Assessment And Improvement Of Echocardiography On Left Ventricular Diastolic And Systolic Function Of Patients With Atrial Fibrillation

BackgroundAtrial fibrillation(AF)is the most common cardiac arrhythmia associated with decreased quality of life as well as increased morbidity and mortality.Atrial fibrillation and heart failure influence each other and are reciprocal causation,and their interactions can lead to impaired left ventricular diastolic and systolic function.Patients with AF are often clinically presented with heart failure with or without reduced ejection fraction,and those patients often have poor prognosis with higher mortality and readmission rate.Therefore,the evaluation of left ventricular diastolic and systolic function is particularly important for the management of AF patients.Currently,echocardiography is the most commonly used method to evaluate left ventricular function.However,the mechanical impairment of the left atrium and the variable cycle lengths in AF render the evaluation of left ventricular function difficult.The conventional echocardiographic parameters and measurement are subject to many limitations in evaluating left ventricular function in AF.In 2016,the American Society of Echocardiography(ASE)updated the recommendations for the evaluation of left ventricular diastolic function by echocardiography,however most of the evidences came from patients with sinus rhythm and recommendations for AF are very few.Left ventricular ejection fraction determined by echocardiography is the most commonly used method for assessing left ventricular systolic function,however,the left ventricular ejection fraction measured by a random single cardiac cycle may vary greatly.Currently,it is recommended to average the left ventricular ejection fraction over several cardiac cycles,however,this is time consuming and tiresome.In our study,we prospectively collected AF patients underwent radiofrequency catheter ablation.Based on the left atrial pressure(LAP)estimated from invasive catheter measurements as the golden standard of left ventricular diastolic function,we aimed to assess the clinical value of echocardiographic diastolic parameters in evaluating the diastolic function of patients with AF.Furthermore,we also assessed the clinical feasibility of the use of an index that is based on the RR1/RR2 ratio to accurately estimate left ventricular systolic function during AF.Objectives1.To observe New York Heart Association(NYHA)functional classification of paroxysmal and persistent AF,and to analyze the influence factors for exercise tolerance of patients with persistent AF;2.To analyze the relationship between echocardiographic diastolic parameters and left atrial pressure of patients with AF,in order to find reliable parameters to evaluate left ventricular diastolic function of patients with AF;3.To investigate the beat-to-beat variability of left ventricular systolic parameters measured by echocardiography,and to assess the clinical feasibility of the use of an index that is based on the RR1/RR2 ratio to accurately estimate left ventricular systolic function during AF.MethodsAs a prospective cohort study,consecutive patients with nonvalvular AF admitted into our department to receive radiofrequency catheter ablation from May 2017 to September 2017 were included.1.Cardiac Function Classification and Exercise Tolerance of Patients with Paroxysmal and Persistent AFNYHA class and echocardiographic parameters were collected before ablation.In addition,the six-minute walk test was also performed in the 43 patients with persistent AF to assess the exercise tolerance.2.Echocardiographic Assessment of Left Ventricular Diastolic Function in AFAll the patients underwent echocardiography in 24 hours before ablation,obtained the echocardiographic diastolic parameters,such as early diastolic transmitral velocity(E)?early diastolic mitral annular velocity(e')?the ratio of E and e'(E/e')?left atrial volume index(LAVI)and pulmonary artery systolic pressure(PASP)based on the peak velocity of the tricuspid regurgitation(VTR).LAP was measured before ablation during the procedure.Linear correlation analysis was used to evaluate the relationship between diastolic parameters and LAP.Receiver operating characteristic curves were used to determine the cut-off values of those diastolic