The autonomic nervous system (ANS) and cardiovascular function are intricately and closely related. One of the most frequently used diagnostic and prognostic tools for evaluating cardiovascular function is the exercise stress test. Exercise is associated with increased sympathetic and decreased parasympathetic activity and the period of recovery after maximum exercise is characterized by a combination of sympathetic withdrawal and parasympathetic reactivation, which are the two main arms of the ANS. Heart rate recovery after graded exercise is one of the commonly used techniques that reflects autonomic activity and predicts cardiovascular events and mortality, not only in cardiovascular system disorders, but also in various systemic disorders. In this article, the definition, applications and protocols of heart rate recovery and its value in various diseases, in addition to exercise physiology, the ANS and their relationship, will be discussed.

ÖZETArteriyel kan basıncı sabahın erken saatlerinde zirveye, gece saatlerinde en düşük değerlere ulaşan sirkadiyen bir ritim paterni izlemektedir. Geceleri arteriyel kan basıncındaki düşüş normal sirkadiyen paternin bir parçasıdır. Bu düşüşün görülmediği "non-dipping" olarak adlandırılan sirkadiyen kan basıncı paterni, özellikle hipertansif hastalarda, daha şiddetli hedef organ hasarı ve artmış kardiyovasküler olaylarla birliktedir. Her ne kadar altta yatan mekanizmalar tam olarak bilinmese de "non-dipping" paterni olan kişilerde anormal parasempatik ve sempatik aktiviteleri içeren otonom sistem bozukluğunun olduğu öne sürülmüştür. "Non-dipping" fenomeninde otonom sinir sisteminin rolü birçok çalışmada incelenmiştir. Bu yazıda, sirkadiyen arteriyel kan basıncı paterni ile kardiyak otonomik işlevlerin göstergeleri arasındaki ilişkiyi değerlendiren çalışmaları derlemeyi amaçladık. ( ABSTRACTArterial blood pressure fluctuates with a pattern that follows a circadian rhythm, with a peak in the early morning hours and a trough during nighttime. Nocturnal dipping of arterial blood pressure is part of this normal circadian pattern, and its absence, which is called non-dipping is associated with more severe end-organ damage and increased risk of cardiovascular events, especially in hypertensive patients. Although pathologic mechanisms are still unclear, it has been suggested that non-dippers show impairment in the autonomic system functions that include abnormal parasympathetic and sympathetic activities. Several studies have examined the role of the autonomic nervous system in the non-dipping phenomenon. In this paper, we aimed to review the studies evaluating the relationship between circadian arterial blood pressure pattern and indices of cardiac autonomic functions. (Anadolu Kardiyol Derg 2011; 2: 168-73)

Background: Catheter ablation of atrial fibrillation is recommended for patients with symptomatic paroxysmal atrial fibrillation (PAF) despite anti-arrhythmic drugs (AADs (HR = 60, p < 0.001)

Patients with AS has lower HRR and HRV indices with respect to normal subjects. Cardiac autonomic functions might be involved in AS patients even in patients without cardiac symptoms.

One of the major complications of arsenic on human health is hypertension. Arsenic-related hypertension and negative effects of arsenic on arterial system such as oxidative stress and vasoconstriction/vasorelaxation imbalance may lead to impair aortic elasticity. The aim of this study was to evaluate the effects of arsenic on aortic elasticity parameters including aortic strain and distensibility. One hundred twelve (112) workers were occupationally exposed to arsenic and 60 healthy control subjects were enroled. All patients underwent transthoracic echocardiography for detecting aortic strain and aortic distensibility. There were no differences in baseline demographic and echocardiographic characteristics between the groups. Aortic strain (10.3±3.9 vs 12.1±2.7%, P=0.001) and aortic distensibility (0.45±0.17 vs 0.54±0.15 cm per dyn, P=0.001) were decreased in arsenic-exposure group compared with controls. Urinary arsenic level was found to be negatively and significantly correlated with aortic strain (r=-0.306, P=0.001) and aortic distensibility (r=-0.259, P=0.006). Duration of arsenic exposure was also found to be negatively and significantly correlated with aortic strain (r=-0.386, P<0.001) and aortic distensibility (r=-0.333, P<0.001). This study suggests that arsenic exposure is related to impairment of aortic elasticity parameters even in subjects without overt cardiovascular disease.