title: The effect of DDD pacing on ergospirometric parameters and neurohormonal activity in patients with hypertrophic obstructive cardiomyopathy.
abstract: This study examined the acute and long-term effects of DDD pacing on ergospirometric parameters and neurohormonal activity in patients with hypertrophic obstructive cardiomyopathy (HOCM). We studied eight patients (five males), aged 56 +/- 7 years, with HOCM refractory to drugs. In all patients a DDD pacemaker was implanted and programmed with an atrioventricular (AV) delay that insured full ventricular activation. The patients underwent echocardiographic examination and exercise stress testing before and 3 days, 3 months, and 12 months after pacemaker implantation. Oxygen consumption was measured at the anaerobic threshold (VO2AT) and peak exercise (pVO2). Atrial natriuretic peptide (ANP) and cyclic adenosine monophosphate (c-AMP) levels were measured concomitantly. Left ventricular outflow tract (LVOT) pressure gradient decreased significantly from 70 +/- 18 to 25 +/- 12 mmHg (P < 0.05) 3 days after pacing and remained unchanged at 3 and 12 months. pVO2 and VO2AT increased significantly, from 20.1 +/- 3 to 23.4 +/- 3 mL/kg/min and from 16 +/- 3 to 17.8 +/- 2 mL/kg/min, respectively (P < 0.05). This improvement continued up to 3 months, and then remained stable until the end of the 12-month follow-up period. ANP levels decreased at 3 days from 85.4 +/- 5.7 to 75.4 +/- 7.3 fmol/mL (P < 0.05), and remained unchanged over the 12 months. c-AMP levels did not change significantly after the onset of pacing. DDD pacing in patients with HOCM not only reduces the LVOT pressure gradient but also causes a significant early and long-term improvement in exercise capacity and neurohormonal profile.
authors.affiliation: Cardiology Department, University Hospital of Heraklion, Crete, Greece.
authors.forename: E N
authors.initials: EN
authors.lastname: Simantirakis
authors.forename: E M
authors.initials: EM
authors.lastname: Kanoupakis
authors.forename: G E
authors.initials: GE
authors.lastname: Kochiadakis
authors.forename: M K
authors.initials: MK
authors.lastname: Kanakaraki
authors.forename: F I
authors.initials: FI
authors.lastname: Parthenakis
authors.forename: E G
authors.initials: EG
authors.lastname: Manios
authors.forename: E
authors.initials: E
authors.lastname: Markianos
authors.forename: P E
authors.initials: PE
authors.lastname: Vardas
mesh_terms: D009320:Atrial Natriuretic Factor / Q000097:blood*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002312:Cardiomyopathy, Hypertrophic / Q000503:physiopathology / Q000628:therapy*; D000242:Cyclic AMP / Q000097:blood*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010138:Pacemaker, Artificial; D013997:Time Factors
chemical_list: D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP