The effect of pacing-induced heart rate variation on longitudinal and circumferential regional myocardial function after acute beta-blockade a cardiac ultrasound study

• Aims: To evaluate the effect of acute beta-blockade in combination with differing heart rates on longitudinal and circumferential regional myocardial function using Doppler myocardial imaging and two-dimensional-echocardiography. Methods and Results: In seven pigs the following echocardiographic indices were measured at baseline, after beta-blockade both without and with atrial pacing: wall thickening fraction, fractional shortening, myocardial peak systolic velocity, transmyocardial velocity gradient and systolic velocity time integral of the posterolateral wall in short-axis view; mitral valve plane excursion, myocardial peak systolic velocity and systolic velocity time integral of the posterolateral wall in an apical five-chamber view. Peak systolic velocities and velocity gradients decreased significantly following acute beta-blockade but no further decay occurred at high heart rate due to pacing. The velocity time integrals and mitral valve plane excursion showed a tendency to decrease following beta-blockade but only after pacing were they significantly reduced. The wall thickening fraction and fractional shortening showed a significant reduction after beta-blockade but no further decay after pacing. Conclusions: Changes in systolic velocities and velocity gradients were independent of heart rate reduction under high dosage beta-blockade, whereas wall thickening fraction, mitral valve plane excursion and velocity time integrals changed due to pacing.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Medicinteknik -- Medicinsk laboratorie- och mätteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Medical Engineering -- Medical Laboratory and Measurements Technologies (hsv//eng)

Nyckelord

doppler myocardial imagingleft ventricular functionbeta-blockadeheart rate variation

Medical engineering

Medicinsk teknik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)