• A rapid heartrate that exceeds the range of the normal resting heartrate for age.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2021
• Abnormally high heart rate. Thresholds for different age, gender, and patient populations exist.
  U.S. FDA Glossary
  U.S. Food & Drug Administration, 2021
• Abnormally rapid heartbeat, usually with a HEART RATE above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• An abnormally fast heartbeat, usually above 100 beats per minute.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• An abnormally high heart rate for age.
  NICHD Pediatric Terminology
  U.S. National Cancer Institute, 2021
• An abnormally rapid heart rate. Thresholds for different age, gender, and patient populations exist.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• Excessive rapidity in the action of the heart.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Rapid beating of the heart, usually defined as greater than 100 beats per minute.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• Tachycardia is the medical term for a heart rate over 100 beats per minute. There are many heart rhythm disorders (arrhythmias) that can cause tachycardia.
  Mayo Clinic
  Mayo Foundation for Medical Education and Research
• Tachycardia, a heart rate of more than 100 beats per minute. Tachycardia occurs normally during and after exercise or during emotional stress and represents no danger to healthy individuals. In some cases, however, tachycardia occurs without apparent cause or as a complication of a myocardial...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2020