title: Long-term improvement of QT dispersion is unaffected by short-term changes in blood pressure during treatment of systemic hypertension with enalapril.
abstract: BACKGROUND
  We report the reduction of QT and QTc dispersion in patients treated for 7 years with enalapril for systemic hypertension with left ventricular (LV) hypertrophy. We assess the correlation between QT dispersion and LV mass during this period and at the end of an 8-week period of suspension of enalapril treatment after 5 years.
  
  
  METHODS
  Twenty-four previously untreated patients with this condition took enalapril (20 mg twice daily) for 7 years, except during an 8-week period following 5-year follow-up. Cardiovascular parameters were determined by two-dimensional guided M-mode echocardiography, and QT interval was measured, in a pretreatment placebo phase, 8 weeks and 1, 3, 5, and 7 years after the start of the therapy, at the end of the 8-week suspension effected after 5 years, and 8 weeks after the end of the suspension.
  
  
  RESULTS
  Therapy rapidly reduced blood pressure (BP) from 156/105 mmHg to normal values: 134/84 mmHg after 8 weeks' treatment, 130-84 mmHg at 7-year follow-up (P < 0.001 with respect to the placebo phase). LV mass index decreased progressively until at 5-year follow-up the reduction had reached 39% (P < 0.001), after which neither LV mass nor any other structural parameter underwent any further significant change. During this time, QT dispersion (DeltaQT) and the dispersion of "corrected" QT (DeltaQTc) decreased significantly: DeltaQT (from 61 +/- 21 to 37 +/- 13 ms) and DeltaQTc (from 67 +/- 27 to 41 +/- 16 ms). After suspension of treatment for 8 weeks following 5-year follow-up, DeltaQT was 40 +/- 14 ms and DeltaQTc was 44 +/- 17 ms; there were no significant changes either in DeltaQT and DeltaQTc or LV hypertrophy although BP had returned to pretreatment values (BP: 150 +/- 16; 101 +/- 10 mmHg).
  
  
  CONCLUSIONS
  Long-term enalapril treatment of hypertensive patients with LV hypertrophy induces marked regression of LV mass and improvement of QT dispersion. These improvements occur on a longer timescale than improvement in BP, and are not affected by transient changes in BP values.
authors.affiliation: Cardiology Department, Hospital Clínico Universitario de Santiago de Compostela, Spain. javierseara@mixmail.com
authors.forename: Francisco Javier García
authors.initials: FJ
authors.lastname: Seara
authors.forename: José Ramón González
authors.initials: JR
authors.lastname: Juanatey
authors.forename: José Luis Martínez
authors.initials: JL
authors.lastname: Sande
authors.forename: Pedro Rigueiro
authors.initials: PR
authors.lastname: Veloso
authors.forename: Antonio Pose
authors.initials: AP
authors.lastname: Reino
authors.forename: Alfonso Varela
authors.initials: AV
authors.lastname: Román
authors.forename: José Cabezas
authors.initials: JC
authors.lastname: Cerrato
authors.forename: Miguel Gil de la
authors.initials: MG
authors.lastname: Peña
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D015897:Comorbidity; D004562:Electrocardiography; D004656:Enalapril / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D017379:Hypertrophy, Left Ventricular / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000187:drug effects; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D000959:Antihypertensive Agents; D004656:Enalapril