Ventricular repolarization duration and dispersion adaptation after atropine induced rapid heart rate increase in healthy adults.

Bergfeldt, Lennart,1950Gothenburg University,Göteborgs universitet,Institutionen för medicin, avdelningen för molekylär och klinisk medicin,Institute of Medicine, Department of Molecular and Clinical Medicine (author)

Proper adaptation of ventricular repolarization (VR) to rapid heart rate (HR) increase is crucial for cardiac electro-mechanical function. The pattern and temporal aspects of this adaptation and its components (duration and dispersion) during normal conduction are, however, incompletely known in humans and were the topic of this study.The VR duration (QT & QTpeak) and dispersion (Tamplitude, Tarea & ventricular gradient; VG) responses were studied by continuous vectorcardiogram after a bolus injection of atropine 0.04mg/kg b.w. in 31 healthy young adults (16 men). The primary measure (T90 End) was the time to reach 90% change from baseline to end value 300s later. Mean (SD) of T90 End was 23 (9) s for a 41% RR decrease, 130 (35) s for a 16% QTend decrease and 110 (36) s for a 19% QTpeak decrease; the response was single-exponential for these measures. For 35-43% decreases of Tamplitude, Tarea & VG, mean (SD) of T90 End were 21 (10), 38 (20) and 40 (23) s and the response pattern was double-exponential with varying overshoot.VR duration and dispersion responses to a very rapid HR increase during normal conduction differed substantially. In contrast to the well-known single-exponential delay in VR duration adaptation the responses of VR dispersion measures were double-exponential and much more rapid. We describe a new and completely non-invasive phenotypic characterization of different components of VR adaptation.

Lundahl, GunillaGothenburg University,Göteborgs universitet,Institutionen för medicin, avdelningen för molekylär och klinisk medicin,Institute of Medicine, Department of Molecular and Clinical Medicine (author)
Bergqvist, GabrielGothenburg University,Göteborgs universitet,Institutionen för medicin, avdelningen för molekylär och klinisk medicin,Institute of Medicine, Department of Molecular and Clinical Medicine (author)
Vahedi, FarzadGothenburg University,Göteborgs universitet,Institutionen för medicin, avdelningen för molekylär och klinisk medicin,Institute of Medicine, Department of Molecular and Clinical Medicine(Swepub:gu)xvahfa (author)
Gransberg, LennartGothenburg University,Göteborgs universitet,Institutionen för medicin, avdelningen för molekylär och klinisk medicin,Institute of Medicine, Department of Molecular and Clinical Medicine (author)
Göteborgs universitetInstitutionen för medicin, avdelningen för molekylär och klinisk medicin (creator_code:org_t)

By the author/editor: Bergfeldt, Lenna ...; Lundahl, Gunilla; Bergqvist, Gabri ...; Vahedi, Farzad; Gransberg, Lenna ...

About the subject

MEDICAL AND HEALTH SCIENCES: MEDICAL AND HEAL ...; and Clinical Medicin ...; and Cardiac and Card ...

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