HRV March 2001 Many abstracts

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HRV March 2001 added 3/09/01

Am J Cardiol 1998 Dec 1;82(11):1323-8

Prognostic role of heart rate variability in patients with a recent acute myocardial infarction.

Lanza GA, Guido V, Galeazzi MM, Mustilli M, Natali R, Ierardi C, Milici C, Burzotta F, Pasceri V, Tomassini F, Lupi A, Maseri A

Istituto di Cardiologia Universita Cattolica del S. Cuore, Rome, Italy.

A low heart rate variability (HRV) has been shown to be a powerful predictor of cardiac events in patients surviving an acute myocardial infarction (MI), but it is not clear yet which among the HRV parameters has the best predictive value. Time domain and frequency domain HRV was assessed on 24-hour predischarge Holter recording of 239 patients with a recent MI. Patients were followed up for 6 to 54 months (median 28), during which 26 deaths (11%) occurred, 19 of which were cardiac in origin and 12 were sudden. Most HRVs did not show any difference between patients with or without mortality end points, but the average low-frequency and low-frequency/high-frequency ratio was lower in patients with events. However, when dichotomized according to cut points that maximized the risk of sudden death, several HRVs were significantly predictive of clinical end points. Overall, the mean of the standard deviations of all RR intervals for all 5-minute segments and the standard deviation of the mean RR intervals for all 5-minute segments were the time domain variables most significantly associated with mortality end points, whereas very low frequency was the most predictive frequency domain variable. Compared with the best time domain variables, very low frequency showed a better sensitivity (0.27 to 0.42 vs 0.19 to 0.33) for end points with only a small loss in specificity (0.92 vs 0.96). On multivariate Cox proportional analysis, a left ventricular ejection fraction <40% and a number of ventricular premature beats > or = 10/hour were the most powerful independent predictors for all end points, whereas no HRV was independently associated with the events. A low frequency/high frequency ratio < 1.05 only had a borderline association with sudden death (RR = 2.86, p = 0.076). Our data show a strong association between HRV and mortality in patients surviving a recent MI, with a slight better sensitivity of frequency domain analysis. In our study, however, HRV did not add independent prognostic information to more classic prognostic variables (e.g., left ventricular function and ventricular arrhythmias).

Int J Cardiol 2001 Feb;77(2-3):255-262

The effects of trimetazidine on heart rate variability and signal-averaged electrocardiography in early period of acute myocardial infarction.

Ulgen MS, Akdemir O, Toprak N

Faculty of Medicine, Departments of Cardiology, Dicle University, Diyarbakir, Turkey

Background: Acute myocardial infarction (AMI) is accompanied by electrophysiological changes in cardiovascular system as well as those in autonomic cardiac control. Heart rate variability (HRV) is depressed due to increased sympathetic activity and/or decreased parasympathetic activity following AMI. Moreover, the frequency of ventricular late potentials (VLP) is increased due to the electrophysiological changes. Based on the hypothesis that the treatments increasing HRV and decreasing the frequency of VLP can improve the prognosis of AMI, we investigated the short-term effects of trimetazidine (TMZ) on HRV and VLP in patients with AMI. Methods: The study group consisted of 64 patients (men 49, mean age 55+/-12 years, range 26-70) suffering from first Q-wave AMI. Thirty-one of them were treated with conventional therapy (thrombolytic therapy, aspirin, beta-blocker, heparin and intravenous nitroglycerin) plus TMZ 20 mg tid. The remaining 33 patients served as controls. Holter monitorization between 24 and 48 h, echocardiography at average day 6 (range 4-7 days) and SAECG and sub-maximal exercise at average day 7 (range 6-9 days) were performed to all patients. Results: While HRV parameters reflecting parasympathetic activity (SDSD: 43+/-16 ms-35+/-13 ms, RMSSD: 34+/-14 ms-27+/-8 ms, HF: 7.8+/-5 ms(2) -4.3+/-4 ms(2), P<0.05) were of significantly higher levels in TMZ group, the low frequency component mainly reflecting sympathetic activity (LF: 10+/-6 ms(2)-10+/-5 ms(2), P>0.05) was similar in both groups. In addition, LF/HF ratio showing sympatho-vagal balance was significantly decreased in TMZ group (1.5-3.0, P=0.005). About VLP, the mean FQRS (105+/-8 ms-107+/-10 ms), LAS (28+/-10 ms-30+/-11 ms) and RMS-40 (34+/-15 ?V-41+/-12 ?V) were not different in both two groups (P>0.05). Conclusion: Our results suggest that TMZ treatment causes changes in sympatho-vagal balance in favor of vagal activity by increasing parasympathetic activity in AMI at early period; however, no effect on VLP was observed.

