Isometric handgrip exercise during cardiovascular magnetic resonance imaging: set-up and cardiovascular effects.
OBJECTIVE
To establish a suitable setup for combining isometric handgrip exercise with cardiovascular magnetic resonance (CMR) imaging and to assess cardiovascular effects.


METHODS
Fifty-three healthy volunteers (31 males, mean age 45 ± 17 years) underwent handgrip exercise in a 3T scanner using a prototype handgrip system and a custom-made feedback system that displayed the force. Handgrip was sustained at 30% of the maximal contraction for 6-8 minutes. Heart rate, blood pressure (BP), and double product were determined sequentially. Stroke volume was quantified in a subgroup (n = 21) at rest and stress using phase contrast acquisitions.


RESULTS
Heart rate increased significantly between rest and stress by 20 ± 13%, systolic / diastolic / mean BP by 15 ± 11% / 20 ± 18% / 17 ± 13%, double product by 37 ± 21%, and cardiac output by 27 ± 16% (each P < 0.001). Stroke volume did not significantly increase (3 ± 9%; P = 0.215). Higher age was associated with reduced increase of stroke volume (P = 0.022) and cardiac output (P < 0.001). Overweight subjects showed less increases in heart rate (P = 0.021) and cardiac output (P = 0.002).


CONCLUSIONS
The handgrip exercise during CMR with the presented set-up leads to considerable hemodynamic changes in healthy volunteers.
Berlin Ultrahigh Field Facility (B.U.F.F), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany. florian.von-knobelsdorff@charite.de
Florian
F
von Knobelsdorff-Brenkenhoff
Matthias A
MA
Dieringer
Katharina
K
Fuchs
Fabian
F
Hezel
Thoralf
T
Niendorf
Jeanette
J
Schulz-Menger
D001676:Biofeedback, Psychology / Q000295:instrumentation* / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005080:Exercise Test / Q000295:instrumentation* / Q000379:methods; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D064368:Healthy Volunteers; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical