Autonomic responses to heartburn induced by esophageal acid infusion

BACKGROUND AND AIM: Studies have shown that altered visceral perception and lower pain thresholds in patients with symptomatic gastroesophageal reflux disease (GERD) and non-cardiac chest pain. Autonomic changes associated with the perception of heartburn in patients with GERD are poorly understood. METHODS: A total of 12 GERD patients (six male, six female; mean age 37.2 +/- 2.7 years) and 12 controls (five male, seven female; mean age 32.8 +/- 2.2 years) were studied. The study protocol included a 20-min water infusion (6 mL/min), and 20-min acid infusion (0.1 N HCl, 6 mL/min). Spectral analysis of heart-rate variability (HRV) was used to assess autonomic functioning. The measured HRV indices included the power in the low-frequency (LF) band (0.04-0.15 Hz) reflecting sympathetic tone, and power in the high-frequency (HF) band (0.15-0.5 Hz) reflecting vagal tone, and the LF/HF ratio as an indicator of sympathovagal balance. RESULTS: The GERD group experienced more heartburn than controls with acid infusion. Between-group comparisons showed no significant changes in LF band power in any period. The HF band power was significantly lower in GERD patients during all infusion periods. The LF/HF ratio was significantly larger in GERD patients. CONCLUSIONS: The perception of heartburn induced by esophageal acid infusion is associated with a simultaneous increase in sympathetic modulation in patients with GERD. The autonomic responses with esophageal acid infusion are significantly different between healthy subjects and GERD patients.     

Sympathetic predominance of cardiac autonomic regulation in patients with left free wall accessory pathway and orthodromic atrioventricular reentrant tachycardia

AIMS: The aim of this study was to compare cardiac autonomic regulationin patients with a history of paroxysmal supraventricular tachyarrhythmias,such as atrioventricular nodal reentrant tachycardia and atrioventricularreentrant tachycardia, and healthy controls. METHODS AND RESULTS: Seventeen patients with paroxysmal atrioventricular nodal reentranttachycardia (atrioventricular nodal reentrant tachycardia group),14 patients with overt preexcitation and paroxysmal atrioventricularreentrant tachycardia caused by a left free wall accessory pathway(atrioventricular reentrant tachycardia group) and 14 healthycontrol subjects, were studied. The patients and the controlswere age and gender matched. Cardiac autonomic regulation wasassessed by means of frequency domain analysis of heart ratevariability at rest, during head-up tilt, active standing, treadmillexercise and after exercise. The high frequency component (0·15–0·5 Hz)of heart rate variability tended to be lower and the low frequencycomponent (0·04–0·15 Hz) tended to be higheramong the atrioventricular reentrant tachycardia patients thanin atrioventricular nodal reentrant tachycardia patients andcontrols. The difference reached statistical significance atrest (P<0·05) and during standing (P<0·05atrioventricular reentrant tachycardia vs atrioventricular nodalreentrant tachycardia and P<0·01 atrioventricularreentrant tachycardia vs controls). Accordingly, the low-to-highfrequency ratio — the marker of cardiac sympathetic regulation— was higher in atrioventricular reentrant tachycardiapatients than in atrioventricular nodal reentrant tachycardiapatients (P<0·05 at rest and during standing) andcontrols (P<0·01 during standing). CONCLUSION: The cardiac autonomic status in atrioventricular reentrant tachycardiapatients was suggestive of a higher sympathetic tone than inatrioventricular nodal reentrant tachycardia patients or healthycontrols. This may be related to inhomogeneous ventricular activationin the presence of antegrade conduction via the accessory atrioventricularpathway.     

