Presence Of Tachycardia Research Articles

The class III effect of azimilide is not associated with reverse use-dependence in open-chest dogs.

Certain class III antiarrhythmic agents manifest loss of effect at short cycle lengths (CLs). This effect may limit their efficacy in the presence of tachycardia. We studied the frequency-dependent effect of azimilide (NE-10064), a new class III agent, on the right ventricular monophasic action potential (APD90) in 12 open-chest dogs. The monophasic action-potential duration at different pacing CLs (140-400 ms), during sinus rhythm, and ventricular fibrillation CL (VFCL) from left epicardial electrograms were recorded before and after increasing doses of intravenous azimilide. At pacing CL of 400 ms, APD90 was significantly prolonged after 7, 17, and 30 mg/kg of azimilide by 5.4, 7.7, and 10.7%, respectively. The extent of APD90 prolongation was independent of rate. Azimilide increased the APD90 by similar amounts at CL of 400 ms and at the fastest possible stimulation rate maintaining 1:1 capture (mean, 171 +/- 23 ms): by 2.6 +/- 8.6% and 5.6 +/- 5.9% at 2 mg/kg, 5.4 +/- 4.8% and 4.8 +/- 4.7% at 7 mg/kg, 7.7 +/- 5.6% and 9.9 +/-4.5% at 17 mg/kg, and 10.7 +/- 2.6% and 19.3 +/- 11.9% at 30 mg/kg, respectively. Azimilide caused no changes in arterial blood pressure or heart rate. Azimilide prolongs APD90 even at very short CLs. The absence of reverse use-dependence of effect on APD90 may have clinical importance.

Relative bradycardia in patients with traumatic hypotension.

Tachycardia is considered a physiologic response to traumatic hypotension. The inability of the heart to respond to shock with tachycardia has been described as paradoxical bradycardia or relative bradycardia. The incidence and clinical significance of this condition in major trauma is not known. The objective of this study was to examine the incidence and prognostic significance of tachycardia and relative bradycardia in patients with traumatic hypotension. Relative bradycardia is defined as a systolic pressure < or = 90 mm Hg and a pulse rate < or = 90 beats per minute. This is a retrospective study conducted at a large Level I academic trauma center during a 4-year period. Seventeen demographic and injury severity factors were analyzed for their possible role in tachycardic or bradycardic response in hypotensive patients. Incidence and mortality were derived for each subpopulation. Bivariate analysis of the association of incidence and mortality with each risk factor was performed. Factors with p values < 0.2 were included in stepwise logistic regression analyses that identified significant risk factors and derived adjusted relative mortality risks between tachycardic and bradycardic hypotensive patients. Excluding transfers and patients dead on arrival, 10,833 major trauma patients were seen during the study period. Seven hundred fifty patients (6.9%) had systolic blood pressure < or = 90 mm Hg; 533 patients had tachycardia (overall incidence of 4.9%, or 71.1% of hypotensive patients), and 217 patients had bradycardia (overall incidence of 2.0%, or 28.9% of hypotensive patients). The overall crude mortality was 29.2% among tachycardia patients and 21.7% among bradycardia patients (crude relative risk = 1.34; 95% confidence interval = 1.00-1.81; p = 0.047). The adjusted relative mortality risk between the two groups was 1.23 (95% confidence interval = 0.84-1.73; p = 0.284). Multivariate analysis showed that patients with relative bradycardia in the subgroups with Injury Severity Scores > or = 16, chest Abbreviated Injury Scale scores > or = 3, or abdominal Abbreviated Injury Scale scores > or = 3 had significantly better survival than patients with similar injuries presenting with tachycardia. Relative bradycardia in hypotensive trauma patients is a common hemodynamic finding. Mortality among tachycardic patients was more predictable than among bradycardic patients using commonly used demographic and injury indicators. The presence of relative bradycardia in some subgroups of patients with severe injuries seems to be associated with better prognosis than the presence of tachycardia.

Can the need for a physician as part of the pediatric transport team be predicted? A prospective study.

