The Applicability Of HRV For AF And Impact Of AF Combined Prolonged QRS On Prognosis In Patients With DCM And HF

Background Atrial fibrillation (AF) is one of the most common sustained arrhythmias. Nowadays, the patients with AF are more ten millions in our country. The fact that autonomic function plays a important role in the initiation, sustain, termination and recurrence of AF has been proved by many studies. Plasma norepinephrine (NE), serum acetylcholine esterase (ACHE) and heart rate variability (HRV) are considered as the marker for evaluating autonomic function. HRV is often used for sinus rhythm (SR) instead of AF because of supreme irregulation of ventricular rhythm. However, HRV is still employed to evaluate autonomic function in patients with persistent AF (PAF) in some studies. AF is usually seen in patients with dilated cardiomypathy (DCM) and heart failure (HF). The prolonged QRS duration (PQRSD,≥120 ms) is often detected on the electrocardiogram. The prognostic significance of AF combined with PQRSD on patients with DCM and HF has not been identified.Objectives To identify whether HRV can be used to evaluate autonomic function in patients with PAF. And to observe the prognostic significance of AF combined PQRSD in patients with DCM and HF.Methods 1. One hundred and ten patients with PAF were enrolled. The diagnosis of PAF was conformed to ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation executive summary. The paroxysmal AF was exclued. Venous blood sample was collected at 6am during 12-lead ambulatory ECG monitoring from every patient. Both plasma NE and serum ACHE were examined. The parameters of 5 minutes HRV before time of collecting blood which include standard deviation of the R-R intervals (SDNN), Root-mean-square of the successive differences of normal R-R intervals (rMSSD), low frequency (LF), high frequency (HF) and LF/HF were calculated and analyzed by 12-lead ambulatory ECG. Then Pearson correlation analysis was done between the parameters of HRV and the average ventricular rate and plasma NE and serum ACHE. 2. One hundred and seventy-three patients with DCM and HF who were consecutively admitted to hospital were studied. The diagnosis of DCM was conformed to the report of the 1995 World Health Organization/International Society and Federation of Cardiology Task Force on the definition and classification of cardiomyopathies. Criteria of Framingham were refered to diagnose HF. The patients with AF combined PQRSD were enrolled as group 1, those with SR combined PQRSD as group 2, with AF combined normal QRS duration as group 3 and those with SR and normal QRS duration as group 4. With a mean follow up of 17.4±2.2 months (The primary end point was cardiac death), their death events and readmission to the hospital because of deterioration of HF were estimated.Results Plasma NE and SDNN, RMSSD and LF were negatively correlated (r values were -0.236, -0.224, -0.191, P values were 0.013, 0.019, 0.046). Correlationship was not found between plasma NE and HF and LF/HF (P>0.05). Plasma NE and the average ventricular rate was positively correlated (r=0.408, P=0.000). There is no correlationship between serum ACHE and SDNN, rMSSD, LF, HF, LF/HF and average ventricular rate (P>0.05). 2. The readmission was 89.7% in group1, 83.6% in group2, 66.7% in group3 and 73.2% in group4. The readmission of group 1 was higher than other three groups (P value were <0.05, <0.001, <0.01). At the end of follow up study, thirteen patients died from progressive HF and three from ventricular fibrillation. The mortality was 24.1% in group 1, 9.1% in group 2, 3.0% in group 3 and 5.4% in group 4. There is association between sex, age, left ventricular end-systolic diameter and left atrial diameter with cardiac death through COX regression analysis. In a further Logistic Regression analysis, The age was found to be an unfavorable prognostic marker. Although the age was adjusted, the mortality of group 1 was higher than other three groups, P<0.01.Conclusions 1. The ventricular rate in patients with PAF is still affected by autonomic function. This functional change can not be reflected directly by HRV. 2. AF combined PQRSD has more worsen prognosis than AF combined normal QRS duration and SR in patients with DCM and HF.