Cardiac autonomic function and oesophageal acid sensitivity in patients with non-cardiac chest pain

BACKGROUND: Acid reflux can elicit non-cardiac chest pain (NCCP), possibly through altered visceral sensory or autonomic function. The interactions between symptoms, autonomic function, and acid exposure are poorly understood. AIM: To examine autonomic function in NCCP patients during exposure to oesophageal acid infusion. SUBJECTS AND METHODS: Autonomic activity was assessed using power spectral analysis of heart rate variability (PSHRV), before and during oesophageal acidification (0.1 N HCl), in 28 NCCP patients (40.5 (10) years; 13 females) and in 10 matched healthy controls. Measured PSHRV indices included high frequency (HF) (0.15-0.5 Hz) and low frequency (LF) (0.06-0.15 Hz) power to assess vagal and sympathetic activity, respectively. RESULTS: A total of 19/28 patients had angina-like symptoms elicited by acid. There were no significant manometric changes observed in either acid sensitive or insensitive patients. Acid sensitive patients had a higher baseline heart rate (82.9 (3.1) v 66.7 (3.5) beats/min; p<0.005) and lower baseline vagal activity (HF normalised area: 31.1 (1.9)% v 38.9 (2.3)%; p< 0.03) than acid insensitive patients. During acid infusion, vagal cardiac outflow increased (p<0.03) in acid sensitive but not in acid insensitive patients. CONCLUSIONS: Patients with angina-like pain during acid infusion have decreased resting vagal activity. The symptoms elicited by perception of acid are further associated with a simultaneous increase in vagal activity in keeping with a vagally mediated pseudoaffective response.     

Poor sleep quality is associated with cardiac autonomic dysfunction in treated hypertensive men

Hypertensives present cardiac autonomic dysfunction. Reduction in sleep quality increases blood pressure (BP) and favors hypertension development. Previous studies suggested a relationship between cardiovascular autonomic dysfunction and sleep quality, but it is unclear whether this association is present in hypertensives. Thus, this study evaluated the relationship between sleep quality and cardiac autonomic modulation in hypertensives. Forty‐seven middle‐aged hypertensive men under consistent anti‐hypertensive treatment were assessed for sleep quality by the Pittsburgh Sleep Quality Index (PSQI—higher score means worse sleep quality). Additionally, their beat‐by‐beat BP and heart rate (HR) were recorded, and cardiac autonomic modulation was assessed by their variabilities. Mann‐Whitney and t tests were used to compare different sleep quality groups: poor (PSQI > 5, n = 24) vs good (PSQI ≤ 5, n = 23), and Spearman’s correlations to investigate associations between sleep quality and autonomic markers. Patients with poor sleep quality presented lower cardiac parasympathetic modulation (HR high‐frequency band = 26 ± 13 vs 36 ± 15 nu, P = .03; HR total variance = 951 ± 1373 vs 1608 ± 2272 ms², P = .05) and cardiac baroreflex sensitivity (4.5 ± 2.3 vs 7.1 ± 3.7 ms/mm Hg, P = .01). Additionally, sleep quality score presented significant positive correlation with HR (r = +0.34, P = .02) and negative correlations with HR high‐frequency band (r = −0.34, P = .03), HR total variance (r = −0.35, P = .02), and cardiac baroreflex sensitivity (r = −0.42, P = .01), showing that poor sleep quality is associated with higher HR and lower cardiac parasympathetic modulation and baroreflex sensitivity. In conclusion, in treated hypertensive men, poor sleep quality is associated with cardiac autonomic dysfunction.     

Inclusion of supine period in short-duration pH monitoring is essential in diagnosis of gastroesophageal reflux disease

