Patent ID: 8886305

Claim:
An implantable ventricular heart stimulator ( 10 ), comprising: an at least partially electrically conductive housing ( 12 ); a terminal comprising a defibrillation electrode line terminal configured to connect a ventricular defibrillation electrode ( 26 , 28 ) with a defibrillation electrode line ( 20 ) wherein said terminal is not connected to an atrial electrode line; a far-field electrocardiogram detection unit ( 70 ), which has a first input that is connected to the terminal for the ventricular defibrillation electrode and has a second input that is connected to the at least partially electrically conductive housing ( 12 ) and wherein the far-field electrocardiogram detection unit ( 70 ) is configured to generate a far-field electrocardiogram based on electric potentials applied to the first input and second input; a far-field electrocardiogram evaluation unit ( 72 ) connected to the far-field electrocardiogram detection unit ( 70 ) and wherein the far-field electrocardiogram evaluation unit ( 72 ) is configured to detect signal features characteristic of atrial depolarization in the far-field electrocardiogram generated by the far-field electrocardiogram detection unit ( 70 ); wherein said implantable ventricular heart stimulator does not comprise an atrial electrode line terminal; wherein the far-field electrocardiogram evaluation unit ( 72 ) is configured to detect sensing events or signal peaks in the far-field electrocardiogram which are not to be assigned to an intrinsic atrial event and to remove such signal peaks from the far-field electrocardiogram and then to further process the far-field electrocardiogram to detect atrial sensing events; and, wherein the implantable ventricular heart stimulator is configured as an implantable cardioverter/defibrillator and comprises a VT/SVT evaluation unit configured to make an assignment of ventricular arrhythmia to a supraventricular tachycardia or a ventricular tachycardia based on successive detected atrial events and successive ventricular events.