Key result
Ventricular (VVI) pacing significantly decreased carotid artery peak systolic velocities (e.g., left CCA 60.1 vs 79.3 cm/s), pulsatility, and resistive indices compared to baseline and DDD pacing.
Why the study?
Does ventricular pacing (VVI) compared to dual chamber pacing (DDD) reduce carotid artery peak systolic velocity and pulsatility in patients with implanted pacemakers?
Does ventricular pacing (VVI) compared to dual chamber pacing (DDD) reduce carotid artery peak systolic velocity and pulsatility in patients with implanted pacemakers?
Absolute Event Rate: 60.1% vs 79.3%
Ventricular (VVI) pacing significantly decreases carotid artery peak systolic velocity and pulsatility compared to dual-chamber (DDD) pacing, providing a potential hemodynamic mechanism for the higher incidence of adverse cerebral outcomes seen with VVI pacing.
VVI pacing linked to lower carotid velocities in cross-sectional data; leaves open whether this mediates higher adverse cerebral outcomes versus DDD.
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.
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Soylu et al. (2004) studied Implanted bipolar DDD pacemakers (n=60). Ventricular (VVI) pacing vs. Dual chamber (DDD) pacing and baseline was evaluated on Peak systolic velocity (PSV) in the left common carotid artery (CCA). Ventricular (VVI) pacing significantly decreased carotid artery peak systolic velocities (e.g., left CCA 60.1 vs 79.3 cm/s), pulsatility, and resistive indices compared to baseline and DDD pacing.
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