title: Incidental detection of apical hypertrophic cardiomyopathy by myocardial perfusion imaging.
abstract: BACKGROUND
  Echocardiography plays a central role in the diagnosis of hypertrophic cardiomyopathy (HCM). However, apical involvement of HCM may be missed because of foreshortening and inadequate clinical suspicion. These patients may be referred for single-photon emission computed tomography imaging.
  
  
  METHODS
  We present three cases of HCM predominantly involving the cardiac apex, whose diagnosis was first suspected on myocardial perfusion imaging. These patients were referred for chest pain syndromes to exclude significant coronary artery disease. All were undiagnosed on initial routine transthoracic echocardiography, and none were specifically suspected by the referring clinicians. All cases underwent an adenosine stress rest technetium-99m tetrofosmin myocardial perfusion protocol, and were subsequently referred for transpulmonary contrast echocardiography.
  
  
  RESULTS
  Single-photon emission computed tomography imaging revealed increased tracer uptake in all cases, most marked in the apical myocardium. Inferior wall ischaemia was detected in one case, consistent with a coronary stenosis seen at angiography. Apical hypokinesia was noted in two patients on gated studies. Contrast echocardiography confirmed the diagnosis of HCM with apical involvement in all cases.
  
  
  CONCLUSIONS
  Echocardiography is the first-line imaging technique for the diagnosis of HCM, but apical involvement may be missed unless a contrast study is performed. The presence of increased apical tracer uptake on perfusion imaging should alert the referring physician to the possibility of apical HCM, irrespective of earlier echocardiographic findings.
authors.affiliation: Manchester Heart Centre, Manchester Royal Infirmary, Manchester, UK. rbirwin@hotmail.com
authors.forename: Richard Bruce
authors.initials: RB
authors.lastname: Irwin
authors.forename: Parthiban
authors.initials: P
authors.lastname: Arumugam
authors.forename: Rajdeep S
authors.initials: RS
authors.lastname: Khattar
mesh_terms: D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D015899:Tomography, Emission-Computed, Single-Photon; D014463:Ultrasonography