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Evaluation of the early hemodynamic changes in carotid arteries during ventricular and dual chamber pacing
Mustafa Soylu1, Ozcan Ozdemir, Bilal Geyik
1Cardiology Clinics, Türkiye Yüksek_htisas Hospital, Ankara, Turkey. soyumo@superonline.com
Insights
Single chamber ventricular pacing (VVI) significantly reduces carotid blood flow velocity and pulsatility compared to dual chamber pacing (DDD). This may contribute to adverse cerebral outcomes in VVI pacemaker patients.
Area of Science:
- Cardiology
- Biomedical Engineering
- Neurology
Background:
- Pacemaker selection and programming often rely on clinical judgment rather than objective data.
- Understanding the hemodynamic impact of different pacemaker modes is crucial for patient care.
Purpose of the Study:
- To quantify differences in carotid artery blood flow parameters between dual chamber (DDD) and single chamber ventricular pacing (VVI) modes.
- To investigate the effect of VVI pacing on carotid flow dynamics compared to DDD pacing and baseline.
Main Methods:
- Sixty patients with DDD pacemakers were studied.
- Carotid artery blood flow parameters (PSV, EDV, RI, PI) were measured in CCA, ICA, and ECA.
- Measurements were taken before implantation, during DDD pacing, and during VVI pacing at 60 bpm.
Main Results:
- VVI pacing significantly decreased Peak Systolic Velocity (PSV) in the common, internal, and external carotid arteries compared to baseline and DDD pacing.
- Resistive Index (RI) and Pulsatility Index (PI) also significantly decreased in carotid arteries during VVI pacing.
- No significant decrease in these parameters was observed during DDD pacing.
Conclusions:
- VVI pacing leads to a significant reduction in carotid artery blood flow velocity and pulsatility.
- These hemodynamic changes during VVI pacing may partially explain the increased risk of adverse cerebral events observed in patients with this pacing mode.
Abstract:
In spite of a wide choice of pacemakers, there are some problems in making more rational clinical decisions for individual patients since mode selection and programming is usually performed on the basis of a clinical hunch. The aim of this study was to measure the differences in carotid flow in patients with a pacemaker programmed in the dual chamber and in the single chamber pacing modes. Sixty patients with implanted bipolar DDD pacemakers were enrolled in this study. Blood peak systolic velocity (PSV) and end-diastolic velocity (EDV), cross-sectional area, resistive index (RI), and pulsatility index (PI) were measured in the common (CCA), internal (ICA), and external (ECA) carotid arteries before pacemaker implantation and after dual chamber and ventricular pacing at 60 beats/min. PSVs in the left CCA (79.3 +/- 24.9 cm/s) and right CCA (84.1 +/- 18.7) were shown to significantly decrease after VVI pacing (60.1 +/- 16.6 and 62.1 +/- 20.0, respectively). There was also a similar significant decrease in PSV in the left and right ICAs and ECAs. Besides PSV, RI, and PI in the left and right CCAs, ICAs, and ECAs significantly decreased after VVI pacing. There was no similar decrease after DDD pacing. Cross-sectional area and flow volume in the CCA, ICA, and ECA were similar after DDD and VVI pacing and before pacemaker implantation suggesting that cardiac output was similar when the measurements were recorded. Carotid artery PSVs, pulsatility, and RIs were found to be significantly decreased during VVI pacing compared to baseline and DDD pacing. The greater incidence of adverse cerebral outcomes in patients with VVI rather than DDD pacing may be partly due to decreased carotid PSVs.
