Patients with HFpEF have reduced cardiac energetic reserve that may underlie marked dynamic slowing of LV active relaxation and abnormal VVC during exercise.

Background-This study assessed the chronotropic response to exercise and heart rate (HR) recovery after exercise in a carefully phenotyped group of patients with heart failure with preserved left ventricular ejection fraction (HfpEF) and a control group of similar age and gender distribution.

Ageing is associated with increased LV torsion secondary to reduced rotational deformation delay and increased peak basal rotation. LV torsion and strain patterns in patients with HfnEF are similar to age-related changes apart from circumferential strain, which is enhanced in patients with HfnEF.

Background-Asymptomatic subjects with diabetes mellitus have an impaired cardiac energetics status that may play a significant role in the development of heart failure. In the present study, we assessed the role of microvascular dysfunction in the development of impaired cardiac energetics in subjects with type 1 diabetes mellitus. Methods and Results-Twenty-five asymptomatic subjects with type 1 diabetes mellitus (mean age Ϯ1 SD 33Ϯ8 years) and 26 age-, sex-, and body mass index-matched healthy control subjects (32Ϯ8 years old) were recruited into the study. The type 1 diabetes mellitus subjects were divided into 2 age-matched groups (newly diagnosed [Ͻ5 years] and longer-duration [Ͼ10 years] diabetes) to assess the impact of microvascular disease. All subjects had an echocardiogram and an exercise ECG performed, followed by magnetic resonance spectroscopy and stress magnetic resonance imaging. Compared with healthy control subjects, the phosphocreatine/␥-ATP ratio was reduced significantly both in subjects with longer-term (2.1Ϯ0.5 versus 1.5Ϯ0.4, PϽ0.000) and newly diagnosed (2.1Ϯ0.5 versus 1.6Ϯ0.2, PϽ0.000) diabetes. The phosphocreatine/␥-ATP ratio was similar in newly diagnosed diabetes subjects and those with longer-term disease (1.6Ϯ0.2 versus 1.5Ϯ0.4, Pϭ0.32). The mean myocardial perfusion reserve index in the longer-term type 1 diabetes mellitus subjects was significantly lower than in healthy control subjects (1.7Ϯ0.6 versus 2.3Ϯ0.4, Pϭ0.005). On univariate analysis, there was no significant correlation of phosphocreatine/␥-ATP ratio with myocardial perfusion reserve index (rϭ0. 21, Pϭ0.26). Conclusions-We demonstrate that young subjects with uncomplicated type 1 diabetes mellitus have impaired myocardial energetics irrespective of the duration of diabetes and that the impaired cardiac energetics status is independent of coronary microvascular function. We postulate that impairment of cardiac energetics in these subjects primarily results from metabolic dysfunction rather than microvascular impairment. (Circulation. 2010;121:1209-1215.)