Prolonged esophageal pH monitoring is the most accurate method for detecting abnormal gastroesophageal reflux (GER) in patients with gastroesophageal reflux disease (GERD). However, some investigators have found that short-duration postprandial pH monitoring in the upright position is also useful, while others have failed to find such results. Therefore, we have compared a 6-hr period of pH monitoring (3-hr postprandial period after daytime meal and 3-hr supine period) with a total 24-hr period in detecting abnormal gastroesophageal reflux. Sixty-five patients (44 men, mean age 41.3 years) with GERD and 16 healthy volunteers (11 men, mean age 34.3 years) underwent 24-hr pH monitoring according to a standard protocol. Various reflux parameters during 24-hr pH monitoring were compared with reflux parameters during the 6-hr period. Abnormal GER was detected in 56 patients presenting with typical symptoms of GERD (sensitivity 86.2%). These patients could be further divided into upright (N=18), supine (N=15), and combined (N=23) refluxers, depending on the posture in which abnormal reflux occurred. Esophageal pH monitoring during the 3-hr postprandial upright period showed abnormal reflux in only 35 patients (sensitivity 53.8%;P<0.00005, compared with the 24-hr pH monitoring period). Abnormal GER was identified in 13 of 18 upright, 19 of 23 combined, and only one of 15 supine refluxers, as well as in two of nine patients with normal 24-hr pH-metry. However, inclusion of the 3-hr supine monitoring period in the 3-hr postprandial upright period improved detection of abnormal GER to 78.5% (51 patients;P=NS compared with 24-hr pH monitoring period). This was related mainly to improved detection of abnormal GER in supine refluxers (11 of 15; 73.3%). Esophageal acid exposure time correlated significantly with severity of esophagitis only during the total and supine periods of both the 24- and 6-hr periods and not during the upright period. Esophageal acid clearance correlated significantly with increasing grades of esophagitis for the supine and total periods only. We conclude that 3-hr postprandial pH monitoring, as has been conventionally practiced, is not appropriate in the detection of abnormal GER; inclusion of a supine period in the short-duration pH monitoring schedule increases the detection of pathological reflux. We therefore recommend that a supine period should be included in short-duration pH monitoring schedules. We also found that supine reflux was the most important factor in the development of esophagitis.     

重度脑外伤患者早期心率变异性的临床研究

目的探讨急性重度脑外伤患者早期自主神经系统（ANS）功能的改变特点。方法对40例急性重度脑外伤患者（脑外伤组）伤后1周内进行24h心率变异性（HRV）检测，采用动态心电图分析系统自动计算HRV各项指标（时域、频域和非线性分析），并与31例正常人（对照组）比较。结果脑外伤组HRV多项指标多明显降低；存活者和死亡者HRV时域分析、频域分析各项指标比较有统计学意义。结论急性重度脑外伤患者存在明显的ANS功能障碍；ANS功能障碍与病情严重性呈正相关。     

心率和心率变异性用于评定颈部手法刺激对自主神经系统的影响

目的应用心率和心率变异性分析,评定颈部手法刺激对自主神经系统的影响。方法选择正常青年男性志愿者,对受试者进行颈部手法刺激,刺激前和刺激后各记录5min动态心电图,以心率和心率变异性作为观测指标,判断颈部手法刺激对自主神经系统的影响。结果对30名正常青年男性志愿者观察发现,颈部手法刺激后,心率显著降低(RR间期延长);时域分析中SDNN有显著性增加,频域分析中VLF和总功力谱有显著性增加。结论心率和心率变异性是一项评定颈部手法刺激对自主神经系统效应的有用指标。     

Evaluation of autonomic nervous function in patients with essential hypertension complicated with peptic ulcer

BACKGROUND AND AIMS: The relationship between peptic ulcer, autonomic activity and the incidence of Helicobacter pylori infection in untreated hypertensive patients complicated with peptic ulcer were evaluated. METHODS: Ten hypertensive patients with peptic ulcer (HT-PU group), 15 untreated essential hypertensive patients without peptic ulcer (HT group) and 10 normal subjects (N group) were enrolled, and a power spectral analysis was performed in each subject. A biopsy urease test was used to detect infection by H. pylori. RESULTS: No significant differences were observed in the values of mean low-frequency (LF) power between the three groups. However, the mean high-frequency (HF) power in the HT-PU group was significantly greater than those of the HT and N groups (P<0.01). The mean LF/HF ratios in the HT-PU and HT groups were significantly greater than that of the N group (P<0.01). With respect to H. pylori infection, no significant differences between the three groups were observed. Sympathetic activity (LF power) was increased in the HT and HT-PU groups. Furthermore, parasympathetic activity (HF power) was increased in the HT-PU group. CONCLUSIONS: These findings suggest the participation of increased parasympathetic activity in peptic ulcer patients. Therefore, it is suggested that new techniques, such as spectral analysis of heart rate variability, as used in this study, will clarify the relationship between peptic ulcer and autonomic nervous function.     

