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Biomedical subjects

W Grimm

Publications and source records attributed to W Grimm.

At least 37 records · Page 2Linked to original sources
PubMed2000

Significance of accelerated idioventricular rhythm in idiopathic dilated cardiomyopathy.

Holter monitoring was performed in 202 patients with idiopathic dilated cardiomyopathy, which revealed accelerated idioventricular rhythm in 16 patients (8%) and nonsustained ventricular tachycardia in 70 patients (35%). During 32 +/- 15-month prospective follow-up, no significant difference was observed for major arrhythmic events and transplant-free survival between patients with and without accelerated idioventricular rhythm, whereas patients with nonsustained ventricular tachycardia had a significantly higher incidence of major arrhythmic events and a lower transplant-free survival rate.

Accelerated Idioventricular Rhythm↗
PubMed2000

Cardiac autonomic tone and its relation to nonsustained ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy.

BACKGROUND: In contrast to postinfarct patients, little is known about cardiac autonomic tone and its relation to spontaneous ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy (IDC). Both heart rate variability (HRV) and baroreflex sensitivity (BRS) are indices of autonomic innervation of the heart. HYPOTHESIS: The aim of the present study was to determine the relation between cardiac autonomic tone assessed by HRV and BRS and spontaneous nonsustained ventricular tachycardia (NSVT) on Holter in a large patient population with IDC. METHODS: 24-h digital Holter recordings including HRV analysis and BRS testing were prospectively performed in 137 patients with IDC and preserved sinus rhythm. Mean age was 48 +/- 12 years, and mean left ventricular (LV) ejection fraction was 32 +/- 9%. The HRV analysis on Holter included the mean RR interval (RRm), the standard deviation of all normal RR intervals (SDNN), the square root of the mean of the squared differences between adjacent normal RR intervals (rMSSD), and the proportion of adjacent normal RR intervals differing more than 50 ms (pNN50). Testing for BRS was performed noninvasively using the phenylephrine method. RESULTS: Of 137 study patients, 42 (31%) had spontaneous NSVT on 24-h Holter. Compared with patients without NSVT, patients with NSVT on Holter had a higher New York Heart Association (NYHA) functional class (NYHA III: 40 vs. 18%, p < 0.01), a lower ejection fraction (29 +/- 9 vs. 34 +/- 9%, p = 0.01), and an increased LV end-diastolic diameter (69 +/- 8 mm vs. 66 +/- 7 mm, p = 0.03). The HRV variables rMSSD, pNN50, RRm, and BRS did not differ significantly between patients with and without spontaneous NSVT. Only SDNN on Holter was slightly lower in patients with versus without NSVT (106 +/- 45 vs. 121 +/- 46 ms, p = 0.08). CONCLUSIONS: Patients with IDC and spontaneous NSVT on Holter are characterized by a higher NYHA functional class, a lower LV ejection fraction, an increased LV end-diastolic diameter, and a tendency toward a lower SDNN value compared with patients without NSVT. The remaining measures of HRV including rMSSD and pNN50 reflecting primarily tonic vagal activity, as well as BRS reflecting predominantly reflex vagal activity, were similar in patients with and without NSVT. The prognostic significance of these findings in patients with IDC is currently under investigation in the Marburg Cardiomyopathy Study (MACAS) at our institution.

Adolescent↗
PubMed2000

Prediction of major arrhythmic events and sudden cardiac death in dilated cardiomyopathy. The Marburg Cardiomyopathy Study design and description of baseline clinical characteristics.

