Sinus arrhythmia

There is a similar high prevalence of peripheral neuropathy (34%) in the pediatric population infected with HIV (Araujo et al. 2000). The frequency of IDP in the HIV-infected population is unknown but is thought to be rare (Wulff et al. 2000). In an outpatient population of HIV positive patients, mononeuritis multiplex and lumbosacral polyradiculopathy were found in less than 1% of patients with AIDS (Fuller et al. 1993). HIV-associated autonomic nervous system dysfunction is also not uncommon as up to 66% of patients have papillary involvement and 15% have sympathetic and parasympathetic involvement causing orthostatic hypotension and respiratory sinus arrhythmia (Gluck et al. 2000). 

Common supraventricular tachycardias requiring drug treatment are atrial fibrillation (AF) or atrial flutter, paroxysmal supraventricular tachycardia (PSVT), and automatic atrial tachycardias. Other common supraventricular arrhythmias that usually do not require drug therapy are not discussed in this chapter (e.g., premature atrial complexes, wandering atrial pacemaker, sinus arrhythmia, sinus tachycardia). 

Atmospheres were within a few percent of nominal concentrations the mean oxygen concentration was approximately 20.5%. No significant or consistent differences were found between air exposure and test chemical exposure for clinical observations, blood pressure, heart rate, peak expiratory flow, or EKG recordings. During blood sampling and blood pressure measurements, all subjects showed sinus arrhythmia before and after exposure. 

Acute digoxin poisoning causes initial nausea and vomiting and hyperkalaemia because inhibition of the Na, K" -ATPase pump prevents intracellular accumulation of potassium. The ECG changes (see Table 24.1) of prolonged use of digoxin may be absent. There may be exaggerated sinus arrhythmia, bradycardia and ectopic rhythms with or without heart block. 

In a 3-week study with test doses of 100-3000 mg/day, atovaquone was well tolerated. Three patients reported increased appetite two of these had transient sinus arrhythmia. One of the 24 patients had a transient... 

Sinus bradycardia was seen in 18% of patients taking mefloquine (SEDA-12, 693) (14), occurring some 4-7 days after administration the bradycardia was asymptomatic and lasted about 3-4 days. Transient sinus arrhythmia was also reported, without a need for treatment (SEDA-12, 808). Asymptomatic dysrhythmias were also recorded in a dosage comparison trial (SEDA-16, 308). 

High frequency oscillations correspond well with vagal tone, and respiratory sinus arrhythmia is a large determinant of the high frequency component (59). Sympathetic and parasympathetic tone contribute to low frequency oscillations the physiology underlying very low frequency and ultra-low frequency is not well understood (59). 

Steinhauer SR, Morrow LA, Condray R, et al Respiratory sinus arrhythmia in persons with organic solvent exposure comparisons with anxiety patients and controls. Arch Environ Health 56 175-180, 2001... 

One of the most frequently applied measures in the field is EIR. It is used as an indicator of physical as well as mental load (see chap. 6, this volume). More refined analyses of evaluating cardiac activity use measures of EIR V, such as the power of the 0.1 EIz component and respiratory sinus arrhythmia (RS A), as very sensitive indicators of mental strain. Additional EIR can be calculated as the... 

Vincente, K. J., Thornton, D. C., Moray, N. (1987). Spectral analysis of sinus arrhythmia A measure ofmental effort./fuwaw Factors, 29, 171-182. 

RSA = Respiratory Sinus Arrhythmia HRV = heart rate variability. 

SC = Sympathetic Component PC = Parasympathetic Component PEP = Pre-ejection Period RSA = Respiratory Sinus Arrhythmia. 

Grossman, P., Svebak, S. (1987). Respiratory sinus arrhythmia as an index of parasympathetic cardiac control during active coping. Psychophysiology, 24, 228-235. 

Fig. 10.8 Narrow QRS type I block registered in a 3-lead Holier recording. There is sinus arrhythmia. The last three PR intervals before the blocked beat (arrow) are constant. This pattern should not be classified as type II block when conduction of the postblock P-wave is not seen. Actually the P-wave after the block was conducted with a shorter PR interval consistent with type I block.

Cardiac variability-vagal tone Changes in heart rate as a function of stimulation are related to changes in respiratory sinus arrhythmia that reflect changes in the parasympathetic nervous system (Posner, 2001)... 

Dizziness or syncope (with marked sinus arrhythmia)... 

If sinus arrhythmia develops suddenly in patient taking digoxin, notify doctor. 

May be difficult to differentiate atrial tachycardia with block from sinus arrhythmia with U waves... 

Sometimes the rhythm will be irregular with all waves present (PQRST). A 10 % variance is considered quite normal. In the case of sinus arrhythmia the rhythm is irregular and corresponds to the respiratory cycle. This is caused by the heart rate inaeasing during inspiration. This is often found in the elderly, children or fit people, and causes no symptoms. 

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