title: Coronary vasodilation is impaired in both hypertrophied and nonhypertrophied myocardium of patients with hypertrophic cardiomyopathy: a study with nitrogen-13 ammonia and positron emission tomography.
abstract: To assess regional coronary reserve in hypertrophic cardiomyopathy, regional myocardial blood flow was measured in 23 patients with hypertrophic cardiomyopathy and 12 control subjects by means of nitrogen-13 ammonia and dynamic positron emission tomography. In patients with hypertrophic cardiomyopathy at baseline study, regional myocardial blood flow was 1.14 +/- 0.43 ml/min per g in the hypertrophied (20 +/- 3 mm) interventricular septum and 0.90 +/- 0.35 ml/min per g (p less than 0.05 versus septal flow) in the nonhypertrophied (10 +/- 2 mm) left ventricular free wall. These were not statistically different from the corresponding values in control subjects (1.04 +/- 0.25 and 0.91 +/- 0.21 ml/min per g, respectively, p = NS). After pharmacologically induced coronary vasodilation (dipyridamole, 0.56 mg/kg intravenously over 4 min), regional myocardial blood flow in patients with hypertrophic cardiomyopathy increased significantly less than in control subjects both in the septum (1.63 +/- 0.58 versus 2.99 +/- 1.06 ml/min per g, p less than 0.001) and in the free wall (1.47 +/- 0.58 versus 2.44 +/- 0.82 ml/min per g, p less than 0.001). In addition, patients with hypertrophic cardiomyopathy who had a history of chest pain had more pronounced impairment of coronary vasodilator reserve than did those without a history of chest pain. After dipyridamole, coronary resistance in the septum decreased by 38% in patients without a history of chest pain, but decreased by only 14% in those with such a history (p less than 0.05). Coronary resistance in the free wall decreased by 45% in patients without and by 27% in those with a history of chest pain (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: C.N.R. Institute of Clinical Physiology, Pisa, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Camici
authors.forename: G
authors.initials: G
authors.lastname: Chiriatti
authors.forename: R
authors.initials: R
authors.lastname: Lorenzoni
authors.forename: R C
authors.initials: RC
authors.lastname: Bellina
authors.forename: R
authors.initials: R
authors.lastname: Gistri
authors.forename: G
authors.initials: G
authors.lastname: Italiani
authors.forename: O
authors.initials: O
authors.lastname: Parodi
authors.forename: P A
authors.initials: PA
authors.lastname: Salvadori
authors.forename: N
authors.initials: N
authors.lastname: Nista
authors.forename: L
authors.initials: L
authors.lastname: Papi
mesh_terms: D000641:Ammonia; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000503:physiopathology*; D004176:Dipyridamole; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009590:Nitrogen Radioisotopes; D014055:Tomography, Emission-Computed; D014664:Vasodilation / Q000502:physiology*
chemical_list: D009590:Nitrogen Radioisotopes; D004176:Dipyridamole; D000641:Ammonia