Evaluation of cardiac function and 30-day clinical outcome with synchronized analysis of phonocardiogram and electrocardiogram in patients with acute myocardial infarction
Authors: Zhang W L , Zhang R Y 
Published: October 2022

Abstract

Background
Acute myocardial infarction (AMI) is associated with short-term and long-term mortality. Survivors of AMI suffer from cardiovascular events, among which heart failure (HF) is the most important factor affecting the prognosis. Echocardiography is a traditional method of measuring cardiac function, but it is inconvenient. Previous studies have identified the effectiveness of a new wearable coin-sized phonocardiogram (PCG) and electrocardiogram (ECG) device in HF patients. In our study, we apply this device in the hospitalization monitoring of post-AMI patients.

Purpose
The purpose of this study was to evaluate the role of the synchronized analysis of PCG and ECG in identifying cardiac functions in hospitalized AMI patients and to forecast adverse events for 30-days post-AMI in general clinical practice.

Methods
One hundred and sixty-three ST-elevated myocardial infarction (STEMI) patients and sixty-nine non-ST-elevated myocardial infarction (NSTEMI) patients were enrolled. All were admitted to the hospital and diagnosed with AMI. The left ventricular ejection function (LVEF) was determined by echocardiography and synchronized PCG and ECG signals were recorded using the wearable coin-sized PCG and ECG device on the first day of admission. PCG and ECG signals were analyzed to determine electromechanical activation time (EMAT), EMAT/RR (EMAT%), pre-ejection period/RR (PEP%), left ventricular systolic time/RR (LVST%), left ventricular ejection time/RR (LVET%). Primary endpoint was defined as the occurrence of major adverse cardiovascular events (MACE) following AMI in thirty days.

Results
ROC analysis demonstrated that the sensitivity and specificity of EMAT% &gt;12.1% for the diagnosis of LVEF &lt;50% were 81% and 82%, respectively. Overall, 232 patients were enrolled who were divided into four groups according to the classification of AMI and EMAT%. Patients in STEMI group with EMAT% &gt;12.1% had a lower LVEF% (p&lt;0.001), greater EMAT (p&lt;0.001), PEP% (p&lt;0.001), LVET% (p&lt;0.001), LVST% (p=0.001), LVEDV (p&lt;0.001) and LVESV (p&lt;0.001). The same pattern was observed in NSTEMI patients between EMAT% &gt;12.1% and EMAT≤12.1% group. Twenty-eight STEMI patients (17.28%) and seventeen NSTEMI patients (24.6%) developed a MACE event. Compared with EMAT≤12.1% group, EMAT% &gt;12.1% group showed a higher occurrence of MACE, especially in post-STEMI patients (36.54% vs 8.11%, p&lt;0.001).

Conclusion
PCG and ECG offer the possibility to assess the systolic parameters associated with left ventricular (LV) function and clinical status that differ between normal and heart failure states in acute AMI patients, with EMAT% &gt;12.1% as a cut-off for deceased LV systolic function. Moreover, EMAT% &gt;12.1% showed strong association with clinical outcome, suggesting EMAT% may be helpful to further improve the risk stratification of post-AMI patients, especially STEMI patients.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Shanghai Clinical Research Center for Interventional Medicine,Clinical Research Plan of SHDC