[Autonomic nervous system damage in diabetes mellitus and cardiac function].
Explore the source record for details and available documents.
Adult↗
SEARCH · Search PubMed
Results for “HEART CONDUCTION SYSTEM”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[The diagnostic value of standard ECG methods, the cold-pressure test and Valsalva maneuver in idiopathic QT syndrome].
The idiopathic Long QT Syndrome is an infrequently occurring disorder. Affected patients usually show ECG alterations and are prone to syncope and sudden arrhythmic cardiac death. Adequate therapy with beta-blocking drugs may significantly improve the prognosis of affected patients. The early and precise diagnosis of the disorder therefore has major prognostic impact. This paper reports the diagnostic significance of standard ECG, exercise stress testing, ambulatory ECG monitoring, cold pressor test and Valsalva maneuver in 14 patients with Long QT Syndrome. The results were compared with those obtained in 14 healthy age matched volunteers. QTc duration was significantly longer in patients with Long QT Syndrome during standard 12-lead ECG at rest (489 +/- 55 ms versus < vs. > 412 +/- 25 ms, p < 0.005), exercise stress test (490 +/- 39 ms vs. 409 +/- 18 ms, p < 0.001), cold pressor test (512 +/- 45 ms vs. 407 +/- 19 ms, p < 0.001), Valsalva maneuver (497 +/- 49 vs. 407 +/- 18 ms, p < 0.001), minimal heart rate during 24-h of ambulatory ECG monitoring (482 +/- 69 ms vs. 402 +/- 22 ms, p < 0.01) and maximal heart rate during Holter monitoring (460 +/- 47 ms vs. 411 +/- 27 ms, p < 0.005). Four of 14 patients with Long QT Syndrome had pathological findings during ambulatory ECG monitoring (two patients showed short episodes of asymptomatic torsade de pointes tachycardia, one patient had an intermittent SA-Block, and one patient showed T-wave alternans). All healthy volunteers had normal ambulatory ECG recordings (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
The heart and cardiac conduction system in polymyositis-dermatomyositis: a clinicopathologic study of 16 autopsied patients.
We reviewed the clinical records of 16 patients with polymyositis-dermatomyositis syndromes autopsied at The Johns Hopkins Hospital to determine the nature and extent of cardiac involvement and its correlation with the severity of disease as a whole. The adult patients ranged in age from 32 to 84 years (average 56); the 2 children were aged 2 and 10 years. The duration of disease ranged from 1 to 72 months (average 21). Seven patients had dermatomyositis, 5 had dermatomyositis with malignancy, 2 had childhood dermatomyositis, and 2 had an overlap syndrome. Seven patients had clinical evidence of congestive heart failure, 4 of whom had microscopic evidence of myocarditis. Two patients had bundle branch block; in 1 there was direct involvement of the conduction system by myositis and contraction band necrosis. Evidence of active myocarditis was present in 4 patients (25%); all had congestive failure. Focal myocardial fibrosis was present in 4 patients. Vascular alterations were present in the coronary arteries in 5 patients (31%). Three had active vasculitis, 1 had intimal proliferation, and 1 had medical sclerosis with calcification. All patients with active myocarditis had skeletal muscle involvement. Nine patients had myositis without myocarditis. There was no correlation of overall severity of the disease with the presence or absence of active myocarditis. The present study shows that cardiac involvement may be common in polymyositis; congestive failure or conduction abnormalities arising in this setting may be indicative of myocarditis.
Adult↗
Evolution of heart rate control after transplantation: conduction versus autonomic innervation.
