Characteristics of extracellular potentials recorded from the sinoatrial pacemaker of the rabbit.

Cramer, Marvin; Siegal, Michael S.; Bigger, J. Thomas; Hoffman, Brian F.

doi:10.1161/01.res.41.3.292

Cited by 49 publications

(11 citation statements)

References 21 publications

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“…This was also demonstrated in a recent report by the characterization of intrinsic action potential (AP) parameters during simultaneous recording of APs and FPs in native murine embryonic cardiomyocytes. As has been described for other models [26][27][28], not only different AP and FP morphologies representing atrial, ventricular or pacemaker-like potentials [29,30], but also a linear relationship between AP and FP rise time as well as a linear relationship between AP duration and FP duration was demonstrated [16]. In line with these similarities between APs and FPs, it was shown that individual ion channels, i.e.…”

Section: Discussionsupporting

confidence: 71%

Beta-adrenergic and Muscarinic Modulation of Human Embryonic Stem Cell-derived Cardio-myocytes

Reppel

Boettinger

Hescheler

2004

Cell Physiol Biochem

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Background: Embryonic stem cells provide the most promising tool for cell replacement therapy including transplantation of human embryonic stem (hES) cell- derived cardiomyocytes in the infarcted area of the heart. Here we provide data for differentiation of cardiomyocytes from hES cells and firstly describe their hormonal modulation. Methods: Using Micro-Electrode Arrays as a novel electrical mapping technique of beating cardiomyocyte clusters within whole hES cell aggregates, we were able to measure the field potential generation and morphology changes during hormonal modulation. Results: We found that isoproterenol provokes, similar to the mouse ES cell system, a strong positive chronotropic effect with an EC₅₀ of around 10^-8 M. Moreover, isoproterenol stimulated with a higher EC₅₀ value the slow field potential amplitude, FP_slow, indicating a stimulation of Ca²⁺ channels in ventricular-like ES cell-derived cardiomyocytes which is shown to be clearly independent from frequence modulation. In contrast, carbachol (10 µM) produced a transient negative chronotropic effect but had no effect on FP_slow. Conclusion: The Micro-Electrode system allows measurement of ionic channel modulation and chronotropic responsiveness in a pharmacological screening setup. Moreover, all our data indicate that cardiomyocytes derived from human embryonic stem cells exhibit a physiological response to the major hormones of the vegetative nervous system and might therefore serve as an ideal candidate for the use in cell replacement strategies.

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Section: Discussionsupporting

confidence: 71%

Beta-adrenergic and Muscarinic Modulation of Human Embryonic Stem Cell-derived Cardio-myocytes

Reppel

Boettinger

Hescheler

2004

Cell Physiol Biochem

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“…Among the investigators there is little agreement concerning the sino-atrial conduction time. In sinus node preparations of the rabbit, Masuda (12) and Bleeker (3) found SACTs of 20-40 ms and 30 ms, respectively, whereas those measured by Cramer (6) and Grant (8) were of double length (70 ms and about 80 ms, respectively). In mapping studies on isolated superfused rabbit hearts from Masuda (12) complex extracellular wave patterns are reported.…”

Section: Discussionmentioning

confidence: 95%

Detection and continuous monitoring of intracardiac low-level potentials from the surface of the Langendorff-perfused heart

et al. 1990

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By appropriate placement of two electrodes on the epicardiac surface of Langendorff-perfused hearts, His-bundle and preatrial signals can be recorded by the surface electrogram (S-ECG). These signals are difficult to detect because of their low amplitude of a few microvolts. To improve the monitoring of these low-level potentials we studied the His-bundle spike as detected by intracardiac electrodes and by epicardial records (S-ECG) and compared these signals in the time and frequency domain. The frequency spectra of these cardiograms were used to develop appropriate filters and high-gain amplifiers for a continuous monitoring of the His-bundle signal from the epicardiac surface. By means of such a monitoring system, high-frequency components of preatrial activities could be resolved also. The time coincidence of these spikes to the simultaneously recorded intraatrial electrogram from electrodes positioned near the sinus node and near the His-bundle is demonstrated. Hence, the early atrial signals likely yield information about sinoatrial conduction. Application examples of monitoring His-bundle signals and preatrial signals in a beat-to-beat manner are described also for various conduction blocks or arrhythmias. With this monitor the evaluation of characteristic parameters of the conduction system of the heart like HV-, AH- and A'H-time, and likely, SACT can easily be performed for every heartbeat on a digital oscilloscope with low resolution or a two-channel chart recorder. Small and intact hearts can be used with this system to detect intracardiac low-level potentials during the heart beat.

