Significant Increase In HR Research Articles

Continuous Cardiac Autonomic and Hemodynamic Responses to Isometric Exercise.

Elevated arterial blood pressure (BP) is associated with autonomic dysfunction and impaired hemodynamic control mechanisms. Isometric exercise (IE) training has been demonstrated effective at reducing BP; however, the continuous cardiovascular responses during IE are underinvestigated. We hypothesized that reflex autonomic cardiovascular control is an important mediator in reducing BP. To test our hypothesis, we investigated continuous cardiac autonomic modulation and baroreceptor reflex sensitivity (BRS) in response to IE. Twenty-five prehypertensive participants performed a single IE wall squat training session. Total power spectral density (PSD) of HR variability (HRV) and associated low-frequency (LF) and high-frequency (HF) power spectral components were recorded in absolute (ms) and normalized units (nu) before, during, and after an IE session. HR was recorded via electrocardiography and BRS via the sequence method. Continuous BP was recorded via the vascular unloading technique and stroke volume via impedance cardiography. Total peripheral resistance was calculated according to Ohm's law. During IE, there were significant reductions in HRV (P < 0.05) and BRS (P < 0.05) and significant increases in HR (P < 0.001), systolic, diastolic, and mean BP (all P < 0.001). In recovery from IE, HRV (P < 0.001), HFnu (P < 0.001), and BRS (P < 0.001) significantly increased with a significant decrease in LFnu (P < 0.001) and LF:HF ratio (P < 0.001), indicative of predominant parasympathetic over sympathetic activity. This autonomic response was associated with a significant reduction in systolic (23.2 ± 18.1 mm Hg, P < 0.001), diastolic (18.7 ± 16.9 mm Hg, P < 0.001), and mean (15.8 ± 15.5 mm Hg, P < 0.001) BP, below baseline and a significant reduction in total peripheral resistance (P < 0.001). A single IE session is associated with improved cardiac autonomic modulation and hemodynamic cardiovascular control in prehypertensive males. These acute responses may be mechanistically linked to the chronic reductions in resting BP reported after IE training interventions.

Heart rate variability changes during and after the practice of bhramari pranayama

Background:Yoga is an ancient Indian science as well as the way of life. Pranayama is one of the most important yogic practices. Bhramari pranayama was shown to produce a reduction in blood pressure after the practice and thus reported to produce parasympathetic activity. However, there are no known studies reported the heart rate variability (HRV) changes either during or after the practice of Bhramari. Hence, this study aims at evaluating the HRV changes during and after the practice.Materials and Methods:Sixteen (9 males, 7 females) healthy volunteers with the mean ± standard deviation age of 23.50 ± 3.01 years were recruited. All the subjects performed Bhramari pranayama for the duration of 5 min. Assessments were taken before, during, and immediately after the practice of pranayama. Statistical analysis was performed using students paired samples t-test, Wilcoxon signed-ranks test and repeated measures of analysis of variance and Post-hoc analysis with Bonferroni adjustment for multiple comparisons.Results:Results of this study showed a significant increase in HR and low frequency spectrum of HRV and a significant reduction in high frequency spectrum of HRV during the practice of Bhramari which revert to normal after the practice.Conclusion:Results of this study suggests that there might be a parasympathetic withdrawal during the practice of Bhramari. However, further studies are required to warrant the findings of this study.

Bougie assisted endotracheal intubation using the Air-Q™ Intubating Laryngeal Airway: A prospective randomized clinical study

