P-262: Excessive sympathetic hyperactivity in hypertensive patients following acute myocardial infarction
ABSTRACT Hypertension is an important risk factor for acute myocardial infarction (AMI). The presence of pre-existent hypertension
following AMI is associated with a higher total mortality and is an independent risk indicator for both reinfarction and death.
An increase in sympathetic neural discharge is known to occur in both hypertension and AMI, and is by itself a prognostic
indicator. This study was planned to quantify the magnitude of sympathetic hyperactivity in hypertensive patients following
AMI. For this purpose, we compared the central sympathetic output in 9 patients with AMI and pre-existent hypertension (HT-AMI)
to that in 9 patients with hypertension (HT) at stage II/III (JNC-VI classification) and 9 normotensive subjects (NT). The
three groups were matched (Table) for age and body mass index (BMI). Muscle sympathetic nerve activity (MSNA) was measured by microneurography from the peroneal
nerve and its mean frequency was expressed as bursts per 100 cardiac beats (b/100b). In the three groups, the data were obtained
using the same protocol. HT-AMI patients were examined 2–4 days following admission.
View this table:
In this window
In a new window