1.   In general, the more complex dual-chamber device allows the heart to function in a more natural, or physiological, way.

2.   The doctors said that Weld will go to Massachusetts General Hospital this morning for a stress test to determine how his heart functions under pressure.

3.   When the heart is functioning properly, its four chambers beat in a well-orchestrated way.

4.   But a later hospital statement said Papandreou was stable and his heart was functioning normally.

5.   Ironically, because the artificial heart has functioned so well, he is healthier than many other heart patients and lower on the transplant priority list.

6.   His heart was functioning normally with no evidence of muscle damage, the government said after the procedure.

7.   Medical bulletins issued by the Onassio clinic however have repeatedly stressed that his heart is functioning normally.