Reintroducing Heart Sounds for Early Detection of Acute Myocardial Ischemia in a Porcine Model - Correlation of Acoustic Cardiography With Gold Standard of Pressure-Volume Analysis.

Marco Luciani,Patricia Arand,Andrea Guidotti,Nikola Cesarovic,Francesco Maisano,Paul Erne,Shingo Kuwata,Michel Zuber,Evelyn Regar,Peter Bauer,Matteo Saccocci,Miriam Lipiski

doi:10.3389/fphys.2019.01090

Marco Luciani, Patricia Arand + Show 10 more

Open Access

https://doi.org/10.3389/fphys.2019.01090

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Abstract

BackgroundAcoustic cardiography is a hybrid technique that couples heart sounds recording with ECG providing insights into electrical-mechanical activity of the heart in an unsupervised, non-invasive and inexpensive manner. During myocardial ischemia hemodynamic abnormalities appear in the first minutes and we hypothesize a putative diagnostic role of acoustic cardiography for prompt detection of cardiac dysfunction for future patient management improvement.Methods and ResultsTen female Swiss large white pigs underwent permanent distal coronary occlusion as a model of acute myocardial ischemia. Acoustic cardiography analyses were performed prior, during and after coronary occlusion. Pressure-volume analysis was conducted in parallel as an invasive method of hemodynamic assessment for comparison. Similar systolic and diastolic intervals obtained with the two techniques were significantly correlated [Q to min dP/dt vs. Q to second heart sound (r2 = 0.9583, p < 0.0001), PV diastolic filling time vs. AC perfusion time (r2 = 0.9686, p < 0.0001)]. Indexes of systolic and diastolic impairment correlated with quantifiable features of heart sounds [Tau vs. fourth heart sound Display Value (r2 = 0.2721, p < 0.0001) cardiac output vs. third heart sound Display Value (r2 = 0.0791 p = 0.0023)]. Additionally, acoustic cardiography diastolic time (AUC 0.675, p = 0.008), perfusion time (AUC 0.649, p = 0.024) and third heart sound Display Value (AUC 0.654, p = 0.019) emerged as possible indicators of coronary occlusion. Finally, these three parameters, when joined with heart rate into a composite joint-index, represent the best model in our experience for ischemia detection (AUC 0.770, p < 0.001).ConclusionIn the rapidly evolving setting of acute myocardial ischemia, acoustic cardiography provided meaningful insights of mechanical dysfunction in a prompt and non-invasive manner. These findings should propel interest in resurrecting this technique for future translational studies as well as reconsidering its reintroduction in the clinical setting.

Highlights

Cardiac auscultation has been a pivotal part of patients’ examination since the stethoscope invention in 1816 by the French physician René Laennec
The present study aims to identify mechanical alterations of physiological significance such as indexes of contractile and relaxation function as well as systolic and diastolic time intervals (STIs and DTIs, respectively) occurring during acute myocardial ischemia (AMI) and detected with two different techniques (AC and PV measurements) in both stable and rapidly evolving conditions (Lewis et al, 1977)
During our 5 min study time-window, 3 out of 10 animals suffered from ventricular arrhythmias which required prompt defibrillation and seven pigs completed the protocol

Summary

Introduction

Cardiac auscultation has been a pivotal part of patients’ examination since the stethoscope invention in 1816 by the French physician René Laennec. By coupling heart sound recordings together with ECG tracings, investigators can acquire important insights regarding the electrical-mechanical activity of the heart in an unsupervised, non-invasive and inexpensive manner Such a hybrid technique, acoustic cardiography (AC) (Erne, 2008), has been proven as a reliable method for patient stratification and prognosis in diverse pathological conditions [pulmonary arterial hypertension (Chan et al, 2013), atrial fibrillation (Dillier et al, 2010), coronary artery disease (Zuber and Erne, 2010; Thomas et al, 2017), acute myocardial ischemia (AMI) (Lee et al, 2009), premature ventricular contractions (Walia et al, 2019), heart failure with either preserved or reduced ejection fraction (Wang et al, 2013, 2016)]. During myocardial ischemia hemodynamic abnormalities appear in the first minutes and we hypothesize a putative diagnostic role of acoustic cardiography for prompt detection of cardiac dysfunction for future patient management improvement

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