The Marburg Cardiomyopathy Study (MACAS) is a prospective observational study designed to determine the value of the following potential non-invasive arrhythmia risk predictors in more than 200 patients with idiopathic dilated cardiomyopathy (IDC) over a 5-year follow-up period: New York Heart Association functional class, left ventricular end-diastolic diameter and ejection fraction, left bundle branch block and atrial fibrillation on ECG, QTc and JTc-dispersion on 12-lead ECG, abnormal time-domain analysis and spectral turbulence analysis of the signal-averaged ECG, ventricular arrhythmias and heart-rate variability on 24-hour Holter ECG, baroreflex sensitivity, and microvolt T wave alternans during exercise. This report describes the rationale of MACAS as well as the clinical characteristics of the first 236 patients enrolled between March 1996 and October 1999. The prognostic significance of the potential arrhythmia risk predictors in MACAS will be determined by multivariate Cox analysis at the end of 5-year follow-up. Primary endpoints are total mortality and major arrhythmic events defined as sustained ventricular tachycardia, ventricular fibrillation or sudden cardiac death. The results of MACAS will have important implications for the design of future studies evaluating the role of prophylactic defibrillator therapy in idiopathic dilated cardiomyopathy.

Adolescent↗
PubMed2000

[Correlation between cardiac autonomic activity and compromise of left ventricular function in dilated cardiomyopathy].

In recent years, evaluation of cardiac autonomic activity by means of heart rate variability (HRV) determination and baroreflex sensitivity (BRS) testing has become readily available. The results of the ATRAMI (Autonomic Tone and Reflexes After Myocardial Infarction) study showed that both diminished HRV and baro-reflex sensitivity are associated with poor outcome in patients after myocardial infarction. In contrast to patients with coronary disease little information is available concerning cardiac autonomic activity in idiopathic dilated cardiomyopathy (IDC). Therefore, HRV and BRS were assessed in 160 patients with IDC and preserved sinus rhythm in order to investigate the relationship between HRV, BRS, and left ventricular ejection fraction. Time domain indices of HRV were computed from 24-hour digital Holter recordings. BRS testing was performed using the noninvasive phenylephrine method. Mean standard deviation of all normal RR intervals (SDNN) of the whole study population was 112 +/- 46 ms. A well preserved HRV (SDNN > 105 ms) was found in 74 patients (46%), a moderately decreased HRV (SDNN 70-105 ms) in 59 patients (37%), and a severely decreased HRV (SDNN < 70 ms) in 27 patients (17%). Mean BRS was 7.5 +/- 5.0 ms/mm Hg. A well preserved BRS (> 6 ms/mm Hg) was present in 78 patients (57%), a moderately decreased BRS (3-6 ms/mm Hg) was present in 38 patients (28%), and a severely decreased BRS (< 3 ms/mm Hg) in 21 patients (15%). There was only a weak correlation between SDNN and BRS (r = 0.19; p < 0.05). A weak correlation was found for SDNN and left ventricular ejection fraction (r = 0.29; p < 0.05). There was no significant correlation between BRS and left ventricular ejection fraction (r = 0.14). In summary, there was only a weak correlation between the HRV, BRS, and left ventricular ejection fraction in patients with IDC suggesting that these 3 variables may be independent predictors of sudden death in IDC. The relative prognostic value of these variables and other potential risk predictors including the presence of arrhythmias on Holter, microvolt T wave alternans, QTc dispersion, and signal-averaged ECG is currently under investigation in a large prospective observational study (Marburg Cardiomyopathy Study (MACAS)) during 5-year follow-up at our institution.

Adolescent↗
PubMed2000

[Risk stratification for sudden cardiac death in post-infarct patients and in patients with dilated cardiomyopathy].

In patients with structural heart disease and sustained symptomatic ventricular tachycardia or ventricular fibrillation without reversible cause, the implantable cardioverter-defibrillator has become the therapy of first choice. Besides the "MADIT indication", however, arrhythmia risk stratification with regard to prophylactic ICD implantation is an unsolved problem. This overview summarizes the currently very limited clinical value of potential risk predictors for sudden cardiac death in postinfarct patients and in patients with dilated cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed2000

Relations among hypoxemia, sleep stage, and bradyarrhythmia during obstructive sleep apnea.