In cardiac transplantation, the donor organ is not initially innervated and demonstrates decreased heart rate variability (HRV). However, HRV may improve after several months. The mechanism for HRV improvement has not been elucidated; autonomic "reinnervation" of the donor heart has been proposed. The role of atrioatrial conduction from recipient to donor organ has not been evaluated. We prospectively evaluated cardiac transplant patients with a limited electrophysiology study at the time of their surveillance biopsies. Recordings were made of recipient and donor signals, observing conduction properties between recipient and donor atria. Holter recordings were analyzed and HRV was determined using spectral analysis techniques, recording mean RR interval, low-frequency power (LF), high-frequency power (HF), and the LF/HF ratio. These were compared to published norms. From November 1999 to May 2000, 21 patients (6 female) who underwent cardiac transplantation participated at a median age of 101 months (range, 4.1-217 months). Time posttransplant ranged from 26 days to 71 months. Holter data were available for 20 patients and demonstrated dissociated P waves in 13 (65%). The mean heart rate on Holter was 111 beats per minute (bpm) (range, 85-161 bpm). We were able to record distinct recipient atrial signals in 16 of 21 (76%) patients. The average recipient tissue heart rate was 55% that of the donor heart rate. We documented atrioatrial association in only 1 patient. HRV did not reach normal values for most patients and did not increase with time posttransplantation. The LF values were in the normal range for most patients, whereas 3 patients had normal HF values and 2 patients had values just below normal. Recipients of heart transplantation have a predominantly sympathetic influence of HRV. These preliminary data suggest that atrioatrial conduction does not play a role in reestablishing normal heart rate control following pediatric cardiac transplantation.
Adolescent↗
[Effect of the calcium antagonist nisoldipine on electrophysiologic parameters in the human].
We investigated the influence of nisoldipine, a new calcium antagonist, on sinus node function, intracardiac conduction times, and the refractoriness of different compartments of the heart. Three catheters were placed in the right heart: a quadripolar one in the high right atrium, a bipolar one in the His position, and one in the apex of the right ventricle. Nisoldipine given i.v. in a dose of 1.5 microgram/kg body weight shortened the sinus node cycle length and the sinus node recovery time by 10%. The rate corrected sinus node recovery time, the sinoatrial conduction time, and the intracardiac conduction times remained unaffected. The effective refractory period of the right ventricle decreased slightly but significantly. The refractoriness of the other compartments did not change significantly. Systolic blood pressure decreased by 6%, whereas diastolic blood pressure remained constant. Nisoldipine thus exhibits no major effects on electrophysiological parameters in man. The increase in heart rate is regarded as a sympathetic reflex mechanism due to the decrease of systemic resistance.
Aged↗
Chronotropic cardiac effects of histamine in the conscious dog with chronic atrioventricular block: interactions with the autonomic nervous system.
Chronotropic effects of histamine and dimaprit were studied in the conscious dog with chronic atrioventricular block. Histamine at 0.2-5 micrograms/kg and dimaprit at equimolar doses (i.e. 0.25-6.25 micrograms/kg) increased atrial rate dose-relatedly. Blockade of muscarinic receptors reduced these effects and simultaneous blockade of muscarinic and beta-adrenergic receptors abolished them. Histamine and dimaprit moderately increased ventricular rate. Blockade of muscarinic receptors did not modify these effects, but blockade of beta-adrenoceptors with or without simultaneous blockade of muscarinic receptors suppressed them. After blockade of beta-adrenoceptors, histamine and more rarely dimaprit sometimes decreased atrial and ventricular rates. These effects were prevented by additional muscarinic blockade. Histamine and dimaprit lowered mean blood pressure to the same degree before and after each antagonist. The positive chronotropic effects of histamine and dimaprit, at these doses, are probably reflex responses to their hypotensive effects. The negative chronotropic effects of histamine after pindolol are due to muscarinic receptor activation. No evidence was found to implicate histamine-specific receptors in any of the chronotropic effects of histamine and dimaprit.
Adrenergic beta-Antagonists↗
Signs of autonomic neuropathy in childhood uremia.
To evaluate the presence of autonomic neuropathy in childhood uremia, cardiovascular autonomic reflexes were examined in children with chronic renal failure. Cardiovascular autonomic reflexes of 10 uremic patients on chronic dialysis and 10 transplanted patients were compared to assess the effect of transplantation on autonomic neuropathy. Resting heart rate, heart rate changes induced by deep breathing, by Valsalva maneuver, and following standing up, and blood pressure change induced by handgrip test were examined. Of the 10 uremic children, 4 showed early involvement and 2 had definite involvement of autonomic neuropathy. Only 1 of the 10 transplanted patients showed early signs of autonomic neuropathy. Autonomic tests demonstrated predominantly parasympathetic dysfunction. In conclusion, cardiovascular autonomic neuropathy is not rare in children and adolescents and young adults with chronic renal failure. In contrast, the prevalence is very low in transplanted patients with similar uremic precedents. Efforts should be made to prevent or delay this uremia-related complication.
Adolescent↗
Behaviorally conditioned changes in atrio-ventricular transmission in awake dog.
