Cardiorespiratory fitness and right ventricular mechanics in uncomplicated diabetic patients: Is there any relationship?

Correlation between Heart rate recovery and Left Atrial phasic functions evaluated by 2D speckle-tracking Echocardiography after Acute Myocardial infarction

BACKGROUND

Heart rate recovery (HRR) in the exercise test is the index of cardiac autonomic system function and sympathovagal balance impaired in patients with myocardial infarction (MI). An instance is left atrial (LA) phasic function, which is impaired in such patients. In this study, we investigated the role of HRR in predicting LA phasic functions in patients with MI.

METHODS

The present study recruited 144 consecutive patients with ST-elevation MI. A symptom-limited exercise test was performed about 5 weeks after MI, with echocardiography conducted just before the exercise test. The patients were divided into abnormal and normal HRR at 60 s (HRR60) and again into abnormal and normal HRR at 120 s (HRR120) after the exercise test. LA phasic functions, evaluated by 2D speckle-tracking echocardiography, were compared between the 2 groups.

RESULTS

Patients with abnormal HRR120 had lower LA strain values and strain rates during the reservoir, conduit, and contraction phases, while those with abnormal HRR60 had lower LA strain values and strain rates during the reservoir and conduit phases. The differences were lost after adjustments for possible confounders, except for LA strain and strain rate during the conduit phase, in patients with abnormal HRR120.

CONCLUSIONS

Abnormal HRR120 in the exercise test can independently predict decreased LA conduit function in patients with ST-elevation MI.

The evaluation of right ventricular function in patients with diabetes mellitus and significant stenosis at the proximal portion of the right coronary artery

PURPOSE

Previous studies have indicated that right ventricular (RV) function is damaged in diabetes mellitus (DM); however, it is not clear whether in the presence of chronic ischemia, RV function is different between patients with and without DM (DM + and DM - , respectively).

METHODS

This cross-sectional study enrolled 90 consecutive candidates for coronary artery bypass graft surgery and allocated them to 3 groups: 24 DM - patients with the absence of stenosis of more than 50% in the proximal and mid parts of the right coronary artery (the DM - RCA - group [control]), 33 DM - patients with the presence of significant stenosis (> 70%) in the proximal part of RCA (the DM - RCA + group), and 33 DM + patients with RCA + (the DM + RCA + group). RV function was evaluated based on longitudinal deformation markers, measured via the 2D speckle-tracking echocardiographic examination of right ventricular free wall (RVFW).

RESULTS

The systolic strain value, systolic strain rate, and late diastolic strain rate of RVFW were not statistically significantly different between the three groups. Our adjusted post hoc analysis showed that the early diastolic strain rate of RVFW in the DM + RCA + group was lower than that in the DM - RCA + and DM - RCA - groups (1.5 s^-1 ± 0.4 vs 1.7 s^-1 ± 0.5 vs 1.7 s^-1 ± 0.4).

CONCLUSIONS

Diastolic function in the presence of DM was impaired irrespective of RCA - or RCA + . Additionally, RCA + had no effect on systolic and diastolic RV functions at rest in our DM - patients.