title: Time to dP/dt(max), a useful index for evaluation of contractility in the catheterization laboratory.
abstract: OBJECTIVE
  The time from onset of contraction to dP/dt(max), td, is suggested as an index of contractility in the catheterization laboratory.
  
  
  METHODS
  We studied 22 normal patients and 18 patients with myocardial failure in the catheterization laboratory. The two groups were completely separated on the td-heart rate (HR) plane. In the normal patients, HR = 73 +/- 19 beats/min, td = 73 +/- 11 ms, and an inverse linear relation td = 109-0.49 x HR (p < 0.001) exist. In the patients with myocardial failure, despite significantly higher HR than in normal patients (HR = 93 +/- 14 beats/min) (p < 0.001), td paradoxically increased (td = 89 +/- 11 ms, p < 0.0001).
  
  
  CONCLUSIONS
  These findings support a mathematical analysis of the left ventricular pressure (LVP) during isovolumic contraction in the time domain which shows that td and (dP/dt)/P reflect the time-dependent aspects of contraction and, hence, decrease with increasing contractility. This study shows that td, at any given HR, is a reliable index of contractility. Thus, a ready-to-use td-HR plot containing a well-based separation line can provide a reliable and simple method for determining contractility in the catheterization laboratory by examining whether a patient's td value at any HR is below (normal) or above (impaired contractility) the separation line.
authors.affiliation: Department of Biomedical Engineering, Hadassah University Hospital, Jerusalem, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Adler
authors.forename: E S
authors.initials: ES
authors.lastname: Monrad
authors.forename: O M
authors.initials: OM
authors.lastname: Hess
authors.forename: H P
authors.initials: HP
authors.lastname: Krayenbuehl
authors.forename: E H
authors.initials: EH
authors.lastname: Sonnenblick
mesh_terms: D006328:Cardiac Catheterization; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008433:Mathematics; D009200:Myocardial Contraction / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*; D017725:Ventricular Pressure