BackgroundAir-Q™ Intubating Laryngeal Airway is an extraglottic airway device used as a primary airway tool or as an adjunct to tracheal intubation. The bougie is a simple flexible device that might increase the success rate of endotracheal intubation either blindly or through a supraglottic device. We hypothesized that using bougie guided intubation through air-Q™ can improve the success rate with minimal complications.MethodsOne hundred and forty patients of either sex, >18 years old, ASA I-II scheduled for elective surgical procedures under general anesthesia with intubation were randomly allocated to one of two groups of 70 patients each. Blind tracheal intubation was performed through air-Q™ with bougie assistance (Group B) or without (Group Q). In both groups, 3 attempts were allowed for successful device insertion. After obtaining normal capnographic wave, 3 more attempts were tried for intubation with or without bougie guidance. Lung ventilation through air-Q™ was permitted between intubation attempts. If tracheal intubation through air-Q™ was unsuccessful, it was performed by direct laryngoscopy.ResultsAir-Q™ time, ease, attempts number of insertion and ventilation grade were comparable between both groups. Total intubation time was significantly longer in group-B (P = 0.001) while overall success rate for intubation was comparable (64.3%). Group-B showed significant (P = 0.001) higher incidence of complications (trauma (P = 0.023), sore throat (P = 0.001), dysphonia (P = 0.023) and dysphagia (P = 0.001)) as compared with group-Q. In spite of significant decrease in both heart rate and mean arterial pressure in both groups after air-Q™ insertion, yet there was significant increase in both parameters after intubation compared to baseline values (P < 0.05) which was more prominent in group-B than in group-Q. Significant increase in HR and MAP was elicited after bougie placement in group-B (P < 0.01).ConclusionBougie guided tracheal intubation through air-Q™ didn’t improve overall success rate with significant longer time, hemodynamic derangement and traumatic sequelae.

Electrocardiographic Studies in Propofol and Ketofol Anaesthesia Following Atropine, Diazepam and Fentanyl Premedication in Dogs

Twelve dogs of either sex presented to the college clinic with surgical were utilized to study the effect of ketofol and propofol after premedication with atropine sulphate, diazepam and fentanyl. The animals were divided into two groups of six animals each. Ketofol (1:1) combination was given intravenously in group I dogs. Propofol @ 6 mg/kg b.wt. intravenously was given in group II dogs. Induction quality was excellent, smooth and attained sternal recumbency rapidly without struggling in all animals in both groups. Recovery from anaesthesia was smooth and excitement free in both groups. However, slightly prolonged recovery was a consistent observation in propofol group. Non significant increase in HR was recorded in group I dogs. A significant decrease in HR was observed in dogs subjected to propofol anaesthesia. ECG studies did not reveal any abnormality except increase in amplitude of QRS complex duration in both groups. Ketofol with atropine, diazepam and fentanyl premedication provided better surgical anaesthesia with smooth induction and rapid, safe and smooth recovery in dogs.

A comparative study of efficacy of intravenous dexmedetomidine and intravenous esmolol for attenuation of stress response during laryngoscopy and endotracheal intubation

Background: The present study compares the effects of I.V. dexmedetomidine and I.V. esmolol on hemodynamic response occurring due to laryngoscopy and endotracheal intubation in elective general surgery. Methods: A total of 60 patients aged 18-60 years, American Society of Anesthesiologists physical status I or II, either sex, scheduled for elective surgical procedures were included in this study. Patients were randomly allocated by chit method into two equal groups of 30 each, comprising of group dexmedetomidine (group D) 1 μg/kg diluted with 0.9% saline to 10 ml I.V. over 10min and group esmolol (group E) 1 mg/kg diluted with 0.9% saline to 10 ml I.V. given just before induction. Heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure were recorded at baseline, after 5 min of infusion, after induction and at 1, 3, 5 and 10 min after endotracheal intubation. Results: In group D, there was no statistically significant increase in HR and blood pressure after intubation at any time intervals, where as in group E, there was a statistically significant increase in blood pressure and heart rate after intubation at 1, 3, 5 and 10 min. Conclusions: Dexmedetomidine 1 μg/kg is more effective than esmolol for attenuating the hemodynamic response to laryngoscopy and intubation in elective surgical patients.

Effect of Sub Maximal Dynamic and Static Exercises on QTc interval in Healthy Young Men.