parameters in the assessment of the LAP status.3.Improvement of Echocardiography Assessment of Left Ventricular Systolic Function in Patients with Persistent AFPatients with persistent AF received echocardiographic examination and LVEF and SV was recorded for at least 10-20 consecutive cardiac cycles.LVEF and SV were measured using two different methods:(1)mean LVEF and SV,the averages of all the calculated RR intervals of every patient;(2)single beat calculated when the ratio of the preceding(RR1)to the pre-preceding(RR2)interval was 1.0(range,0.91-1.10).Compared with the golden criteria of the averages of all the calculated RR intervals of every patient,we aimed to assess the clinical feasibility of the use of an index that is based on the RR1/RR2 ratio to accurately estimate left ventricular systolic function during AF.Results1.Cardiac Function Classification and Exercise Tolerance of Patients with Paroxysmal and Persistent AFA total of 109 AF patients were included(66 patients with paroxysmal AF and 43 patients with persistent AF).Patients with persistent AF had a significant higher proportion of NYHA class ? and ? compared with those patients with paroxysmal AF(39.6%vs 6.1%,p<0.001).Logistic regression model showed that persistent AF was the independently risk factor for impaired NYHA classification of AF patients(OR=9.109,95%CI:1.053-78.823,p=0.045).For 43 patients with persistent AF,six minute walk distance(6MTD)had significant negative correlation with age(r=-0.487,p=0.001),mean E/e'(r=-0.595,p<0.001)and log BNP(r=-0.575,p<0.001).Logistic regression model showed that advanced age was the independent risk factor for significantly impaired exercise tolerance(6MTD<375m)of patients with persistent AF(OR=0.860,95%CI:0.751-0.985,p=0.030).2.Echocardiographic Assessment of Left Ventricular Diastolic Function in AFA total of 82 consecutive patients with non-valvular atrial fibrillation and preserved left ventricular ejection fraction were included.According to mean LAP,they were divided into two groups of normal LAP(mean LAP?12mmHg,n=60)and elevated LAP(mean LAP>12mmHg,n=22).Both E and E/e' had significant difference between the two groups(p<0.05).In 35 patients with persistent AF,E?E/e' and PASP correlated well with mean LAP(E,r=0.533,p=0.001;septal E/e',r=0.430,p=0.010;lateral E/e',r=0.400,p=0.017;mean E/e',r=0.423,p=0.011;PASP,r=0.364,p=0.032);in 47 patients with paroxysmal AF,E/e' and LAVI correlated well with mean LAP(septal E/e',r=0.350,p=0.016;lateral E/e',r=0.383,p=0.008;mean E/e',r=0.3 89,p=0.007;LAVI,r=0.347,p=0.017).For patients with persistent AF,the optimal cut-off for E was 0.91m/s(sensitivity,85%;specificity,77%)and that for mean E/e' was 13(sensitivity,69%;specificity,82%)in order to predict mean LAP>12mmHg,when both of the two parameters were positive,the specificity of predicting elevated LAP were 96%;for patients with paroxysmal AF,the optimal cut-off for E was 0.85m/s(sensitivity,78%;specificity,79%)and that for mean E/e' was 11(sensitivity,100%;specificity,50%)in order to predict mean LAP>12mmHg,when both of the two parameters were positive,the specificity of predicting elevated LAP were 90%.3.Improvement of Echocardiography Assessment of Left Ventricular Systolic Function in Patients with Persistent AFA total of 21 patients with persistent AF were included.LVEF and SV showed significantly positive correlation with RR interval,which was also affected by heart rate variability.Bland-Altman analysis showed excellent correlation and agreement between the LV systolic parameters of a single beat with identical RR1 and RR2 intervals and measured average values over all cardiac cycles(r>0.85,p<0.001).Conclusions1.Patients with persistent AF are more likely to have impaired clinical cardiac function.Age and diastolic function significantly correlated with exercise tolerance for persistent AF patients.2.E and E/e' were well correlated with LAP in patients with AF,and the combination of E and mean E/e' had a good prediction of elevated LAP in patients with AF.3.Left ventricular systolic function was significantly correlated with RR interval and was also affected by heart rate variability.Single beat based on ratio of RR1/RR2 to assess left ventricular systolic function in patients with AF was as accurate as the time-consuming method of averaging multiple cardiac cycles.