The underlying mechanism of inter-site discrepancies in ejection time measurements from arterial waveforms and its validation in the Framingham Heart Study

2021 ◽  
Author(s):  
Jing Liu ◽  
Niema M Pahlevan
Keyword(s):  
Sensitivity Analysis ◽  
Framingham Heart Study ◽  
Radial Pressure ◽  
Left Ventricular Ejection ◽  
Pressure Waveform ◽  
Ejection Time ◽  
Decomposition Model ◽  
Heart Study ◽  
Ventricular Ejection Time ◽  
Wave Decomposition

Radial applanation tonometry is a well-established method for clinical hemodynamic assessment and is also becoming popular in wrist-worn fitness trackers. The time difference between the foot and the dicrotic notch of the arterial pressure waveform is a well-accepted approximation for the left ventricular ejection time (ET). However, several clinical studies have shown that ET measured from the radial pressure waveform deviates from that measured centrally. In this work, we consider the systolic wave and the dicrotic wave as two independent traveling waves and hypothesize that their wave speed difference leads to the inter-site differences of measured ET (ΔET). Accordingly, we derived a mathematical dicrotic wave decomposition model and identified the most influential factors on ΔET via global sensitivity analysis. In our clinical validation on a heterogeneous cohort (N = 5742) from the Framingham Heart Study (FHS), the local sensitivity analysis results resembled the sensitivity variations patterns of ΔET from model simulations. A regression analysis on FHS data, using morphological features of radial pressure waveforms to estimate the Carotid ET, produced a root mean square error of 3.76 ms and R2 of 0.91. The proposed dicrotic wave decomposition model can explain the inter-site ET measurement discrepancies observed in the clinical data of FHS and can facilitate the precise identification of ET with radial pressure waveforms. Therefore, the proposed model will improve various physics-based pulse wave analysis methods as well as prospective artificial intelligence methods for tackling the subsequent big data produced­ from widespread wearable radial pressure monitoring.

scholarly journals Improvement of Left Ventricular Ejection Time Measurement in the Impedance Cardiography Combined with the Reflection Photoplethysmography

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3036 ◽  
Author(s):  
Shing-Hong Liu ◽  
Jia-Jung Wang ◽  
Chun-Hung Su ◽  
Da-Chuan Cheng
Keyword(s):  
Impedance Cardiography ◽  
Left Ventricular ◽  
Ventricular Ejection ◽  
Left Ventricular Ejection ◽  
Artificial Noise ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Noise Interference ◽  
Non Invasive ◽  
Ventricular Ejection Time

Cardiac stroke volume (SV) is an essential hemodynamic indicator that can be used to assess whether the pump function of the heart is normal. Non-invasive SV measurement is currently performed using the impedance cardiography (ICG). In this technology, left ventricular ejection time (LVET) is an important parameter which can be determined from the ICG signals. However, the ICG signals are inherently susceptible to artificial noise interference, which leads to an inaccurate LVET measurement and then yields an error in the calculation of SV. Therefore, the goal of the study was to measure LVETs using both the transmission and reflection photoplethysmography (PPG), and to assess whether the measured LVET was more accurate by the PPG signal than the ICG signal. The LVET measured by the phonocardiography (PCG) was used as the standard for comparing with those by the ICG and PPG. The study recruited ten subjects whose LVETs were simultaneously measured by the ICG using four electrodes, the reflection PPG using neck sensors (PPGneck) and the transmission PPG using finger sensors (PPGfinger). In each subject, ten LVETs were obtained from ten heartbeats selected properly from one-minute recording. The differences of the measured LVETs between the PCG and one of the ICG, PPGneck and PPGfinger were −68.2 ± 148.6 ms, 4.8 ± 86.5 ms and −7.0 ± 107.5 ms, respectively. As compared with the PCG, both the ICG and PPGfinger underestimated but the PPGneck overestimated the LVETs. Furthermore, the measured LVET by the PPGneck was the closest to that by the PCG. Therefore, the PPGneck may be employed to improve the LVET measurement in applying the ICG for continuous monitoring of SV in clinical settings.