The QTc interval depends largely on cardiac repolarization since the duration of cardiac depolarization is fairly constant in the normal heart. QTc at rest as well as during exercise has many clinical implications. In this study, we have compared the relative effects of dynamic and static exercise on QTc. To measure QTc interval in young men at rest and also assess how it is further modulated by submaximal dynamic and static exercises. This observational study was conducted in the Department of Physiology on 30 non-obese young men randomly selected from the students of our institute after obtaining the consent and institutional ethical clearance. Continuous blood pressure monitoring and ECG recording was done in the subjects. Baseline (pre-exercise), post submaximal dynamic (Harvard's step test) and post submaximal static exercise (hand-grip exercise) recordings of ABP and ECG were taken for analysis. The measured QT interval was corrected for heart rate using the formula of Bazett et al., {QTc=QT/RR(1/2)}.Statistical analysis was done using Graph pad Prism 5 software (California, USA). The baseline and post-exercise data were compared using paired t-test. A p<0.05 was taken to be statistical significant. There were statistically significant increases in HR, SBP, DBP and QTc interval after dynamic exercise in comparison to the baseline values (p<0.05). Significant increase in HR (p<0.05) with no significant change in QTc and other cardiovascular parameters were recorded following static exercise (p>0.05). Significant increase in QTc interval was observed after dynamic exercise, however, no change in QTc was observed following static exercise, and hence we conclude that static exercises may not be useful in assessing the cardiovascular status of an individual or in predicting cardiovascular events.

Comparative evaluation of dexmedetomidine and esmolol on hemodynamic responses during laparoscopic cholecystectomy.

The advent of laparoscopic surgery has benefited the patient and surgeon; however creation of pneumoperitoneum for same has bearings during the perioperative period. These effects of pneumoperitoneum are associated with significant haemodynamic changes, increasing the morbidity of the patient. The present study compared the efficacy of dexmedetomidine and esmolol on hemodynamic responses during laparoscopic cholecystectomy Materials and Methods: A total of 90 patients aged 20-60 y, American Society of Anaesthesiologists (ASA) physical status I or II, of either sex, planned for laparoscopic cholecystectomy were included. The patients were randomly divided into three groups of 30 each. Group D received dexmedetomidine loading dose 1 mcg/kg over a period of 15 min and maintenance 0.5 mcg/kg/h throughout the pneumoperitoneum. Group E received esmolol loading dose 1 mg/kg over a period of 5 min and maintenance 0.5 mg/kg/h throughout the pneumoperitoneum. Group C received same volume of normal saline. Heart rate (HR), systolic blood pressure, diastolic blood pressure and mean arterial pressure (MAP) were recorded preoperative, after study drug, after induction, after intubation, after pneumoperitoneum at 15 min intervals, post pneumoperitoneum and postoperative period after 15 min. Propofol induction dose, intraoperative fentanyl requirement and sedation score were also recorded. In group D, there was no statistically significant increase in HR and blood pressure after pneumoperitoneum at any time intervals, whereas in Group E, there was a statistical significant increase in MAP after pneumoperitoneum at 15, 45, and 60 min only and HR during the whole pneumoperitoneum period. There was a significant decrease in induction dose of propofol and intraoperative fentanyl requirement in Group D and E, compared to Group C (p<0.0001). Dexmedetomidine is more effective than esmolol for attenuating the hemodynamic response to pneumoperitoneum in elective laparoscopic cholecystectomy. Dexmedetomidine and esmolol also reduced requirements of anaesthetic agents.

Effect of fiberoptic intubation on myocardial ischemia and hormonal stress response in diabetics with ischemic heart disease

