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

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.