Relationship Between Coronary Lesions And Heart Rate Variability

Heart rate variability ( HRV) is the indices of sympathetic and parasympathetic activity. At present HRV has been regarded as one of the most effective and noninvasive method to assess cardiac autonomic activity. Several recent studies have demonstrated that HRV is obvious lower in some cardiovascular diseases, such as coronary heart disease (CHD) and congestive heart failure. Low HRV, suggesting a reduction in vagal activity, is an independent prognostic determinant in the patients with myocardial infarction ( MI) and sudden cardiac death. In this study, according to the results of selective coronary angiogra-phy ( C AG) , we prospectively investigated the relationship between HRV and the severity of coronary artery lesions, by observing time domain and frequency domain parameters of HRV. We aimed to evaluate , by means of HRV analysis, the influence of the angiographic severity of coronary artery disease on cardiac autonomic control.Materials and Methods31 patients with CHD and 27 healthy controls were involved in the study. 31 patients were selected from China Medical University from Jan. 2001 to Dec. 2001. 22 patients were male, 9 patients were female. Their average age was (57.7 ±11.0) years old (from 31 to74) . There were 14 patients with MI and 17 patients with unstable angina pectoris. Patients were excluded from atrial flutter, atrial fibrillation, second or third degree atrioventricular block, sick sinus syndrome, diabetes. Medications such as beta - blocker , ACEI and sco-polamine couldnt be used before Holter monitoring.All subjects were performed 24 - hour ambulatory electrocardiogram and the parameters of HRV were obtained from the computer , including time domain (SDNN, SDANN, RMSSD, SDNN Index, PNN50) and frequency domain (TP, VLF, VF, HF). All patients underwent angiographic examination by the Jukdins technique. Angiographic results showed at least one major coronary artery existed > 50% narrowing. Patients with left ventricular ejection fraction (LVEF) < 50% were excluded. According to the results of GAG, CHD patients were divided into three groups; ① single - vessel, double - vessel and triple - vessel disease groups; ②50% -69% narrowing, 70%-89% narrowing and 90% ~ 100% narrowing disease groups; ③left coronary and right coronary disease groups. Statistical analysis was performed based on these parameters of HRV respective-Results1 . Compared with the control group , all values of HRV ( including time domain and frequency domain) were markedly and significantly reduced in CHD patients. Special in double - vessel , triple -vessel disease groups and 90% ~ 100% narrowing disease group. There were significantly statistical differences ( p <0. 05 ~0. 01 ) .2. HRV in double - vessel and triple - vessel disease groupsshowed significantly statistical differences (p <0.05 -0.01) , in contrasting with single - vessel disease group, but there was no statistical difference between double - vessel disease group and triple - vessel disease group ( p > 0. 05).3. HRV in 90% ~ 100% narrowing disease group showed significantly statistical difference (p <0. 01) , in contrasting with the other two groups, but there were no statistical difference between 50% ~ 69% narrowing disease group and 70% -89% narrowing disease group (p >0.05).4. Although HRV in right coronary disease group was weakly lower than left coronary disease group, but there was no statistical difference between the two groups (p >0. 05) .DiscussionGAG was once regarded as a gold standard to assess coronary stenosis degree, but in the basic hospitals it couldnt be performed widely. Analysis of HRV is a simple and noninvasive method for quantifying cardiac autonomic control. HRV analysis from 24 - hour Holier has been widely used in risk stratification of patients after MI.It is still an issue whether HRV has relationship with coronary lesions, there are some different views. Some studies came to the conclusion that HRV showed strong relationship with coronary artery stenosis degree, wh...