BackgroundDiabetic patients with ischemic heart disease can greatly benefit from decreasing the stress response to intubation with its metabolic sequelae. The use of fiberoptic bronchoscopy will eliminate the response to direct laryngoscopy while lubrication of ETT with lidocaine gel 2% will decrease the response to endotracheal intubation. This study was conducted to compare the stress response hormones (glucose, cortisol and c-peptide) and the hemodynamic responses to intubation between direct laryngoscopy and fiberoptic bronchoscopy in diabetic ischemic patients.Patients and methodsForty-four adult diabetic patients with ischemic heart disease, ASA II, with a blood glucose level between 120 and 180 mg/dL, requiring orotracheal intubation under general anesthesia were divided into 2 equal groups. The laryngoscopic group (n = 22) and the fiberoptic group (n = 22). Ovassapian airway was used to facilitate fiberoptic intubation with avoidance of jaw thrust maneuver. Blood glucose, cortisol and c-peptide were recorded before induction and 10 min after intubation and compared between both groups. The hemodynamic parameters were recorded and compared between both groups. Automated ST segment monitoring was used to detect ischemia.ResultsThere was statistically significant increase in HR, SBP and DBP in laryngoscopic group than in fiberoptic group. However, the incidence of ECG ST-segment changes was comparable with no statistically significant difference between groups. There were no statistically significant differences regarding glucose, cortisol and c-peptide levels between the study groups pre and post-induction. The intubation time in the fiberoptic group showed a statistically significant increase in comparison with the laryngoscope group (39 ± 12.04 vs. 29.3 ± 8.54 s; P < 0.05).ConclusionThe optimum use of fiberoptic bronchoscope with avoidance of jaw thrust maneuver attenuates the hemodynamic response to intubation which is beneficial in diabetic patients with ischemic heart disease. Stress response hormones showed no statistically significant difference between groups.

Comparative Effects of Caffeine &amp; L-theanine Consumption on Subjective Cardiovascular Signs and Neurophysiological Responses

Non-alcoholic beverages comprise of Caffeine and L-theanine as core ingredients. Caffeine is attributed to augment cardiovascular and neurophysiological responses by enhancing the neurotransmission of catecholamines after binding with adenosine receptors antagonistically. L-theanine, as a constituent of green tea is helpful in lowering blood pressure by antagonizing the effects of excitatory neurotransmitters after subsequent release of inhibitory neurotransmitter GABA. 87 healthy females with age 18-19 years, participated in the study were divided into three different groups. Group A was subjected to consume cold beverage (soft drink). Participants of group B & C were allowed to take hot beverages in the form of tea and green tea respectively. Cardiovascular parameters and neurophysiological responses were assessed before and after 45 minutes of beverages intake.Statistical analysis revealed a significant improvement in the reaction time of tea and in concentration test of both tea and green tea consumers. In addition, a less significant increase in HR with tremendous decrease in PR was observed among green tea consumers. Furthermore, significant reduction in both systolic & diastolic blood pressure was evident with green tea consumers.Experimental results are unveiling effectiveness of L-theanine over caffeine in lowering BP, HR & PR after antagonizing the release of excitatory neurotransmitter along with the opening of ligand gated chloride channels that leads to hyperpolarization. Moreover, a favorable combination of caffeine & L-theanine is responsible for enhancing cognitive performances, alertness and well being.

Macintosh laryngoscope versus Bonfils Intubation Endoscopes in endotracheal intubation: Hemodynamic, intra-ocular pressure and serum catecholamine responses

ObjectiveOne of the alternative methods in managing patients for endo-tracheal intubation is the Bonfils fiberscope. We studied the efficacy of Bonfils fiberscope in comparison to the classical laryngoscope with Macintosh blade inhemodynamic, serum catecholamine and intra-ocular pressure responses.MethodsIn a prospective, randomized trial 40 patients ASA I or II aged ⩾18 years scheduled for gynecological, urinary and lower abdominal procedures in supine position were randomly allocated to one of two groups; 20 patients each; according to intubating device by using either Macintosh laryngoscope (L) group or Bonfils Intubation Endoscopes (B) group. Pre-induction (baseline) and pre-insertion values of HR, MAP, IOP and blood samples for catecholamine level were recorded and repeated at 1, 3, and 5 min after intubation.ResultsThere was significant increase in HR, MAP, IOP and catecholamine level in L group at 1, 3, and 5 min after intubation.ConclusionBonfils laryngoscope had superiority over Macintosh as a method of intubation in situations where minimal changes in hemodynamic, catecholamine level and intraocular pressure are desirable.

