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Montino Pelagi G, Baggiano A, Regazzoni F, Fusini L, Alì M, Pontone G, Valbusa G, Vergara C. Personalized Pressure Conditions and Calibration for a Predictive Computational Model of Coronary and Myocardial Blood Flow. Ann Biomed Eng 2024; 52:1297-1312. [PMID: 38334838 PMCID: PMC10995040 DOI: 10.1007/s10439-024-03453-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 01/14/2024] [Indexed: 02/10/2024]
Abstract
Predictive modeling of hyperemic coronary and myocardial blood flow (MBF) greatly supports diagnosis and prognostic stratification of patients suffering from coronary artery disease (CAD). In this work, we propose a novel strategy, using only readily available clinical data, to build personalized inlet conditions for coronary and MBF models and to achieve an effective calibration for their predictive application to real clinical cases. Experimental data are used to build personalized pressure waveforms at the aortic root, representative of the hyperemic state and adapted to surrogate the systolic contraction, to be used in computational fluid-dynamics analyses. Model calibration to simulate hyperemic flow is performed in a "blinded" way, not requiring any additional exam. Coronary and myocardial flow simulations are performed in eight patients with different clinical conditions to predict FFR and MBF. Realistic pressure waveforms are recovered for all the patients. Consistent pressure distribution, blood velocities in the large arteries, and distribution of MBF in the healthy myocardium are obtained. FFR results show great accuracy with a per-vessel sensitivity and specificity of 100% according to clinical threshold values. Mean MBF shows good agreement with values from stress-CTP, with lower values in patients with diagnosed perfusion defects. The proposed methodology allows us to quantitatively predict FFR and MBF, by the exclusive use of standard measures easily obtainable in a clinical context. This represents a fundamental step to avoid catheter-based exams and stress tests in CAD diagnosis.
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Affiliation(s)
- Giovanni Montino Pelagi
- LABS, Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, 20133, Milan, Italy.
| | - Andrea Baggiano
- Perioperative Cardiology and Cardiovascular Imaging Department, Centro Cardiologico Monzino IRCCS, Via Carlo Parea 4, 20138, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Francesco Regazzoni
- MOX, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Laura Fusini
- Perioperative Cardiology and Cardiovascular Imaging Department, Centro Cardiologico Monzino IRCCS, Via Carlo Parea 4, 20138, Milan, Italy
- Department of Electronics, Information and Biomedical Engineering, Politecnico di Milano, 20133, Milan, Italy
| | - Marco Alì
- Bracco Imaging S.p.A., Via Caduti di Marcinelle 13, 20134, Milan, Italy
- Department of Diagnostic Imaging and Stereotactic Radiosurgery, Centro Diagnostico Italiano S.p.A., Via Saint Bon 20, 20147, Milan, Italy
| | - Gianluca Pontone
- Perioperative Cardiology and Cardiovascular Imaging Department, Centro Cardiologico Monzino IRCCS, Via Carlo Parea 4, 20138, Milan, Italy
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, 20134, Milan, Italy
| | - Giovanni Valbusa
- Bracco Imaging S.p.A., Via Caduti di Marcinelle 13, 20134, Milan, Italy
| | - Christian Vergara
- LABS, Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, 20133, Milan, Italy
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Abushouk A, Kansara T, Abdelfattah O, Badwan O, Hariri E, Chaudhury P, Kapadia SR. The Dicrotic Notch: Mechanisms, Characteristics, and Clinical Correlations. Curr Cardiol Rep 2023; 25:807-816. [PMID: 37493873 DOI: 10.1007/s11886-023-01901-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/05/2023] [Indexed: 07/27/2023]
Abstract
PURPOSE OF REVIEW The dicrotic notch (DN) has long been considered a marker of arterial stiffness and compliance. Herein, we explored the recent developments in vascular medicine research in an attempt to assess the DN utility in clinical cardiovascular medicine. RECENT FINDINGS Since its discovery, several studies have attempted to measure the changes in different parameters of the DN in physiological and pathological states. Despite the significance of their findings, the clinical role of the DN remained limited. This may have been related to the difficulty of measuring the DN via indwelling arterial catheters in the past. However, over the past two decades, several non-invasive methods have been developed, which may re-ignite interest in DN research. The DN may have broader applications in clinical cardiovascular medicine. Further research is needed to establish the accuracy of DN non-invasive measurement methods and compare its prognostic value to other circulatory parameters.