Cerebrovasc Dis 2001 Jan;11(1):2-8

Autonomic Nervous System Function in Patients with Acute Brainstem Stroke.

Meglic B, Kobal J, Osredkar J, Pogacnik T

Department of Neurology, University Medical Centre, Ljubljana, Slovenia.

Dysfunction of the autonomic nervous system (ANS) often complicates the clinical course in patients with acute stroke. The studies of the function of ANS in patients with brainstem stroke are scarce. The purpose of our study was to evaluate the function of ANS in the early period after acute brainstem stroke and to find out whether the location of stroke in brainstem influences the function of ANS. We studied heart rate variability (HRV) and plasma levels of catecholamines in 14 eligible patients with medullary (6 patients) and non-medullary (8 patients) brainstem stroke during the first 6 weeks after stroke. Integrals over the low- (LFB; 0.04-0.15 Hz) and high-frequency bands (HFB; 0.15-0.40 Hz) of power spectra were calculated. When compared to controls, the integrals over HFB in the hyperacute (p < 0.001) and over LFB in the hyperacute (p < 0.005) and in the acute (p < 0.05) phases were significantly smaller in patients with medullary strokes. Integrals over LFB and HFB in patients with non-medullary strokes did not differ significantly from controls, regardless of the phase of the disease. Plasma levels of epinephrine in patients with non-medullary stroke in the hyperacute and in the acute phases were significantly higher than in controls (p < 0.005). We conclude that there is transient dysfunction of ANS in patients with acute medullary stroke, in contrast to those with non-medullary brainstem stroke. Copyright 2001 S. Karger AG, Basel

J Am Coll Cardiol 2001 Jan;37(1):157-62

Heart rate variability and early recurrence of atrial fibrillation after electrical cardioversion.
Lombardi F, Colombo A, Basilico B, Ravaglia R, Garbin M, Vergani D, Battezzati PM, Fiorentini C

Cardiologia, Dipartimento di Medicina, Chirurgia e Odontoiatria, Ospedale S. Paolo, Universita degli Studi di Milano, Milan, Italy. federico.lombardi@unimi.it

OBJECTIVES: The study evaluated the role of the autonomic nervous system in atrial fibrillation (AF) recurrence. BACKGROUND: Early recurrence of AF after cardioversion (CV) is attributed to electrical remodeling. The possibility that an abnormal autonomic modulation might contribute to this phenomenon has not yet been adequately tested. METHODS: We analyzed short-term heart rate variability (HRV) in 93 patients with persistent AF and on chronic amiodarone treatment, after restoration of sinus rhythm by electrical CV. RESULTS: Two weeks later, 25 patients presented with AF. Spectral analysis of HRV revealed that patients wi - - - -

Med Sci Sports Exerc 2000 Nov;32(11):1894-901

Resting heart rate variability in men varying in habitual physical activity

Melanson EL

Department of Exercise Science, University of Massachusetts, Amherst, USA. ed.melanson@uchsc.edu

PURPOSE: The aims of this study were 1) to assess day-to-day stability of resting heart rate variability (HRV) in healthy adults; 2) to determine whether the reliability of these measures is influenced by self-reported habitual physical activity level; and 3) determine whether the magnitude of HRV is related to self-reported habitual physical activity level. METHODS: A resting electrocardiogram was obtained on five consecutive mornings in 37 men (age = 33+/-6 yr) grouped according to their self-reported level of weekly physical activity (LOW, N = 15; MOD, N = 10; HIGH, N = 12). All measurements were obtained while subjects breathed at 10 breaths x min(-1) (0.167 Hz). RESULTS: HRV was assessed using time and frequency domain measures. Most measures were highly reproducible (R > 0.90) regardless of activity level. After adjusting for differences in age and body mass index, weekly physical activity level was not a significant predictor of any measure of HRV. However, all time and frequency domain measures of HRV tended to be higher in active (MOD and HIGH) compared with inactive (LOW) subjects. No measure of HRV differed between the two most active groups. CONCLUSIONS: Heart rate and HRV are highly reproducible, regardless of physical activity level. Additionally, although time and frequency domain measures of HRV may be greater in active than sedentary individuals, HRV does not appear to be increased in a dose-dependent manner with increasing levels of physical activity.

