System for the measurement of the effects of ultrasound on membrane electrical and mechanical properties of the myocardium

Therapeutic Ultrasound in Cardiovascular Medicine

“…Another study 22 showed that the release and transport of calcium were highly likely to be involved in the potentiation of the developed force. Ultrasound (CW 1 MHz, 1.5 W/cm 2 SATA) caused simultaneous alterations in isolated cardiac muscle 17 . In a previous study, 15 a decrease of diastolic tension had been observed, whereas in this later study, an increase of the action potential amplitude was reported in addition to the decrease of the diastolic force.…”

“…In vitro and in vivo studies in subsequent years found that the decrease of the diastolic force is a recurrent US effect 16,17 . With CW 1‐MHz, 1‐W/cm 2 SATA intensity US, a decrease of diastolic force was observed in rat hearts without simultaneous modification of the developed force.…”

“…The mechanism of therapeutic US on the cardiovascular system was first identified by the increase and decrease of zones of pressure in the cardiac tissue, causing a rhythmic contraction in the ventricular muscles 13 and possible changes in the diastolic force 15–17 . Studies also suggested that US irradiation might accelerate calcium release or accumulation in the cardiac tissue 18–20 …”

“…In vitro experimental setups. A , Papillary muscle exposed at 953‐kHz continuous waves (modified from Mortimer et al 17 ). B , Cells exposed at 1‐Hz pulsed waves (modified from Mortimer and Dyson 19 ).…”

“…Therapeutic‐level CW US 16,22 was reported to increase the force and enhance the effect of graded intensities on rat isolated papillary muscle contractile performance. Based on studies by Mortimer et al 15,17 and Forester et al, 16,18,22 the US stimulation might accelerate a release or accumulation of calcium in the cardiac tissue, and the effect mechanism was viewed to be with nonthermal effects.…”