Air-Q the Intubating Laryngeal Airway: Comparative study of hemodynamic stress responses to tracheal intubation via Air-Q and direct laryngoscopy

Background: Tracheal intubation is the gold standard for securing airway. Tracheal intubation through DLS produces marked hemodynamic stress responses. The Air-Q is a new supraglottic airway device. The purpose of this study was to determine whether endotracheal intubation through Air-Q is associated with lesser hemodynamic stress responses.Methods: 60 patients scheduled for elective surgery under general anesthesia requiring endotracheal intubation were randomly assigned into two groups. Direct laryngoscopy group and Air-Q group. Blood pressure and heart rate were recorded before, after induction, immediately after intubation and every minute for 4 min after intubation. The intubation time was recorded. Upon removal of the Air-Q, trauma to the upper airway was reported.Results: The intubation time was shorter in the DLS group compared with the Air-Q group (P value < 0.05). A significant reduction in BP was evident after the induction of anesthesia in both groups. Immediately after intubation, there was a significant increase in BP compared with the preintubation values. A decline was inspected between 1 and 4 min postintubation in both groups with significant difference immediately, at 1 and 2 min postintubation between the two groups. There were significant increase in HR immediately, at 1 and 2 min postintubation compared with the preintubation values, but there was no significant difference at each time point between two groups. Sore throat was more in the Air-Q group (P value <0.05).Conclusion: The hemodynamic stress response to intubation by Air-Q is less than that of DLS despite the longer duration of the former.

Increases in heart rate and systolic blood pressure in anesthetized dogs affected with X-linked muscular dystrophy after cisatracurium administration: a retrospective study

Most patients affected with Duchenne muscular dystrophy (DMD) present with arrhythmias and cardiomyopathies. Drugs which potentially may induce tachycardia or hypertension could precipitate acute cardiac failure in these patients and should be avoided. Thirty anesthesia records of five experimental male golden retriever cross-bred dogs affected with X-linked muscular dystrophy (GRDM), a model of DMD, were retrospectively reviewed (DMD group). Anesthesia records were compared with those of 10 golden retriever dogs not affected with muscular dystrophy (control group). Records were excluded if dogs received anticholinergics or vasoactive amines. Anesthesia was induced with fentanyl followed by propofol, both intravenously. After orotracheal intubation, all dogs' lungs were mechanically ventilated. Anesthesia was maintained with infusion of fentanyl and propofol (DMD group) or isoflurane in oxygen (control group). Pure O(2) was provided to the DMD group. Cisatracurium (0.1 mg·kg(-1) ) was administered intravenously to all dogs. Five-min interval recordings of HR and systolic blood pressures (SAP) were obtained. Immediately after the administration of cisatracurium, absolute values for HR and SAP significantly increased by 78.3 ± 37.0 b·min(-1) (115.4 ± 64.9%) and 33.0 ± 28.3 mmHg (33.5 ± 31.2%), respectively, in all DMD dogs and remained significantly increased for 10 and 30 min, respectively. Dogs in the control group did not show significant increases in HR or SAP after cisatracurium administration. All dogs recovered from anesthesia without complications. In this report, increases in HR and SAP could be associated with the administration of cisatracurium in individuals affected with X-linked muscular dystrophy. These cardiovascular changes deserve further investigation.

Smoking and Smoking Cessation in Relation to All-Cause Mortality and Cardiovascular Events in 25,464 Healthy Male Japanese Workers

Smoking is still a major health problem among males in Japan. The effects of smoking and quitting on mortality and cardiovascular disease (CVD) need updating. This was a prospective cohort study with a median follow-up of 7.5 years of a total of 25,464 healthy male Japanese workers aged 20-61 years who were not on any medication. The adjusted hazard ratios (HR; 95% confidence interval) for all-cause death were 1.51 (0.73, 2.94), 1.68 (1.07, 2.70), 1.30 (0.70, 2.34), and those for total CVD events 1.91 (0.72, 4.67), 2.94 (1.65, 5.63), and 3.25 (1.69, 6.54) for light smokers (1-10 cigarettes/day), moderate smokers (11-20/day), and heavy smokers (≥ 21/day) compared to never-smokers, respectively. Total CVD events increased dose-dependently as the number of cigarettes/day increased. Acute myocardial infarction was increased at any level of smoking. Stroke was increased at a moderate level of smoking. Quitting for ≥ 4 years, compared with continuing smokers, reduced the HR for all-cause death to 0.64 (0.38, 1.01), and total CVD events to 0.34 (0.17, 0.62). In healthy young- and middle-aged Japanese males, a significant increase in HR for total CVD events was confirmed for a smoking level of 11-20 cigarettes/day. Quitting reduced the HR for total CVD events, with quitting for ≥ 4 years being statistically significant. A similar trend was observed for all-cause mortality.