The purpose of this study was to examine the effects of behaviorally conditioned changes in autonomic activity on atrio-ventricular (AV) transmission in dog. To produce consistent activation of the cardiac nerves in the awake animal (n = 7), a classical appetitive conditioning paradigm was used. A conditioning trial consisted of a 30 s control period followed by one of two differing situations: (1) a 60-s conditional stimulus (CS+) tone wherein food (i.e. 'UCS' or unconditioned stimulus) was given during the last 30 s; or (2) at 30-s discriminative stimulus (CS-) tone which was never followed by food reward. Eight of each type trial were given daily until a stereotypic cardiovascular response was developed for the CS+ but not the CS-. The hemodynamic conditional response (i.e. 'CR', the response to the CS+) consisted of a moderate tachycardia (+14.5%, P less than or equal to 0.05), a small pressor response (+6.7%, P less than or equal to 0.01), and a moderate increase in the first time derivative of left ventricular pressure (+14.9%, P less than or equal to 0.01) reflecting an increase in inotropic state. The unconditional response (i.e., 'UCR', the response to the food reward) consisted of a substantial increase in HR (25.7%, P less than or equal to 0.01) above CR values while left ventricular pressure (LVP) and d(LVP)/dt increased 5.0% and 10.0% (P less than or equal to 0.01 for both) above their CR values. The effect of the conditioned changes in neural activity on the AV node was observed by pacing the atrium from 110 to 180 bpm during the first 15 s of each trial period (i.e. control, CS+, UCS). The discrepancy between the atrial pace rate and the transmitted ventricular rate is expressed as a 'mean difference score' and serves as an index of the fidelity of the AV transmission process: the smaller the difference, the closer a 1:1 ratio of atrial vs ventricular beats is approached. The relatively large mean difference score for the control periods (46.0 +/- 9 bpm) indicates that the paced atrial impulse did not faithfully precede ventricular contraction during these periods. The mean difference significantly decreased (34.6%, P less than or equal to 0.05) during the CS+, and approached an almost 1:1 ratio (75.6% decrease from CS+ values, P less than or equal to 0.01) during food delivery. beta-Adrenergic blockade (propranolol, 1 mg/kg, i.v.) eliminated the changes in mean difference during the CS+ but not during food delivery. There were no statistically significant physiological changes during CS-.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Effects of circumferential or segmental pulmonary vein ablation for paroxysmal atrial fibrillation on cardiac autonomic function.
BACKGROUND: Circumferential and segmental pulmonary vein ablations are two established treatment strategies for ablation of atrial fibrillation. Both techniques require the application of radiofrequency current at anatomical sites that are close to autonomic ganglia. However, the effects of current pulmonary vein ablation techniques on cardiac autonomic function are unknown. OBJECTIVE: The purpose of this study was to analyze the short- and long-term effects of circumferential and segmental pulmonary vein ablation on cardiac autonomic function. METHODS: One hundred patients with highly symptomatic atrial fibrillation were randomly assigned to undergo either circumferential or segmental pulmonary vein ablation. Holter recordings were recorded at baseline and at regular intervals for up to 1 year after ablation. Autonomic function was assessed by deceleration capacity and acceleration capacity of heart rate as well as by standard measures of heart rate variability. RESULTS: In the circumferential pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased highly significantly from 5.7 +/- 2.1 ms and -8.0 +/- 1.9 ms at baseline to 3.3 +/- 1.8 ms and -5.5 +/- 2.3 ms directly after ablation, respectively (P<.00001). Impairment of deceleration capacity and acceleration capacity was present up to 1 year after ablation. In the segmental pulmonary vein ablation group, deceleration capacity and acceleration capacity decreased from 5.8 +/- 2.0 ms and -7.8 +/- 1.6 ms at baseline to 3.4 +/- 1.2 ms and -6.0 +/- 2.4 ms directly after ablation (P<.00001), respectively. However, deceleration capacity and acceleration capacity returned to baseline values within 1 month. CONCLUSIONS: Circumferential and segmental pulmonary vein ablations induce an immediate decrease of autonomic function. However, while this decrease is only transient with segmental pulmonary vein ablation, it persists with circumferential pulmonary vein ablation for at least 1 year.
Aged↗
Power spectral analysis of heart period variability of preceding sinus rhythm before initiation of paroxysmal atrial fibrillation.
