1. Rapid, uncoordinated contractions of muscle fibers in the heart, causing irregular heartbeat and reduced blood flow.
Usage: Medical term; plural of fibrillation; Commonly used in cardiology
2. Fine, involuntary trembling or twitching of muscle fibers in any part of the body.
Usage: Medical/physiological term; broader usage beyond the heart

Examples

• The patient experienced atrial fibrillations that required immediate medical attention.
• Ventricular fibrillations can be life-threatening if not treated promptly.
• The cardiologist detected fibrillations on the ECG monitor.
• Fibrillations in the heart muscle reduce its ability to pump blood effectively.
• The medication was prescribed to prevent recurrent fibrillations.
• Muscular fibrillations may indicate nerve damage or disease.