Atrial rate variations in atrioventricular block patients: influences of ventricular rate and atrioventricular delay

Chiu, Hung-Wen; Kao, Tsair; Hsiao, H.H.; Kong, Chi Woon

doi:10.1109/cic.1999.826031

Cited by 2 publications

(1 citation statement)

References 6 publications

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“…But in our previous study under an AV disassociation condition, e.g. fixed-rate ventricular pacing, the atrial rate variability (ARV), was measured and showed a pattern in which the main frequency components varied with the ventricular rates [1]. Some studies was reported that ventricular rate and AV-delay have marked influences on ARV [2,3] Moreover, some evidences have shown that beat-to-beat blood pressure (BP) variation (BPV) may play a role for this phenomenon [4,5].…”

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confidence: 99%

The interaction of heart rate and blood pressure variations for av dissociation illustrated by a closed-loop heart rate control model

Chiu

Computers in Cardiology, 2004

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The atrial rate variability measured under an atrialventricular (AV) IntroductionHeart rate (HR) variability (HRV) had been widely used to assess the autonomic nervous activities (ANA) in many different situations including physiologically or pathologically changes. Mostly HRV is measured under an atrial-ventricular (AV) synchronization condition. In this normal condition the frequency power of HRV mainly locate at low-frequency (LF) band (0.04-0.15 Hz) and high-frequency (HF) band (0.15-0.4 Hz). But in our previous study under an AV disassociation condition, e.g. fixed-rate ventricular pacing, the atrial rate variability (ARV), was measured and showed a pattern in which the main frequency components varied with the ventricular rates [1]. Some studies was reported that ventricular rate and AV-delay have marked influences on ARV [2,3] Moreover, some evidences have shown that beat-to-beat blood pressure (BP) variation (BPV) may play a role for this phenomenon [4,5]. In our later investigation [6], we found that the oscillation frequency of ARV may be an aliasing phenomenon of BP pulse frequency exactly equal to ventricular rate when the mean atrial rate is considered as the sample rate of ARV signal. Hence we suggested that the BP pulse dominate the ARV in AV dissociation situation. Cardiac aliasing phenomena were also observed in other different experiments [7,8] in which the respiration frequency is over 1/2 mean heart rate so that the HF of HRV is not equal to the breathing rate. Although the relationship between the oscillation frequencies of ARV and ventricular pacing rate (or BP pulse rate) could be derived by the cardiac aliasing, how the ARV is regulated by the BPV needs to be revealed. The regulatory effect of blood pressure on heart rate control is known as baroreflex. Most studies use systolic BP or diastolic BP, instead of the entire BP waveform, to model this control mechanism [9]. However, the information embedded in systolic BP or diastolic BP is not enough to explain the ARV feature in AV dissociation situation. In this study, a model is created to illustrate the frequency features of ARV in response to entire BP waveform to explain the changes of ARV under AV dissociation. Methods IPFM modelMany heart rate control models have been proposed to simulate the heart rate in response to different physiological situations. Among these models, the integrating pulse frequency modulation (IPFM) model was frequently used to simulate the heartbeat generation [10,11]. Suppose that the modulation signal is m(t). When it is integrated to reach a threshold T, a heartbeat generates. The IPFM model is mathematically described as follows:

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Section: Introductionmentioning

confidence: 99%

The interaction of heart rate and blood pressure variations for av dissociation illustrated by a closed-loop heart rate control model

Chiu

Computers in Cardiology, 2004

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Cardiac aliasing in atrial rate variation response to fixed-rate ventricular pacing

Chiu

Kao

Hsiao

et al.

Computers in Cardiology 2001. Vol.28 (Cat. No.01CH37287)

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It is found that the frequency components of atrial rate variation (ARV) of A V-block patient with fixed-rate ventricular pacing valy irregularly with the pacing rates.We attempt to learn about the relationship between the oscillation frequency of AR V and the blood pressure (BP) pattern in this study.The beat-to-beat AR Vs extracted from esophageal ECG and noninvasive BP waveforms of seven AV-block patients were recorded. Each patient was paced under 60, 90, 120 beatdmin of three ventricular rates. Results reveal that the oscillation frequency of ARV does not correlate to the variation frequency of systolic or diastolic BP or respiration frequenc.y. Instead, it may be an aliasing phenomenon of BP pulse frequency exactly equal to ventricular rate when the mean atrial rate is considered as the sample rate of ARV signal. This study suggests that the BP pulse dominate the ARV in AV asynchronous situation IntroductionTwo main frequency components of heart rate variation (HRV) in low frequency (0.04-0.15 Hz) and high frequency (0.15-0.4 Hz) bands, respectively, have been identified and used to clinical assessment of autonomic balance in cardiac control. The high frequency oscillation of HRV correlating to the respiration has been verified. But the origin of low frequency oscillation is more complicated and still under investigation.The heart rate variation expresses the dynamics in the feedback system of heart rate control. To observe the atrial rate variability (ARV) of AV-block patient paced with different fixed ventricular pacing rate will help to understand the heart rate control mechanism. Recently, we have used the PP intervals on an esophageal lead for analysis of ARV in patients with AV block [ 11. It was shown that AV block patients had ARV differing from normal subjects. Some studies also have reported that ventricular rate and AV-delay have marked influences on ARV [2-41. Moreover, we found that the frequency components of ARV of AV-block patient with fixed-rate ventricular pacing vary irregularly with the pacing rates in a pilot study [5]. Hence we hardly figured out any conclusion for the influences of ventricular rates and AVdelays to ARV. Some evidences have reveal that the blood pressure (BP) variations play an important role in HRV [6,7]. Therefore, we attempt to learn about the relationship between the oscillation frequency of ARV and the BP pattern in this study. 2.Materials and methods PatientsSeven AV block patients loaded with VDD pacemakers were included in this study. All these patients demonstrated normal atrial activity in surface ECG and absence of ventriculo-atrial conduction during ventricular pacing. Patients lay on a table and breathed normally. During the whole experimental procedure, the breathing rate had no marked change. MethodsAn esophageal lead was used to non-invasively record the atrial ECG. PP intervals on the atrial ECG were acquired with the method used in a previous studyThe ARVs of each patient at three different fixed ventricular pacing rates (VVI mode, 60, 90 and 120 bp...

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Atrial rate variations in atrioventricular block patients: influences of ventricular rate and atrioventricular delay

Cited by 2 publications

References 6 publications

The interaction of heart rate and blood pressure variations for av dissociation illustrated by a closed-loop heart rate control model

The interaction of heart rate and blood pressure variations for av dissociation illustrated by a closed-loop heart rate control model

Cardiac aliasing in atrial rate variation response to fixed-rate ventricular pacing

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