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Diabet. Med. 29, e312-e320 (2012) Abstract Aims Poor prognosis associated with blunted post-exercise heart-rate recovery may reflect autonomic dysfunction. This study sought the accuracy of post-exercise heart-rate recovery in the diagnosis of cardiac autonomic neuropathy, which represents a serious, but often unrecognized complication of Type 2 diabetes. Methods Clinical assessment of cardiac autonomic neuropathy and maximal treadmill exercise testing for heart-rate recovery were performed in 135 patients with Type 2 diabetes and negative exercise echocardiograms. Cardiac autonomic neuropathy was defined by abnormalities in ≥ 2 of 7 autonomic function markers, including four cardiac reflex tests and three indices of short-term (5-min) heart-rate variability. Heart-rate recovery was defined at 1-, 2- and 3-min post-exercise. Results Patients with cardiac autonomic neuropathy ( n = 27; 20%) had lower heart-rate recovery at 1-, 2- and 3-min post-exercise ( P < 0.01). Heart-rate recovery demonstrated univariate associations with autonomic function markers ( r-values 0.20-0.46, P < 0.05). Area under the receiver-operating characteristic curve revealed good diagnostic performance of all heart-rate recovery parameters (range 0.80-0.83, P < 0.001). Optimal cut-offs for heart-rate recovery at 1-, 2- and 3-min post-exercise were ≤ 28 beats/min (sensitivity 93%, specificity 69%), ≤ 50 beats/min (sensitivity 96%, specificity 63%) and ≤ 52 beats/min (sensitivity 70%, specificity 84%), respectively. These criteria predicted cardiac autonomic neuropathy independently of relevant clinical and exercise test information (adjusted odds ratios 7-28, P < 0.05). Conclusions Post-exercise heart-rate recovery provides an accurate diagnostic test for cardiac autonomic neuropathy in Type 2 diabetes. The high sensitivity and modest specificity suggests heart-rate recovery may be useful to screen for patients requiring clinical autonomic evaluation. [ABSTRACT FROM AUTHOR]

A response from the authors of the article "Diagnostic accuracy of heart-rate recovery after exercise in the assessment of diabetic cardiac autonomic neuropathy" that appeared in the 2012 issue is presented.

A letter to the editor is presented in response to the article by C. M. Zubrinich and colleagues regarding the association between exogenous catecholamines and tako-tsubo cardiomyopathy.

A letter to the editor is presented regarding the case of a 57-year-old man with hypertension and underwent extensive type A aortic dissection.

Diabet. Med. 29, e33-e40 (2012) Abstract Aims Heart rate variability may be used to assess diabetic cardiac autonomic neuropathy. The aim of the present study was to determine the reliability of standard short-term clinical measurements of heart rate variability in patients with Type 2 diabetes. Methods In 24 patients with Type 2 diabetes (11 male, age 61 ± 9 years), parameters of heart rate variability in the time domain (standard deviation of RR intervals, coefficient of variation of RR intervals and root mean square of successive RR interval differences) and frequency domain (very low frequency, low frequency, high frequency and total spectral power) were derived from a 5-min electrocardiograph recorded during two laboratory visits separated by 16 ± 8 days. Absolute and relative reliability were assessed by 95% limits of random variation and the intraclass correlation coefficient, respectively. Categorical agreement of classifications of heart rate variability and sample size estimates for clinical trials were calculated. Results Despite no significant difference in mean heart rate variability between tests, 95% limits of random variation indicated that repeated measurements were between 58% higher/37% lower (most reliable parameter; coefficient of variation of RR intervals) and 443% higher/82% lower (least reliable parameter; very low frequency power) than the first measure. The intraclass correlation coefficient ranged from 0.58 to 0.90 and sample size requirements from 20 to 93 patients per group. Agreement of categories of heart rate variability ranged from 79 to 96%. Conclusions Short-term clinical measurements of heart rate variability in patients with Type 2 diabetes are characterized by poor absolute reliability, but substantial to good relative reliability, suggesting greater clinical utility in diagnosis than in sequential follow-up. [ABSTRACT FROM AUTHOR]