Time domain analysis of heart period variability in patients without structural heart disease demonstrated increased parasympathetic modulation before paroxysmal atrial fibrillation (AF) occurring predominantly at night. However, diurnal differences in autonomic activity preceding AF episodes in a diverse patient population have not been assessed. Accordingly, we performed spectral analysis of heart period variability on Holter recordings during sinus rhythm preceding AF in 29 patients, 17 with night and 12 with day episodes. Samples taken 5, 10, and 20 minutes before AF onset were compared. Normalized high-frequency (HF) spectral power change was greater when comparing the interval 10 to 5 minutes with 20 to 10 minutes preceding AF in 26 of 29 patients (0.09 +/- 0.07 vs 0.03 +/- 0.02; p < 0.0001). HF spectral power increased before 3 of 12 AF episodes during the day compared with 15 of 17 AF episodes during the night (p = 0.001). Nocturnal AF episodes were preceded by increased HF spectral power in the 5- versus the 20-minute sample expressed as natural logarithm-transformed values (5.6 +/- 4.8 vs 4.2 +/- 4.0; p < 0.005) and normalized values (0.19 +/- 0.09 vs 0.10 +/- 0.07; p < 0.02), a decrease in low-frequency/HF ratio (1.05 +/- 0.61 vs 2.21 +/- 1.75; p < 0.05) and heart rate (60 +/- 13 vs 71 +/- 13 beats/min; p = 0.06). Structural heart disease was more common with daytime than nocturnal AF episodes (58% vs 18%, p < 0.05). In conclusion, HF spectral power change was increased preceding most AF episodes. However, diurnal differences were demonstrated. Contrary to daytime AF, increased parasympathetic activity preceded predominantly nocturnal AF, mostly in younger patients with structurally normal hearts.
Aged↗
Effects of streptozotocin-induced diabetes on heart rate, blood pressure and cardiac autonomic nervous control.
Diabetes-associated alterations in resting heart rate and blood pressure have been demonstrated in clinical studies and in animal models of insulin-dependent diabetes mellitus (IDDM). These alterations may result from changes in the heart, vasculature or autonomic nervous system control. Using the streptozotocin- (STZ-) treated rat model of IDDM, the current study was designed to: (1) monitor changes in heart rate and blood pressure continually during a 10-week period in conscious unrestrained animals; and (2) determine if observed alterations in heart rate were mediated by changes in sympathetic and/or parasympathetic nervous control. Biotelemetry techniques were used. Heart rate and blood pressure were recorded 24 h a day at 10 min intervals before and after induction of diabetes. Diabetes was induced by i.v. administration of 50 mg/kg STZ. Resting autonomic nervous system tone was estimated by chronotropic responses to full-blocking doses of nadolol (5 mg/kg i.p.) and atropine (10 mg/kg i.p.). STZ-induced diabetes was associated with time-dependent reductions in heart rate and its circadian variation. Diastolic blood pressure and mean arterial pressure did not differ significantly when compared between control and STZ-treated animals; however, pulse pressure was diminished in diabetic rats. Chronotropic responses to both nadolol and atropine were blunted significantly in diabetic animals suggesting that resting levels of both vagal and sympathetic nervous tone to the heart were diminished. Heart rate in the presence of both nadolol and atropine was also decreased in diabetic rats. All effects observed following administration of STZ were reversed, at least in part, by insulin treatment. These results suggest that IDDM is associated with time-dependent reductions in resting heart rate and autonomic nervous control of cardiac function.
Adrenergic beta-Antagonists↗
Effect of radiofrequency catheter ablation of accessory pathways on autonomic tone in children.
