title: Acoustic phenomena and valve dysfunction in cardiac prostheses: data acquisition and collection via the Internet.
abstract: OBJECTIVE
  The study aim was to investigate whether: (i) by detection of changing acoustic sound phenomena, minimal changes in prosthetic valve function may be detected earlier than with echocardiography, invasive diagnosis or clinically; (ii) patients can record and pass on signals with a high level of reproducibility from any location via the Internet; and (iii) clinical data evaluation permits conclusions to be drawn on changes in the functional state of a prosthetic replacement valve.
  
  
  METHODS
  Simulation studies were carried out using a mock circulation device. Aortic valve replacement (AVR) using extracorporeal circulation was performed in pigs, valve function was artificially disturbed, and valve sounds were recorded. Patients were equipped with briefcase-like devices to record their valve sounds after AVR and to transfer them via the Internet.
  
  
  RESULTS
  Simulation studies produced a typical sound spectrum for each tested valve that remained constant under variable conditions. Experiments in animals proved that minimal changes in prosthetic valve function led to a significant change in the sound phenomena. The degree of sensitivity was significantly greater than that in echocardiographic control experiments. All patients in the clinical study regularly recorded and passed on their signals. Surveys revealed high acceptance and easy handling of the compiled devices. Valve dysfunctions were not detected.
  
  
  CONCLUSIONS
  On-line registration of acoustic sound phenomena and ECG seems suited to detect minimal changes in prosthetic function. In particular, the registration of flow, acoustics and ECG envisaged at the next level opens up diverse potential applications for Internet-based, remote monitoring of patients following cardiac surgery or cardiologic treatment.
authors.affiliation: Department of Thorax and Cardiovascular Surgery, Heart- and Diabetes Center Northrhine-Westfalia, Bad Oeynhausen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eitz
authors.forename: Dirk
authors.initials: D
authors.lastname: Fritzsche
authors.forename: Oliver
authors.initials: O
authors.lastname: Grimmig
authors.forename: Inez
authors.initials: I
authors.lastname: Frerichs
authors.forename: Alexander
authors.initials: A
authors.lastname: Frerichs
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hellige
authors.forename: Kazumoto
authors.initials: K
authors.lastname: Minami
authors.forename: Reiner
authors.initials: R
authors.lastname: Körfer
mesh_terms: D000162:Acoustics; D000328:Adult; D000818:Animals; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D001185:Artificial Intelligence; D003198:Computer Simulation; D003326:Coronary Circulation / Q000502:physiology; D003625:Data Collection; D004195:Disease Models, Animal; D004452:Echocardiography; D004548:Elasticity; D004562:Electrocardiography; D004869:Equipment Safety; D006349:Heart Valve Diseases / Q000503:physiopathology* / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006801:Humans; D020407:Internet; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D008955:Models, Cardiovascular; D011664:Pulmonary Valve / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D013552:Swine; D016896:Treatment Outcome