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Electrocardiogram Recordings (electrocardiogram + recording)
Selected AbstractsCharacteristics of Heart Rate Variability Can Predict Impending Septic Shock in Emergency Department Patients with SepsisACADEMIC EMERGENCY MEDICINE, Issue 5 2007Wei-Lung Chen MD ObjectivesTo determine whether heart rate variability (HRV) measures can be used to predict which septic patients in the emergency department (ED) will progress to septic shock. MethodsThe authors prospectively enrolled consecutive patients who met the 2001 International Sepsis Definitions Conference criteria of sepsis and visited the ED of a university teaching hospital over a six-month period. In addition to the septic workup, a continuous 10-minute electrocardiogram recording was performed at the same time. The HRV measures were calculated off-line and correlated with the outcome of the patients. ResultsEighty-one patients aged 30,84 years who met the inclusion criteria were enrolled. The patients were classified as those with no septic shock (n= 60) and those with septic shock (n= 21), according to their outcome within six hours. The baseline root mean square successive difference, high-frequency power, and normalized high-frequency power of the septic shock group were significantly higher than those of the no septic shock group. The low-frequency power, normalized low-frequency power, and low-/high-frequency power ratio of the septic shock group were significantly lower than those of the no septic shock group. Multiple logistic regression analysis identified root mean square successive difference as the best predictor of impending septic shock for septic ED patients. ConclusionsHRV measures may be used to identify septic ED patients with impending septic shock. Among those HRV measures, root mean square successive difference seems to be the best indicator to predict the occurrence of septic shock. [source] Endurance exercise is associated with increased plasma cardiac troponin I in horsesEQUINE VETERINARY JOURNAL, Issue S36 2006T. C. HOLBROOK Summary Reason for performing study: Information is lacking regarding the influence of long distance exercise on the systemic concentration of cardiac troponin I (cTnl) in horses. Objectives: To determine if the concentration of cTnl in horses competing in 80 and 160 km endurance races increases with exercise duration and if cTnl concentrations can be correlated with performance data. Methods: Blood samples for the measurement of cTnl and 3 min electrocardiogram recordings were obtained from horses prior to, during and after completion of 80 and 160 km endurance races at 3 ride sites during the 2004 and 2005 American Endurance Ride Conference competition seasons. Results: Full data sets were obtained from 100 of the 118 horses. Endurance exercise was associated with a significant increase in cTnl over baseline in both distance groups. Failure to finish competition (poor performance) was also associated with an increased cTnl concentration over baseline at the time of elimination when data from both distances were combined. Other than one horse that developed paroxysmal atrial fibrillation, no arrhythmias were noted on the 3 minute ECG recordings that were obtained after endurance exercise in either distance group. Conclusions: Systemic concentrations of cTnl increase in endurance horses competing in both 80 and 160 km distances. Although final cTnl concentrations were significantly increased over their baseline values in horses that failed to finish competition, the degree of increase was not greater than the increase over baseline seen in the horses that successfully completed competition. The clinical significance of increased cTnl in exercising horses could not be ascertained from the results of this study. Potential relevance: These data indicate that cardiac stress may occur in horses associated with endurance exercise. Future studies utilising echocardiograpy to assess cardiac function in horses with increased cTnl are warranted. [source] Sex Differences in the Effect of Heart Rate on Mortality in the ElderlyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 9 2003Gila Perk MD Objectives:, To examine the association between heart rate and mortality risk in the elderly. Design:, Longitudinal cohort. Setting:, Outpatient. Participants: Four hundred twenty-two people, aged 70 upon entry, were surveyed and followed for 6 years. Measurements: Pulse rate was measured manually, while sitting and standing, and heart rate was measured from electrocardiogram recordings. The population was divided into quartiles of heart rate, with the top quartile comprising those with heart rate