Optimising the diagnostics of atrial fibrillation (AF) in implantable devices by checking atrial refractory period and atrial sensitivity

EP Europace ◽  
2001 ◽  
Vol 2 ◽  
pp. A41-A41
Keyword(s):  
Atrial Fibrillation ◽  
Refractory Period ◽  
Implantable Devices

scholarly journals Abolishment of high-risk left lateral accessory pathway by myocardial infarction: a blessing in disguise? A case report

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Jim O’Brien ◽  
Nikola Kozhuharov ◽  
Shui Hao Chin ◽  
Mark Hall
Keyword(s):  
Atrial Fibrillation ◽  
Acute Coronary Syndrome ◽  
Case Report ◽  
High Risk ◽  
Coronary Sinus ◽  
Refractory Period ◽  
Accessory Pathway ◽  
Coronary Syndrome ◽  
Electrophysiology Study ◽  
Anomalous Coronary

Abstract Background Antegradely conducting left lateral accessory pathways are a risk for supraventricular tachycardias and pre-excited atrial fibrillation. Rarely, an anomalous coronary sinus can cause difficulty in locating the pathway. The left circumflex coronary artery and obtuse marginal branches supply the posterolateral left ventricle. We describe a case report of a high-risk accessory pathway associated with an anomalous coronary sinus which, between successive electrophysiology studies, was obliterated by a felicitous acute coronary syndrome in the left circumflex territory. Case summary A 49-year-old male with palpitations and manifest pre-excitation was referred for electrophysiology study. Initial study revealed a high-risk left lateral accessory pathway with antegrade effective refractory period of 240 ms and rapidly conducting pre-excited atrial fibrillation. The coronary sinus could not be cannulated to localize the pathway. Coronary angiography and cardiac computed tomography showed an anomalous coronary sinus emptying into the right atrial free wall and patent coronaries. While awaiting repeat electrophysiology study, the patient suffered an acute coronary syndrome with immediate loss of previously visible pre-excitation on electrocardiogram, and underwent stenting of an occluded marginal branch of the circumflex. Repeat electrophysiology study demonstrated a now low-risk accessory pathway (effective refractory period 390 ms). Since infarction, the patient’s palpitations have fully settled with all subsequent electrocardiograms devoid of manifest pre-excitation. Discussion Left lateral accessory pathways, which can associate with an anomalous coronary sinus, derive from tissue similar to normal ventricular myocardium and are vulnerable to ischaemic insults in the area subtended by the circumflex artery.

scholarly journals Angiotensin-(1–7) attenuates atrial tachycardia-induced sympathetic nerve remodeling

2017 ◽  
Vol 18 (3) ◽  
pp. 147032031772928 ◽  
Author(s):  
Wenfeng Shangguan ◽  
Wen Shi ◽  
Guangping Li ◽  
Yuanyuan Wang ◽  
Jian Li ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Tyrosine Hydroxylase ◽  
Sympathetic Nerve ◽  
Refractory Period ◽  
Atrial Tachycardia ◽  
Effective Refractory Period ◽  
Sympathetic Nerve Stimulation ◽  
Atrial Effective Refractory Period

Introduction: The effect of Angiotensin-(1–7) (Ang-(1–7)) on atrial autonomic remodeling is still unknown. We hypothesized that Ang-(1–7) could inhibit sympathetic nerve remodeling in a canine model of chronic atrial tachycardia. Materials and methods: Eighteen dogs were randomly assigned to sham group, pacing group and Ang-(1–7) group. Rapid atrial pacing was maintained for 14 days in the pacing and Ang-(1–7) groups. Ang-(1–7) was administered intravenously in the Ang-(1–7) group. The atrial effective refractory period and atrial fibrillation inducibility level were measured at baseline and under sympathetic nerve stimulation after 14 days of measurement. The atrial sympathetic nerves labeled with tyrosine hydroxylase were detected using immunohistochemistry and Western blotting, and tyrosine hydroxylase and nerve growth factor mRNA levels were measured by reverse transcription polymerase chain reaction. Results: Pacing shortened the atrial effective refractory period and increased the atrial fibrillation inducibility level at baseline and under sympathetic nerve stimulation. Ang-(1–7) treatment attenuated the shortening of the atrial effective refractory period and the increase in the atrial fibrillation inducibility level. Immunohistochemistry and Western blotting showed sympathetic nerve hyperinnervation in the pacing group, while Ang-(1–7) attenuated sympathetic nerve proliferation. Ang-(1–7) alleviated the pacing-induced increases in tyrosine hydroxylase and nerve growth factor mRNA expression levels. Conclusion: Ang-(1–7) can attenuate pacing-induced atrial sympathetic hyperinnervation.

scholarly journals Measurement of the atrial refractory period and the excitable gap during atrial fibrillation by single extrastimulus.

1998 ◽  
Vol 18 (6) ◽  
pp. 875-885
Author(s):  
Kaori Shinagawa ◽  
Hideo Mitamura ◽  
Akiko Takeshita ◽  
Toshiaki Sato ◽  
Hideaki Kanki ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Refractory Period ◽  
Excitable Gap

Abstract 1364: Not All Refractory Period Abbreviation Promotes Atrial Fibrillation Equally: A Comparison Between Vagal and Atrial Tachycardia Remodeled Substrates

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Grigorios Katsouras ◽  
Masao Sakabe ◽  
Kristina Lemola ◽  
Philippe Comtois ◽  
Michael Ting ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Refractory Period ◽  
Atrial Tachycardia ◽  
Molecular Mechanisms ◽  
Acetylcholine Release ◽  
Autonomic Ganglia ◽  
Bipolar Electrodes ◽  
Important Contributor ◽  
Stimulation Parameters ◽  
Dominant Frequencies

Background: Vagal (VG) and atrial tachycardia remodeled (ATR) AF substrates share many features: reduced effective refractory period (ERP), increased ERP heterogeneity and some common molecular mechanisms (I KACh enhancement by acetylcholine release in VG, constitutive I KACh enhancement in ATR). This study compared VG and ATR substrates at comparable ERP abbreviation. Methods: In each of 5 VG dogs, bilateral cervical VG stimulation parameters were adjusted (mean±SD: 3.6±1.7 V and 12.2±1.5 Hz; 0.2 ms) to produce the same mean ERP (at 4 RA and 4 LA sites) as a sex and weight matched ATR dog (RA paced 400 bpm × 7 days). Mean duration of burst pacing induced AF (DAF) and local dominant frequencies (DFs, analyzed by FFT at 240 bipolar electrodes, Fig A ) were determined. Results: Mean ERP was 79±13 ms in VG and 78±13 ms in ATR dogs. DAF was greater in VG than ATR dogs (1056±323 vs 289±510 s *P<0.01; both significantly > control, 43±61 s). Despite matched ERPs, there were significant differences in DF distribution (Fig B ): DF was faster (mean DF: 11.8±1.1 Hz VG vs 9.7±1.3 Hz ATR*) and DF variability greater (indicated by SD: 1.8±0.6 Hz VG vs 0.8±0.5 Hz ATR*) in VG dogs. AF drivers reflected by maximum DF zones were adjacent to autonomic ganglia (over RA in 4/5) for VG dogs; in ATR dogs driver zones were less clear and showed variable location. Conclusions: For a comparable atrial ERP, VG AF is faster and more persistent than AF with an ATR substrate. These results are consist with modeling work suggesting that VG-induced hyperpolarization is an important contributor to AF-maintaining rotor stabilization and acceleration, and indicate important differences between these superficially similar AF substrates.

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