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Carotid sinus hypersensitivity: beneficial effects of dual-chamber pacing
Insights
Ventricular demand pacing (VVI) worsens symptoms in carotid sinus syndrome patients compared to atrioventricular sequential pacing (DVI). DVI pacing is recommended for managing these patients, especially those experiencing vasodepression.
Area of Science:
- Cardiology
- Electrophysiology
- Nephrology
Background:
- Carotid sinus (CS) syndrome presents in cardioinhibitory, vasodepressor, and mixed forms.
- Permanent ventricular demand pacing (VVI) is used for symptomatic CS patients with cardioinhibition.
- Some patients remain symptomatic due to persistent or worsened vasodepression despite VVI pacing.
Purpose of the Study:
- To assess the hemodynamic effects of VVI versus atrioventricular sequential (DVI) pacing in patients with CS hypersensitivity.
- To evaluate the impact of loss of atrial preloading and orthostasis on hemodynamic stability during different pacing modes.
Main Methods:
- Eleven patients with CS hypersensitivity underwent constant intra-arterial pressure measurements.
- Hemodynamic parameters were recorded during VVI and DVI pacing in both supine and upright positions.
- Measurements included arterial blood pressure (BP) decrease magnitude, rate of BP decrease, and percent change in BP.
Main Results:
- All patients exhibited greater hemodynamic deterioration with VVI pacing compared to DVI pacing, irrespective of position.
- Systolic BP decreased significantly more with VVI pacing (supine: 48 mm Hg; upright: 59 mm Hg) versus DVI pacing (supine: 29 mm Hg; upright: 37 mm Hg).
- VVI pacing, particularly when upright, led to a significant increase in patient symptoms (p = 0.03).
Conclusions:
- Ventricular demand pacing (VVI) causes significant hemodynamic compromise in patients with carotid sinus hypersensitivity.
- This hemodynamic deterioration is linked to an aggravation of the vasodepressor component, increasing patient symptoms.
- Atrioventricular sequential (DVI) pacing is the optimal pacing mode for managing these patients.
Abstract:
Three types of carotid sinus (CS) syndrome have been described: cardioinhibitory, vasodepressor and mixed. For the treatment of symptomatic patients with associated significant cardioinhibition, permanent ventricular demand pacing systems are often implanted. Even with this pacing modality, some patients remain symptomatic because of continued (and at times aggravated) vasodepression. This study assesses the effects of loss of atrial preloading and orthostasis after carotid massage in patients with CS hypersensitivity. Eleven patients were studied using constant intra-arterial pressure measurements during either ventricular (VVI) or atrioventricular sequential (DVI) pacing in both supine or upright positions. The measurements performed included the magnitude of decrease in arterial blood pressure (BP), the rate of decrease of BP and the percent change in BP from baseline values. After carotid massage, all 11 patients had greater hemodynamic change with the VVI than DVI pacing mode, whether in the supine or upright position. The decreases in systolic BP were: DVI (supine) 29 mm Hg, VVI (supine) 48 mm Hg, DVI (upright) 37 mm Hg, and VVI (upright) 59 mm Hg (mean group values, p less than 0.001). The rates of decrease of systolic BP were: DVI (supine) 2.9 mm Hg/s, VVI (supine) 5.7 mm Hg/s, DVI (upright) 4.1 mm Hg/s, and VVI (upright) 8.3 mm Hg/s (mean group values, p less than 0.001). VVI pacing, particularly in the upright position, resulted in a significant increase in the incidence of patient symptoms (p = 0.03). Thus, in CS hypersensitivity, VVI pacing results in significant hemodynamic deterioration compared to DVI mode. This aggravation of the vasodepressor component results in increased patient symptoms, and therefore, DVI is the optimal pacing mode.