Evans D W, Lum L C
Lancet. 1977 Jan 22;1(8004):155-7. doi: 10.1016/s0140-6736(77)91760-3.
50 patients initially referred to a cardiac clinic for confirmation or exclusion of angina were found to be habitual hyperventilators. 13 of them also had some organic heart disease. Simple physiotherapy aimed at restoring a normal breathing pattern proved an effective treatment, 76% of those followed for 11-68 months being symptom-free.