Definition and diagnosis
Arrhythmia characteristics contributing to TCM include not only the
heart rate but also the arrhythmia type, duration, irregularity, and
persistence [18]. An arrhythmia that is insidious, persistent, and
well-tolerated is more likely to result in TCM [18]. Lack of
persistent tachycardia from autonomic influences and resultant slower
rates during sleep are likely to be the reasons that TCM is rare with
inappropriate sinus tachycardia and postural orthostatic tachycardia
syndrome. However, the average heart rate can be > 100
beats/min. There is no specific heart rate cutoff at which TCM develops,
it seems to be age-dependent, and a heart rate two-times faster than the
normal heart rate can be considered as a threshold for TCM [19].