BACKGROUND: Obesity, apneic hypoxemia, and rapid eye movement (REM) sleep are supposed to be the major causes for bradyarrhythmia in patients with obstructive sleep apnea. The aims of this study were to compare clinical findings and diagnoses in patients with obstructive sleep apnea with and without nocturnal bradyarrhythmia and to analyze the relations among hypoxemia, sleep stage, and bradyarrhythmia. METHODS: During a 17-month period 239 patients were found to have sleep apnea in an ambulatory study. Patients with nocturnal bradyarrhythmia were hospitalized for 3 days and polysomnographies were performed over 2 successive nights. A Holter electrocardiogram was recorded for 48 hours. RESULTS: Nocturnal episodes of bradyarrhythmia were identified in 17 (7%) of 239 patients. Body mass index (39 +/- 7 vs 31 +/- 5 kg/m(2)) and respiratory disturbance index (90 +/- 36 per hour vs 24 +/- 24 per hour) were significantly different (P <.01) between patients with (n = 17) and without bradyarrhythmia (n = 222). Bradyarrhythmia occurred significantly more often during REM than non-REM sleep (P <.01). There was a significant difference in end-apneic oxygen saturation in apnea/hypopnea episodes with and without bradyarrhythmia (71% +/- 9% vs 75% +/- 10%; P <.01). A linear relation between end-apneic oxygen saturation and number of sinus arrests and heart blocks could not be found. CONCLUSIONS: Patients with apnea-associated bradyarrhythmia are more overweight than patients without bradyarrhythmia. The higher respiratory disturbance index measurements found in these patients may be caused by this difference. Bradyarrhythmia occurs predominantly during REM sleep and occurred independently from decrease in oxygen saturation; a threshold value as an upper limit could not be found.

Adolescent↗
PubMed2000

Arrhythmia risk stratification in idiopathic dilated cardiomyopathy based on echocardiography and 12-lead, signal-averaged, and 24-hour holter electrocardiography.

BACKGROUND: To date, considerable controversy exists regarding noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy (IDC). Methods and Results Between 1992 and 1997, 202 patients with IDC without a history of sustained ventricular tachycardia (VT) underwent echocardiography, signal-averaged electrocardiogram (ECG), and 24-hour Holter ECG in the absence of antiarrhythmic drugs. During 32 +/- 15 months of prospective follow-up, major arrhythmic events, including sustained VT, ventricular fibrillation, or sudden death, occurred in 32 (16%) of 202 patients. After adjusting for baseline medical therapy and antiarrhythmic therapy during follow-up, multivariate Cox regression analysis identified a left ventricular (LV) end-diastolic diameter >/=70 mm and nonsustained VT on Holter as the only independent arrhythmia risk predictors. The combination of an LV end-diastolic diameter >/=70 mm and nonsustained VT was associated with a 14. 3-fold risk for future arrhythmic events (95% confidence interval 2. 3-90). To further elucidate the prognostic value of LV ejection fraction, multivariate Cox analysis was repeated with ejection fraction forced to remain in the model. In the latter model, an ejection fraction </=30% combined with nonsustained VT on Holter was found to be a significant arrhythmia risk predictor with a relative risk of 14.6 (95% confidence interval 2.2-97). CONCLUSIONS: The combination of an LV end-diastolic diameter >/=70 mm and nonsustained VT on Holter, and the combination of LV ejection fraction </=30% and nonsustained VT on Holter, identify a subgroup of patients with IDC with a 14-fold risk for subsequent arrhythmic events. These findings have important implications for the design of future studies evaluating the role of prophylactic defibrillator therapy in patients with IDC.

Adolescent↗
PubMed2000

Simultaneous stimulation of growth hormone, adrenocorticotropin and cortisol with L-dopa/L-carbidopa and propranolol in children of short stature.