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Affiliation(s)
- Abdelrahman Abushouk
- Department of Cardiovascular Medicine, Heart, Vascular, and Thoracic Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, USA
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Tikal Kansara
- Department of Hospital Medicine, Union Hospital, Cleveland Clinic Foundation, Dover, OH, USA
| | - Omar Abdelfattah
- Division of Cardiovascular Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Osamah Badwan
- Department of Internal Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Essa Hariri
- Department of Internal Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
- Division of Cardiovascular Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Pulkit Chaudhury
- Department of Cardiovascular Medicine, Heart, Vascular, and Thoracic Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, USA
| | - Samir R Kapadia
- Department of Cardiovascular Medicine, Heart, Vascular, and Thoracic Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, USA.
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Hametner B, Weber T, Wassertheurer S. Heart Failure: Insights From the Arterial Waves. J Am Heart Assoc 2023; 12:e029116. [PMID: 36892064 PMCID: PMC10111562 DOI: 10.1161/jaha.123.029116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Affiliation(s)
- Bernhard Hametner
- Center for Health & Bioresources AIT Austrian Institute of Technology Vienna Austria
| | - Thomas Weber
- Cardiology Department, Klinikum Wels-Grieskirchen Wels Austria
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Helms F, Haverich A, Wilhelmi M, Böer U. Establishment of a Modular Hemodynamic Simulator for Accurate In Vitro Simulation of Physiological and Pathological Pressure Waveforms in Native and Bioartificial Blood Vessels. Cardiovasc Eng Technol 2021; 13:291-306. [PMID: 34558032 PMCID: PMC9114050 DOI: 10.1007/s13239-021-00577-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 08/22/2021] [Indexed: 11/28/2022]
Abstract
Purpose In vitro stimulation of native and bioartificial vessels in perfusable systems simulating natural mechanical environments of the human vasculature represents an emerging approach in cardiovascular research. Promising results have been achieved for applications in both regenerative medicine and etiopathogenetic investigations. However, accurate and reliable simulation of the wide variety of physiological and pathological pressure environments observed in different vessels still remains an unmet challenge. Methods We established a modular hemodynamic simulator (MHS) with interchangeable and modifiable components suitable for the perfusion of native porcine—(i.e. the aorta, brachial and radial arteries and the inferior vena cava) and bioartificial fibrin-based vessels with anatomical site specific pressure curves. Additionally, different pathological pressure waveforms associated with cardiovascular diseases including hyper- and hypotension, tachy- and bradycardia, aortic valve stenosis and insufficiency, heart failure, obstructive cardiomyopathy and arterial stiffening were simulated. Pressure curves, cyclic distension and shear stress were measured for each vessel and compared to ideal clinical pressure waveforms. Results The pressure waveforms obtained in the MHS showed high similarity to the ideal anatomical site specific pressure curves of different vessel types. Moreover, the system facilitated accurate emulation of physiological and different pathological pressure conditions in small diameter fibrin-based vessels. Conclusion The MHS serves as a variable in vitro platform for accurate emulation of physiological and pathological pressure environments in biological probes. Potential applications of the system include bioartificial vessel maturation in cardiovascular tissue engineering approaches as well as etiopathogenetic investigations of various cardiovascular pathologies. Supplementary Information The online version contains supplementary material available at 10.1007/s13239-021-00577-0.
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Affiliation(s)
- Florian Helms
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625, Hannover, Germany.
| | - Axel Haverich
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625, Hannover, Germany.,Division for Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Mathias Wilhelmi
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625, Hannover, Germany.,Department of Vascular- and Endovascular Surgery, St. Bernward Hospital, Hildesheim, Germany
| | - Ulrike Böer
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625, Hannover, Germany.,Division for Cardiothoracic-, Transplantation- and Vascular Surgery, Hannover Medical School, Hannover, Germany
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5
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Wiegerinck AIP, Thomsen A, Hisdal J, Kalvøy H, Tronstad C. Electrical Impedance Plethysmography Versus Tonometry To Measure the Pulse Wave Velocity in Peripheral Arteries in Young Healthy Volunteers: a Pilot Study. JOURNAL OF ELECTRICAL BIOIMPEDANCE 2021; 12:169-177. [PMID: 35111272 PMCID: PMC8776312 DOI: 10.2478/joeb-2021-0020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Indexed: 06/14/2023]
Abstract
The leading cause of health loss and deaths worldwide are cardiovascular diseases. A predictor of cardiovascular diseases and events is the arterial stiffness. The pulse wave velocity (PWV) can be used to estimate arterial stiffness non-invasively. The tonometer is considered as the gold standard for measuring PWV. This approach requires manual probe fixation above the artery and depends on the skills of the operator. Electrical impedance plethysmography (IPG) is an interesting alternative using skin surface sensing electrodes, that is miniaturizable, cost-effective and allows measurement of deeper arteries. The aim of this pilot study was to explore if IPG can be a suitable technique to measure pulse wave velocity in legs as an alternative for the tonometer technique. The PWV was estimated by differences in the ECG-gated pulse arrival times (PAT) at the a. femoralis, a. popliteal, a. tibialis dorsalis and a. dorsalis pedis in nine healthy young adults using IPG and the SphygmoCor tonometer as a reference. The estimated PWV results from bioimpedance and the tonometer were fairly in agreement, and the beat-to-beat variability in PAT was similar. This pilot study indicates that the use of IPG may be a good alternative for estimating PWV in the legs.
