In their series of 99 achalasia patients, Pandolfino et al.12 classified 21 patients as type I, 49 as type II, and 29 as type III; follow-up information in sufficient detail and of sufficient duration (at least a year) was available for 83 of these patients. Fourteen patients were given botox injections, 43 were treated with PD, and 26 underwent LHM. From a clinical point of view, type I patients were more likely to have esophageal dilation, whereas type II and III patients had chest pain significantly more often. The success of treatment was strongly influenced by the achalasia subtype, irrespective of the type of therapy involved. Achalasia subtype II was much more likely, and type III much less likely to respond to treatment than type I (Table 1). Patients with type II did respond excellently, with a success rate of 96%, as opposed to 56% and 29% for types I and III, respectively. In this study, success was defined as a documented improvement recorded at one or more postintervention clinical visits, such that no further intervention was recommended for at least 12 months. Although patients with type I achalasia seemed to respond best to LHM, the number of patients involved was rather small and larger studies are needed to confirm this finding. It became clear from subsequent studies, however, that the success of therapy is indeed determined by the achalasia subtype. Although largely conventional (sleeve) manometry rather than high resolution manometry was used in these studies, similar patterns can be distinguished with this technique allowing reliable sub-classification. In a large series of patients treated with LHM, Salvador et al.13 studied 249 consecutive patients (with a median follow-up of 31 months): 39% of patients were classified as having achalasia type I, 51.6% as type II and 9.4% as type III (Table 1). Patients were considered treatment failures if their postoperative symptom score was >7. At multivariate analysis, the manometric pattern was confirmed as an independent predictor of success: type II patients responded best to treatment (95.3% success rate), and patients with type III had the lowest response rate (69.6%). A smaller study reported on the short-term results (after a mean follow-up of 6 months) in 45 achalasia patients treated with PD14. As in the previous studies, patients with type II had a better clinical response (90%) than types I (63%) or III (33%) (Table 1). Finally, when the manometric tracings of the achalasia patients included in the European achalasia trial were classified according to the criteria proposed by Pandolfino et al., type I achalasia was identified in 44 patients (25%), type II in 114 (65%), and type III in 18 (10%)15. Of these 175 patients, 84 were randomized to PD and 91 to LHM. After 2 years of follow-up, the success rates were significantly higher for type II cases (96%) than for type I (81%) and type III (66%) patients, irrespective of the type of treatment15 (Table 1). The response rate was particularly low in type III patients who had PD (n = 10, 40% success rate), but otherwise largely comparable for PD and LHM in types I and II.