The Significance of the Sinus Node Recovery Time in the Sick Sinus Syndrome

Delius, W; Wirtzfeld, A

doi:10.1007/978-3-642-66356-7_4

Cited by 11 publications

(2 citation statements)

References 22 publications

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“…S1). The electrophysiological indicators SNRT and CSNRT are also commonly used to assess the function of the SAN [24][25][26][27]. The SNRT increased from 412 ± 32 ms in the young group to 620 ± 56 ms in the adult group and to 838 ± 120 ms in the aged group (P < 0.01 or P < 0.05 Fig.…”

Section: Resultsmentioning

confidence: 99%

Age-dependent down-regulation of hyperpolarization-activated cyclic nucleotide-gated channel 4 causes deterioration of canine sinoatrial node function

Deng

et al. 2017

ABBS

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The activity of pacemaker cells in the sinoatrial node (SAN) is an indicator of normal sinus rhythm. Clinical studies have revealed that the dysfunction of the SAN progressively increases with aging. In this study, we determined the changes in hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) expression and the relationship between aging and canine SAN dysfunction. The results of cardiac electrophysiological determination revealed that the intrinsic heart rate decreased from 168 ± 11 beats min −1 in young canines to 120 ± 9 beats min −1 in adults and to 88 ± 9 beats min −1 in aged canines. The sinus node recovery time (SNRT) increased from 412 ± 32 ms in young canines to 620 ± 56 ms in adults and to 838 ± 120 ms in aged canines. Corrected SNRT (CSNRT) increased from 55 ± 12 ms in young canines to 117 ± 27 ms in adults and to 171 ± 37 ms in aged canines. These results indicated that SAN function deteriorated with aging in the canine heart. However, histological staining illustrated that fibrosis was not significantly increased with aging in canine SAN. Real-time polymerase chain reaction indicated that the expression of HCN4 mRNA was downregulated in the elderly canine SAN. Similarly, we also verified that HCN4 protein expression within the SAN declined with aging via immunofluorescence staining and western blot analysis. Taken together, our data show that electrical remodeling, related to the down-regulation of HCN4, is responsible for the gradually increased incidence of SAN dysfunction with aging. Our results provide further evidence for explaining the mechanisms of age-related deterioration in the SAN.

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Section: Resultsmentioning

confidence: 99%

Age-dependent down-regulation of hyperpolarization-activated cyclic nucleotide-gated channel 4 causes deterioration of canine sinoatrial node function

Deng

et al. 2017

ABBS

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“…The sinus node typically recovers with progressive decrease in cycle length over five-10 -pacing sequences were analysed d manner for our laboratory, 3. The response to incremental high right atrial was commenced at a rate just inherent sinus rate and progressively imrepsed by 10 Ventricular irritability assessed using programmed single and paired ventricular extrastimuli during sinus rhythm, and after a train of eight paced beats at both 100 bpm and 130 bpm. The extrastimulus was advanced in 10 ms decrements until ventricular refractoriness was encountered.…”

Section: Indcand Of Sinus Node Automaticity and Sinoatrial Ctionmentioning

confidence: 99%

Clinical Implications of Electrophysiology Study Findings in Patients With Chronic Bifascicular Block and Syncope

Twidale

Heddle

Ayres

et al. 1988

Australian and New Zealand Journal of Medicine

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Electrophysiology study was performed in 93 patients with bifascicular block and unexplained syncope. Clinical evidence of organic heart disease was present in 33 (35%). Electrophysiological abnormalities were detected in 45 patients (48%). Of these, 36 had distal conduction disease, including 28 with an HV interval greater than 55 ms (mean 76.4 ms), and eight who developed infraHisian block following either intravenous procainamide (four) or atrial pacing (four). Sick sinus syndrome was evident in six patients and a further two had carotid sinus hypersensitivity. Sustained monomorphic ventricular tachycardia (VT) was induced in only three patients, two of whom also had prolonged HV interval. Among the 93 patients, 45 had therapy which was guided by positive findings at electrophysiology study (Group 1). Of these, 42 received permanent pacemakers, two were treated with combined permanent pacing and antiarrhythmic drug therapy, and one was treated with antiarrhythmic drug alone. In addition, eight patients without electrophysiologic abnormalities were treated empirically by pacing (Group 2). Finally, 40 patients without electrophysiologic abnormalities received no specific therapy (group 3). At a mean follow-up of 39 months (range two-125 months), recurrence of syncope had occurred in 4% of Group 1 patients, and 25% of Group 3 patients (p less than 0.05). No patient in Group 2 had had recurrence. Total mortality was 40%, including 47% of patients in Group 1, 25% of Group 2, and 35% of Group 3. Death was sudden in seven patients. We concluded that among patients with bifascicular block and syncope, therapy directed by findings at electrophysiology study was associated with symptomatic improvement, but mortality was not significantly influenced.(ABSTRACT TRUNCATED AT 250 WORDS)

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