In 59 otherwise healthy children of short stature, the simultaneous response of growth hormone, cortisol and plasma adrenocorticotropin (ACTH) to L-dopa/L-carbidopa and propranolol at 45 and 90 min after administration were investigated. A growth hormone response of 10 microg/l or higher was considered positive. The definition of a positive cortisol response included either a hormone increase of at least 193 nmol/l or a peak hormone level of at least 497 nmol/l. The ACTH increase had to be fourfold above 11 pmol/l to be considered positive. In the 59 investigated children, the median basal growth hormone levels increased from 1.35 microg/l to 18.05 microg/l and 10.15 microg/l at 45 and 90 min after stimulation (p < 0.05). The median cortisol levels rose from 242 nmol/l to 439 nmol/l and 612 pmol/l, and the corresponding median ACTH levels from 2.94 pmol/l to 9.63 pmol/l and 11.13 pmol/l at 45 and 90 min after stimulation. Significant positive hormone response rates were 88.1% for growth hormone, 88.1% for cortisol and 69% for ACTH. These results could be attributed to the enhanced stimulating effect of the additional administration of L-carbidopa and propranolol. We conclude that the administration of L-dopa/L-carbidopa and propranolol is useful for the simultaneous evaluation of growth hormone, cortisol and ACTH secretion in children of short stature.

Adolescent↗
PubMed2000

Linear lesion formation by ND:YAG laser versus radiofrequency energy in porcine atria.

The efficacy of RF energy versus the neodymium:yittrium aluminum-garnet laser to create linear lesions was compared in fresh ex vivo swine hearts. A total of 598 lesions were created in four locations: ostium of the pulmonary veins, trabeculated lateral left atrium, smooth posterior part of the right atrium, and the isthmus between the inferior vena cava and tricuspid valve. A 400-micron bare quartz fiber with CO2 cooling (distance to the tissue 5, 10, and 15 mm) and an RF ablation catheter (4-mm tip) were mechanically dragged over the tissue at speeds 0.5, 1.0, and 1.5 mm/s. A continuous and transmural ablation line was recorded as successful. A 100% success rate was achieved at the pulmonary veins and the isthmus at some settings of energy delivery by the laser and RF. In the thick posterior right atrium, RF resulted in transmural lesions only when associated with carbonization, while the laser produced successful ablation lines in 100% of the attempts. In the left atrium, because of the presence of prominent trabeculations, RF was unsuccessful at all settings of energy delivery. In contrast, deep photocoagulation by laser resulted in successful ablations in the left atrium in 100% of attempts. Lesion formation was faster by laser ablation and mean lesion width was at least 25% smaller with the laser than with RF. In conclusion, the formation of linear lesions at the isthmus and at the pulmonary veins was successful with the laser and RF. In the trabeculated left atrium and the thick posterior right atrium, only laser ablation was successful.

Animals↗
PubMed2000

Circadian variation and onset mechanisms of ventricular tachyarrhythmias in patients with coronary disease versus idiopathic dilated cardiomyopathy.

To determine the circadian variations and the onset mechanisms of ventricular tachyarrhythmias (VT) in patients with implantable cardioverter defibrillators, stored electrograms of 364 VT episodes occurring in 40 patients with coronary artery disease (CAD) and in 29 patients with idiopathic dilated cardiomyopathy (DCM) were analyzed. A similar circadian distribution of VT episodes was observed in both groups, with a morning peak and less pronounced evening peak. After exclusion of patients with atrial fibrillation, VT onset was classified as (1) sudden if preceded by > or = 8 regular cycles without ventricular premature beats, (2) onset with a short-long-short interval, and (3) a more complex onset with variable patterns of ventricular premature beats before initiation of VT. Sudden onset was found in 26% and 21% of VTs in CAD and DCM respectively. A short-long-short interval preceded 29% of VTs in CAD compared to 14% of VTs in DCM (P < 0.05). A more complex onset was observed in the remaining 45% of VTs in CAD and 65% of VTs in DCM (P < 0.05). In conclusion, patients with DCM and CAD had similar circadian distributions of VT episodes. The majority of episodes were preceded by complex occurrence of ventricular premature beats rather than by the classic short-long-short sequence. These findings have important implications for the development of preventive pacing methods.

Cardiomyopathy, Dilated↗
PubMed2000

Relation between microvolt level T wave alternans and other potential noninvasive predictors of arrhythmic risk in the Marburg Cardiomyopathy Study.

