Are tertiary waves a sign of disturbed esophageal motility ?
L. Tibbling (Linkoping)
Esophageal motor activity can be described in terms of primary peristaltic contractions, secondary peristaltic contractions, and tertiary contractions. The contraction wave which starts high up in the pharynx and progresses down the whole length of the esophagus is initiated by the voluntary act of swallowing. This wave is called primary peristalsis (figure 1).
Secondary peristalsis is a peristaltic contraction of the esophageal circular muscle which begins without swallowing. This secondary wave originates in the esophagus as a result of distension and gives a similar manometric pattern as primary peristalsis. Tertiary waves are defined as contractions which occur simultaneously at different levels of the esophagus . They represent nonperistaltic, contractions either of isolated (figure 2) or repetitive (figure 3) character and can be elicited spontaneously or by swallowing. Tertiary waves can appear segmentally or in the entire esophageal body.
Spontaneous tertiary waves
A spontaneous wave is a contraction of the body of the esophagus that is not initiated by a swallow. A spontaneous tertiary wave of non-repetitive character can
Figure 1. Primary peristalsis.
Figure 2. Multiple-peaked tertiary contraction of non-repetitive character.
Figure 3. Tertiary contractions of repetitive character in a patient with achalasia.
be elicited by strong acoustic stimulation in normal people [2, 3]. This wave probably originates in the outer muscle layer of the esophagus which normally serves as a framework supporting the activity of the inner layer and is responsible for axial shortening of the esophagus. Tertiary waves can also be provoked by strong flashes of light or by putting a hand in ice-cold water (author's observation). They can be regarded as a sign of an alarm reaction induced by the sympathetic system.
Richter  found that 50 p. cent of healthy adults will show repetitive spontaneous contractions even during a 5-min quiet period. He concluded that frequent spontaneous activity may be a variation of the normal and must be interpreted cautiously.
Swallowing induced tertiary waves
Any evaluation of tertiary contractions must take into consideration the methodology used to evaluate esophageal motor function. Esophageal motility is commonly recorded with three catheter orifices placed in the body of the esophagus and spaced 5 cm apart. The swallowing induced waves are regarded as simultaneous if the onset of waves from the three orifices are not separated in time. The onset of each wave is determined by the maximum upstroke . Wet swallows have now replaced dry swallows as the conventional means of inducing peristaltic activity. According to Richter , the prevalence of non-peristaltic contractions after dry swallows (18 %) is significantly greater (p < 0.001) than after wet swallows (4%) in healthy subjects. From a study on 15 healthy and symptom-free subjects , normal peristalsis was defined as peristaltic activity following 80 p. cent of a series of wet swallows at 30 second intervals. Simultaneous, repetitive and non-transmitted contractions were regarded as non-peristaltic activity. In other words, simultaneous, repetitive contractions were seen in a low frequency in normal subjects. In patients with symptoms of diffuse esophageal spasm, simultaneous contractions are observed after approximately 40 p. cent of wet swallows .
Achalasia is a primary esophageal motility disorder with absence of peristalsis. This is manifested by the appearance of tertiary waves throughout the entire esophagus in all swallowings. The occurrence of tertiary waves following all wet swallows is usually abnormal. However, a non-peristaltic activity has been noticed in a symptom-free subject in a population study of 209 people . This man, aged 25 years, developed an achalasia with dysphagia more than three years later.
The function of the esophagus is to convey material from the pharynx to the stomach. Clinically seen, the concept disturbed motility must refer to symptoms of dysphagia or impaired esophageal clearance. Patients who have undergone a myotomy of the entire esophageal body can achieve a more or less complete restoration of their swallowing ability. However, only tertiary waves are then recorded at manometry. Tertiary repetitive waves as a constant finding after swallowing can therefore not always be regarded as disturbed motility.
Conversely, can a disturbed motility or dysphagia always be established as tertiary waves after swallowing ? Motility studies at esophageal manometry were performed
on 37 patients with gastroesophageal reflux disease and on 15 control subjects . It was shown that the predictive accuracy of motility disturbance for dysphagia was 56 p. cent, the sensitivity was 33 p. cent and the specificity 36 p. cent. The low reliability of motility examinations makes therefore these methods unsuitable for clinical practice.
In conclusion, tertiary esophageal waves of the non-repetitive type can be found in normal subjects. Swallowing induced repetitive tertiary waves are usually abnormal. A disturbed motility will not necessarily present itself by tertiary waves in manometric examinations.