Validation of a new method of measuring esophageal acid exposure: comparison with 24-hour pH monitoring

Recently, we developed a disposable acid exposure sensor whose in vitro response to acid below pH 4 is linearly determined by the duration of exposure and the degree of acidity. The aim of the present study was to compare the SR to simultaneous esophageal pH and duodenogastroesophageal reflux (DGER) monitoring (Bilitec) in patients investigated for presumed gastroesophageal reflux disease (GERD). Twenty-six patients (16 men, mean age 46 ± 2 years) with symptoms suggestive of GERD underwent 24-hr ambulatory pH monitoring and SR monitoring at 5 cm proximal to the LES. DGER monitoring was performed in 21 patients. Exposure of the esophagus to acid and to DGER were analyzed. These data were compared to SR. A significant correlation was found between the exposure of the distal esophagus to acid and SR (R = 0.85; P < 0.0001). Similarly, the area below a cutoff pH 4 was significantly correlated to SR (r = 0.81; P < 0.0001). SR was not correlated to DGER (r = 0.16; NS). At a cutoff of 50, the sensitivity and specificity of SR to predict esophageal acid exposure >5% of time were 91% and 93%, respectively conclusion, the response of the acid exposure sensor is strongly correlated with the results of simultaneous esophageal pH monitoring. The sensor seems able to reliably predict pathological esophageal acid exposure. These findings warrant larger studies of the clinical potential of the acid exposure sensor in the diagnosis and quantification of GERD.     

Changes in autonomic nervous activity during endoscopic retrograde cholangiopancreatography: a possible factor in cardiac complications

BACKGROUND AND AIMS: The changes of autonomic nervous activity during endoscopic retrograde cholangiopancreatography (ERCP) are closely related to the development of cardiovascular complications, such as arrhythmias and acute coronary syndrome. In the present study, the correlation between changes in hemodynamics and autonomic nervous activity during ERCP procedures was evaluated by analyzing heart rate variability and blood catecholamine levels. METHODS: Twenty-three patients who underwent ERCP (ERCP group) and 15 control subjects who were only premedicated (C group) were studied. Ambulant ECG, blood pressure, arterial oxygen saturation, and blood level of catecholamine were measured. Autonomic nervous function was assessed by analyzing the spectral analysis and 1/f fluctuation. The low frequency power (LF power; 0.04-0.15 Hz), high frequency power (HF power; 0.15-0.40 Hz, indicator of parasymapathetic tone), the ratio of LF power to HF power (LF/HF ratio, indicator of sympathetic tone), and 1/f fluctuation (indicator of pleasant mood) were calculated. RESULTS: Blood pressure and heart rate were increased and arterial oxygen saturation was decreased in the ERCP group during the endoscopic procedure. Changes in the parameters of autonomic nervous function (LF power, HF power, LF/HF ratio, and 1/f fluctuation) were significantly greater in the ERCP group than in the C group, especially during cholangiography. Moreover, blood levels of catecholamines were significantly increased during the ERCP procedure. In the C group, however, blood levels of catecholamines did not significantly change except directly after premedication. CONCLUSIONS: Autonomic nervous activity varied greatly during cholangiography, demonstrating that ERCP has more than a little influence on the cardiovascular system. The results of the present study indicated that attention should be focused on changes in hemodynamics in patients with cardiovascular complications by monitoring the aforementioned hemodynamic parameters during ERCP.     