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“…Sinus node electrogram is referred to as a slowly up-or down-sloping wave or ramp which precedes atrial depo larization [ 1,2] in intracardiac catheter electrode record ings from the endocardial surface of the sinus node area [3][4][5], Up to now, the low voltage of sinus node depolari zation (less than 20-30 pV) has made a noninvasive sur face recording of sinus node activity impossible, because of high voltage of random background electrical activity ('noise')-Such an electrophysiological problem can be solved by means of direct intracardiac catheter record ings; nevertheless, a noninvasive surface measurement could be useful for routine studies. Some attempts of noninvasive pre-P activity recording have been per formed [8], but no study has been published directly comparing externally recorded pre-atrial potentials to simultaneous intracardiac catheter recordings from the sinus node area.…”

Section: Discussionmentioning

confidence: 99%

“…brane and extracellular recordings) which precedes atrial depolarization [1,2]. Such preatrial depolarizations have also been found in humans, by means of intracardiac catheter electrode recordings from the endocardial sur face of the sinus node area [3][4][5], However, noninvasive…”

Section: Introductionmentioning

confidence: 99%

Noninvasive Recording of Sinus Node Activity by P-Wave-Triggered Signal-Averaged Electrocardiogram: Validation Using Direct Intra-Atrial Recording of Sinus Node Electrogram

Michelucci¹,

Toso²,

Mezzani³

et al. 1993

Am J Noninvas Cardiol

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In order to evaluate if sinus node activity can be detected by surface ECG, at least 200 sinus beats of 3 bipolar orthogonal leads (horizontal, vertical, and sagittal position) were averaged in 33 consecutive patients (mean age: 58 ± 19 years). Each lead signal (0.5-300 Hz) was independently averaged triggering P wave by the template-comparing method and then filtered (0.5-25 Hz) and amplified. In 29 patients (88%), amplification revealed the presence of a progressive upstroke slope beginning during the isoelectric line and ending at the earliest observed atrial activation in the 3 nonamplified and nonfiltered leads (mean voltage: 9.3 ± 6.4 pV). Such pre-P signal was always lost with 50-Hz high-pass filtering, and could be present in 1 or more leads; in the latter case, the longest duration was considered. The length of pre-P signal proved to be strictly correlated (r = 0.9932, p < 0.001) with that contemporaneously furnished by the direct intra-atrial recording of sinus node electrogram (0.05-35 Hz, mean of at least 20 measurements). Mean values of noninvasive and invasive pre-P lengths were 76 ± 29 and 74 ± 30 ms, respectively. In conclusion, it seems possible to detect from surface ECG a pre-P activity whose character and timing are well correlated to those obtained by endocavitary recording of sinus node signal. These findings suggest the possibility of a clinical use of noninvasive sinus node activity recording for diagnostic purposes.

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Characteristics of extracellular potentials recorded from the sinoatrial pacemaker of the rabbit.

Cited by 49 publications

References 21 publications

Beta-adrenergic and Muscarinic Modulation of Human Embryonic Stem Cell-derived Cardio-myocytes

Beta-adrenergic and Muscarinic Modulation of Human Embryonic Stem Cell-derived Cardio-myocytes

Detection and continuous monitoring of intracardiac low-level potentials from the surface of the Langendorff-perfused heart

Noninvasive Recording of Sinus Node Activity by P-Wave-Triggered Signal-Averaged Electrocardiogram: Validation Using Direct Intra-Atrial Recording of Sinus Node Electrogram

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