Cardiovascular behavior during rehabilitation after coronary artery bypass grafting

The aim of the present study was to assess the behavior of cardiovascular variables during an in-hospital cardiovascular rehabilitation program in patients following myocardial revascularization surgery.A total of 14 patients (mean age: 55.4 ± 6.4 years, 78.6% male) participated in the study, all of whom had a previous diagnosis of coronary insufficiency and indication for elective surgery. The protocol consisted of a group of low-impact (2-3 METs) upper/lower extremity and walking exercises performed both pre and post-operatively (3rd and 4th days). The following variables were evaluated at rest and following the exercise program: heart rate (HR, bpm); systolic arterial pressure (SAP, mmHg); diastolic arterial pressure (DAP, mmHg); mean arterial pressure (MAP, mmHg); double product (DPr, bpm/mmHg); and the Rating of Perceived Exertion (RPE) scale.There was a significant increase in HR and DPr in the individual analysis (P<0.001) as well as in between days (P<0.001 for HR and P<0.05 for DPr), but only attaining maximal values that were ≤ 30% of predicted. Moreover, a negative correlation was found between the RPE scale and both SAP and MAP.The exercises proposed proved to be safe with the change in key physiologic variables throughout the experiment below recommended values for the hospitalization phase. Furthermore, the RPE scale appears to have a correlation with some hemodynamic variables and thus may be a useful tool for this group of patients.

Pro72 Allele Potentially Increases the Poor Prognostic Value of p53 Mutations In Chinese Patients with Chronic Lymphocytic Leukemia.

