Does heart rate variability correlate with long-term prognosis in myocardial infarction patients treated by early revascularization?

Abstract

AIMTo assess the prevalence of depressed heart rate variability (HRV) after an acute myocardial infarction (MI), and to evaluate its prognostic significance in the present era of immediate reperfusion.METHODSTime-domain HRV (obtained from 24-h Holter recordings) was assessed in 326 patients (63.5 ± 12.1 years old; 80% males), two weeks after a complicated MI treated by early reperfusion: 208 ST-elevation myocardial infarction (STEMI) patients (in which reperfusion was successfully obtained within 6 h of symptoms in 94% of cases) and 118 non-ST-elevation myocardial infarction (NSTEMI) patients (percutaneous coronary intervention was performed within 24 h and successful in 73% of cases). Follow-up of the patients was performed via telephone interviews a median of 25 mo after the index event (95%CI of the mean 23.3-28.0). Primary end-point was occurrence of all-cause or cardiac death; secondary end-point was occurrence of major clinical events (MCE, defined as mortality or readmission for new MI, new revascularization, episodes of heart failure or stroke). Possible correlations between HRV parameters (mainly the standard deviation of all normal RR intervals, SDNN), clinical features (age, sex, type of MI, history of diabetes, left ventricle ejection fraction), angiographic characteristics (number of coronary arteries with critical stenoses, success and completeness of revascularization) and long-term outcomes were analysed.RESULTSMarkedly depressed HRV parameters were present in a relatively small percentage of patients: SDNN < 70 ms was found in 16% and SDNN < 50 ms in 4% of cases. No significant differences were present between STEMI and NSTEMI cases as regards to their distribution among quartiles of SDNN (χ2 =1.536, P = 0.674). Female sex and history of diabetes maintained a significant correlation with lower values of SDNN at multivariate Cox regression analysis (respectively: P = 0.008 and P = 0.008), while no correlation was found between depressed SDNN and history of previous MI (P = 0.999) or number of diseased coronary arteries (P = 0.428) or unsuccessful percutaneous coronary intervention (PCI) (P = 0.691). Patients with left ventricle ejection fraction (LVEF) < 40% presented more often SDNN values in the lowest quartile (P < 0.001). After > 2 years from infarction, a total of 10 patients (3.1%) were lost to follow-up. Overall incidence of MCE at follow-up was similar between STEMI and NSTEMI (P = 0.141), although all-cause and cardiac mortality were higher among NSTEMI cases (respectively: 14% vs 2%, P = 0.001; and 10% vs 1.5%, P = 0.001). The Kaplan-Meier survival curves for all-cause mortality and for cardiac deaths did not reveal significant differences between patients with SDNN in the lowest quartile and other quartiles of SDNN (respectively: P = 0.137 and P = 0.527). Also the MCE-free survival curves were similar between the group of patients with SDNN in the lowest quartile vs the patients of the other SDNN quartiles (P = 0.540), with no difference for STEMI (P = 0.180) or NSTEMI patients (P = 0.5...

Influences of Thyroid Hormones on the Alteration of Autonomic Nervous System in Female Patients with Overt Hyperthyroidism

“…The study of HRV and HRT is a highly debated topic in the literature and is used to ascertain the influences of the ANS on the heart [1,3,18]. Several scientific papers have been written about their significance in various physiological states and in pathological conditions [2,5,12]. Fluctuations of HRV and HRT parameters were observed in thyroid disorders [9,14,17].…”

“…HRT studies the sinus rhythm cycle length variation after isolated premature ventricular contractions (PVC). These methods are used in studies to estimate the presence of sympathovagal imbalance in patients with congestive heart failure [2], or after myocardial infarction [5], in order to predict an increased cardiovascular risk and morbidity [5]. Some studies have evidenced that an increased HR, induced by sympathetic hyperactivity, is a negative prognostic factor [5].…”

“…These methods are used in studies to estimate the presence of sympathovagal imbalance in patients with congestive heart failure [2], or after myocardial infarction [5], in order to predict an increased cardiovascular risk and morbidity [5]. Some studies have evidenced that an increased HR, induced by sympathetic hyperactivity, is a negative prognostic factor [5]. The sympatovagal imbalance favours the onset of arrhythmias and increases the risk of sudden death [2,[5][6][7].…”

“…Some studies have evidenced that an increased HR, induced by sympathetic hyperactivity, is a negative prognostic factor [5]. The sympatovagal imbalance favours the onset of arrhythmias and increases the risk of sudden death [2,[5][6][7]. The significance of these methods for the assessment of the cardiovascular risk in hyperthyroid patients, without other structural heart diseases, except the ones induced by thyroid hormones in excess, is still a subject to debate [8,9].…”

Renal denervation improves cardiac function by attenuating myocardiocyte apoptosis in dogs after myocardial infarction

“…Myocardial infarction is a leading cause of death in the world [ 1 ]. Heart failure (HF) is a common complication of acute myocardial infarction (AMI) and is characterized by cardiac dysfunction along with autonomic imbalance.…”