Study Of Correlation Between Time-frequency Characteristics Of Heart Sound And Echocardiography And Its Applied Value In Classification Of CHF

Objective: To explore the correlation of time-frequency characteristics of heart sound to echocardiographic indicators and its role in the diagnosis of chronic heart failure(CHF)classification.Methods: Inpatients with CHF in the division of cardiology of the First Affiliated Hospital of Chongqing Medical University were enrolled in from October 2019 to September 2020.All participated patients underwent echocardiography who were categorized into heart failure with reduced ejection fraction(HFr EF)、heart failure with mid-range ejection fraction、(HFmr EF)and heart failure with preserved ejection fraction(HFp EF)groups according to left ventricular ejection fraction(LVEF).Heart sound signals were acquired and recorded from each patient with heart sound characteristics extracted by Matlab software.Spearman correlation was performed to analyze the relevance of heart sound characteristics(the ratio of diastolic to systolic durations,D/S;maximum frequency,f-max;energy fraction of heart sound signal in low frequency,EF-LF;energy fraction of heart sound signal in high frequency,EF-HF)to echocardiographic indicators and length of stay(LOS).The optimal cutoff values of D/S to distinguish CHF subtypes were calculated and then ordinal Logistic regression was applied to study the indicators with statistical differences among the three groups to build a CHF subtype identification model and the influence of various factors on CHF typing was analyzed.Results: One hundred and thirty-seven patients with CHF including39 patients with HFr EF,26 patients with HFmr EF and 72 patients with HFp EF were enrolled in.There were more males(p=0.01)and more patients with dilated cardiomyopathy(P<0.01)in HFr EF group compared with HFp EF group.There were more patients with pulmonary hypertension in HFp EF group than the other two groups(P<0.01).D/S was increased successively with significant difference while the differences of the other three heart sound characteristics were not significant.D/S was positively correlated with LVEF(r=0.785,P<0.01)、fraction shortening(FS)(r=0.737,P<0.01)、 left ventricular posterior wall excursion(LVPWE)(r=0.691,P<0.01)、interventricular septum excursion(IVSE)(r=0.651,P<0.01)、early diastolic mitral annular velocity(e’)(r=0.341,P<0.01)、 interventricular septum end-diastolic thickness(IVSEDT)(r=0.334,P<0.01)、 left ventricular posterior wall end-diastolic thickness(LVPWEDT)(r=0.215,P=0.01)while negatively correlated with left ventricular end-systolic diameter(LVESD)(r=-0.723,P<0.01)、 left ventricular end-diastolic diameter(LVEDD)(r=-0.621,P<0.01)、left atrium anteroposterior diameter(LAAD)(r=-0.364,P<0.01)、the ratio of E to e’(E/e’)(r=-0.275,P=0.02)and right ventricular anteroposterior diameter(RVAD)(r=-0.218,P=0.01).D/S discriminated patients with HFr EF from those with HFmr EF(AUC:0.922,95%CI:0.855-0.988,P<0.001)with D/S=1.36 that yielded92.3% sensitivity and 82.1% specificity and differentiated patients with HFmr EF from those with HFp EF(AUC:0.779,95%CI:0.670-0.888,P<0.001)with D/S=1.47 that yielded 79.2% sensitivity and 76.9%specificity.Both univariate and multivariate Logistic regressions showed that D/S was the influencing factor for CHF typing.Conclusion: D/S was significantly associated with echocardiographic indicators and could be an assist in the evaluation of cardiac function and CHF subtypes.