Physicians have long puzzled over diagnosis and treatment of patients with irritable or "hyperkinetic" hearts. These patients commonly suffer from labile tachycardia, palpitations, and increased awareness of their heart beat, associated with chest discomfort and varying degrees of intolerance to exercise. The absence of a consistent pattern of organic abnormalities has prevented meaningful classification and diagnosis. Lack of information regarding the natural history and prognosis of the syndrome has made evaluation of therapy virtually impossible.
Therefore, keen interest greeted the suggestion of Frohlich et al1 that at least some of these patients suffer from hyperresponsiveness of their cardiac beta-adrenergic receptors. Although these hyperresponsive patients were not typical of the textbook picture of the hyperkinetic heart syndrome in that most of them had hypertension, the suggestion was attractive because, in addition to illumination of one of the murky areas of diagnostic medicine, it contained a satisfying rationale for therapy with