Heart rate tracings

Introduction to Blood Pressure/Heart Rate Tracings... 

Top Effects of phentolamine, an a-receptor-blocking drug, on blood pressure in an anesthetized dog. Epinephrine reversal is demonstrated by tracings showing the response to epinephrine before (middle) and after (bottom) phentolamine. All drugs given intravenously. BP, blood pressure HR, heart rate. 

Figure I /./ Loewi s demonstration of the chemical nature of neurotransmission. Heart D (donor) represents heart 1 while heart R (recipient) represents heart 2. Tracings R and D represent the respective heart beats of the two hearts. When fluid from the stimulated donor heart was allowed to interact with the recipient heart (middle of tracing R), heart rate was obviously abbreviated.

Cardiopulmonary parameters and rectal body temperature are determined while the rabbit is in the sling and also at 15 min intervals following induction of anesthesia with the rabbit in lateral recumbency. Heart rate, mean arterial blood pressure, respiratory rate and respiratory pattern are calculated from tracings from the physiological recorder. Arterial blood pH, partial pressure of oxygen (PaQz), and partial pressure of... 

Oral. Doses ranged from 4.5 to 5 Mg/kg and were given to five subjects. The major focus seemed to be on following heart rates and Che EEC. Clinical manifestations noted with the other routes of administration probably also occurred here. Some heart rates became fairly high (130/mln). One subject had an EEC tracing that showed episodes of light sleep with spindling. 

Recording of the ECG has several standard features. The paper is divided into squares of 1 mm each 10 mm (10 small boxes) is equivalent to 1 mV. Paper speed is 25 mm/s. Each small box on the tracing paper equals 0.04 second (40 ms), and each big box is 0.2 second. If there is one QRS complex per six big boxes (6 x 0.20 second), the patient has a heart rate of 50 beats per minute, whereas one QRS per big box indicates a heart rate of 300 beats per minute. 

Quinidine has anticholinergic properties that can result in the blockade of impulses from the vagus nerve to the heart. This would prevent the slowing of the heart rate that is ordinarily produced by normal vagal stimulation. The resulting increased heart rate counters the direct depressant effect on the pacemaker. This can understandably complicate therapy from the clinical standpoint. The effectiveness of quinidine and procainamide treatment can be traced on ECG by the increase in the Q-T interval, which can be attributed to the increased duration of systole, as well as decreased intraventricular conduction velocity. 

In rats intravenously administered 5 to 40 mg/kg of the aqueous fraction of a hydroalcoholic extract of heart-leaf sida, a reduction in heart rate and blood pressure was observed (Medeiros et al. 2006). The activity has been traced to the compound vasicine, which caused hypotension and a marked reduction in heart rate after intravenous administration to rats at doses of 2.5 to 10 mg/kg (Silveira et al. 2003). 

Cardiotocographs (CTGs) are used to monitor and display foetal heart rate during labour. They rely on ultrasonic detection of foetal heart movements. Reports to the Medical Devices Agency revealed that several incidents occurred where, despite the fact that the monitors were showing a heart trace, babies were delivered stillborn. In all probability, the CTG was recording the mother s heartbeat rather than that of the foetus. A safety... 

The vital signs monitoring capability was tested by a subject wearing the garment and measuring the heart rate and electrocardiogram (EKG) through the sensors and T-connectors. In Fig. 13.4, the EKG trace from the Wearable... 

Figure 1 A beagle dog was anesthetized with propofol and etomidate and intubated. One 250-mL breath of ammonia vapor above an 8-M ammonia solution was administered to the dog. The end-tidal COj shows an apnea followed by rapid, shallow breathing. The arterial pressure tracing demonstrates the short-lived decrease in heart rate and attendant hypotension. The transpulmonary pressure illustrates that the apnea and tachypnea was due to the absence of ventilatory drive, rather than airway occlusion.

Serum samples and autopsy specimens were examined from two infants with congenital diaphragmatic hernia who had received life support with extracorporeal membrane oxygenation (ECMO). The serum levels of di(2-ethylhexyl) phthalate after 14 and 24 days of ECMO support were 26.8 and 33.5 mg/L respectively, and levels of 3.5, 1.0 and 0.4 mg/kg di(2-ethylhexyl) phthalate were found in liver, heart and testicular tissues, respectively, and trace quantities were found in the brain. The rate of di(2-ethylhexyl) phthalate extraction from the model PVC circuits was linear with time (rate, 3.5 and 4.1 mg/L per hour). The exposure to di(2-ethylhexyl) phthalate for a 4-kg infant on ECMO support for 3-10 days was estimated to be 42-140 mg/kg (Shneider et al., 1989). 

The net result of the action of therapeutic concentrations of a cardiac glycoside is a distinctive increase in cardiac contractility (Figure 13-5, bottom trace). In isolated myocardial preparations, the rate of development of tension and of relaxation are both increased, with little or no change in time to peak tension. This effect occurs in both normal and failing myocardium, but in the intact patient the responses are modified by cardiovascular reflexes and the pathophysiology of heart failure. 

Figure 4.6 PET pictures of the heart of a patient with acute myocardial infarction treated with a thrombolytic agent. Top row shows scans after administration of water containing lsO to trace blood flow. Bottom row shows tomograms obtained after administration of acetate containing nC to trace the heart s metabolism, that is, its rate of oxygen use. The defects tire clearly visible on day 1, both in the impaired blood flow (top left) and the impaired metabolic use of oxygen (bottom left). Recovery of blood circulation has taken place on day 2 and is maintained. (Figure also appears in color figure section.)...

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