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Affiliation(s)
- A. I. P. Wiegerinck
- Department of Physiology, Radboud University Medical Center, Nijmegen, Netherlands
- Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - A. Thomsen
- Department of Physics, University of Oslo, Oslo, Norway
| | - J. Hisdal
- Department of Vascular Surgery, Division of Cardiovascular and Pulmonary Diseases, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - H. Kalvøy
- Department of Clinical & Biomedical Engineering, Oslo University Hospital, Oslo, Norway
| | - C. Tronstad
- Department of Clinical & Biomedical Engineering, Oslo University Hospital, Oslo, Norway
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Hametner B, Kastinger H, Wassertheurer S. Simulating re-reflections of arterial pressure waves at the aortic valve using difference equations. Proc Inst Mech Eng H 2020; 234:1243-1252. [PMID: 32686581 DOI: 10.1177/0954411920942704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Re-reflections of arterial pressure waves at the aortic valve and their influence on aortic wave shape are only poorly understood so far. Therefore, the aim of this work is to establish a model enabling the simulation of re-reflection and to test its properties. A mathematical difference equation model is used for the simulations. In this model, the aortic blood pressure is split into its forward and backward components which are calculated separately. The respective equations include reflection percentages representing reflections throughout the arterial system and a reflection coefficient at the aortic valve. While the distal reflections are fixed, different scenarios for the reflection coefficient at the valve are simulated. The results show that the model is capable to provide physiological pressure curves only if re-reflections are assumed to be present during the whole cardiac cycle. The sensitivity analysis on the reflection coefficient at the aortic valve shows various effects of re-reflections on the modelled blood pressure curve. Higher levels of the reflection coefficient lead to higher systolic and diastolic pressure values. The augmentation index is notably influenced by the systolic level of the reflection coefficient. This difference equation model gives an adequate possibility to simulate aortic pressure incorporating re-reflections at the site of the aortic valve. Since a strong dependence of the aortic pressure wave on the choice of the reflection coefficient have been found, this indicates that re-reflections should be incorporated into models of wave transmission. Furthermore, re-reflections may also be considered in methods of arterial pulse wave analysis.
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Affiliation(s)
- Bernhard Hametner
- Center for Health & Bioresources, AIT Austrian Institute of Technology, Vienna, Austria
| | - Hannah Kastinger
- Center for Health & Bioresources, AIT Austrian Institute of Technology, Vienna, Austria.,Institute for Analysis and Scientific Computing, Vienna University of Technology, Vienna, Austria
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Eisenried A, Klarwein R, Ihmsen H, Wehrfritz A, Tandler R, Heim C, Fechner J. Accuracy and Trending Ability of the Fourth-Generation FloTrac/EV1000 System in Patients With Severe Aortic Valve Stenosis Before and After Surgical Valve Replacement. J Cardiothorac Vasc Anesth 2019; 33:1230-1236. [DOI: 10.1053/j.jvca.2018.09.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Indexed: 11/11/2022]
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9
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Puyo L, Paques M, Fink M, Sahel JA, Atlan M. In vivo laser Doppler holography of the human retina. BIOMEDICAL OPTICS EXPRESS 2018; 9:4113-4129. [PMID: 30615709 PMCID: PMC6157768 DOI: 10.1364/boe.9.004113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 05/20/2023]
Abstract
The eye offers a unique opportunity for the non-invasive exploration of cardiovascular diseases. Optical angiography in the retina requires sensitive measurements, which hinders conventional full-field laser Doppler imaging schemes. To overcome this limitation, we used digital holography to perform laser Doppler perfusion imaging of human retina with near-infrared light. Two imaging channels with a slow and a fast CMOS camera were used simultaneously for real-time narrowband measurements, and offline wideband measurements, respectively. The beat frequency spectrum of optical interferograms recorded with the fast (up to 75 kHz) CMOS camera was analyzed by short-time Fourier transformation. Power Doppler images drawn from the Doppler power spectrum density qualitatively revealed blood flow in retinal vessels over 512 × 512 pixels covering 2.4 × 2.4 mm2 on the retina with a temporal resolution down to 1.6 ms. The sensitivity to lateral motion as well as the requirements in terms of sampling frequency are discussed.
