Breath-holding during ECG generally has an effect on early supraventricular tachycardia, physiologic sinus arrhythmia, and stress-induced sinus tachycardia, slowing the heart rate; however, it does not have much effect on pathologic tachycardia such as rapid atrial fibrillation and ventricular tachycardia.
Breath-holding action will cause increased vagal excitability, heart rate slowing, part of the early episodes of supraventricular tachycardia, breath-holding action may be able to terminate the tachycardia, but also may affect the physiological sinus arrhythmia and tension and anxiety caused by sinus tachycardia.
If the tachycardia is pathologic, heart rate >100 beats/min, such as rapid atrial fibrillation, ventricular tachycardia, atrial tachycardia and other arrhythmias, the breath-holding action tends to have little effect.
It is recommended that patients need to rest for a period of time before testing the ECG, do not be overly nervous, and if there is an abnormality in the ECG, it is recommended to ask the doctor’s opinion.