Interaction between the autonomic nervous system and atrial tachyarrhythmias

Atrial tachyarrhythmias are the most common arrhythmias in the general population. The abundant experimental evidence suggests that the autonomic nervous system plays an important role in the occurrence of atrial arrhythmias. However, complex interactions of the autonomic nervous system with the arrhythmogenic substrate make it difficult to correlate human arrhythmias with the laboratory data. Development of new methods to explore the subtle modulation of the autonomic nervous system may have implications for understanding the arrhythmogenic mechanism and providing an effective therapy.     

冠心病心肌缺血发作前后心脏自主神经功能的变化

为了解冠心病慢性心肌缺缺血发生前后心脏自主神经变化情况，采用频域法对比分析３０例冠心病和６０例正常对照组和心率变异性变化，及冠心病心肌缺血前后心率变异的变化。结果冠心病组全频和主频面积显著降低，低频面积明显增高，低频／高频比值极显著增高；心肌缺血发作前低频，低频／高频显著增高，而高频降低。     

Inflammation-related effects of adjuvant influenza A vaccination on platelet activation and cardiac autonomic function

Abstract. Lanza GA, Barone L, Scalone G, Pitocco D, Sgueglia GA, Mollo R, Nerla R, Zaccardi F, Ghirlanda G, Crea F (Istituto di Cardiologia; and Università Cattolica del Sacro Cuore, Roma; Italy). Inflammation‐related effects of adjuvant influenza A vaccination on platelet activation and cardiac autonomic function. J Intern Med 2010; 269 : 118–125. Background. Inflammation, platelet reactivity and cardiac autonomic dysfunction increase the risk of cardiovascular events, but the relationships between these prognostic markers are poorly defined. In this study, we investigated the effect of an inflammatory stimulus (influenza A vaccine) on platelet activation and cardiac autonomic function. Methods. We measured serum C‐reactive protein (CRP) and interleukin‐6 levels, monocyte–platelet aggregates (MPAs) and monocyte/platelet receptor expression before and after adjuvant influenza A vaccination in 28 patients with type II diabetes (mean age 62.1 ± 8 years, 18 men). Twenty‐four‐hour Holter electrocardiogram was recorded 24 h before and after vaccination; heart rate variability (HRV) was assessed as a measure of cardiac autonomic function. Results. Inflammatory cytokines, MPA formation and monocyte/platelet receptor expression increased after vaccination. CRP was 2.6 ± 2.8 and 7.1 ± 5.7 mg L^?1 48 h before and after vaccination, respectively (P < 0.0001). HRV parameters decreased after vaccination compared to baseline, with very low‐frequency amplitude showing the most significant change (34.6 ± 11.8 and 31.0 ± 10.2 ms 48 h before and after vaccination, respectively; P = 0.002). A significant correlation was found between percentage changes in CRP levels and in most HRV variables, with the most significant correlations between changes in CRP levels and changes in standard deviation of all normal RR intervals (r = 0.43; P = 0.02). Conclusions. Together with an inflammatory reaction, influenza A vaccine induced platelet activation and sympathovagal imbalance towards adrenergic predominance. Significant correlations were found between CRP levels and HRV parameters, suggesting a pathophysiological link between inflammation and cardiac autonomic regulation. The vaccine‐related platelet activation and cardiac autonomic dysfunction may transiently increase the risk of cardiovascular events.     

