The influence of the vegetative nerve system on the maximal conduction velocity in the atrioventricular bundle and in the cardiac ventricles measured by the differential quotient of QRS. Investigations in dogs

Hahn, N; W, Kau; B, Falke; Sharif, Rayhan; Brinckmann, Paul

doi:10.1007/bf01906204

Cited by 2 publications

(1 citation statement)

References 7 publications

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“…Animal studies have demonstrated that sympathetic activity increases and parasympathetic activity reduces ventricular conduction velocity [23,24]. A reduced conduction velocity induced by parasympathetic activity will prolong the ventricular conduction time and by that SA-QRS and LPD.…”

Section: Possible Mechanismsmentioning

confidence: 99%

Effect of parasympathetic blockade on the signalaveraged electrocardiogram

Christiansen

Fröbert

1998

Clinical Autonomic Research

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Low parasympathetic activity is associated with late potentials detected at a noise level of 0.4 microV in a signal-averaged electrocardiogram (SAECG) following myocardial infarction. In contrast, at a noise level of 0.2 microV, lowering parasympathetic activity influences late potential parameters in the opposite direction in healthy subjects. The aim of this study was to estimate the relationship between parasympathetic activity and the SAECG obtained at noise levels of 0.4 and 0.2 microV in healthy subjects. Two SAECG recordings in 10 healthy subjects were obtained at noise levels of 0.2 and 0.4 microV before and after parasympathetic blockade using atropine (1 mg). Signal-averaged QRS duration (SA-QRS), late potential duration (LPD) defined as duration of terminal signals below 40 microV, and root mean square voltage of the terminal 40 ms of the averaged QRS (RMS40) were measured. At a noise level of 0.2 microV SA-QRS reduced from 124 +/- 14 to 114 +/- 17 ms (P = 0.008), LPD from 37 +/- 10 to 28 +/- 14 ms (P = 0.01), and RMS40 increased from 26 +/- 22 to 41 +/- 25 microV (P = 0.006) during parasympathetic blockade compared to baseline values. At a noise level of 0.4 microV the SA-QRS (115 +/- 15 ms) and LPD (29 +/- 11 ms) were lower and the RMS40 (37 +/- 23 microV) was higher compared to the noise level 0.2 microV, and no systematic alterations of the three variables were found during parasympathetic blockade. The parasympathetic nervous system may induce a very low-amplitude late potential in the SAECG. The data suggest that parasympathetic activity and a low noise level may lead to a false late potential-positive SAECG in low arrhythmia risk subjects. Therefore, we recommend the use of a noise level of 0.4 microV or identification of high arrhythmia risk patients by late potential and low parasympathetic activity.

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Section: Possible Mechanismsmentioning

confidence: 99%

Effect of parasympathetic blockade on the signalaveraged electrocardiogram

Christiansen

Fröbert

1998

Clinical Autonomic Research

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Association Between Parasympathetic Activity and Late Potentials at Low Noise Level

Christiansen

Frost

Mølgaard

et al. 1997

Noninvasive Electrocardiol

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Background: Late potentials (LP) in the signal-averaged ECC represent activation of myocardial areas with slow conduction and predicts re-entrant malignant ventricular arrhythmias in coronary artery disease. Low heart rate variability, which reflects low vagal and concomitantly elevated sympathetic activation also predicts ventricular arrhythmia. This autonomic profile is associated with the presence of LP (detected at noise level 0.4 pV) early after myocardial infarction. In contrast, sympathetic stimulation and diminution of vagal tone influence LP parameters (detected at noise level 0.2 pV) in the opposite direction in healthy subjects. The aim of this study was to estimate the possible association between measures of cardiac autonomic function and LP (detected at 0.4 and 0.2 pV) in patients with chronic coronary artery disease.Methods: ECGs of 1 74 consecutive patients with angiographical ly documented coronary artery disease and without myocardial infarction during the last 3 months were signal-averaged to noise level 0.2 and 0.4 pV. LP were considered to be present if any two of the following criteria were present:signal-averaged QRS duration > 120 ms, root-mean-square voltage of the terminal 40 ms of the averaged QRS complex < 25 pV, and late potential duration > 40 ms. Heart rate variability was measured at rest in 5-minute ECC recordings as: the standard deviation (SD) of all RR intervals, SD corrected for RR (SD/mean RR), and the power of high frequency (HF) component (0.15-0.40 Hz). Results: One hundred seven (61%) of the patients had LP at noise level 0.2 pV. LPs were more frequently observed in patients with slow heart rate, high heart rate variability, and high levels of vagal activity (mean RR = 1000 ms, SD 2 60 ms, and HF 2 100 ms2) than in patients with higher heart rate, low heart rate variability and attenuated vagal activity: 73% vs 54% (P = 0.02), 71 % vs 53% (P = 0.02), 72% vs 51 O/ O (P = 0.005) for mean RR, SD, and HF power, respectively. Adjustment for possible confounding from mean RR level, gender, previous acute myocardial infarction, treatment with betablocker, and left ventricular ejection fraction did not significantly alter these associations. At noise level 0.4 pV 26% (45/174) had LP and the diagnosis of LP was not significantly associated with heart rate variability. Conclusions: At low noise level (0.2 pV) higher parasympathetic activity is associated with the diagnosis of LP. The predictive power of presence of LP diagnosed at low noise level for development of sudden cardiac death may be reduced by this association. In order to increase the predictive accuracy of LP we recommend either the use of noise level 0.4 pV, or identification of high arrhythmia-risk patients by a combination of the presence LP and impaired heart rate variability. signal-averaged ECG; heart rate variability; parasympathetic activity; late potentials However, a prognostic study is needed to further clarify this.The presence of late potentials (LP) in the signalaveraged electrocardiogram and impaired hea...

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The influence of the vegetative nerve system on the maximal conduction velocity in the atrioventricular bundle and in the cardiac ventricles measured by the differential quotient of QRS. Investigations in dogs

Cited by 2 publications

References 7 publications

Effect of parasympathetic blockade on the signalaveraged electrocardiogram

Effect of parasympathetic blockade on the signalaveraged electrocardiogram

Association Between Parasympathetic Activity and Late Potentials at Low Noise Level

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