BACKGROUND: Radiofrequency catheter ablation is standard treatment for children with re-entrant supraventricular tachycardias. Autonomic changes have been noted after such ablation for atrioventricular nodal re-entry tachycardia, but not as well documented with atrioventricular re-entry over an accessory pathway. METHODS AND RESULTS: In 10 normal paediatric volunteers and 12 children referred for electrophysiologic testing and radiofrequency ablation of supraventricular tachycardia, non-invasive autonomic function tests and tilt-table testing were performed, and the variability in 24-h heart rate was analysed. Patients with supraventricular tachycardia underwent these tests both 24-72 h before and 24 h after ablation. Patients with tachycardia underwent additional autonomic testing to assess the sensitivity of baroreceptors and the intrinsic heart rate with autonomic blockade immediately before and after ablation. One non-invasive autonomic function test, namely handgrip, demonstrated significant differences (p < 0.05) in diastolic blood pressure before and after ablation, though these values did not differ from controls. Significant decreases were noted in two indexes of the variability of heart rate before and after ablation (p < 0.05). Certain tilt test variables also demonstrated significant differences between controls and those with tachycardia subsequent to ablation. Intracardiac testing demonstrated changes (p < 0.05) in sinus cycle lengths, effective refractory periods and/or blood pressures at baseline and during testing of the sensitivity of baroreceptors before and after ablation. These changes were consistent with increased sympathetic or decreased parasympathetic tone. With autonomic blockade, these differences were abolished. CONCLUSIONS: Catheter ablation of accessory pathways in children was associated with changes consistent with increased sympathetic or decreased parasympathetic tone. These autonomic changes persisted 24 h after the ablation procedure.
Adolescent↗
Clustering of RR intervals predicts effective electrical cardioversion for atrial fibrillation.
INTRODUCTION: Atrial fibrillation (AF) is characterized by an irregularly irregular ("random") heart beat. However, controversy exists whether the ventricular rhythm in AF is truly random. We investigated randomness by constructing three-dimensional RR interval plots (3D plots), allowing identification of "clustering" of RR intervals. It was hypothesized that electrical cardioversion (ECV) would be more effective in AF patients with clustering, because clustering might reflect a higher degree of organization of atrial fibrillatory activity. METHODS AND RESULTS: The study group consisted of 66 patients (44 men and 22 women; mean age 68 +/- 11 years), who were referred for ECV because of persistent AF. Twenty-four-hour Holter recordings were used to construct 3D plots by plotting each RR interval (x axis) against the previous RR interval (y axis) and the number of occurrences of each of these x,y combinations (z axis). A clustering index was calculated as the percentage of beats within the peaks in the 3D plot. Based on the 3D plots, clustering of RR intervals was present in 31 (47%) of the 66 patients. ECV was effective in restoring sinus rhythm in 29 (94%) of these 31 patients, whereas sinus rhythm was restored in only 25 (71%) of the remaining 35 patients without clustering (P = 0.020). The clustering index ranged from <2% in the 12 patients with failed ECV to >8% in the 32 patients with sinus rhythm at the end of the study (4 weeks after the ECV); the clustering index in the 22 patients with a relapse of AF after effective ECV was intermediate (P = 0.034 and P = 0.042, respectively). CONCLUSION: This study indicates that ECV is more effective in restoring sinus rhythm in AF patients with clustering compared to patients in whom no clustering is apparent on 3D plots. In addition, the degree of clustering appears to be predictive of the overall outcome of ECV; the higher the degree of clustering, the higher the likelihood of sinus rhythm at follow-up.
Aged↗
Assessment of cardiac autonomic control by heart period variability in patients with early-onset familial obesity.
For quantitative assessment of cardiac autonomic control, time and frequency domain measures of heart period variability were calculated by 24 h Holter recording in 10 young obese women with early-onset familial obesity and in 10 control subjects. Ultra low frequency and very low frequency power were lower in obese subjects than in controls (P < 0.05). High frequency power, a pure measure of vagal tone, was comparable between the two groups. However, low frequency power, which analysed over a 24 h Holter recording reflects parasympathetic more than sympathetic activity, was slightly lower in obese subjects than in controls (P = 0.06). Body mass index showed an inverse correlation with total power (r = -0.62; P < 0.05) and separately with ultra low (r = -0.59; P < 0.01), very low (r = -0.64; P < 0.005), low (r = -0.61; P < 0.005) and high frequency power (r = -0.53; P < 0.05). These results demonstrate a parasympathetic withdrawal increasing body weight. The reduction of ultra low frequency and very low frequency power, which are associated with sudden death, may help to explain the higher cardiovascular risk in obesity.
Adolescent↗
Autonomic interactions for control of atrial rate are maintained after SA nodal parasympathectomy.