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Affiliation(s)
- L. Puyo
- Institut Langevin, Centre National de la Recherche Scientifique (CNRS), Paris Sciences & Lettres (PSL Research University), École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris) - 1 rue Jussieu, 75005 Paris,
France
| | - M. Paques
- Institut de la Vision, INSERM UMR-S 968, CNRS UMR 7210, UPMC, 17 rue Moreau, 75012 Paris,
France
- Centre d’Investigation Clinique (CIC) Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM, 28 rue de Charenton, 75012 Paris,
France
| | - M. Fink
- Institut Langevin, Centre National de la Recherche Scientifique (CNRS), Paris Sciences & Lettres (PSL Research University), École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris) - 1 rue Jussieu, 75005 Paris,
France
| | - J.-A. Sahel
- Institut de la Vision, INSERM UMR-S 968, CNRS UMR 7210, UPMC, 17 rue Moreau, 75012 Paris,
France
- Centre d’Investigation Clinique (CIC) Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM, 28 rue de Charenton, 75012 Paris,
France
| | - M. Atlan
- Institut Langevin, Centre National de la Recherche Scientifique (CNRS), Paris Sciences & Lettres (PSL Research University), École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris) - 1 rue Jussieu, 75005 Paris,
France
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10
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Berg RMG, Toksvang LN, Jabbari R. Using an essay competition as an alternative tool for enhancing the "learning from learners" teaching approach. ADVANCES IN PHYSIOLOGY EDUCATION 2013; 37:264-265. [PMID: 24022773 DOI: 10.1152/advan.00054.2013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Ronan M G Berg
- Centre of Inflammation and Metabolism, Department of Infectious Diseases, University Hospital Rigshospitalet, Copenhagen, Denmark
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Abstract
The purpose of this study was to compare coronary blood flow in the presence of multiple fixed coronary arterial stenoses with that in the presence of a single stenosis of equivalent length and diameter. The study was performed using an in vitro pulse duplicating system. The aortic root section consisted of an acrylic mold of the root of the aorta of a calf. The coronary system was designed to produce coronary flow with physiological magnitudes and phasic patterns. Aortic and left ventricular pressures as well as the reduction in pressure across the coronary test section containing the stenotic segments were measured with catheter-tip micromanometers. Coronary flow was measured with a cannulating electromagnetic flow transducer. The fluid viscosity was 0.04 poise. Studies were performed sequentially with one 2 mm long arterial segment with a stenosis of 50 percent of luminal diameter, two such stenotic segments and three such stenotic segments in series. A single 4 mm long, 50 percent diameter stenotic segment and a 6 mm long, 50 percent diameter stenotic segment were also studied. The heart rate was 71 beats/min, stroke volume 80 ml and aortic pressure 140/75 mm Hg. A single 2 mm long, 50 percent stenotic segment caused a 6 percent reduction of coronary flow; three such stenoses in series caused a 19 percent reduction of coronary flow. In contrast, a single 6 mm long, 50 percent diameter stenotic segment caused only an 8 percent reduction of coronary flow. The results suggest that in a maximally dilated coronary bed, a greater reduction of coronary flow would occur in the presence of multiple short stenoses than in the presence of a single stenosis of equivalent length and diameter.
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Sabbah HN, Magilligan DJ, Lakier JB, Stein PD. Hemodynamic determinants of the frequency and amplitude of a musical murmur produced by a regurgitant mitral bioprosthetic valve. Am J Cardiol 1982; 50:53-8. [PMID: 7091006 DOI: 10.1016/0002-9149(82)90008-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The purpose of this study was to assess the hemodynamic determinant of the amplitude and frequency of a musical murmur produced by a regurgitant degenerated bioprosthetic valve in the mitral position. The prosthetic valve, obtained at surgery, was studied in the mitral position of an in vitro pulse duplicating system. In vitro, the valve produced a musical murmur that was caused by flutter of a flail leaflet. When the peak pressure difference between the left ventricle and left atrium was increased from 95 to 150 mm Hg, the fundamental frequency of the musical murmur increased from 91 to 187 hertz and the amplitude increased from 2,080 to 11,420 dynes/cm2. The fundamental frequency of the musical murmur was linearly related to the peak systolic pressure difference between the left ventricle and the left atrium (correlation coefficient [r] = 0.99). Similarly, the fundamental frequency of the musical murmur was linearly related to the magnitude of regurgitant flow across the valve (r = 0.99); and the regurgitant flow as expected was linearly related to the systolic pressure difference between the left ventricle and left atrium. The amplitude of the musical murmur was also related to both the peak systolic pressure difference between the left ventricle and left atrium (r = 0.99) and the magnitude of regurgitant flow (r = 0.99). These results indicate that the magnitude of regurgitant flow, determined by the systolic pressure difference between the left ventricle and left atrium, was a determinant of both the amplitude and the frequency of the musical murmur.