Responses of peak ear-pulse derivative to changing left ventricular function

1980 ◽  
Vol 238 (3) ◽  
pp. H355-H359 ◽  
Author(s):  
Y. Nakamura ◽  
B. G. Haffty ◽  
D. H. Spodick ◽  
D. Paladino ◽  
K. Moreau ◽  
...  
Keyword(s):  
Ventricular Function ◽  
Cycle Length ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ejection Time ◽  
Pressure Derivative ◽  
Left Ventricular Ejection Time ◽  
Ejection Rate ◽  
Ventricular Ejection Time ◽  
Technical Reliability

The ear densitograph displacement pulse derivative (dD/dtear) is the analog of the arterial pressure derivative (dP/dt) and behaves comparably under a variety of cardiocirculatory challenges. Technical reliability and uniform application of the transducer are advantages that make it ideal for intrasubject monitoring. With atrial fibrillation as a model of functional variability in eight subjects, peak dD/dtear (P) tracked echocardiographic stroke volume, ejection fraction, ejection rate, and velocity of circumferential fiber shortening quite closely with the exception of some values in three subjects, two of whom had mitral regurgitation and one paradoxic septal movement. In all subjects, P showed good to excellent correlations with cycle length, preejection period (PEP), LVET (left ventricular ejection time), and PEP/LVET. The method appears to be ideally suited to intrasubject monitoring for changing ventricular function.

scholarly journals Systolic Time Interval (STI) in Hypothyroid Patients Receiving High Dose L-Thyroxine

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Nurul Aulia Zakaria ◽  
Hafizah Pasi ◽  
Mohammad Arif Shahar
Keyword(s):  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Lv Function ◽  
High Dose ◽  
Time Interval ◽  
Ejection Time ◽  
Systolic Time Interval ◽  
Systolic Time ◽  
Ventricular Ejection Time ◽  
Significant Increment

Introduction: Systolic Time Interval (STI) is a simple,noninvasive and precise technique to assess left ventricular (LV) function. It measures aortic Pre-Ejection Period (PEP) over Left Ventricular Ejection Time (LVET) from echocardiogram. Thyrotoxicosis will enhance LV function and cause reduction of STI.  This study was perform to measure the changes of STI after administration of high dose L-thyroxine and to determine the correlation between high dose L-thyroxine administration and STI. Materials and Method: A Total of 22 patients were screened. Those with cardiac diseases and high Framingham risk score were excluded. Nine patients were started on high dose L-thyroxine (7x their usual dose) once a week during the month of Ramadan.Thyroid hormones ( T3,T4,TSH)  and STI (PEP/LVET) were measured at baseline and within 24 hrs after high dose L-thyroxine ingestion. Results: All patients have normal thyroid hormones level and normal cardiac function at baseline. The median dose (mcg) of L-thyroxine was 600 (437.5,700) while the median level of fT4 (pmol/L) was 17.43(12.38,20.8). Despite the significant increment of fT4 after Lthyroxine ingestion [baseline 13.21(8.19,14.63) vs high dose 17.43(12.38,22.55) p; 0.011] there was no significant change in STI [baseline 0.3(0.2,0.4) vs high dose 0.28(0.26,0.45) p; 0.513]. There was no correlation found between the dose of Lthyroxine and STI (r=0.244 , p;0.526).  Conclusion: Administration of high dose Lthyroxine did not significantly alter STI despite significant increment of fT4 level unlike the naturally occurring thyrotoxicosis.Therefore ‘exogenous’ administration of high dose L-thyroxine is cardiac safe.

Abstract 17298: Validation of Beat-to-Beat Blood Pressure and Left Ventricular Ejection Time by the Caretaker Physiological Monitor Against Invasive Central Aortic Measurement

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Evan Harmon ◽  
Younghoon Kwon ◽  
Patrick Stafford ◽  
Martin Baruch ◽  
Sung-Hoon Kim ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Unmet Need ◽  
Aortic Pressure ◽  
Left Ventricular ◽  
Ventricular Ejection ◽  
Left Ventricular Ejection ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Monitoring Technologies ◽  
Ventricular Ejection Time

Objective: There is an unmet need for noninvasive continuous blood pressure (BP) monitoring technologies in various clinical settings. We examined the accuracy of noninvasive Caretaker device against invasively measured central aortic BP. Methods: Beat-to-beat BP by Caretaker was recorded simultaneously with central aortic BP measured in patients undergoing cardiac catheterization. We derived correlations and Bland-Altman comparisons, after calibrating the Caretaker with 20 seconds of the initial catheter readings, as well as trend analyses for both systolic (SBP) and diastolic BP (DBP). We also measured left ventricular ejection time (LVET) from both aortic pressure tracing and Caretaker and compared the two. Results: A total of 47 patients were included in the study. A total of 31,369 beats obtained during the diagnostic portion of coronary angiogram were used for analysis. The correlations for SBP and DBP were 0.89 and 0.78, respectively (p < 0.001 for both). The Bland-Altman comparison yielded overall mean differences of 2.11 mmHg (SD 7.40) for SBP and 1.46 mmHg (SD 6.12) for DBP respectively (p <0.001 for all comparisons). The trend analysis yielded concordances of 86% and 85% for SBP and DBP, respectively. The correlation and Bland-Altman analyses for the LVET comparison yielded 0.89 (p< 0.001) with a mean difference of 13.9 ms (SD 14.4 ms). Conclusion: Beat-to-beat BP by Caretaker showed excellent agreement and high concordance in the direction and the degree of BP change with central aortic BP. This study supports the satisfactory performance of the Caretaker device in continuous tracking of beat-to-beat BP and LVET measurements.