AbstractAbstract 4612 Background:The poor prognosis of chronic lymphocytic leukemia (CLL) patients with del(17p13) is well established. Association of p53 mutations and its codon 72 polymorphism with CLL prognosis has been studied. However, there is no study on p53 mutations in Chinese patients with CLL to date, and the joint effect of p53 mutations and p53 codon 72 polymorphism on the prognosis of CLL remains uncertain. Methods:The frequency of p53 codon 72 genotype and the p53 mutations status were assessed by direct sequencing and correlated with clinical outcome in 180 CLL patients. p53 deletions of 168 patients were detected by interphase fluorescence in situ hybridization (FISH). Results:1. p53 mutations were detected in 17.8% (32/180) of samples. Most patients with del(17p13) had p53 mutations (73.7%; 14/19) and mutations in the absence of del(17p13) were found in 10.7% (18/168) in our cohort, which were much higher than other countries. The frequencies of p53 Arg72Pro genotypes were similar across the control (Arg/Arg: 29.6%; Arg/Pro: 50.5%; Pro/Pro: 19.9%) and patient groups (Arg/Arg: 28.3%; Arg/Pro: 45.6%; Pro/Pro: 26.1%). 2. Compared with cases without p53 mutations, p53 mutations were associated with advanced stages (P<0.001), unmutated immunoglobulin heavy-chain variable region (IGHV) status (P=0.016) and chemorefractoriness (P<0.001). The Pro/Pro genotype was associated with an increased incidence of p53 mutations (P=0.003) and deletions (P=0.02) but did not appear to influence other biological behavior or clinical response. Compared to the cases with p53 wild-type, patients with p53 mutations and Pro72 allele (Arg/Pro + Pro/Pro genotypes) were associated with advanced stages (P=0.002) and chemorefractoriness (P<0.001) but not with p53 mutations and Arg/Arg. 3. Survival analysis showed that the occurrence of p53 mutations and del(17p13) were associated with shorter overall survival (OS). Mean OS for patients with p53 mutations was 83.2 months (95% CI, 61.6–104.8 months), whereas mean OS for patients without p53 mutations was 148.8 months (95% CI, 134.5–163.1 months) (P <0.001). Mean OS for patients with del(17p13) was 58.7 months (95% CI, 39.1–78.4 months) versus 142.5 months (95% CI, 128.2–156.9 months) for patients devoid of del(17p13) (P<0.001). Binet stages B+C (P=0.026), p53 deletions (P=0.01), and p53 mutations (P=0.014) were the variables strongly associated with OS by multivariate Cox regression analysis. The p53 codon 72 polymorphisms did not influence OS in the entire patient group. But there was significant difference in OS among p53 mutations with Arg/Arg homozygotes and Pro72 allele (P=0.046). When patients with p53 wild-type and p53 codon 72 Arg/Arg genotype were selected as a reference (HR = 1.00), patients with p53 mutation and p53 codon 72 Arg/Arg genotype did not show a significant increase in HR for OS (HR = 1.82; 95% CI 0.16–20.13; P = 0.628). Notably, patients with both p53 mutation and p53 codon 72 Pro72 allele experienced a 10.5-fold HR for OS (95% CI 2.13–51.8; P = 0.004). Similarly, there was statistically significant influence on OS among p53 mutation and p53 codon 72 Pro/Pro genotype (HR = 7.73; 95% CI 1.39–43.03; P = 0.02). 4. We also found that cases with p53 mutations in the absence of del(17p13) had a similar clinical and biological course and similar poor short OS as cases carrying del(17p13) in Chinese population. Compared with CLL without p53 disruptions, cases harboring del(17p13) or isolated p53 mutations, uniformly displayed an unmutated IGHV status (P=0.014), Binet stages B+C (P=0.003) and chemorefractoriness (P=0.009). Survival analysis also showed that the patients with isolated p53 mutations had significantly shorter OS (mean, 95.3 months) (95% CI, 72.3–118.3 months) than the patients without p53 disruptions (P=0.014). Conclusion:Our study showed that cases with p53 mutations and p53 mutations without del(17p13) may be adverse prognostic factors in Chinese CLL cohort. Moreover, p53 Pro72 allele potentially increases the prognostic value of p53 mutations in CLL. Disclosures:No relevant conflicts of interest to declare.

Regadenoson, a Novel Pharmacologic Stress Agent for Use in Myocardial Perfusion Imaging, Does Not Have a Direct Effect on the QT Interval in Conscious Dogs

Our goal was to determine the effect of regadenoson (a novel A2A adenosine receptor agonist) on the QT interval in conscious dogs. Sixteen mongrel dogs were chronically instrumented for measurements of blood pressure and ECG. Regadenoson (2.5, 5, and 10 microg/kg, IV) caused a dose-dependent QT interval shortening (DeltaQT: 14 +/- 3, 24 +/- 5, and 27 +/- 5 ms, mean +/- SEM; n = 7 to 11; all P < 0.05) associated with significant increases in HR (Peak HR: 114 +/- 9, 125 +/- 6, and 144 +/- 7 bpm). Atrial pacing (135, 150, and 165 bpm) also caused a frequency-dependent shortening of the QT interval (DeltaQT: 15 +/- 3, 22 +/- 3, and 39 +/- 5 ms; n = 6 to 7; all P < 0.05). Regadenoson- and pacing-induced shortenings in the QT interval were significantly correlated with the R-R interval (r = 0.67 and 0.8, both P < 0.05). Regadenoson at 5 and 10 microg/kg did not cause a significant change in HR or QT interval either during atrial pacing at 165 bpm or after administration of propranolol and atropine to prevent HR from changing or after treatment of dogs with hexamethonium to block autonomic ganglia. Regadenoson (5 to 10 microg/kg) caused no significant changes of QT interval in the heart in which HR was kept constant via physiological or pharmacological procedures, indicating that regadenoson has no direct effect on the QT interval.

