Archive for the ‘Cardiology’ Category

RESULTS Action potentials of human atrial myocytes are much shorter in duration and possess a less prominent plateau than those in subepicardial ventricular myocytes (Figure 1).The current measured with this slow ramp should not be contaminated significantly by rapidly activating and inactivating currents such as sodium and calcium currents, although window currents contribute if present. […]

In order to correct for variability in cell size, the cell capacitance was measured before compensation using depolarizing ramps (1 V/s) from-40 to -35 mV. Access resistance was kept below 10 MQ. The series resistance was compensated by at least 70%.  For experimentation, the cells were allowed to settle on the bottom of a small […]

MATERIALS AND METHODS Isolation of human myocytes: Atrial tissue samples were obtained from the right atrial appendage of patients undergoing coronary bypass surgery, and ventricular subepicardial samples were taken from the free left ventricular wall of explanted hearts from transplant recipients. Tissue specimens were transported to the laboratory in either Tyrode’s solution (inmM: NaCl 127, […]

The major potassium currents detected in human ventricular myocytes are the transient outward current (Ito) and the inward rectifier Ik1, while the delayed rectifier Ik is difficult to detect . In atrial myocytes an additional current, the sustained outward current (Iso), can be distinguished . Antiarrhythmic drugs that prolong the action potential duration may affect […]