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Stein PD, Sabbah HN, Magilligan DJ, Lakier JB. Mechanism of a musical systolic murmur caused by a degenerated porcine bioprosthetic valve. Am J Cardiol 1982; 49:1874-82. [PMID: 7081071 DOI: 10.1016/0002-9149(82)90205-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The cause of a musical (cooing) murmur produced by a degenerated bioprosthetic valve in the mitral position was investigated. Spectral analysis of the murmur recorded at the chest wall at the site of the maximum palpable impulse showed virtually all sound in a narrow frequency band around the dominant frequency of 158 hertz. The same valve, surgically removed and mounted in the mitral position in a pulse duplicating system, produced an audible musical murmur detected by a phonocatheter in the atrial chamber. Nearly all of the sound-pressure occurred in a narrow band of frequency around 145 hertz. High speed motion pictures (500 frames/s) showed systolic flutter of a flail leaflet. The frequency of this leaflet flutter was 142 hertz. Hot film anemometry showed minimal turbulence, all located near the margin of the regurgitant leaflet. The intensity of the murmur was unrelated to the intensity of turbulence. A second degenerated bioprosthetic valve that produced in vivo a typical blowing holosystolic mitral regurgitant murmur produced in vitro a murmur with a broad range of frequencies (20 to 500 hertz). With this valve, the intensity of the murmur was related to the intensity of the turbulence. Motion pictures showed no leaflet flutter. Flutter of an insufficient valve leaflet causing uniform and periodic high frequency fluctuating pressures therefore appeared to be the cause of the musical quality of the systolic murmur in a degenerated bioprosthetic valve.
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Sabbah HN, Stein PD. Mechanism of early systolic closure of the aortic valve in discrete membranous subaortic stenosis. Circulation 1982; 65:399-402. [PMID: 7198519 DOI: 10.1161/01.cir.65.2.399] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The mechanism of the apparent early closure of the aortic valve in patients with discrete membranous subaortic stenosis was studied. Discrete membranous subaortic stenosis was simulated in vitro to assess the fluid dynamic characteristics in the region of the aortic valve that may be responsible for the early closure. In the presence of a simulated fixed membranous subaortic obstruction, early systolic closure of the aortic valve was observed on high-speed motion pictures. Opening and early closure of the valve involved only one of the three aortic leaflets. Closure of the open leaflet was associated with the development of a pronounced pressure drop across the open leaflet caused by a large decrease of pressure in the main stream of flow relative to the pressure in the sinus of Valsalva. The pressure decrease in the main stream of flow resulted from a loss of pressure energy caused by an increase in the kinetic energy of the fluid caused by turbulence. Early systolic closure of the aortic valve in discrete membranous subaortic stenosis, therefore, results from the development of a pressure drop across the open leaflet caused by fluid dynamic factors related to the development of turbulent blood flow distal to the subvalvular obstruction.
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Sabbah HN, Blick EF, Anbe DT, Stein PD. Effect of turbulent blood flow on systolic pressure contour in the ventricles and great vessels: significance related to anacrotic and bisferious pulses. Am J Cardiol 1980; 45:1139-47. [PMID: 7189639 DOI: 10.1016/0002-9149(80)90471-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The effect of turbulent blood flow on the contour of systolic pressure in the left and right ventricles and great vessels was investigated in 64 patients undergoing diagnostic cardiac catheterization. Intracardiac pressure and sound were recorded using a catheter-tip micromanometer. Measurements were made in normal subjects and patients with a variety of disorders including aortic stenosis, hypertrophic obstructive cardiomyopathy, coarctation of the aorta and atrial septal defect. Observations showed a consistent association of the intracardiac murmur, which is indicative of turbulence, with a transient reduction of the centrally recorded systolic pressure. The resultant abnormal systolic pressure contour can be explained on the basis of fluid dynamic considerations related to turbulence.
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Sabbah HN, Khaja F, Anbe DT, Folger GM, Stein PD. Determinants of the amplitude of the aortic component of the second heart sound in aortic stenosis. Am J Cardiol 1978; 41:830-5. [PMID: 645590 DOI: 10.1016/0002-9149(78)90721-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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