Exclusion of meal periods from ambulatory 24-hour pH monitoring May improve diagnosis of esophageal acid reflux

Distal esophageal pH less than 4 is frequently seen during meal ingestion in 24-hr ambulatory pH monitoring for the diagnosis of gastroesophageal reflux disease (GERD). The characteristics of this meal-related apparent reflux without diet restriction was evaluated. Data from normal volunteers (N=21) and consecutive patients (N=66) referred with heartburn and/or chest pain were studied with ambulatory pH monitoring. The median percent times pH<4 in the distal esophagus were significantly greater in symptomatic patients than controls for total 24-hr, upright, and supine periods, and postprandial periods of 30, 60, 90, 120, and 150 min (P values of 0.007–0.03). However, the median percent time pH<4 during the meal periods was the same for patients (4.4%) and for controls (6.6%) withP=0.23. Excluding the meal periods from analysis resulted in greater separation between controls and patients with abnormal acid exposure when compared to the conventional method. Patients should maintain their usual routine without diet restriction during 24-hr ambulatory pH studies in the clinical setting. Furthermore, exclusion of meal periods can eliminate meal-time pH variabilities without affecting postprandial acid exposure and improve the diagnosis of GERD.     

阻塞性睡眠呼吸暂停低通气综合征患者的自主神经功能的评估

目的采用24h动态心电图心率变异性分析,研究阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的自主神经功能状态变化。方法入选我院诊断的OSAHS患者50例,并将其分为轻中度组和重度组2组。对照组为年龄相匹配的正常男性26名,所有受试者均在睡眠监测的同时进行24h动态心电图检查,并进行心率变异性分析。结果时域指标:轻中度组和重度组SDNN和pNN50明显低于对照组;重度组SDNNi和RMSSD明显降低。频域分析:重度组低频功率谱明显高于对照组,轻中度组和重度组的高频功率谱明显减低而低频功率谱/高频功率谱明显增高。结论OSAHS男性患者24h的自主神经功能状态发生了异常改变,并且与其病情的严重程度相关。     

Circadian Variation of Heart Rate Variability in Postinfarction Patients With and Without Life-Threatening Ventricular Tachyarrhythmias

Circadian Variation of HRV. Introduction: Determination of heart rate variability (HRV) is widely used for noninvasive assessment of cardiac autonomic tone. A decreased HRV is associated with an increased mortality in patients surviving an acute myocardial infarction. There are, however, only sparse data about the circadian variation of different components of HRV that may be linked to the well-known circadian fluctuations in the occurrence of sudden death. In addition, the potential prognostic impact of circadian variations of HRV has not been examined. Methods and Results: The present study compared the circadian variation of HRV from 14 postinfarction patients who had survived at least one episode of out-of-hospital cardiac arrest (cardiac arrest group) with that of 14 age- and sex-matched patients without a history of malignant arrhythmias after their index infarct (control group). Several time- and frequency-domain measures of HRV were assessed from 24-hour Holter recordings. Circadian variations of high- (HF), low- (LF), and total-frequency (TF) components were determined by calculating for each parameter the hourly difference from the day's mean. The average of these differences was calculated for every hour as well as for predefined day and night periods. There was no significant difference between the two groups with regard to HRV indices that predominantly reflect vagal tone, such as SDNN (78 ± 25 vs 96 ± 24 msec), pNN50 (2.7%± 4.6% vs 4.9%± 4.2%), or HF (6.3 ± 3.0 vs 7.8 ± 3.2 msec; cardiac arrest vs control group). There was also no significant difference in the circadian variation of LF or TF between the two groups during daytime and nighttime. However, a significant difference in circadian variation of HF was found during daytime (0.02 ± 0.5 vs -0.6 ± 0.5 msec; P = 0.006) and nighttime (0.19 ± 0.64 vs 1.5 ± 0.75 msec; P = 0.0002). In cardiac arrest survivors, there was no difference in the mean deviation of HF between the day-and the nighttime periods. Conclusions: These results show an almost complete abolition in circadian variation of parasympathetic tone in postinfarction patients surviving an episode of out-of-hospital cardiac arrest, whereas circadian variation of sympathetic tone is comparable to that of postinfarction patients without arrhythmic episodes. These findings indicate that determination of diurnal variation of HRV may add to the prognostic value of HRV with respect to identifying patients at high risk of sudden death.     

