title: Termination of ventricular bigeminy by conversion to concealed forms.
abstract: Ventricular bigeminy may be either overt or concealed. In this study, we attempted to determine the frequency with which the overt form converted to the concealed variety. Ambulatory electrocardiographic recordings from 25 patients with greater than 40 episodes of monomorphic ventricular bigeminy were examined. A statistically significant (P less than 0.01, binomial distribution) predominance of odd or even number of sinus beats between the end of a bigeminal episode and the next ventricular premature beat was considered to be evidence for conversion of overt to concealed bigeminy. In 14 of the 25 cases, the number of episodes of bigeminy followed by odd numbers of sinus beats was beyond these statistical bounds. In 74 episodes in 9 patients, progressive prolongation of the coupling interval during bigeminy occurred before termination. These data demonstrate the high prevalence of concealment as a mode of termination of bigeminy. In a small number of episodes, this occurs in a pattern suggestive of progressive delay of conduction in or around an arrhythmogenic locus.
mesh_terms: D005117:Cardiac Complexes, Premature / Q000503:physiopathology*; D004562:Electrocardiography; D006327:Heart Block / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008991:Monitoring, Physiologic