Decreased intralymphocytic magnesium content is associated with diastolic heart dysfunction in patients with essential hypertension

Abstract

Diastolic heart failure (DHF) is a clinical syndrome characterized by the symptoms and signs of heart failure, preserved ejection fraction (EF) and abnormal diastolic function [1]. Hypertension is the most common risk factor and the principal precursor for DHF [2]. Hypertension-induced left ventricular (LV) hypertrophy that includes myocardial hypertrophy and abnormal accumulation of fibrillar collagen causes a decreased compliance and LV diastolic dysfunction. It is estimated that 20–60% of patients with heart failure have preserved EF [3,4]. Unfortunately, in contrast to the situation of heart failure with low EF, the mortality and morbidity of DHF have not been significantly decreased in the past decades [5,6]. Magnesium is the second most abundant intracellular cation. As a cofactor formany enzymes,magnesiumplays a role in various biological functions including energy metabolism and muscle contraction [7]. It is known that activation of the rennin–angiotensin–aldosterone system and the use of diuretics in patients with essential hypertension or cardiac failure may deplete serum potassium and affect intracellular magnesium homeostasis [8,9]. We have shown the importance of maintaining magnesium homeostasis in reducing arrhythmia and myocardial hypertrophy in patients with heart failure or hypertension [10,11]. However, the role of magnesium homeostasis in diastolic heart dysfunction is not known yet. Thus, we designed this study to address this issue. Since myocardium of patients is usually not easily accessible, we measured intralymphocytic magnesium content to reflect the magnesium content in myocardial cells. This was a single center prospective study that conformed to the ethical principles outlined in the Declaration of Helsinki. The study protocol was approved by the ethics committee of the First Affiliated Hospital of the SunYat-SenUniversity (Guangzhou, China). Consecutive 206 essential hypertension patients with diastolic heart dysfunction documented by Doppler echocardiography from November 2007 to October 2009 were enrolled. Patients with diastolic heart dysfunction and clinical signs and symptoms of heart failure as described in the European Society of Cardiology Guidelines published in 2008 [12] were attributed to DHF group (group A). Those free of signs and symptoms of