiac device (100) for use in detecting QRS signals within a composite heart signal of a body, comprising:

• an input unit (10) configured to provide at least two input heart signals via at least two separate input channels, wherein each channel is connected to pairs of external sensing electrodes, and wherein at least two input heart signals are recorded by said pairs of external sensing electrodes and provided coincidental in time;
• an estimation unit (20) configured to generate estimated signals from the at least two input heart signals;
• a combination unit configured to combine the estimated signals to a combined input stream (SECG);
• and,
• an automatic sensor control unit (50) configured compare the combined input stream (SECG) to an adaptive detection threshold (ATHR) which adapts throughout time to detect a QRS signal.