To evaluate the quality of objective information obtained during telephone requests for the transport of pediatric patients. To evaluate the ability of subjective judgment, the Pediatric Risk of Mortality (PRISM) score, and the presence of tachycardia for age to predict the need for a physician on as a member of the pediatric transport team. Prospective data collection. The pediatric transport program of a children's hospital. All 129 infants and children transported over a 4-month period. We defined an objective measure of the need for a physician's presence during the transport of a pediatric patient, based on either the necessity for procedural or medical interventions during the time of transport or on direct admission to the pediatric ICU after transport. At the time of initial telephone contact, a physician's subjective opinion of the need for physician presence was recorded, a PRISM score was derived, and the presence of tachycardia (adjusted for age) was determined. Subsequently, the vital signs recorded on the record of this request were compared with those vital signs charted at the referring hospital at the time of the initial telephone request. A total of 96% of vital signs obtained during the initial telephone contact were consistent with those percentages in the referring hospital medical records. Fifty (39%) of 129 transported patients required procedural or medical interventions or pediatric ICU admission. Subjective judgments predicted physician need with a high sensitivity (0.98), but with a low specificity (0.18). PRISM score predicted 62 (48%) of 129 transports to be "physician-required" (sensitivity = 0.72; specificity = 0.67). There was no statistical association between tachycardia for age and the objective need for a physician's presence. Objective information obtained during request for transfer was reliable. At the time of request for transfer, subjective judgment, PRISM score, and the presence of tachycardia did not predict the need for a physician presence during transport.

Evaluation of variable decelerations of fetal heart rate with the deceleration index: influence of associated abnormal parameters and their relation to the state and evolution of the newborn

The deceleration index of the Fetal heart rate (FHR) (Acién P. et al. (1979) J. Perinat Med 7, 7–18) was used to analyze 157 cardiotocographic registers that displayed variable deceleration during labor. We have related the deceleration index value to perinatal results and to other abnormal parameters of FHR. An increase in neonatal pathology was observed in the deceleration group compared to a group of 50 controls with normal FHR, when the deceleration index was greater than 150 and specially if it was greater than 200. The association of other abnormal parameters of FHR (especially absence of variability between or during decelerations, absence of transitory ascents, presence of tachycardia and, of less importance, absence of ascents at the beginning of deceleration or presence of overshoot acceleration following deceleration) yields a worse prognosis for the fetus than does an increased deceleration index alone. The deceleration index is a good method for evaluation of variable decelerations of FHR, and is well correlated to the condition of the newborn.

Noninvasive estimation of peak pulmonary artery pressure by M-mode echocardiography

In an attempt to predict peak pulmonary artery pressure from routine M-mode echocardiographic tracings, 95 infants and children with congenital heart disease were examined. Following the Burstin method for prediction of peak pulmonary artery pressure, which was originally based on the phonocardiogram and jugular phlebogram, M-mode echocardiography was used to measure the interval from pulmonary valve closure to tricuspid valve opening, namely, the period of isovolumic diastole. The measured interval was plotted on a modified table relating the interval, heart rate and predicted peak pulmonary artery pressure. The peak pulmonary artery pressure predicted by echocardiography was compared with that measured at cardiac catheterization. The correlation between predicted and actual peak pulmonary artery pressure was good (r = 0.86) for routine studies with the patient in the nonsedated state. All patients with a predicted peak pressure less than 40 mm Hg were found at catheterization to have a pressure less than 40 mm Hg. The correlation was better (r = 0.96) when comparing predictions made from the echocardiogram obtained while the patient was sedated for catheterization. Prediction of the magnitude of elevation of peak pressure was especially good when prediction and measurement were nearly simultaneous. Predictions were less accurate in the presence of tachycardia at rates of more than 155 beats/min. The method for estimating peak pulmonary artery pressure from M-mode echocardiographic tracings is reliable, relatively simple and clinically useful.

Assessment of myocardial damage in patients with acute myocardial infarction by serial measurement of serum α-hydroxybutyrate dehydrogenase levels

