Abstract
This research was designed to assess the prevalence, characteristics, natural course and autonomic regulation of ectopic atrial tachycardia (EAT) and inappropriate sinus tachycardia (IST) and the response of IST to adenosine.
The prevalence of EAT, as estimated from the electrocardiograms (ECG) of males applying for a pilot's licence, was 0.34%. During a mean follow-up time of 8 years among 10 asymptomatic subjects and 7 years among 17 symptomatic patients, a majority of the subjects showed a reduction of the heart rate (HR), either with restoration of sinus rhythm (SR) (37%) or with a change in P wave morphology (37%).
The prevalence of IST in a random sample of 604 middle-aged subjects was 1.16%. The systolic and diastolic ambulatory blood pressures were higher among the subjects with IST than subjects with SR (P < 0.001). The other laboratory, echocardiographic and personality measurements, with the exception of the hostility score (P < 0.001), revealed no differences between the groups. During a mean follow-up of 6 years, none of the subjects with IST developed any evidence of structural heart disease despite ongoing palpitations, and there was no significant reduction of the 24-hour average HR.
In an analysis of R-R interval variability from 24-hour ECG recordings in 12 patients with incessant EAT, 12 subjects with IST and 24 subjects with SR, the time- and frequency-domain measures of HR variability did not differ between the subjects with EAT and IST. However, the short-term fractal HR behaviour differed between EAT and IST.
In studies of the effects of adenosine in 18 patients with IST and 18 subjects with SR, adenosine prolonged significantly the sinus interval (P < 0.001) in the control subjects, but did not cause any significant changes of atrial cycle length in the patients with IST.
Conclusions: 1. EAT has a tendency towards gradual degeneration over time. 2. The prevalence of IST is higher than previously assumed, but the overall prognosis is good. 3. EAT and IST seem to be under similar autonomic regulation as the sinus node, but the firing of ectopic atrial foci shows more random behaviour. 4. The usual negative chronotropic effect of adenosine is impaired in subjects with IST.
| Identifer | oai:union.ndltd.org:oulo.fi/oai:oulu.fi:isbn951-42-7381-8 |
| Date | 28 May 2004 |
| Creators | Still, A.-M. (Aino-Maija) |
| Publisher | University of Oulu |
| Source Sets | University of Oulu |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/publishedVersion |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess, © University of Oulu, 2004 |
| Relation | info:eu-repo/semantics/altIdentifier/pissn/0355-3221, info:eu-repo/semantics/altIdentifier/eissn/1796-2234 |
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