Clin Cardiol 2000 Mar;23(3):187-94

Clinical and demographic determinants of heart rate variability in patients post myocardial infarction: insights from the cardiac arrhythmia suppression trial (CAST).

Stein PK, Domitrovich PP, Kleiger RE, Schechtman KB, Rottman JN

Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.

BACKGROUND: Clinical and demographic determinants of heart rate variability (HRV), an almost universal predictor of increased mortality, have not been systematically investigated in patients post myocardial infarction (MI). HYPOTHESIS: The study was undertaken to evaluate the relationship between pretreatment clinical and demographic variables and HRV in the Cardiac Arrhythmia Suppression Trial (CAST). METHODS: CAST patients were post MI and had > or =6 ventricular premature complexes/h on pretreatment recording. Patients in this substudy (n = 769) had usable pretreatment and suppression tapes and were successfully randomized on the first antiarrhythmic treatment. Tapes were rescanned; only time domain HRV was reported because many tapes lacked the calibrated timing signal needed for accurate frequency domain analysis. Independent predictors of HRV were determined by stepwise selection. RESULTS: Coronary artery bypass graft surgery (CABG) after the qualifying MI was the strongest determinant of HRV. The markedly decreased HRV associated with CABG was not associated with increased mortality. Ejection fraction and diabetes were also independent predictors of HRV. Other predictors for some indices of HRV included beta-blocker use, gender, time from MI to Holter, history of CABG before the qualifying MI, and systolic blood pressure. Decreased HRV did not predict mortality for the entire group. For patients without CABG or diabetes, decreased standard deviation of all NN intervals (SDANN) predicted mortality. Clinical and demographic factors accounted for 31% of the variance in the average of normal-to-normal intervals (AVGNN) and 13-26% of the variance in other HRV indices. CONCLUSIONS: Heart rate variability post MI is largely independent of clinical and demographic factors. Antecedent CABG dramatically reduces HRV. Recognition of this is necessary to prevent misclassification of risk in patients post infarct.

Pol Arch Med Wewn 1998 Dec;100(6):515-25

[Studies of arrhythmia incidence and heart rate variability in patients suffering from cerebral stroke].

[Article in Polish]

Negrusz-Kawecka M, Kobusiak-Prokopowicz M ,Katedra i Klinika Kardiologii AM, Wroclawiu.

Patients with cerebral stroke develop electrocardiographic changes concerning the period of ventricular muscle repolarization and cardiac arrhythmias, which may results in the possibility of acute circulatory arrest. ECG monitoring by means of Holter method provides not only information concerning arrhythmias, episodes of ischaemia of the cardiac muscle, but it is also a recognised and generally accepted method of investigation of the autonomic system. The aim of the study was to assess the incidence of arrhythmias and heart rate variability in patients suffering from recent cerebral stroke. The studies involved 36 patients, in that 22 women (mean age 67.7 +/- 7.2 years) and 14 men (mean age 66.5 +/- 11.3 years) within first 24 hours after cerebral stroke confirmed by computerised tomography (CT). One the basis of CT scan haemorrhagic stroke was diagnosed in 7 patients and ischaemic stroke, after ruling out haemorrhagic stroke and neurological consultations, in 29 patients. Moreover, all patients revealed hypertension, 12 of them mild degree (1 degree), and 21 of moderate degree (2 degrees), and 3 of severe degree (3 degrees). The control group comprised 65 patients suffering from primary hypertension without concomitant cerebral stroke, matching the study group as to sex and age as well as the degree of hypertension. All of them were submitted to 24-hour Holter monitoring on tape by means of 3-channel registrator MR45, analysis of ECG tracings was carried out according to Optima Jet system manufactured by Oxford. In order to facilitate further analysis, the automatic recording was verified visually and next heart rate variability (HRV) was estimated within 24 hours and separately for day hours 6:00-22:00 and night hours 22:00-6:00. In comparison to patients with hypertension, but without stroke, subjects with hypertension and accompanying cerebral stroke more often reveal premature supraventricular beats, pairs of ventricular beats as well as episodes of nonsustained ventricular tachycardia; they also reveal lower 24-hours heart rate variability.

