Effect of physiological mechanical perturbations on intact human myocardial repolarization
| Autor: | Miney Paquette, Kumar Nanthakumar, Paul Dorian, Stuart Hutchison, Janice Andrews, David Newman |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Atropine
Male medicine.medical_specialty Ventricular End-Diastolic Volume Heart disease Valsalva Maneuver Physiology Heart Ventricles Action Potentials Propranolol law.invention Tilt-Table Test law Physiology (medical) Internal medicine Heart rate medicine Humans Tachycardia Atrioventricular Nodal Reentry Repolarization Single-Blind Method Prospective Studies Endocardium Aged Ultrasonography Sick Sinus Syndrome business.industry Cardiac Pacing Artificial Heart Middle Aged medicine.disease Autonomic Agents Autonomic nervous system Anesthesia Cardiology Artificial cardiac pacemaker Female Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | Cardiovascular Research. 45:303-309 |
| ISSN: | 0008-6363 |
| Popis: | Objective: The objective of this study was to investigate the relationship between acute decreases in right ventricular volume during Valsalva strain (with resultant changes in autonomic neural tone) and measures of local endocardial repolarization time independent of heart rate and autonomic neural tone. Methods: Patients implanted with a stimulus to T wave (Stim-T) sensing pacemaker specially adapted to output a validated measure of beat to beat local repolarization ( n =9) performed Valsalva manoeuvers (40 mmHg for 15 s) while paced at a cycle length of 500 ms. Stim-T intervals were measured before and after autonomic blockade (Block: 0.03 mg/kg i.v. atropine±0.15 mg/kg propranolol). Right ventricular end diastolic volume was estimated by simultaneous 2D-echocardiography. Results: Without autonomic blockade, compared to baseline, repolarization significantly prolonged during Valsalva strain (1.1±0.7%) and shortened during release (−1.4±1.0%). After block, strain related repolarization prolongation was also observed (1.0±0.6%), with significantly less release related repolarization shortening (−0.8±0.8%) compared to pre-block ( P |
| Databáze: | OpenAIRE |
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