title: Computerized acoustic cardiographic insights into the pericardial knock in constrictive pericarditis.
abstract: BACKGROUND
  One of the clinical hallmarks of constrictive pericarditis is the pericardial knock, a high-pitched early diastolic heart sound. Making the clinical diagnosis of constrictive pericarditis is challenging, as is accurate auscultation of the pericardial knock.
  
  
  OBJECTIVE
  We sought to assess the utility of a computerized acoustic cardiographic device in the assessment of the pericardial knock in patients with constrictive pericarditis.
  
  
  METHODS
  We report a case series in which computerized acoustic cardiography (Audicor, Inovise Medical Inc., Portland, OR) is performed in patients with constrictive pericarditis.
  
  
  RESULTS
  Three patients with constrictive pericarditis underwent computerized acoustic cardiographic recordings at the time of cardiac catheterization. In each case, initial physical examination by the internist and referring cardiologist did not appreciate a pericardial knock. Acoustic cardiography demonstrated a high-pitched early diastolic sound in each case. Time-frequency representation analyses showed the high-frequency components of the pericardial knock sound. Repeat acoustic cardiography demonstrated resolution of the pericardial knock after pericardiectomy in two patients.
  
  
  CONCLUSIONS
  Non-invasive computerized acoustic cardiography can demonstrate the high-pitched pericardial knock in patients with constrictive pericarditis. This may aid the bedside assessment of patients with diastolic heart failure, improving the clinician's ability to appreciate the ausculatory findings in constrictive pericarditis.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Utah, Salt Lake City, Utah 84132-2401, USA. andrew.michaels@hsc.utah.edu
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Michaels
authors.forename: Mohan N
authors.initials: MN
authors.lastname: Viswanathan
authors.forename: Mark V
authors.initials: MV
authors.lastname: Jordan
authors.forename: Kanu
authors.initials: K
authors.lastname: Chatterjee
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006347:Heart Sounds; D006801:Humans; D008297:Male; D008875:Middle Aged; D010494:Pericarditis, Constrictive / Q000175:diagnosis* / Q000503:physiopathology*; D010701:Phonocardiography; D012815:Signal Processing, Computer-Assisted