The relation between microvolt level T wave alternans (TWA) and other noninvasive arrhythmia risk predictors was analyzed in 221 consecutive patients with idiopathic dilated cardiomyopathy (IDC) and sinus rhythm enrolled in the Marburg Cardiomyopathy Study between March 1996 and May 2000. TWA analysis was also performed in 110 healthy controls of similar age and sex. TWA during symptom-limited exercise was positive, negative and indeterminate in, respectively, 108 (49%), 65 (29%) and 48 (22%) patients with IDC versus, respectively, 5 (5%), 98 (89%) and 7 (6%) healthy controls (P < 0.05). Patients with IDC and positive TWA had a lower left ventricular (LV) ejection fraction (29 +/- 9% vs 34 +/- 10%, P < 0.05) and greater LV end-diastolic diameter (69 +/- 8 mm versus 64 +/- 6 mm, P < 0.05) than patients with negative TWA. Other variables, including age, gender, New York Heart Association functional class, presence of bundle branch block, arrhythmias on 24-hour ambulatory electrocardiogram, heart rate variability and baroreflex sensitivity, were not significantly different between patients with positive vs negative TWA. The prognostic significance of TWA in IDC with regard to arrhythmic events and total mortality will be determined by multivariate Cox analysis at the end of a 5-year follow-up in this ongoing study.

Adolescent↗
PubMed2000

Heart rate variability and baroreflex sensitivity in idiopathic dilated cardiomyopathy.

OBJECTIVE: To examine the relation between cardiac autonomic tone, assessed by baroreflex sensitivity and heart rate variability, and left ventricular function, arrhythmias on Holter monitoring, and clinical variables in patients with idiopathic dilated cardiomyopathy. DESIGN: A prospective observational study. PATIENTS: 160 patients with idiopathic dilated cardiomyopathy and preserved sinus rhythm in the absence of antiarrhythmic drug treatment. Measures of heart rate variability obtained by digital 24 hour Holter recordings included the mean of all coupling intervals between normal beats (RRm), the standard deviation of the mean of normal RR intervals (SDNN), and the square root of the mean of the squared differences between adjacent normal RR intervals (rMSSD). Baroreflex sensitivity testing was performed using the phenylephrine method. RESULTS: Mean SDNN (SEM) was 112 (46) ms, and baroreflex sensitivity was 7.5 (5.0) ms/mm Hg. SDNN showed a weak correlation with baroreflex sensitivity (r = 0.19, p < 0.05) and with left ventricular ejection fraction (r = 0.29, p < 0.05). SDNN showed no significant correlation with age (r = -0.07), the presence of non-sustained ventricular tachycardia (r = -0.13), or left ventricular end diastolic diameter (r = -0.07). In addition, baroreflex sensitivity showed no significant correlation with age (r = -0.13), non-sustained ventricular tachycardia (r = -0.08), left ventricular end diastolic diameter (r = 0.09), or ejection fraction (r = 0.14). CONCLUSIONS: The weak correlation between baroreflex sensitivity and heart rate variability suggests that these two indices explore different aspects of cardiac autonomic control in patients with idiopathic dilated cardiomyopathy. The weak or absent correlation between baroreflex sensitivity, heart rate variability, and other potential non-invasive risk predictors, including left ventricular ejection fraction, left ventricular end diastolic diameter, and non-sustained ventricular tachycardia on Holter monitoring, indicate that these variables may have independent prognostic value in idiopathic dilated cardiomyopathy.

Adolescent↗
PubMed2000

Induction of DNA single-strand breaks by 131I and 99mTc in human mononuclear blood cells in vitro and extrapolation to the in vivo situation.

