The concept that the positive inotropic effect of cardiac glycosides is dependent on the contractile state of the myocardium was tested. Isolated left atria of rabbits, when driven electrically at 15, 30, 60 and 120/min (at 30, 33, or 37°C), responded to ouabain (1 yug/ml) in proportion to the number of contractions and not to the time of exposure or frequency of drive. Contraction-related effe...

Zhu, Jiequan, and Gregory R. Ferrier. Regulation of a voltage-sensitive release mechanism by Ca-calmodulin-dependent kinase in cardiac myocytes. Am J Physiol Heart Circ Physiol 279: H2104–H2115, 2000.—A role for Ca-calmodulin-dependent kinase (CamK) in regulation of the voltagesensitive release mechanism (VSRM) was investigated in guinea pig ventricular myocytes. Voltage clamp was used to separ...

In this study, we describe new methods for recording gastric emptying and in vivo measurements of intragastric pressure in fish. Using these methods, we investigated the effects of the sulphated octapeptide of cholecystokinin (CCK8) on gastric emptying and on stomach motility in vivo and in vitro. Gastric emptying of 99Tcm-labelled food was measured in swimming fish by using a gamma camera, cou...

Sarcomere length measurement by microscopic and laser diffraction techniques in trabeculae of rat heart, superfused with Krebs-Henseleit solution at 21 degrees C, showed spontaneous local sarcomere shortening after electrically stimulated twitches. The contractions originated in a region of several hundred micrometers throughout the width of the muscle close to the end of the preparation that w...

Distal esophageal spasm is characterized by premature contractions of the distal smooth muscle leading to non-obstructive dysphagia and non-cardiac chest pain. Diagnosis requires presence symptoms along with evidence at least 20% in setting a normal lower sphincter relaxation on high-resolution manometry. New updates Chicago Classification have improved diagnostic accuracy this method. Function...

A recent study of the postextrasystolic T wave changes, associated with interpolated premahire ventricular beats, revealed that this phenomenon is not rare and, unlike the T wave changes which occasionally occur in the first sinus beat following the more common premature ventricular beats with compensatory pauses, are not usually related to the presence of significant heart disease.’ Despite th...

The interest in localization of the site of origin of ventricular extrasystoles by study of their electrocardiographic configuration does not arise from a sense of the importance of such a localization in the case of the majority of ventricular extrasystoles observed in man. It is, rather, founded on the recognition in the earliest days of electrocardiography'5 26, 27, 28 that the electrocardio...

Twenty patients with frequent ventricular ectopic beats had a 5 1/2 hour ECG rhythm strip recorded. Individual patients showed a marked spontaneous variability from one half-hour to the next in the total number of ectopic beats (-99% to +1100%) and the occurrence of pairs or salvos. Although no patient received antiarrhythmic drugs, some patients showed a spontaneous change in arrhythmia which ...

HERE have been no reports on the U vector loop or arc of ventricular premature beats. Recently a systematic study was carried out on the vectorcardiogram of ventricular premature beats. The QRS and T vector loop of the ventricular premature beats will be reported elsewhere. Since the U vector loop could not be studied in all these cases because of technical difficulties, and since it needs a de...