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Sinoatrial Response to Premature Atrial Stimulation during Atrial Pacing in Aged Patients with and without Sinus Node Dysfunction

1978; Japanese Heart Journal Assoc; Volume: 19; Issue: 5 Linguagem: Inglês

10.1536/ihj.19.677

1573-8612

Keiji Ueda, Kan Takayanagi, Hiroshi Matsuo, Takao Okimoto, Junichiro Mifune, Shin-ichiro Ohkawa, Chizuko KAMATA, Masaya Sugiura,

Parkinson's Disease Mechanisms and Treatments

Sinus node function was analysed in 15 aged patients, including 8 with sick sinus syndrome and 7 without apparent sinus node dysfunction, by rapid atrial pacing and premature atrial stimulation during sinus rhythm and 5 beats of atrial pacing.Three patterns of sinoatrial response were identified by premature atrial stimulation during atrial pacing. Type I response (3 cases) represented approximately constant return cycles and type II (2 cases) represented a markedly prolonged return cycles following premature stimulation. Type III response was characterized by a progressive shortening of return cycles as the prematurity of atrial extrastimuli was increased.Underlying mechanisms responsible for these responses were discussed in relation to the sinus node automaticity and sinoatrial conduction.