The radionuclides (131)I and (99m)Tc are frequently used for therapy of benign and malignant thyroid disease ((131)I) and for diagnosis of thyroid and other diseases ((99m)Tc). However, the levels of DNA single-strand breaks (SSBs) induced in cells of patients after administration of (131)I and (99m)Tc are not known. In this study, we measured the number of SSBs per cell induced by (131)I and (99m)Tc in vitro, extrapolated the results to the clinical situation, and assessed their biological relevance by comparing levels of SSBs induced after therapeutic administration of (131)I and (99m)Tc to those induced by endogenous processes or by occupational exposure to genotoxic substances. A linear dose-response relationship between the radioactivity concentrations of (131)I and (99m)Tc and SSBs in human mononuclear blood cells (determined by alkaline elution) was obtained after incubation at 4 and 37 degrees C. At 4 degrees C, where almost no repair of SSBs takes place, (131)I and (99m)Tc induced 81 and 7 SSBs per cell per hour/(MBq/ml), respectively. At 37 degrees C, only 20 and 1.6 SSBs per cell per hour/(MBq/ml) were observed after incubation with (131)I and (99m)Tc. To estimate the induction of SSBs in vivo in cells of patients after administration of 3700 MBq (131)I (oral) or 60 MBq (99m)Tc (i.v.), the rates of induction of SSBs obtained in vitro were extrapolated to the concentrations of (131)I and (99m)Tc measured in blood of patients. The total number of SSBs (mean +/- standard deviation) accumulated after oral administration of 3700 MBq (131)I up to 70 h after administration was calculated as 200 +/- 59 SSBs/cell. After administration of 60 MBq (99m)Tc (i.v.), 0.032 +/- 0.009 SSBs per cell (total SSBs up to 2 h after administration) were cumulated. The induction of SSBs by endogenous processes (estimated 2,000 SSBs per cell per hour) and by occupational exposure to genotoxic substances (125-430 SSBs per cell) has been estimated in earlier studies. In conclusion, the frequency of SSBs induced by thyroid diagnosis with 60 MBq (99m)Tc is approximately 5 orders of magnitude smaller than the frequency of spontaneous SSBs and thus is most probably without biological relevance. Since the frequency of induction of SSBs by therapy with (131)I (3700 MBq) is about 6000-fold higher compared to thyroid diagnosis by (99m)Tc, its biological relevance is more difficult to assess. Nevertheless, the number of SSBs induced by therapy with (131)I is substantially lower than that induced by endogenous processes.

DNA Damage↗
PubMed1999

Heart rate variability in carcinoid heart disease.

Time domain heart rate variability measurements and echocardiographic studies were performed in 35 patients with carcinoid syndrome. Carcinoid heart disease was present in 18 patients (51%). Heart rate variability parameters (standard deviation of all normal RR intervals, percentage of the number of pairs of adjacent normal RR intervals differing by >50 ms) were significantly reduced in patients with than in those without carcinoid heart disease.

Adult↗
PubMed1999

Intrapericardial treatment of inflammatory and neoplastic pericarditis guided by pericardioscopy and epicardial biopsy--results from a pilot study.

From a registry of 136 patients undergoing pericardiocentesis, 14 patients with autoimmune and 15 patients with neoplastic effusions were selected. All underwent pericardioscopy, epicardial and pericardial biopsy with histologic, immunohistologic, and polymerase chain reaction/or in situ hybridization analysis for microbial DNAs and RNA. Pericardioscopy identified neoplastic effusions by the high occurrence of protrusions. Fibrin threads and layers and neovascularization were found in both groups. For identification of the inflammatory and neoplastic process, the combined analysis of the cytology of the effusion and epicardial biopsy evaluation proved to be most important. Epicardial biopsy demonstrated a slightly higher sensitivity for identifying neoplastic disorders in the pericardium than cytology alone. Pericardial biopsy was inconclusive. Intrapericardial administration of 1 g of crystalloid triamcinolone in autoreactive pericarditis prevented recurrence in 13 of the 14 cases after 3 months and in 12 of the 14 cases after 1 year. In neoplastic effusion, intrapericardial administration of 50 mg cis-platin for 24 h prevented recurrence of a hemodynamically relevant effusion after 3 months in all, and after 6-12 months in 14 of 15 patients. Mortality in neoplastic effusion due to noncardiac tumor progression was 47 and 80%, respectively, after 3 and 6 months, as can be expected in endstage neoplastic disease. This pilot study demonstrates that local drug application is feasible, life-saving, and well tolerated by the patients. It opens perspectives for local drug application in other cardiac disorders as well.