Autonomic control of atrial rate was evaluated in anesthetized dogs by electrical stimulation of stellate ganglia and/or cervical vagi before and after the intrinsic cardiac right atrial ganglionated plexus (RAGP) was injected with the nicotinic blocker hexamethonium or the membrane stabilizing chemical lidocaine, or the RAGP was surgically removed. Injections of lidocaine or hexamethonium into or surgical removal of the RAGP eliminated the bradycardia elicited by vagal stimulation without reducing the tachycardia induced by stellate stimulation. Yet, after surgical ablation of the RAGP, the tachycardia induced by sympathetic stimulation was still reduced by 94% by parasympathetic stimulation. After injections of hexamethonium or lidocaine into the RAGP were administered, the sympathetically induced tachycardia was reduced by 39 and 85%, respectively, by parasympathetic stimulation. After RAGP ablation, when atrial rate was increased by infusion of beta-adrenergic agonists, parasympathetic stimulation reduced atrial rate by 13%. Sinoatrial (SA) nodal parasympathectomy, produced by disrupting the RAGP, eliminates direct vagal control of the SA node while leaving prejunctional parasympathetic projections to sympathetic afferents innervating the SA node intact.
Animals↗
Cardiac response to cephalic ischemia.
Explore the source record for details and available documents.
Animals↗
Remodeling of sinus node function in patients with congestive heart failure: reduction in sinus node reserve.
BACKGROUND: Experimental and clinical studies have demonstrated diffuse atrial remodeling in congestive heart failure (CHF). We hypothesized that patients with CHF would demonstrate derangement of sinus node function. METHODS AND RESULTS: Eighteen patients with symptomatic CHF (left ventricular ejection fraction, 26+/-5%) and 18 age-matched control subjects were studied. Under autonomic blockade, the following were evaluated: intrinsic sinus cycle length, corrected sinus node recovery time (CSNRT), sinoatrial conduction time, number and duration of fractionated electograms or double potentials along the crista terminalis, and location of the earliest sinus activity. Electroanatomic mapping was performed to evaluate the location and nature of the sinus node complex, to characterize sinoatrial propagation, and to evaluate conduction abnormalities and voltage amplitude along the crista terminalis. Patients with CHF demonstrated the following findings compared with age-matched control subjects: prolongation of the intrinsic sinus cycle length (P=0.005), prolongation of CSNRT (P<0.0001), caudal localization of sinus activity both during sinus rhythm (P=0.03) and after pacing (P=0.002), prolongation of sinoatrial conduction time (P=0.02), greater number (P<0.0001) and duration (P<0.0001) of fractionated electrograms or double potentials along the crista terminalis, loss of voltage amplitude along the crista terminalis (P=0.02), and abnormal and circuitous propagation of the sinus impulse. CONCLUSIONS: This study demonstrates that patients with CHF have significant sinus node remodeling characterized by anatomic and structural changes along the crista terminalis with a reduction in functional sinus node reserve. This finding may have implications for the development of clinical bradycardia in CHF and for the use of negatively chronotropic agents and pacing in this condition.
Adult↗
Continuous autonomic assessment in patients with symptomatic heart failure: prognostic value of heart rate variability measured by an implanted cardiac resynchronization device.
BACKGROUND: Heart rate variability (HRV) as an indirect autonomic assessment provides prognostic information when measured over short time periods in patients with heart failure. Long-term continuous HRV can be measured from an implantable device, but the clinical value of these measurements is unknown. METHODS AND RESULTS: A total of 397 patients with New York Heart Association class III or IV heart failure were studied. Of these, 370 patients had information from their implanted cardiac resynchronization device for mortality risk stratification, and 288 patients had information for measured parameters (ie, HRV, night heart rate, and patient activity) and clinical event analyses. Continuous HRV was measured as the standard deviation of 5-minute median atrial-atrial intervals (SDAAM) sensed by the device. SDAAM <50 ms when averaged over 4 weeks was associated with increased mortality risk (hazard ratio 3.20, P=0.02) and SDAAM were persistently lower over the entire follow-up period in patients who required hospitalization or died. SDAAM decreased a median of 16 days before hospitalization and returned to baseline after treatment. Automated detection of decreases in SDAAM was 70% sensitive in detecting cardiovascular hospitalization, with 2.4 false-positives per patient-year of follow-up. CONCLUSIONS: This study demonstrates that SDAAM continuously measured from an implanted cardiac resynchronization device is lower in patients at high mortality and hospitalization risk. SDAAM declines as patient status decompensates. Continuous long-term SDAAM may be a useful tool in the clinical management of patients with chronic heart failure.
Aged↗