1.   Doctors ran tests to determine the cause of his irregular heartbeat.

2.   Large amounts of strong coffee can cause insomnia and, in extreme cases, palpitations and irregular heartbeats.

3.   Put simply, cardiac arrhythmia is an irregular heartbeat.

4.   The irregular heartbeat of battle was distant as yet but throbbing closer.

5.   Two years ago, she was hospitalized because of an irregular heartbeat.

6.   Shelley listened to her chest, and heard the tell-tale irregular heartbeat, saw the clammy face and grey pallor.

7.   Samples from Hamanaka and Badastan, who returned with irregular heartbeats following their defeats at Leicester and Sandown last Thursday, have also proved negative.

8.   An irregular heartbeat, or cardiac arrhythmia, causes the heart to quiver and not produce a useful blood flow to the brain and the heart.

9.   And it made for a happy return for Dodgers manager Davey Johnson, who returned from a four-game absence after being hospitalized with an irregular heartbeat.

10.   And the company already has some promising drugs in its system, including Azimilide, which is being tested now to treat irregular heartbeats.