It is known that with every degree (1°F) rise of temperature, the pulse rate is increased by 10 beats/minute.
Relative bradycardia
In this condition, the increase in pulse rate is less than 10 beats/minute with per degree (1°F) rise of temperature.
For example, the pulse rate in relative bradycardia will be about 80/minute, when the temperature is increased by 2°F (actually it should be 92/minutc).
This is is seen in :
- Any viral fever.
- First week of enteric fever.
- Sometimes in pyogenic meningitis.
- Brucellosis, psittacosis.
- The relative bradycardia in yellow fever is known as Faget's sign.
The increase in pulse rale is more than 10 beats/minute with per degree (1°F) rise of temperature. For example, the pulse rate will be about 120/minute, when the tem-
perature is raised by 3°F (actually it should be 102/minute).
This is seen in :
- Acute rheumatic carditis.
- Tuberculosis.
- Diphtheritic myocarditis.
- Polyarteritis nodosa.
