Increased Cerebral Blood Flow in the Anterior Cingulate Cortex and Plasma Noradrenaline Level During Cardiac...

Chest symptoms, such as angina and palpitation, are common complaints in patients with cardiovascular diseases, but few studies have addressed how cardiac afferent information is processed through the brain.

We recruited 10 patients (mean age 74.7±1.9 years; 9 men) with cardiac pacemaker implantation. The patients underwent brain H₂¹⁵O positron emission tomography (PET) followed by blood sampling during right ventricular pacing of sham (1.5 V) and stimulation (7.5-8 V) conditions with a 10min interval. A voxel-wise analysis of the brain PET images identified the anterior cingulate cortex (ACC), posterior cingulate cortex, prefrontal cortex, thalamus, amygdala and midbrain as regions of increased regional cerebral blood flow (rCBF) under stimulation compared to sham conditions at a family-wise error-corrected cluster-extent threshold of P<0.05 with an underlying voxel level of P<0.001. The stimulation conditions increased rCBF in the ACC (59.8±4.4 vs. 49.2±3.5 mL/100 g/min, P<0.001) and plasma noradrenaline levels (332.3±139.0 vs. 312.0±139.8 pg/mL, P=0.004) compared to the sham stimulation. A linear mixed-effects model showed a significant positive correlation between the changes in rCBF in the ACC and those in plasma noradrenaline levels (P<0.001).

Cardiac electrical stimulation increased both rCBF in the ACC and plasma noradrenaline levels, and the changes were correlated. The ACC may be the brain center that transfers cardiac afferent information into autonomic arousal during cardiac pacing.