scholarly journals Wearable Cardiorespiratory Monitoring Employing a Multimodal Digital Patch Stethoscope: Estimation of ECG, PEP, LVET and Respiration Using a 55 mm Single-Lead ECG and Phonocardiogram

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2033 ◽  
Author(s):  
Michael Klum ◽  
Mike Urban ◽  
Timo Tigges ◽  
Alexandru-Gabriel Pielmus ◽  
Aarne Feldheiser ◽  
...  
Keyword(s):  
Cause Of Death ◽  
Left Ventricular ◽  
Noncommunicable Diseases ◽  
Left Ventricular Ejection ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Respiratory Parameters ◽  
Respiratory Signal ◽  
Ventricular Ejection Time ◽  
The Impact

Cardiovascular diseases are the main cause of death worldwide, with sleep disordered breathing being a further aggravating factor. Respiratory illnesses are the third leading cause of death amongst the noncommunicable diseases. The current COVID-19 pandemic, however, also highlights the impact of communicable respiratory syndromes. In the clinical routine, prolonged postanesthetic respiratory instability worsens the patient outcome. Even though early and continuous, long-term cardiorespiratory monitoring has been proposed or even proven to be beneficial in several situations, implementations thereof are sparse. We employed our recently presented, multimodal patch stethoscope to estimate Einthoven electrocardiogram (ECG) Lead I and II from a single 55 mm ECG lead. Using the stethoscope and ECG subsystems, the pre-ejection period (PEP) and left ventricular ejection time (LVET) were estimated. ECG-derived respiration techniques were used in conjunction with a novel, phonocardiogram-derived respiration approach to extract respiratory parameters. Medical-grade references were the SOMNOmedics SOMNO HDTM and Osypka ICON-CoreTM. In a study including 10 healthy subjects, we analyzed the performances in the supine, lateral, and prone position. Einthoven I and II estimations yielded correlations exceeding 0.97. LVET and PEP estimation errors were 10% and 21%, respectively. Respiratory rates were estimated with mean absolute errors below 1.2 bpm, and the respiratory signal yielded a correlation of 0.66. We conclude that the estimation of ECG, PEP, LVET, and respiratory parameters is feasible using a wearable, multimodal acquisition device and encourage further research in multimodal signal fusion for respiratory signal estimation.

Phase II Study of 4'Epi-Doxorubicin

1982 ◽  
Vol 68 (5) ◽  
pp. 431-435 ◽  
Author(s):  
Eros Ferrazzi ◽  
Ornella Nicoletto ◽  
Orazio Vinante ◽  
Piero Pagnin ◽  
Giuseppe Maraglino ◽  
...  
Keyword(s):  
Phase Ii Study ◽  
Clinical Signs ◽  
Soft Tissue Sarcomas ◽  
Hormonal Treatment ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ejection Time ◽  
Left Ventricular Ejection Time ◽  
Ventricular Ejection Time ◽  
Electrocardiographic Abnormalities

Sixty-five patients with advanced solid tumors were treated with 4'epi-doxorubicin, a new analogue of doxorubicin (DXR). Forty-three of 61 evaluable patients had not received previous chemotherapy and/or hormonal treatment. 4'Epi-doxorubicin has been administered at the dose of 75 mg/m2 i.v. once every 21 days, for a minimum of 2 courses. The pattern of acute toxicity was similar to that of DXR. Transient electrocardiographic abnormalities were found in about 50% of patients. The ratio of pre-ejection period to the left ventricular ejection time (PEP/LVET) increased within 1 h after drug injection and returned to near basal values after 24 h. Three patients received a total dose of more than 550 mg/m2, still maintaining a baseline PEP/LVET ratio near to pretreatment values. Up to now, no patient has developed clinical signs of heart failure. Partial responses were seen in patients with tumors generally sensitive to DXR such as breast carcinoma (6 of 14) and soft tissue sarcomas (2 of 6), and in patients with tumors generally resistant to DXR such as melanoma (1 of 9), colorectal carcinoma (3 of 18) and pancreatic carcinoma (1 of 2). These data suggest that 4'epi-doxorubicin may have a broader spectrum of antitumor activity than DXR.

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