Effects of Fire Fighting Gear on Physiological and Perceptual Responses to Short-Term Fire Fighting Activity

Firefighters (FF) routinely perform arduous work in extreme environmental temperatures, thus they require protective clothing. However, the weight and encapsulating nature of the clothing can add to the thermal and cardiovascular strain of a firefighter. PURPOSE: The purpose of this study was to examine the effect of fire fighting gear on the physiological and perceptual responses to an acute bout of fire fighting activity. METHODS: Male FF (N=50) between the ages of 18-50 yrs who were free of known cardiovascular disease participated in 18 minutes of simulated fire fighting activity (stair climbing, forcible entry, searching, advancing a line) in a training structure that contained live fires. Participants were assigned to one of two gear ensembles: standard (n=25) or enhanced (n=25), both of which meet NFPA 1971 standards. The standard gear (avg. wt. 11 kg) consisted of bunker gear with a spun Nomex® lining, a Kevlar fully-encapsulating hood, leather gloves, rubber boots and a traditional-style helmet. The enhanced gear (avg. wt. 8.6 kg) consisted of bunker gear with an Indura FR cotton lining, which circulated exhaled air from the firefighter to the coat's inner lining, a Nomex® hood, a low-profile helmet, leather gloves, and lightweight leather boots. Physiological and perceptual measures were obtained immediately before and after fire fighting activities. RESULTS: There was no significant difference between the descriptive measures (age, ht, wt, BMI) of fire fighters assigned to the two gear ensembles. Performing fire fighting activity resulted in significant increases in HR (~80 b·min-1), Tco (~1.2oC), and Tskin-arm (~5.1oC), but there were no significant differences between the increases observed in the two gear ensembles. Perceptions of temperature (using a thermal sensations scale) and respiration (using a respiratory distress scale) increased significantly as a result of fire fighting activity, but there was no difference between post firefighting values, nor were there any differences in RPE post firefighting, as a function of gear ensemble. CONCLUSION: Fire fighting resulted in significant physiological and perceptual changes; however, the effects of the gear ensemble were small compared to the effects of the fire fighting activity itself. This study was supported by DHS AFG EMW-2006-FP-02459

Methylphenidate appears to be associated with small but statistically significant increases in HR and BP in children with ADHD

Methylphenidate appears to be associated with small but statistically significant increases in HR and BP in children with ADHD

Methylphenidate appears to be associated with small but statistically significant increases in HR and BP in children with ADHD

Methylphenidate appears to be associated with small but statistically significant increases in HR and BP in children with ADHD

Dual sensor pacemakers in children: what is the choice of sensor blending?

Dual sensor pacemakers were developed to obtain more appropriate responses to activity. We evaluated ten children with dual sensor pacemakers in different sensor blending circumstances using exercise testing to assess which ratio was optimal. Ten patients with several bradydysrhythmias (ages 6-16 years; mean 10.1 years) were included in the study. Eight patients had VVIR pacemakers (Vitatron Topaz), models and two patients had VDD pacemakers implanted via the transvenous route. All patients were in a paced rhythm (98.5% pacing). Accurate T wave sensing ranged from 81%-100%; mean 92%, median 95%. Voluntary exercise testing with a CAEP protocol was performed using a treadmill with the pacemaker in VVIR mode. Medium activity threshold with three sensor blending ratios (QT = ACT, QT > ACT, and QT < ACT) were done in all patients. The mean duration of exercise was not statistically different among the three sensor blending ratios. After 90 seconds of exercise, the mean pacing rate had increased by 12%, 3%, and 5%, respectively, in the three groups. At maximal exercise, the increases were 45%, 42%, and 54%. Mean HRs during exercise in each of the three ratios were not significantly different, although we found a statistically significant increase in HR during the first two stages of rest period in the QT = ACT sensor blending ratio compared to the QT > ACT ratio. No difference was observed after the second stage. (1) there is no difference between the QT = ACT, QT < ACT, and QT > ACT sensor blending ratios; and (2) each child has to be evaluated by exercise testing to program a correct sensor blending ratio.