Device and method for assessment of left ventricular ejection fraction and other parameters of cardiac performance

• US 9,955,876 B2
• Filed: 09/08/2016
• Issued: 05/01/2018
• Est. Priority Date: 09/08/2016
• Status: Active Grant

• Current Assignee: Dr. Raul Chirife
• Original Assignee: Dr. Raul Chirife
• Inventors: Chirife, Raul
• Primary Examiner(s): Gedeon, Brian T
• Application Number:
  US15/260,126
• Publication Number:
  US 20180070833A1
• Time in Patent Office: 600 Days
• Field of Search: None
• CPC Class Codes: A61B 2505/07 Home care
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/346 Analysis of electrocardiograms
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/4848 Monitoring or testing the effects of treatment, e.g. of medication
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/746 : Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 7/04 : Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: A61N 1/36585 : controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3682 : with a variable atrioventricular delay

Abstract

The invention consists of a device and method for the prediction of left ventricular ejection fraction (EF) and other cardiac hemodynamic parameters using systolic time intervals in patients with narrow QRS, right bundle branch block, left bundle branch block, right ventricular and/or left ventricular cardiac pacing and in the presence of arrhythmia, such as atrial fibrillation. The device has three inputs: the ECG, a peripheral pulse and a phonocardiogram. Timing parameters are obtained from these signals to calculate a systolic function index, used for the prediction of ejection fraction. Given the invention'"'"'s features it would be now possible to assess cardiac performance and specifically left ventricular ejection fraction in ambulatory patients as well as during invasive procedures such as the implant of cardiac rhythm management devices. Also, an implantable embodiment of the invention would allow constant monitoring of cardiac performance, parameter adjustment of cardiac devices and automatic drug infusion.

Claims

1. A device for automatic measurement of systolic time intervals, including heart rate (HR), QRS duration, a surrogate of left ventricular pre-ejection period (PEPsu), left ventricular ejection time (LVET), inter-ventricular delay (IVD) and pulse transit time (PTT) allowing automatic detection and display of corrected systolic time intervals, the calculation of a systolic function index, and estimation of left ventricular ejection fraction in patients with narrow QRS, bundle branch block and artificial cardiac pacing, wherein the device comprises:

a. amplifiers and filters for each of;

ECG, arterial pulse and phonocardiogram,

b. a first timer for the onset of QRS or ventricular pacing pulse, whichever is first to occur,

c. a second timer for detecting end of QRS,

d. a third timer for the upstroke of the arterial pulse,

e. a fourth timer for the dicrotic notch of the arterial pulse (Tnotch),

f. a fifth timer for detecting aortic component of the second heart sound (TS2A),

g. a processor unit for running software for;

calculating a beat to beat heart rate,

calculating QRS duration (QRSd),

calculating rate-corrected LVET as;

LVETc=LVET+k*(HR−

60),

wherein k is a value between 1.0 and 2, which can be defaulted as 1.5 or calculated as the ratio delta LVET/delta HR,

calculating of inter-ventricular delay caused by bundle branch block and/or cardiac pacing, as;

IVD=0.38*QRSd−

8,

calculating PTT as;

Tnotch−

TS2A

obtaining a corrected PEP as;

PEPc=PEPsu−

PTT−

IVD,

wherein PTT=0 for central pulse recordings

calculating a systolic function index as;

SFI=LVETc/PEPc,

calculating a left ventricular ejection fraction (EF) as;

EF=(0.45*LN(SFI)−

0.03)*100,

wherein LN(SFI) is the natural logarithm of the SFI.

2. The device according to claim 1, wherein said systolic time intervals and said systolic function index and ejection fraction are obtained as integral part of an implantable medical device such as a pacemaker, cardiac defibrillator, monitoring device or drug infusion apparatus.

3. The device according to claim 1, wherein said ECG, pulse and phonocardiogram amplifiers, filters are the integral part of a system including analysis, calculation software and display means.

4. The device according to claim 1 wherein said ECG, pulse and phonocardiogram amplifiers, filters, are connected via USB, Bluetooth or other transmission means to a computer running the software for measurement and calculations of said systolic time intervals, heart rate, corrections of PEP, corrections of LVET, systolic function index and ejection fraction.

5. A device as described in claim 1 wherein said parameters of cardiac performance are used for diagnosis, automatic adjustment of medical devices, such as home monitoring, arrhythmia detection, device optimization, drug delivery, rate adaptive pacing, pacing mode selection and/or atrio-ventricular interval optimization in pacemaker patients.

6. A device and method as described in claim 2 wherein said parameters of cardiac performance are used to trigger an alarm when one or more of said detected parameters exceed a pre-selected or programmable risk level.