Stroke 1999 Jul;30(7):1307-11

Effects of stroke localization on cardiac autonomic balance and sudden death.

Tokgozoglu SL, Batur MK, Top uoglu MA, Saribas O, Kes S, Oto A

Department of Cardiology, Hacettepe University School of Medicine, Ankara, Turkey.

BACKGROUND AND PURPOSE: Stroke has been shown to alter autonomic function. The purpose of this study was to show the differential effects of stroke localization on autonomic function parameters assessed by heart rate variability (HRV). METHODS: To determine the differential effect of ischemic stroke localization on autonomic cardiac innervation, we evaluated 62 patients with ischemic stroke and 62 age- and sex-matched controls. The localization of the infarct was determined by CT and MRI. Power spectrum analysis of HRV was performed. Myocardial necrosis was ruled out by echocardiography and creatine kinase myocardial isoenzymes measurements. RESULTS: All stroke patients had significantly decreased low frequency, high frequency, and standard deviation of all relative risk intervals values (P<0.001). However, patients with right-middle cerebral artery (R-MCA) and insula lesions had significantly lower power spectrum analysis values compared with all other localizations (P<0.001). In addition, 5 patients with R-MCA insular lesions died suddenly compared with 2 patients with left-middle cerebral artery insular lesions during hospitalization. Both sympathetic- and parasympathetic-controlled HRV were decreased in patients with ischemic stroke. The most pronounced decrease was found in the territory of R-MCA insular cortex, which suggests that cardiac autonomic tone may be regulated by insula and that these patients are more prone to cardiac complications such as arrhythmias and sudden death due to autonomic imbalance. CONCLUSION: We conclude that stroke in the region of insula (especially the right) leads to decreased HRV and to increased incidence of sudden death.

Clin Auton Res 1998 Aug;8(4):195-9

Heart rate variability in patients with the first and recurrent myocardial infarction.

Ristimae T, Huikuri HV, Teesalu R

Department of Cardiology, University of Tartu, Estonia. tiinar@cut.ee

Impairment of heart rate variability (HRV) has been reported in patients after myocardial infarction (MI). However, it is currently unknown whether the similar alterations of autonomic profile that accompany the first MI will evolve after a recurrent MI. Forty male outpatients with a previous first MI (group I) and 20 age-matched male patients with a recurrent MI (group II) were studied and measures of HRV were estimated from 24-hour electrocardiograms. In comparison with group I, group II had significantly higher values of ratio of low- to high-frequency power (6.9 +/- 5.7 vs 3.7 +/- 1.8, respectively, p < 0.05), and a tendency to lower values of all other measures of HRV. We conclude our study indicates that in comparison to group I, group II demonstrated augmented sympathetic drive as assessed by the indices of HRV. The shift toward adrenergic predominance detected after recurrent MI may result from altered afferent feedback from abnormally contracting left ventricular segments to the autonomic modulation of sinus node, or accompany subclinical state of heart failure not readily accessible with hemodynamic measurements.

Psychiatry Clin Neurosci 2000 Jun;54(3):303-4

Sleep stage transition and changes in autonomic function in newborn infants.

Goto K, Sato K, Izumi T

Department of Pediatrics, Oita Medical University, Japan. kgoto@oita-med.ac.jp

The relationships between sleep stage, startle response, electroencephalogram (EEG) pattern, and autonomic function in sleeping full-term infants was examined. Using autoregressive analysis of heart rate variability (HRV), 12 infants at a mean post-conception age of 41.1 weeks were studied. Based on HRV characteristics, the present study shows sympathetic nervous system activation during active sleep (AS) and distinct changes in autonomic function based on the startle response and EEG features during quiet sleep (QS). The findings might reflect structural and functional maturation of the central nervous system of newborn infants.