Frequency Modulation of Heart Rate to Increase Low-Frequency Content of Cardiovascular Signals

Ringo, J. A.; Campbell, Kenneth B.; Peterson, Nils S.; Baker, R. A.

doi:10.1109/tbme.1982.324926

Cited by 3 publications

(1 citation statement)

References 2 publications

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“…personal computer. To enhance the low frequency content of the derived data, we used a modification of the square-wave rate-modulation technique described by Ringo et al 10 Rather than switching between two predetermined heart rates, as described by these authors, the computer was programmed to switch between two cycles with different heart rate ranges. During each cycle, the next RR interval was randomly selected but was limited to intervals corresponding to rates within the allowable range for that cycle.…”

Section: In Vivo Methodsmentioning

confidence: 99%

Effect of nitroglycerin on aortic impedance, diameter, and pulse-wave velocity.

Latson

Hunter

Katoh

et al. 1988

Circulation Research

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The effects of an intravenous infusion of 1 |xg/kg/min nitroglycerin were studied on systemic arterial properties in nine acutely instrumented dogs. Aortic impedance and pulse-wave velocity were calculated from measured pressure and flow signals collected during random ventricular pacing. Central aortic diameter was simultaneously determined with ultrasonic dimension crystals. Mean blood pressure was maintained constant to avoid the confounding effects of passive, pressure-induced changes in vascular properties. Nitroglycerin both reduced the amplitude of peripheral vascular reflections and delayed the return of these reflections to the aortic root. This reflection delay was manifested as a consistent leftward shift in both impedance modulus and phase. The magnitude of this reflection delay could not be entirely accounted for on the basis of the measured changes in average pulse-wave velocity along the aorta. ; 2) increased arterial compliance, as determined by both the rate of aortic diastolic pressure decay and pressure-diameter relations in peripheral arteries 6 ; and 3) decreased magnitude of arterial pulse-wave reflections. -3This study used an acute canine preparation to further define the effects of nitroglycerin on systemic arterial properties. We measured the effects of intravenous nitroglycerin on aortic impedance, diameter, and pulse-wave velocity (PWV). The use of spectral analysis techniques, in conjunction with random cardiac pacing, allowed us to determine the impedance spectrum with a frequency resolution as small as 0.1 Hz. Our results indicate that nitroglycerin has significant effects on both the magnitude and timing of peripheral vascular reflections. Materials and Methods In Vivo MethodsNine mongrel dogs (body weight 17-23 kg) were anesthetized with a combination of pentobarbital and fentanyl (initial dose: 12 mg/kg pentobarbital and 50 u.g/kg fentanyl; subsequent infusion: 1.1 mg/kg/hr and 15 u,g/kg/hr, respectively). Instrumentation in all dogs included a nonconstricting ultrasonic flow probe (model T-101, Transonic Systems, Ithaca, New York) in the ascending aorta, a Millar pressure catheter (Houston, Texas) in the ascending aorta, inserted through the right common carotid artery, and a central venous pressure catheter passed through the femoral vein. The Millar catheter was positioned at the same level as the aortic flow probe by palpating the catheter tip within the aorta. Additional instrumentation in seven dogs included a second Millar catheter in the femoral artery, inserted and attached with a nonocclusive purse-string suture, and a pair of ultrasonic crystals on the aortic arch (5-HHz crystals connected to a sonomicrometer; model 401, Schuessler, Cardiff by the Sea, California). These ultrasonic crystals, used to measure aortic diameter, were attached to opposing sides of the aortic adventitia with either fine sutures (tied to a flexible woven backing sheet) and/or a small amount of cyanoacrylate glue.7 Permanent atrioventricular block was produced in all dogs by injection of 40% ...

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Section: In Vivo Methodsmentioning

confidence: 99%

Effect of nitroglycerin on aortic impedance, diameter, and pulse-wave velocity.

Latson

Hunter

Katoh

et al. 1988

Circulation Research

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The effect of respiration-induced heart movements on the ECG

Pallás-Areny¹,

Colominas-Balague²,

Rosell³

1989

IEEE Trans. Biomed. Eng.

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Abstruct-We present a model describing the rotation of the cardiac vector as a possible mechanism resulting in the presence of respiratory information in the ECG. The way in which this information is revealed is analyzed and the predictions subjected to qualitative experimental assessment via spectral analysis.The results show that respiratory frequencies occur in the ECG spectrum due to heart movement. By measuring on a patient wearing a pacemaker and ventilated to control respiratory rate we show that even in the absence of respiratory sinus arrhythmia (RSA) there is a baseband information in the ECG spectrum, attributable neither to electrode artifacts nor to emg, and sidebands from the respiratory cycle.

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True Arterial System Compliance Estimated From Apparent Arterial Compliance

Quick¹,

Berger²,

Hettrick³

et al. 2000

Annals of Biomedical Engineering

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A new method has been developed to estimate total arterial compliance from measured input pressure and flow. In contrast to other methods, this method does not rely on fitting the elements of a lumped model to measured data. Instead, it relies on measured input impedance and peripheral resistance to calculate the relationship of arterial blood volume to input pressure. Generally, this transfer function is a complex function of frequency and is called the apparent arterial compliance. At very low frequencies, the confounding effect of pulse wave reflection disappears, and apparent compliance becomes total arterial compliance. This study reveals that frequency components of pressure and flow below heart rate are generally necessary to obtain a valid estimate of compliance. Thus, the ubiquitous practice of estimating total arterial compliance from a single cardiac cycle is suspect under most circumstances, since a single cardiac cycle does not contain these frequencies.

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Frequency Modulation of Heart Rate to Increase Low-Frequency Content of Cardiovascular Signals

Cited by 3 publications

References 2 publications

Effect of nitroglycerin on aortic impedance, diameter, and pulse-wave velocity.

Effect of nitroglycerin on aortic impedance, diameter, and pulse-wave velocity.

The effect of respiration-induced heart movements on the ECG

True Arterial System Compliance Estimated From Apparent Arterial Compliance

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