A method is presented for routine estimation of ultimate infarct size in patients with acute myocardial infarction (AMI). This method implies the calculation of the total quantity of α-hydroxybutyrate dehydrogenase (HBDH) released by the heart per liter of plasma, with the use of five to seven plasma samples per patient during the first 4 days after onset of infarction. The choice of HBDH for this purpose was motivated by a relatively small error in estimated enzyme release for slowly eliminated enzymes. The practicality of this method was studied in the coronary care unit at Leiden University Hospital where, in 1979, 146 patients with AMI were included in the study. In 100 patients (68%) HBDH-infarct size could be calculated precisely, and in 12 other patients (8%) the assessment of HBDH-infarct size was less accurate. In 34 patients (23%), HBDH-infarct size was unobtainable because of early death (eight cases), infarctions too small in size to assess or nonexistent (six cases), too much time elapsed since infarction (six cases), and incomplete plasma sampling (14 cases). Analysis of data shows that the larger HBDH-infarct sizes were found to be associated significantly with signs of heart failure, low stroke index and low ejection fraction, presence of tachycardias and interventricular conduction disturbances, high score of left ventricular wall motion abnormalities, large myocardial perfusion defect measured with thallium-201, in-hospital death, and death in the first year after infarction. A low but significant correlation was observed between HBDH-infarct size and the severity of coronary arterial lesions.

A study of variable decelerations in association with other heart rate patterns during monitored labor

A review of 1,011 consecutive intrapartum heart rate tracings yielded 37.3% with some degree of variable deceleration pattern. No differences in Apgar score distribution were observed in the presence of uncomplicated variable deceleration pattern when compared to those tracings marked normal. However, the presence of variable decelerations in association with other heart rate patterns resulted in lower mean Apgar scores at 1 and 5 minutes, which were significantly different from those of the fetal heart rate (FHR) normal group. Mean Apgar scores at 1 and 5 minutes were significantly different from normal when variable decelerations were noted in the presence of tachycardia and loss of variability. Mean Apgar scores were lower when bradycardia (prolonged episodes of heart rate <120 bpm) was present in the record when compared to normal, but the presence of variable decelerations with bradycardia did not result in different mean scores. The presence of baseline changes with loss of variability and variable decelerations appeared to result in the lowest mean scores. When bradycardia or tachycardia occurred in exclusive association with variable decelerations, the percentage of depressed newborn infants was relatively high.

Hypertension in children with burns.

Hypertension has been observed to occur frequently in children with burns. In a series of children admitted to the St. Agnes Burn Treatment Center, sustained systolic and diastolic hypertension occurred in 31.5%, and 57.4% of the children demonstrated episodic periods of hypertension which were unsustained. The only clinical finding which significantly correlated with the hypertension was the presence of tachycardia, which persisted into the late healing phase of the thermal injury. Hypertension was more prevalent at younger ages. However, there was no other correlation of the development of hypertension with sex, race, or extent of thermal injury. The development of hypertension in itself did not worsen the prognosis for survival in the cases presented in this series. Possible pathogenic mechanisms which result in hypertension (elevated catecholamines, norepinephrine, renin secretion) are discussed.

Overlapping of ventricular filling and contraction

Three cases are reported in which overlapping of ventricular filling and contraction was demonstrated by phonocardiograms and apex cardiograms. In two instances of aortic regurgitation, the sharply defined outline of a musical diastolic murmur signified that regurgitation extended into early ventricular systole. In a case of mitral regurgitation with atrial fibrillation, rapid emptying of the atrium was marked by a third heart sound and a synchronous peak in the apex cardiogram. When diastole was short, the signs of rapid atrial emptying fell in the early part of the following ventricular systole. Significant associated features were an increase in the intensity of the third heart sound, a particularly forceful “ventricular knock,” and delayed occurrence of the first heart sound. Filling of the ventricle in early systole may be a mechanism by which circulation is maintained in the presence of tachycardia with marked shortening of the diastolic phase.

Final report on a case of myocarditis following measles.

IN 1950, Giustra and Nilsson 1 reported a case of myocarditis following measles in a child of 5½ years of age. Examination of the heart presented varied and serious disorders of cardiac rhythm, consisting of bizarre arrhythmias, supraventricular tachycardias, and conduction blocks. These attacks occurred frequently during a three-year observation, necessitating hospitalization and quinidine therapy. The pattern of each attack was similar, being ushered in by severe intermittent abdominal pain followed by vomiting, the presence of tachycardia, and enlargement of the liver. The acute attacks were relieved by intravenous quinidine therapy. However, three years following the initial observation, the child died during a convulsive seizure which accompanied an attack of tachycardia. The autopsy findings relating to the heart were interesting and worthy of comment. They revealed a generalized subendocardial sclerosis and focal fibrosis in the left bundle branch. The dilatation and hypertrophy of the heart was more pronounced on the