title: [THE IMPORTANCE OF STRESS-ECHOCARDIOGRAPHY FOR DIFFERENTIAL DIAGNOSTICS OF APNEA IN PATIENTS WITH PERMANENT ELECTROCARDIOSTIMULATION].
abstract: Differential diagnostics of apnea regarded as an equivalent to angina or a manifestation of cardiac failure in patients with permanent electrocardiostimulation (PECS) encounters difficulties. Stress-EchoCG is the most adequate method of programmed high-frequency cardiac stimulation with the implanted pacemaker (PM) for excluding stress-induced myocardial ischemia in patients undergoing continuous stimulation of the right ventricle. The aim of the study was to assess the effectiveness and safety of stress-EchoCG by means of programmed high-frequency cardiac stimulation with the implanted PM for patients with single-chamber PECS and complaints of apnea.
  
  
  METHODS
  The study included patients with single-chamber PECS in the VVIR mode (rate-responsive pacing), complaints of apnea under physical load, and suspected coronary heart disease. All of them underwent stress-EchoCG by means of programmed high-frequency cardiac pacing with the implanted PM. Positive results of the test served as indications for coronary angiography (CAG).
  
  
  RESULTS
  The study included 31 patients. In 24 (77.4%) of them with a pacing rate of 90-120/min disturbances of left ventricular local contractility were induced. 18 patients underwent CAG. 15 (83%) of them had normal coronary arteries while 3 (17%) suffered hemodynamically significant stenosis. In other words, 3 patients presented with angina, in the remaining ones apnea was regarded as a manifestation of heart failure.
  
  
  CONCLUSIONS
  In patients undergoing permanent stimulation of the right ventricle, stress-induced disturbances of left ventricular local contractility may be attributed to constrictive lesions of coronary arteries on the one hand and impaired myocardial perfusion due to disordered physiological sequence of cardiac stimulation on the other hand. Coronary atherosclerosis in patients with positive results of stress-EchoCG needs to be confirmed by CAG.
authors.forename: M V
authors.initials: MV
authors.lastname: Kuznetsova
authors.forename: D A
authors.initials: DA
authors.lastname: Andereev
authors.forename: V P
authors.initials: VP
authors.lastname: Sedov
authors.forename: D G
authors.initials: DG
authors.lastname: Alimov
authors.forename: I V
authors.initials: IV
authors.lastname: Samoilenko
authors.forename: A L
authors.initials: AL
authors.lastname: Syrkin
mesh_terms: D000368:Aged; D001049:Apnea / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D025401:Echocardiography, Stress / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000628:therapy; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D015203:Reproducibility of Results