B L Bergfeldt | PubMed Health

PubMed1987

Analysis of sinus cycle variation: a new method for evaluation of suspected sinus node dysfunction.

Momentary sinus cycle variations in 30 patients with unequivocal sinus node disease (SND) were compared with those found in 18 healthy control subjects to assess their potential diagnostic value. The range of variation of sinus cycle length (SCL; standardized by dividing by mean SCL) and the maximal change in SCL between any two consecutive cycles (max delta SCL) were measured in short (about 1 minute) continuous ECG recordings from invasive electrophysiologic investigations. Age-stratified reference values from 1 minute surface ECG recordings obtained at rest during quiet breathing in about 70 healthy persons were applied. For diagnosing SND, an increased standardized variation range had a sensitivity of 63%, a specificity of 94%, and a predictive value of a positive test of 95%. The corresponding figures for an increased max delta SCL were 77%, 78%, and 85%, respectively. A combination of increased range of variation and increased max delta SCL was observed in 63% of the patients but not in any healthy subject, which gives a specificity and a predictive value of a positive test of 100% for this combination.

Adult↗

PubMed1985

Electrophysiologic evaluation of the cardiac conduction system and its autonomic regulation in familial amyloid polyneuropathy.

A high incidence of cardiac conduction disturbances is a salient feature in familial amyloid polyneuropathy (FAP) and amyloid infiltration of the conduction system has been found. In patients with FAP autonomic nervous dysfunction involving gastrointestinal, urogenital and cardiovascular systems has been described. However, the present study is the first to evaluate the results of autonomic tests and pharmacologic intervention in the autonomic nervous regulation of the cardiac conduction system during an invasive electrophysiologic study. Seven patients with FAP and severe disturbances of the conduction system, evaluated concerning indications for pacemaker treatment, were studied; in 3 of them the parasympathetic regulation was found to be abolished. In 1 patient the observations indicated either vagal overactivity or denervation oversensitivity of the receptors. The function of the beta adrenoceptors was intact in all patients, but a disturbance of sympathetic innervation could not be excluded. Dysfunction of autonomic nervous regulation of the cardiac conduction system was thus found in 4 of 7 patients. However, most conduction abnormalities were irreversible, indicating amyloid infiltration of the conduction system as the predominant pathophysiologic mechanism, in accordance with the findings of pathoanatomic studies.

Amyloidosis↗