Routine noninvasive hemodynamic monitoring in acute myocardial infarction: application possibilities

Introduction

Use of hemodynamic monitoring allows one to evaluate and follow-up patients with acute myocardial infarction (AMI), monitor the effect of treatment, and compare different treatment options. On the other hand this creates additional problems, such as how to choose the method for monitoring that should be cheap, reliable and easy to use for the staff.

Aim

To evaluate the possibility of continuous hemodynamic monitoring application for patients with AMI and compare the results of two noninvasive methods – impedance cardiography (ICG) and transthoracic echocardiography (TTE) – in patients with AMI.

Design

A prospective study.

Setting

Kaunas University of Medicine, Clinic of Cardiology.

Patients

Patients with AMI, admitted within 12 hours after the onset of disease.

Methods

A standard eight-electrode ICG was recorded. The average value of the stroke volume (SV) derived from the last 10 min of the ICG record (60 SV instantaneous values) was used for the comparison of ICG and TTE results. SVTTE was calculated as the difference of left ventricular end-diastolic and end-systolic volumes. A four-chamber and two-chamber view was used for SVTTE analysis. SVTTE was alternatively evaluated by measuring the flow velocity-time integral in the left ventricular outflow tract.

Results

Eighty-seven patients were investigated according to study protocol. The results of 74 patients were used for comparative analysis: 56 (75.7%) men and 18 (24.3%) women. The average age was 64.2 ± 14.9 years, body mass index (BMI) was 28.6 ± 3.9, and ejection fraction was 42.8 ± 10.6%.

Comparing the values of SV derived from ICG and TTE, the calculated correlation coefficient (r) was 0.73. The correlation between the methods of ICG and TTE reached r = 0.79 in men, but only r = 0.32 in women.

Week correlation between methods was observed when SV values were compared for patients with BMI > 29 or < 19 (r = 0.42), as well as SV measured by evaluating the flow velocity-time integral in the left ventricle outflow tract (r = 0.37).

Conclusions

Significant correlation of SV was observed between ICG and TTE. Noninvasive monitoring during AMI can be considered a reliable method for further application.

Figure 1