greater than 77 beats per minute (bpm) and the bottom quartile those with heart rate less than 60 bpm. Results: After controlling for possible confounders, there was a clear correlation (r) between heart rate and all-cause mortality in elderly women (r=0.25, P=.0003). The correlation in women was observed using the three different methods for measuring heart rate. Heart rate was associated with all-cause and cardiovascular mortality. There was no relationship between heart rate and level of exercise or smoking status. In multiple regression analysis, the increased risk of death in the women was independent of previous cardiovascular or cerebrovascular disease, hypertension, anemia, congestive heart failure, smoking, and level of exercise or activities of daily living (relative odds ratio (ROR)=3.37, 95% confidence interval (CI)=0.96,11.8). When women using beta-blockers were excluded, this relationship became even stronger (ROR=8.5, 95% CI=1.19,60.1). Conclusion: Elevated heart rate is related to increased mortality in elderly women, thus representing a simple index of general health status in this population. Elevated heart rate did not predict mortality in elderly men. [source] Lack of correlation between canine heart rate and body size in veterinary clinical practiceJOURNAL OF SMALL ANIMAL PRACTICE, Issue 8 2010L. Ferasin Objectives: An association between heart rate (HR) and bodyweight has been reported in dogs and it is common belief that small breeds of dog exhibit higher HR than large breeds. The first aim of this study was to test the null hypothesis that, in veterinary clinical practice, bodyweight does not affect HR measured in healthy dogs. A second objective of this investigation was to assess whether other variables, such as gender, breed morphology, age and demeanour, may have a significant effect on dog's HR measured in a clinical setting. Methods: The investigation was performed via two different studies: a retrospective analysis performed on 243 electrocardiogram recordings and a prospective study based on 153 standardised clinical examinations. Results: The two separate studies did not show any significant correlation between HR and bodyweight (P=0·5705 and P=0·4682, respectively). Subject's breed morphology and gender did not appear to affect HR measured under these circumstances. However, dogs under the age of one year seem to have significantly higher HRs than older dogs (P < 0·05). Finally, subject's demeanour was also found to have a significant influence on HR; lower values were recorded in relaxed dogs, and higher rates were documented in excited, nervous dogs (P < 0·05). Clinical Significance: Normal HR could be erroneously interpreted as bradycardia or tachycardia if bodyweight was to be considered a determinant factor. Instead, HR in healthy dogs undergoing routine clinical examination is related to their demeanour or age, if younger than 12 months, but does not appear to be related to bodyweight. [source] Anterior Mitral Valve Length is Associated with Ventricular Tachycardia in Patients with Classical Mitral Valve ProlapsePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2010MURAT AKCAY M.D. Background: The aim of this study was to investigate the electrocardiographic and echocardiographic predictors of ventricular tachycardia (VT) in patients with classical mitral valve prolapse (MVP). Methods: Thirty patients (nine men and 21 women; mean age, 41.5 ± 15 years) in sinus rhythm with mitral valve prolapse who had VT in 24-hour Holter analysis and 30 patients with MVP without VT (eight men and 22 women; mean age, 43 ± 16 years) were included in this study. Transthoracic echocardiography, QT analyses from 12-lead electrocardiography, and 24-hour Holter electrocardiogram recordings were performed. Results: Mitral posterior leaflet thickness (0.48 ± 0.03 cm vs 0.43 ± 0,08 cm, P = 0.025), mitral anterior leaflet length (3.2 ± 0.24 cm vs 2.9 ± 0.36, P < 0.001), mitral posterior leaflet length (2.2 ± 0.3 cm vs 1.9 ± 0.35 cm, P = 0.01), left atrium anteroposterior diameter (4.2 ± 0.8 cm vs 3.5 ± 0.5 cm, P = 0.001), and mitral annulus circumference (15.7 ± 1.3 cm vs 14.6 ± 1.6 cm, P = 0.004) were increased significantly in MVP cases with VT. No significant difference was found between the cases with and without VT in terms of frequency- and time-domain analysis. QT dispersion (72 ± 18 ms vs 55 ± 15 ms, P = 0.0002) and corrected QT dispersion (QTcD) (76 ± 18 ms vs 55 ± 15 ms, P = 0.0002) were significantly increased in cases with VT compared with those without VT. Based on logistic regression analysis for MVP cases, in the case of VT, an enhancement in QTcD (P = 0.01) and the mitral anterior leaflet length (P = 