title: Influence of the elevation of the left ventricular diastolic pressure on the values of the first temporal derivative of the ventricular pressure (dP/dt).
abstract: OBJECTIVE
  To assess the effects of the elevation of the left-ventricular end-diastolic pressure (LVEDP) on the value of the 1st temporal derivative of the ventricular pressure (dP/dt).
  
  
  METHODS
  Nineteen anesthetized dogs were studied. The dogs were mechanically ventilated and underwent thoracotomy with parasympathetic nervous system block. The LVEDP was controlled with the use of a perfusion circuit connected to the left atrium and adjusted to the height of a reservoir. The elevation of the LVEDP was achieved by a sudden increase in the height of a reservoir filled with blood. Continuous recordings of the electrocardiogram, the aortic and ventricular pressures and the dP/dt were performed.
  
  
  RESULTS
  Elevation of the LVEDP did not result in any variation of the heart rate (167 +/- 16.0 bpm, before the procedure; 167 +/- 15.5 bpm, after the procedure). All the other variables assessed, including systolic blood pressure (128 +/- 18.3 mmHg and 150 +/- 21.5 mmHg), diastolic blood pressure (98 +/- 16.9 mmHg and 115 +/- 19.8 mmHg), LVEDP (5.5 +/- 2.49 and 9.3 +/- 3.60 mmHg), and dP/dt (4,855 +/- 1,082 mmHg/s and 5,149 +/- 1,242 mmHg/s) showed significant increases following the expansion of the ventricular cavity. Although the elevation of the dP/dt was statistically significant, 6 dogs curiously showed a decrease in the values of dP/dt.
  
  
  CONCLUSIONS
  Sudden elevation of the LVEDP resulted in increased values of dP/dt; however, in some dogs, this response was not uniform.
authors.affiliation: Faculdade de Medicina de Botucatu, UNESP, Brazil.
authors.forename: K
authors.initials: K
authors.lastname: Okoshi
authors.forename: J R
authors.initials: JR
authors.lastname: Fioretto
authors.forename: R C
authors.initials: RC
authors.lastname: Bonatto
authors.forename: M T
authors.initials: MT
authors.lastname: Tornero
authors.forename: P J
authors.initials: PJ
authors.lastname: Tucci
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D003971:Diastole / Q000502:physiology; D004285:Dogs; D006339:Heart Rate / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology*