title: Comparison of sublingual isosorbide dinitrate and Valsalva maneuver for detection of obstruction in hypertrophic cardiomyopathy.
abstract: BACKGROUND
  A left ventricular outflow tract (LVOT) obstruction assessment with a provoking test should be a routine part of the evaluation of patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to compare the utility of the Valsalva maneuver (VM) and sublingual spray application of isosorbide dinitrate (ISDN) for detection of an obstruction.
  
  
  METHODS
  We prospectively evaluated 81 consecutive HCM patients without severe rest LVOT obstruction (defined as peak rest pressure gradient (PG) ≥ 50 mm Hg). We measured PG at rest, during the VM, after sublingual ISDN spray, and during the VM after ISDN. An obstruction was defined as a PG ≥ 30 mm Hg.
  
  
  RESULTS
  An obstruction was present in 15 patients (19%) at rest (median and interquartile range of PG 16 (7-26) mm Hg), in 38 patients (47%) during the VM (PG 28 (12-49) mm Hg), in 50 (62%) patients after ISDN (PG 50 (12-79) mm Hg), and in 55 patients (68%) during the VM after ISDN (PG 59 (20-87) mm Hg). The difference in occurrence of obstruction among different provoking tests was statistically significant for all comparisons (p < 0.001, except for the comparison of the ISDN test with the VM during ISDN, p = 0.025).
  
  
  CONCLUSIONS
  The ISDN test and the VM are useful screening methods for the detection of an HCM obstruction. Although ISDN appears to be more precise than the VM, the best option is a combination of both methods, which maximizes inducement of LVOT obstruction in patients with HCM.
authors: Department of Cardiology, 2 Medical School of Charles University and University Hospital Motol, Prague, Czech Republic ; International Clinical Research Center Brno, Brno, Czech Republic.
authors: David
authors: D
authors: Zemanek
authors: Department of Cardiology, 2 Medical School of Charles University and University Hospital Motol, Prague, Czech Republic.
authors: Pavol
authors: P
authors: Tomasov
authors: International Clinical Research Center Brno, Brno, Czech Republic.
authors: Miloš
authors: M
authors: Bělehrad
authors: Department of Cardiology, 2 Medical School of Charles University and University Hospital Motol, Prague, Czech Republic.
authors: Katarína
authors: K
authors: Hladká
authors: International Clinical Research Center Brno, Brno, Czech Republic.
authors: Jana
authors: J
authors: Košťálová
authors: International Clinical Research Center Brno, Brno, Czech Republic.
authors: Tomáš
authors: T
authors: Kára
authors: Department of Cardiology, 2 Medical School of Charles University and University Hospital Motol, Prague, Czech Republic.
authors: Josef
authors: J
authors: Veselka
keywords: Valsalva maneuver; hypertrophic cardiomyopathy; left ventricular outflow tract obstruction; nitrate