0.003) were the independent predictors of VT. Conclusion: Mitral anterior leaflet length and enhanced QTcD are closely related with VT in patients with classical MVP. (PACE 2010; 33:1224,1230) [source] QT Interval Variability and Adaptation to Heart Rate Changes in Patients with Long QT SyndromePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2009JAN N, MEC M.D. Background: Increased QT variability (QTV) has been reported in conditions associated with ventricular arrhythmias. Data on QTV in patients with congenital long QT syndrome (LQTS) are limited. Methods: Ambulatory electrocardiogram recordings were analyzed in 23 genotyped LQTS patients and in 16 healthy subjects (C). Short-term QTV was compared between C and LQTS. The dependence of QT duration on heart rate was evaluated with three different linear models, based either on the RR interval preceding the QT interval (RR0), the RR interval preceding RR0 (RR -1), or the average RR interval in the 60-second period before QT interval (mRR). Results: Short-term QTV was significantly higher in LQTS than in C subjects (14.94 ± 9.33 vs 7.31 ± 1.29 ms; P < 0.001). It was also higher in the non-LQT1 than in LQT1 patients (23.00 ± 9.05 vs 8.74 ± 1.56 ms; P < 0.001) and correlated positively with QTc in LQTS (r = 0.623, P < 0.002). In the C subjects, the linear model based on mRR predicted QT duration significantly better than models based on RR0 and RR -1. It also provided better fit than any nonlinear model based on RR0. This was also true for LQT1 patients. For non-LQT1 patients, all models provided poor prediction of QT interval. Conclusions: QTV is elevated in LQTS patients and is correlated with QTc in LQTS. Significant differences with respect to QTV exist among different genotypes. QT interval duration is strongly affected by noninstantaneous heart rate in both C and LQT1 subjects. These findings could improve formulas for QT interval correction and provide insight on cellular mechanisms of QT adaptation. [source] Investigational New Drug-Directed Toxicology and Pharmacokinetic Study of 4-[3-(2-Nitro-1-Imidazolyl)-Propylamino]-7-Chloroquinoline Hydrochloride (NLCQ-1, NSC 709257) in Beagle DogsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2010Maria V. Papadopoulou The present study is one of several pre-clinical toxicology studies conducted in support of an ,investigational new drug' (IND) application to test this agent as an adjuvant to radio/chemotherapy for the treatment of cancer in humans. Twenty-four dogs were each assigned to one vehicle control group or to one of three test article-treated groups (three dogs/sex/treatment group). Intravenous (i.v.) doses of 0, 2.74, 5.48 and 10.95 mg/kg/day (54.8, 109.6 or 219 mg/m2/day) were administered on a per day × 5 days (qd × 5) schedule. NLCQ-1 was formulated as a solution in sterile saline at 1.5 mg/ml. None of the dogs died during this 33-day study. With few exceptions, most of the clinical signs of toxicity were noted within 2 hr following dosing in the 10.95 mg/kg/day dose group. These observations included aggressive behaviour, ataxia, tachypnea, emesis, hypoactivity, excessive salivation, tremors, and involuntary urination and defecation. Aggressive behaviour was judged to be dose-limiting. No clinical signs of toxicity were noted during the 28-day observation period that followed the 5-day dose period. Findings in a functional observation battery examination were consistent with the clinical observations. No drug-related effects were noted on the body weight or food consumption values, and no drug-related changes were noted during ocular examinations made on these animals prior to scheduled necropsy or during examination of electrocardiogram recordings made at 15 min. and 2 hr after dosing on days 1 and 5. No definitive changes in haematology, clinical chemistry or coagulation values were noted in dogs treated with NLCQ-1. NLCQ-1 was detected in the plasma of treated dogs on days 1 and 5, up to 60 min. after dosing (2.74 and 5.48 mg/kg/day) and up to 8 hr after dosing (10.95 mg/kg/day). There was a dose-related increase in maximum plasma concentration of NLCQ-1 at 5 min. after dosing; comparable concentrations were noted on days 1 and 5. No definitive test article-related lesions were noted during microscopic evaluation of tissues from dogs in this study, although lesions noted at the injection site and in the vascular tissue, lungs, thymus, prostate gland, muscle, adrenal cortex and tongue may have resulted from treatment with this drug. Any drug-related toxicity noted was readily reversible and not cumulative. No sex difference was detected in the susceptibility to NLCQ-1-induced toxicity. [source] | ||||||||||