Correlation of 24-hr esophageal pH patterns with clinical features and endoscopy in gastroesophageal reflux disease

We performed 24-hr ambulatory esophageal pH monitoring in north Indian patients with gastroesophageal reflux disease (GERD) and correlated it with symptom severity and endoscopic abnormalities. Thirty-six consecutive patients with symptomatic GERD and 16 healthy volunteers underwent objective grading of clinical symptoms and endoscopic findings. Total, supine, and upright reflux periods as well as frequency and duration of reflux episodes were determined from the 24-hr pH-metry record using standard software. This was abnormal in 32 patients, who could be categorized into upright refluxers (31.2%), supine refluxers (34.4%), and combined refluxers (34.4%). Supine reflux and upright reflux were distinct entities that did not correlate with each other (r=0.22,P=NS). In upright refluxers, symptoms (P<0.02) and=" endoscopic=" abnormalities=">P<0.005) were=" milder=" than=" in=" combined=" refluxers.=" total=" duration=" of=" acid=" exposure=" correlated=" significantly=" with=" severity=" of=" symptoms=">P<0.001) and=" endoscopic=" esophagitis=">P<0.005). patients=" with=" gerd=" had=" three=" distinct=" patterns=" of=" abnormal=" gastroesophageal=" reflux,=" with=" upright=" refluxers=" having=" milder=" disease=" and=" supine=" and=" combined=" refluxers=" having=" more=" severe=" disease.=" this=" may=" reflect=" differences=" in=" underlying=" mechanisms=" of=">     

Factors influencing heart rate variability in patients with severe aortic valve disease

Background and hypothesis: Heart rate variability (HRV) is an accepted tool for the assessment of cardiovascular autonomic tone. There are no sufficient data concerning its application to patients with severe aortic valve disease (AVD) requiring cardiac surgery. Methods: It was the aim of this study to examine HRV and its physiologic correlates in patients with severe aortic valve disease requiring cardiac surgery. The correlates of time domain indices of HRV obtained from 24-h Holter electrocardiographic recordings were analyzed in 36 consecutive patients (23 men and 13 women, mean age 62 ± 11 years) with AVD prior to cardiac surgery (aortic stenosis: 17 patients, aortic valve regurgitation: 3 patients, combined aortic valve disease: 16 patients). Results: Low values of HRV were found in the entire study group: SDNN 96.8 ± 30.9 ms, SDNNI 39.3 ± 14.4 ms, SDANN 86 ± 28.9 ms, and RMSSD 30 ± 18.1 ms. In a univariate analysis, there was no significant correlation between the time domain measures of HRV and age, gender, medication, left ventricular ejection fraction, peak aortic pressure gradient, fraction of aortic valve regurgitation, and left ventricular mass assessed by echocardiography. Patients in advanced functional classes of heart failure [New York Heart Association (NYHA) III or IV] had significantly lower values for SDNN (83.8 ± 33.6 vs. 107.3 ± 24.7 ms; p<0.05) and SDANN (72.7 ± 29.4 vs. 96.6 ± 24.3 ms; p<0.05) than patients in NYHA class I or II. Reassessment of HRV 1 week after aortic valve replacement was performed in 17 patients and showed a significant further decrease of SDNN (102.4 ± 29.7 vs. 61.5 ± 23.5 ms; p<0.001), SDNNI (40.7 ± 13.6 vs. 23.4 ± 12.4 ms; p<0.001) and SDANN (91.8 ±29.2 vs. 54.2 ± 22.8 ms;p<0.001). Conclusion: Patients with AVD requiring cardiac surgery reveal reduced time domain indices of HRV. This observation is pronounced in patients with a progressed clinical class of heart failure, whereas hemodynamic and echocardiographic parameters seem to have no significant influence on HRV parameters in this population. In addition, there is evidence of a further reduction of HRV time domain indices 1 week after uncomplicated aortic valve replacement.