Correlations between echocardiographic findings and heart rate recovery after exercise stress test in patients with autonomic nervous system dysfunction

Abstract

The importance of an integer autonomic nervous system function is well known since Loewi demonstrated in the 20th century the moderating cardiac effect of the vagal nerve and unfortunately autonomic impairment is a reality of everyday clinical practice. Its role it was already been demonstrated in the major cardiovascular risk factors such as diabetes and hypertension. This study is based upon the typical patients which asociate numerous cardiovascular risk factors but without a cardiovascular event and it is meant to increase the awareness for the importance of primary prevention as they may also associate an autonomic nervous system impairment. We performed a retrospective 3 years study on 81 patients (mean age 66.6 years) who underwent non-invasive cardiovascular investigations: echocardiography, exercise stress test and ECG Holter. The study group presented 4 major cardiovascular risk factors: smoking 33%, hypertension (74%), diabetes (31%) and obesity (47%). A total of 13 patients had an ejection fraction (EF) 50–40% and 4 less than 40%. All of the patients included had an abnormal heart rate recovery starting from the 3rd minute of recovery (with a cut-off of 13 beats per minute of recovery). We found a positive correlation between the heart rate in the second minute of recovery and diastolic type I dysfunction( P = 0.05) and also with the presence of a minor aortic ( P = 0.001) or mitral insufficiency ( P = 0.049). The ejection fraction demonstrated to have a negative correlation with the heart rate in the third minute of recovery (R2 = −0.137) ( Fig. 1 ). We propose a new approach when considering the traditional cardiovascular risk assessment and perhaps the presence of autonomic dysfunction should be consider among the risk factors for a more thorough primary prevention for this category of patients.