Suppression of cardiac sympathetic nervous system during dental surgery inhypertensive patients

We determined the changes in blood pressure, pulse rate, and heart rate var iability during dental surgery in hypertensive patients. The study included 18 essential hypertensives and 18 age and sex matched normotensive control s who underwent tooth extraction at our hospital. Holter electrocardiograph ic monitoring was used to determine the power spectrum of R-R variability b efore and during dental surgery. The low frequency (LF: 0.041 to 0.140 Hz), high frequency(Hf: 0.140 to 0.500 Hz), and total spectral powers (TF: 0.00 0 to 4.000 Hz) were calculated, and the ratio of LF to HF and the percentag e of HF relative to TF (%HF: HF/TF x 100) were used as indexes of sympathet ic and parasympathetic activities, respectively. The baseline blood pressur e for hypertensive patients (149 +/- 4/85 + 2 mmHg) was significantly highe r than that for normotensive patients(119+/-3/71 +/- 2 mmHg). The baseline pulse rates were similar between the two groups. Blood pressure increased d uring tooth extraction in both groups; however, changes in blood pressure d id not differ between them. Administration of local anesthetic significantl y decreased the %HF in normotensive patients (before vs. after anesthesia; 22.3+/-2.4 vs. 13.8+/-2.7%, p < 0.05). In contrast, the LF/HF significantly decreased during the local anesthesia and tooth extraction in hypertensive patients. These results suggest that presser response induced by tooth ext raction did not differ between normotensive and hypertensive patients, and that suppression of the cardiac sympathetic nervous system during dental su rgery might attenuate the presser response in patients with hypertension.