The term hesitant arose in the Essential of Acupuncture and is, I believe still used in Chinese Acupuncture and Moxibustion. The California Acupuncture Board continues to use the term hesitant as a translation of the rough pulse (sè mài,??)
http://www.acupuncture.ca.gov/students/exam_preparation.pdf. In this instance, the notion of hesitant sprang from what I consider to be an excessive focus upon time based distortions in the wave: "faltering and balking".

This tract focuses upon Leon Hammer's hesitant pulse as a wave with such a rapid arrival and departure that it feels like a line straight up and down. If we apply the Pulse Classic and divide the arrival into the yang portion and the departure into the yin portion of the wave, then Hammer's hesitant suggests both yin and yang are affected. It is one of Shen's push pulses related to obsessive overworking and we can see it in government and stock market. It reminds me of the trader who has monitors in the kitchen and the bathroom so as not to miss a trade.

The wave analysis method for Hammer's 'hesitant' pulse also confirms yin depletion (rapid departure), but also a slight hyperactivity ofyang (rapid arrival). Since it is in the wave, the heart is the primary indication. Thus, the notion of yin depletion that Dr. Shen identifies is reiterated using early wave analysis methods. As for the yi, as one of the shen it resides in the heart. Of course, the spleen is the natural residence of the yi. That is the paradox.

The hesitant pulse is distinct from Professor Xie Zhufa's description of the "Bird-pecking Pulse" as described in English Translation of Common Terms in Chinese Medicine (2004). Clearly, this is an arrhythmia:

The pulse is middle-sited with rapid rhythm . After three or five beats , the pulse pauses suddenly for a long interval, then the pulse appears again as if a bird pecks food . It indicates that primordial energy of spleen and essential substances from cereals exhaust inside body.

A feature of the ideal pulse is that it has stomach qi (wei), spirit (shen), and root (gen).. The stomach qi causes the pulse to be moderate and represents the gu qi that comes slowly with harmony. Stomach qi is postnatal qi, it is the source of the postnatal qi and blood, and the transformation of the pulse is full. The spirit of the pulse is the stability of shape volume and temporal factors. Spirit depletion is signified by inconsistent comings and goings. When the pulse begins to flicker, develop arrhythmias and is easily changed in terms of shape and volume, then the spirit of the pulse is absent. There is no spirit if the pulse disappears. The root is representative of the essence; it is the deep area of the organ depth and it is the proximal positions. The weird pulses all have a distinct absence of one or more of spirit, root or stomach qi. This hesitant wave is not full. It virtually has no arrival nor departure. This is a concern in the area of stomach qi as opposed to spirit or root.

The hesitant pulse involves automaticity which is an intrinsic property of some types of cardiac tissues, like the nodes and the conducting fibers. Automatic cells are characterized by the appearance, during diastole, of a slow depolarization which is capable of reaching threshold and generate an action potential. This depolarization may also be called a slow diastolic depolarization, or pacemaker potential. In the hesitant pulse, the automaticity depolarizes more quickly, this gives the sensation of no ramp up in the wave.

The refractoriness property is defined as the period of recovery that cells required after being discharged before they can be reexcited by a stimulus. This refractory period is reduced in the hesitant pulse, giving the impression of no departure portion of the wave. The electro-phathophysiological mechanisms of the hesitant pulse can be divided into disorders of impulse propagation and the disorders of impulse formation. There are three factors affecting automaticity. They are the maximum diastolic potential, threshold potential and the slope of repolarization.

I think it is important to raise the notion that early Chinese texts on rate do not articulate the difference for a fast pulse between beats per breath and an elevated rate of arrival or departure. The rate of the wave's arrival can be fast - and it is in the hesitant pulse, just as it is in the departure. So this is a pulse that in early times may have been described as fast. If it is without force, it is yin depletion. If there is force, there can be excess heat involved. The problem is that both the automaticity and the refractory period are so short, there is insufficient time to fill the heart with blood, so there is a reduced ejection fraction. This creates a scenario where a forceful hesitant pulse is rarer.

So - in pursuit of a treatment for the patient with the hesitant pulse, and assuming confirmation of yin depletion,

Treatment principles:
Nourish Yin, enrich the Kidney and Heart, clear the Depletion-Fire
Formula:
1.“Huang Lian E Jiao Tang” (Coptis-Gelatinum Corii Asini Decoction)
Huang Lian 9g, Huang Qin 9g, Bai Shao 10g, Ji Zi Huang 2 yolks,
EJiao 10g.
2.“Tian Wang Bu Xin Dan”(Emperor of Heaven’s Special Pill To Tonify
The Heart)
Sheng Di Huang 12g, Ren Shen 6g, Tian Men Dong 12g,
Mai Men Dong 12g, Xuan Shen 9g, Dan Shen 10g, Fu Ling 12g,
Yuan Zhi 6g, Dang Gui 9g, Wu Wei Zi 5g, Bai Zi Ren 10g,
Suan Zao Ren 10g, Jie Geng 9g, Zhu Sha 10g.

For severe yin deficiency, add
Mai Men Dong (Ophiopogonis Japonici, Tuber) 10g
Sheng Di Huang (Rehmanniae Glutinosae, Radix) 10g
Dang Gui (Angelicae Sinensis, Radix) 6g
For irritability and insomnia, add
Long Chi (Draconis, Dens) 15g
Mu Li (Ostreae, Concha) 15g
For significant empty heat, add
Xi Yang Shen (Panacis Quinquefolii, Radix) 8g
Lian zi xin (Nelumbinis Nuciferae, Plumula) 10g

Electrophysiological study of Dang Gui:
Treating experimental arrhythmia with the alcohol purified extracts of Dong Gui was reported by Dr. Wei Zhong Min (Biejin University of TCM). The results suggest that Dang Gui can slow conduction, increase refractoriness, and depress phase 0 depolarization by increase action potential amplitude (APA), prolong the effective refractory period (ERP), and decrease the rate of rise of action potential (Vmax).

Further, complex patterns of blood stasis, excess heat and phlegm heat are common concomitants with the hesitant pulse, the whole picture must be considered. If there is qi depletion also present, Baked Licorice Combination (zhi gan cao tang) also has Ginseng and Ophiopogonis (Sheng Mai San) in it.