Method and apparatus to determine the end of the systolic part of a pressure curve

• US 8,506,496 B2
• Filed: 11/24/2008
• Issued: 08/13/2013
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Edwards Lifesciences AG (Edwards Lifesciences Corporation)
• Original Assignee: Edwards Lifesciences AG (Edwards Lifesciences Corporation)
• Inventors: Knoll, Reinhold, Borg, Ulf, Pfeiffer, Ulrich
• Primary Examiner(s): Natnithithadha, Navin
• Assistant Examiner(s): BERHANU, ETSUB D
• Application Number:
  US12/744,772
• Publication Number:
  US 20110040195A1
• Time in Patent Office: 1,723 Days
• Field of Search: 600/485, 600/481, 600/509, 600/513
• US Class Current: 600/485
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence

Abstract

The invention relates to a method and an apparatus for determining the systolic phase interval (SP) of an arterial pressure curve with a starting point (t0) of the systolic phase interval (SP) and an end point (tN) of the systolic phase interval (SP) wherein a QT interval is defined as the start of the Q wave and the end of the T wave in the hearts electrical cycle and wherein the determination of the end point (tN) of the systolic phase interval (SP) is restricted to the measured points of arterial pressure which fulfill the condition that the difference in time between the end point (tN) to be determined of the systolic phase interval (SP) and the starting point (t0) of the systolic phase interval (SP) is smaller than the QT interval.

Claims

1. A method for computing a systolic phase interval of an arterial pressure curve, comprising:

determining, by a processor, a time interval between a starting point (t₀) of the systolic phase interval and a time instant (t_k), wherein t_k is when a mean arterial pressure is reached for a first time following the starting point (t₀);

calculating, by the processor, a product of a factor and a QT interval, the QT interval being the time between a start of a Q wave and an end of a T wave in an electrical cycle of a heart; and

summing, by the processor, the time interval and the product to obtain an end point (t_N) of the systolic phase interval.

2. The method of claim 1, wherein the factor is a value between 0.25 and 0.8.

3. The method of claim 1, wherein the factor is a square root of (SAP-MAP)/(SAP-P ₀), wherein SAP is a maximum arterial pressure, MAP is the mean arterial pressure, and P₀ is a base line pressure.

4. An apparatus comprising:

an input port to receive signals representing an arterial pressure;

a processor coupled to the input port for computing a systolic phase interval of an arterial pressure curve, the processor adapted to;

determine a time interval between a starting point (t₀) of the systolic phase interval and a time instant (t_k), wherein t_k is when a mean arterial pressure is reached for a first time following the starting instant point (t₀);

calculate a product of a factor and a QT interval, the QT interval being the time between a start of a Q wave and an end of a T wave in an electrical cycle of a heart; and

sum the time interval and the product to obtain an end point (t_N) of the systolic phase interval.

5. The apparatus of claim 4, wherein the factor is a value between 0.25 and 0.8.

6. The apparatus of claim 4, wherein the factor is a square root of (SAP-MAP )/(SAP-P₀), wherein SAP is a maximum arterial pressure, MAP is the mean arterial pressure, and P₀ is a base line pressure.