Adolescent↗
PubMed1999

[Prospective evaluation of effect of carvedilol therapy on heart rate variability in patients with dilated cardiomyopathy].

The aim of the present study was to assess the effects of carvedilol therapy in addition to conventional heart failure therapy on heart rate variability (HRV) and on left ventricular function in 14 patients with mild to moderate heart failure due to idiopathic dilated cardiomyopathy (IDC). After a 3- to 4-week titration period, carvedilol was titrated up to 50mg daily, or the highest dose tolerated (at least 25mg daily). Maintenance treatment was then continued for 8 weeks. Digital 24-hour Holter recordings were obtained at baseline and after 8 weeks of carvedilol therapy. HRV for the entire 24-hour period was computed in the time domain using the Oxford Medilog Excel 2 analysis system. Measures of HRV included the mean of all coupling intervals between normal beats (RRm), the standard deviation of all normal RR intervals (SDNN), the square root of the mean of the squared differences between adjacent normal RR intervals (rMSSD), and the proportion of adjacent normal RR intervals differing >50 ms (pNN50). Additional treatment with carvedilol induced a significant increase in HRV: SDNN increased from 77+/-21 ms to 110+/-22 ms (p=0.001), rMSSD from 19+/-7 ms to 26+/-7 ms (p=0.02), and mean pNN50-value increased from 1.7+/-1.3% to 5.5+/-4.5% (p<0.01) under therapy with carvedilol. Mean heart rate on carvedilol calculated over 24 hours was 13 beats less than at baseline (75 bpm versus 88 bpm, p<0.01). After 2 months of additional treatment with carvedilol, both hemodynamic and clinical parameters improved: left ventricular ejection fraction increased from 24+/-7% to 30+/-10% (p<0.05), and New York Heart Association class decreased from 2.5+/-0.8 to 1.8+/-0.7 (p<0.05). In summary, eight weeks of additional carvedilol therapy induced a significant increase in HRV parameters related to parasympathetic activity in patients with IDC. Whether increased vagal tone may contribute to the protective effect of carvedilol has to be evaluated by further studies.

Adrenergic beta-Antagonists↗
PubMed1999

A randomized controlled trial of the effect of fluid extract of Echinacea purpurea on the incidence and severity of colds and respiratory infections.

PURPOSE: Fluid extracts of Echinacea purpurea are widely used for the prevention and treatment of colds and respiratory infections, although the clinical efficacy of this agent has not been proven. PATIENTS AND METHODS: A total of 109 patients with a history of more than 3 colds or respiratory infections in the preceding year were randomly assigned to receive 4 mL fluid extract of Echinacea purpurea or 4 mL placebo-juice twice a day in a double-blind manner. (One patient withdrew his consent before taking the first dose of the allocated medication; thus, only 108 patients were included for analysis.) The incidence and severity of colds and respiratory infections were determined during 8 weeks of follow-up, based on patient reported symptoms together with findings on physical exam. The severity of each infection was graded by the investigators. Relative risks (RR) and 95% confidence intervals (CI) were estimated. RESULTS: During the 8-week treatment period, 35 (65%) of 54 patients in the Echinacea group and 40 (74%) of 54 patients in the placebo group had at least one cold or respiratory infection [RR = 0.88; 95% CI (0.60, 1.22)]. The average number of colds and respiratory infections per patient was 0.78 in the Echinacea group, and 0.93 in the placebo group [difference = 0.15; 95% CI (-0.12, 0.41), P = 0.33]. Median duration of colds and respiratory infections was 4.5 days in the Echinacea group and 6.5 days in the placebo group (95% CI: -1, +3 days; P = 0.45). There were no significant differences between treatment groups in the number of infections in each category of severity. Side effects were observed in 11 patients (20%) of the Echinacea group and in seven patients (13%) of the placebo group (P = 0.44). CONCLUSION: Treatment with fluid extract of Echinacea purpurea did not significantly decrease the incidence, duration or severity of colds and respiratory infections compared to placebo.

Adult↗