Influence of ageing on circadian rhythm of heart rate variability in healthy subjects.

BACKGROUND: The analysis of the circadian rhythm of heart rate variability (HRV) represents a relevant physiological tool to assess the vagal system. However, the influence of age (mostly >75 years) on HRV is not widely known. AIMS: The aim of this study was to evaluate the influence of age on HRV, particularly in the elderly and to identify a model of this relationship. The study was carried out by examining linear and nonlinear parameters extracted from HRV, including individuals over 75 years for which there is no research available. METHODS: Data from 140 healthy subjects were sex matched and divided into young (young group: 15-39 years old), adult (adult group: 40-64 years old) and senior (senior group: 65-90 years old) groups. 24-h Holter monitoring was used and several HRV parameters were extracted from time, and spectral and nonlinear analyses were examined. RESULTS: Time-domain parameters, mainly standard deviation of the NN interval (SDNN) and number of successive differences of intervals which differ by more than 50 ms, presented significant differences between the young group and the other two groups during the 24-h period, while normalized spectral parameters (LFn, HFn and low frequency/high frequency), as well as nonlinear parameters, mainly ß exponent and fractal dimension, showed significant difference between the senior group and the other two groups. All these parameters showed a similar circadian rhythm with significant differences between the mean day and night values, especially in young and adult group cohorts. Moreover, a parabolic relationship between these parameters and age was highlighted with an opposite trend over about 60 years compared with younger people. CONCLUSION: A progressive physiological autonomic imbalance is present in ageing. The inverse trend in the relation between HRV parameters and age found in the senior group could be mainly due to a faster fluctuation of RR. This should be considered when studying changes in the cardiac autonomic nervous control.

Short and long-term outcome in very old patients with ST-elevation myocardial infarction after primary percutaneous coronary intervention.

BACKGROUND: Although octogenarians constitute a fast-growing portion of cardiovascular patients, few data are available on the outcome of patients aged ≥85 years with ST-Elevation Myocardial Infarction (STEMI). METHODS AND RESULTS: We analyzed 126 consecutive patients aged ≥85 years (age 88±2 years) with STEMI, undergoing primary percutaneous coronary intervention (pPCI) within 12 hours from symptoms onset. Long-term follow-up (median 898 days) was obtained for the 102 patients surviving the index-hospitalization. In-hospital mortality rate was 19%. Nonagenarians, diabetes mellitus, severe left ventricular systolic dysfunction and intra-aortic balloon pumping were significantly and independently correlated to in-hospital mortality at the multivariate analysis. A low rate of complications was detected. Among patients surviving the index hospitalization, 32 (31%) patients died during follow-up. 55 patients (54%) had re-hospitalization due to cardiovascular causes. The univariate analysis identified chronic renal failure, Killip class ≥ 3, TIMI Risk Score >8 and very high risk of bleeding as predictors of long-term overall mortality. At the multivariate analysis only chronic renal failure and very high risk of bleeding were significantly and independently correlated to long-term all-cause mortality. Renal function and anterior myocardial infarction were significantly and independently associated with the combined end-point of cardiac mortality and re-hospitalization due to cardiovascular disease at the multivariate analysis. CONCLUSIONS: PPCI in patients ≥85 years old is relatively safe. In this population, pPCI is associated with a good long-term survival, although still worse than in younger patients, despite a considerable incidence of re-hospitalization due to cardiovascular events.

ST-elevation myocardial infarction with reduced left ventricular ejection fraction: Insights into persisting left ventricular dysfunction. A pPCI-registry analysis.

Primary percutaneous coronary intervention (pPCI) largely reduced the rate of left ventricular (LV) dysfunction after ST-segment elevation acute myocardial infarction (STEMI). Though LV recovery begins early following revascularization, the optimal timing for re-assessment of LV function is still unclear. We sought to assess the proportion and timing of LV recovery in STEMI patients presenting with LV dysfunction treated by pPCI and to identify possible early predictors of adverse LV remodeling. STEMI patients with LV ejection fraction (LVEF ≤40%) at presentation treated by pPCI from 2007 to 2013 were included whether they had an available 3-step LVEF assessment (<24h post-pPCI, discharge and follow-up). Primary endpoint was LVEF ≤35% at follow-up. At a median time of 3months, 43 out of 154 patients (28%) had LVEF ≤35%. In patients with persistent LV dysfunction, LVEF was lower at admission and increased less during hospitalization (from 31±6 to 35±4% Vs 35±5 to 43±8% for patients with 3-months LVEF >35%, p<0.001). Independent predictors of 3-months LVEF ≤35% were creatinine at admission, peak troponin I and LVEF. Of note, LVEF re-assessment at discharge (median time 6days, IQR 4-9) showed an increased accuracy to predict 3-months LV dysfunction compared to LVEF at admission (AUC 0.80, 95% CI 0.72-0.88 vs AUC 0.69, 95% CI 0.58-0.79 respectively, p=0.03). In most of patients presenting with STEMI and LV dysfunction, a significant LV recovery can be observed early following pPCI. LVEF measurement at discharge indeed emerged as the best indicator of late persistence of severe LV dysfunction.