title: Noninvasive assessment of left ventricular contractility by pacemaker stress echocardiography.
abstract: BACKGROUND
  Estimating contractility of the left ventricle with noninvasive techniques is an important yet elusive goal. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon).
  
  
  OBJECTIVE
  To assess the feasibility of a noninvasive estimation of force-frequency relation (FFR) during pacing stress in the echo lab in patients with permanent pacemaker (PM).
  
  
  METHODS
  Transthoracic stress pacing echocardiography was performed in 26 patients with a permanent pacemaker (age 69+/-11 years; 21 men, 5 women). Seven patients had normal function at baseline and during stress ("normals"); eight had angiographically assessed coronary artery disease (three with and five without induced ischemia with stress echo); eleven patients had dilated cardiomyopathy (DC). To build the FFR, the force was determined at different steps as the ratio of the systolic pressure (SP, cuff sphygmomanometer)/end-systolic volume index (ESV, biplane Simpson rule/body surface area). Heart rate was determined from ECG.
  
  
  RESULTS
  The absolute value of the FFR slope was highest in controls and lowest in DC patients. A flat-downsloping FFR was found in 12/19 patients but not for normals (p<0.01).
  
  
  CONCLUSIONS
  Noninvasive pacemaker stress echocardiography (PASE) is a simple and efficient option to assess left ventricular (LV) contractility in patients with permanent pacemaker.
authors.affiliation: CNR, Institute of Clinical Physiology, Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Tonino
authors.initials: T
authors.lastname: Bombardini
authors.forename: Marco
authors.initials: M
authors.lastname: Agrusta
authors.forename: Nino
authors.initials: N
authors.lastname: Natsvlishvili
authors.forename: Francesco
authors.initials: F
authors.lastname: Solimene
authors.forename: Robert
authors.initials: R
authors.lastname: Pap
authors.forename: Fernando
authors.initials: F
authors.lastname: Coltorti
authors.forename: Albert
authors.initials: A
authors.lastname: Varga
authors.forename: Gaetano
authors.initials: G
authors.lastname: Mottola
authors.forename: Eugenio
authors.initials: E
authors.lastname: Picano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D025401:Echocardiography, Stress / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*