Ejection fractions and pressure-heart rate product to evaluate cardiac efficiency. Continuous, real-time diagnosis using blood pressure and heart rate

The Importance of the Double Product in the Six-Minute Walk Test to Predict Myocardial Function

Introduction

The Six-Minute Walk Test (6MWT) is a widely used test to measure the physical performance of patients to assess the effectiveness of treatment, to qualify for rehabilitation, and to evaluate its effects..

Aim

This paper focuses on the assessment of the growth of a double product (DP) during the 6MWT and its diagnostic value in the assessment of patients with heart failure.

Material and Methods

The paper has retrospective character. We analyzed medical records of 412 patients hospitalized for cardiac reasons, in whom a 6MWT was performed. The patients were divided into two groups: one with diagnosed heart failure and a control group.

Results

The patients with diagnosed heart failure, compared to the control group, were characterized by a shorter walking distance and greater DP increase at equal walking intervals. After distinguishing the group with the preserved and decreased left ventricle ejection fraction, the value of the DP increase was still higher compared to the control group. The mean DP increase corresponding to one meter of walk was the only one that correlated negatively with the left ventricular ejection fraction.

Conclusion

The assessment of the increase of the DP during the march test seems to be a better parameter reflecting the efficiency of the myocardium from the distance of the march.

[Blood pressure monitoring - Status quo and future : A contribution to the personalized medicine]

Sustainment of life demands that the heart create sufficient pressure to maintain enough flow to keep the body healthy and oxygenated. Blood pressures can be easily measured, while volume measurements required additional invasive procedures. In analogy to volumetrically determined ejection fraction, a pressure ejection fraction EF(P) may be calculated. When standardized to heart rate and body surface area, a new, effective performance metric may be defined. These metrics enable the long-term monitoring of the critically ill patient. When presented in a performance diagram, the metrics contain prognostic implications and enable a real-time evaluation of the efficacy of therapeutic measures. Until now, pressure-related prognostic statements were based on statistical averages, which by definition apply to groups. With this new analytical approach, we have the ability to provide patient-specific therapeutics in an area of medicine that requires individualized treatment. Here, we show preliminary results of applying a mathematical risk analysis to blood pressure metrics to assess therapeutic risk.

Study of the Blood Supply Fraction of the Ascending Aorta and Its Effect in Diagnosing Early Ascending Aortic Atherosclerosis

OBJECTIVES

To investigate the capacity of blood storage of certain large arteries during diastole, we first studied the ascending aorta by echocardiography. The concept of the blood supply fraction of the ascending aorta was then introduced to evaluate elastic retraction of the ascending aortic wall and determine its role in diagnosing early atherosclerosis of the ascending aorta.

METHODS

First, we enrolled 120 healthy volunteers and divided them into 3 groups according to age: 20 to 35 years (B1 group), 36 to 50 years (B2 group), and 51 to 65 years (B3 group); there were 40 volunteers in each group. We used echocardiography to measure the blood supply fraction in each volunteer and compared the results for each group. Then we enrolled 40 patients (51-65 years) with early atherosclerosis of the ascending aorta, measured the blood supply fraction of each, and compared the results with the B3 group.

RESULTS

The mean blood supply fractions ± SD in the B1, B2, and B3 groups were 21.75% ± 1.53%, 20.76% ± 1.62%, and 18.44% ± 1.19%, respectively. The fraction in the B3 group was significantly lower than those in the B1 and B2 groups (P < .01). The fraction in the patients with early atherosclerosis was 14.92% ± 1.01%, which was obviously lower than that in the B3 group (P < .01).

CONCLUSIONS

The blood supply fraction of the ascending aorta decreases with age, and it could be used as a parameter for diagnosis of early atherosclerosis of the ascending aorta.