AH Interval

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Clifford J. Garratt - One of the best experts on this subject based on the ideXlab platform.

  • Structural and functional remodeling of the atrioventricular node with aging in rats: The role of hyperpolarization-activated cyclic nucleotide-gated and ryanodine 2 channels.
    Heart rhythm, 2017
    Co-Authors: Yawer Saeed, Ian P. Temple, Zoltan Borbas, Andrew Atkinson, Joseph Yanni, Michal Maczewski, Urszula Mackiewicz, Mariam Aly, Sunil Jit R. J. Logantha, Clifford J. Garratt
    Abstract:

    Background Aging is associated with an increased incidence of atrioventricular nodal (AVN) dysfunction. Objective The aim of this study was to investigate the structural and functional remodeling in the atrioventricular junction (AVJ) with aging. Methods Electrophysiology, histology, and immunohistochemistry experiments on male Wistar Hannover rats aged 3 months (n = 24) and 2 years (n = 15) were performed. Atrio-His (AH) Interval, Wenkebach cycle length (WBCL), and AVN effective refractory period (AVNERP) were measured. Cesium (2 mM) was used to block hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, while ryanodine (2 μM) was used to block ryanodine 2 (RyR2) channels. Protein expression from different regions of the AVJ was studied using immunofluorescence. The expression of connexins (connexin 43 and connexin 40), ion channels (Hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4), voltage sensitive sodium channel (Na v 1.5), and L-Type calcium channel (Ca v 1.3)), and calcium handling proteins (RyR2 and sarco/endoplasmic reticulum calcium ATPaset type 2a (SERCA2a)) were measured. Morphological characteristics were studied with histology. Results Without drugs to block HCN and RyR2 channels, there was prolongation of the AH Interval, WBCL, and AVNERP ( P P P v 1.5, and RyR2 downregulate in the regions of the AVJ and connexin 40, SERCA2a, and Ca v 1.3 upregulate ( P Conclusion Heterogeneous ion channel expression changes were observed in the AVJ with aging. For the first time, we have shown that HCN and RyR2 play an important role in AVN dysfunction with aging.

  • Structural and functional remodeling of the atrioventricular node with aging in rats: The role of hyperpolarization-activated cyclic nucleotide-gated and ryanodine 2 channels.
    Heart rhythm, 2017
    Co-Authors: Yawer Saeed, Ian P. Temple, Zoltan Borbas, Andrew Atkinson, Joseph Yanni, Michal Maczewski, Urszula Mackiewicz, Mariam Aly, Sunil Jit R. J. Logantha, Clifford J. Garratt
    Abstract:

    Background Aging is associated with an increased incidence of atrioventricular nodal (AVN) dysfunction. Objective The aim of this study was to investigate the structural and functional remodeling in the atrioventricular junction (AVJ) with aging. Methods Electrophysiology, histology, and immunohistochemistry experiments on male Wistar Hannover rats aged 3 months (n = 24) and 2 years (n = 15) were performed. Atrio-His (AH) Interval, Wenkebach cycle length (WBCL), and AVN effective refractory period (AVNERP) were measured. Cesium (2 mM) was used to block hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, while ryanodine (2 μM) was used to block ryanodine 2 (RyR2) channels. Protein expression from different regions of the AVJ was studied using immunofluorescence. The expression of connexins (connexin 43 and connexin 40), ion channels (Hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4), voltage sensitive sodium channel (Nav1.5), and L-Type calcium channel (Cav1.3)), and calcium handling proteins (RyR2 and sarco/endoplasmic reticulum calcium ATPaset type 2a (SERCA2a)) were measured. Morphological characteristics were studied with histology. Results Without drugs to block HCN and RyR2 channels, there was prolongation of the AH Interval, WBCL, and AVNERP (P Conclusion Heterogeneous ion channel expression changes were observed in the AVJ with aging. For the first time, we have shown that HCN and RyR2 play an important role in AVN dysfunction with aging.

Yoshio Hatano - One of the best experts on this subject based on the ideXlab platform.

Yawer Saeed - One of the best experts on this subject based on the ideXlab platform.

  • Structural and functional remodeling of the atrioventricular node with aging in rats: The role of hyperpolarization-activated cyclic nucleotide-gated and ryanodine 2 channels.
    Heart rhythm, 2017
    Co-Authors: Yawer Saeed, Ian P. Temple, Zoltan Borbas, Andrew Atkinson, Joseph Yanni, Michal Maczewski, Urszula Mackiewicz, Mariam Aly, Sunil Jit R. J. Logantha, Clifford J. Garratt
    Abstract:

    Background Aging is associated with an increased incidence of atrioventricular nodal (AVN) dysfunction. Objective The aim of this study was to investigate the structural and functional remodeling in the atrioventricular junction (AVJ) with aging. Methods Electrophysiology, histology, and immunohistochemistry experiments on male Wistar Hannover rats aged 3 months (n = 24) and 2 years (n = 15) were performed. Atrio-His (AH) Interval, Wenkebach cycle length (WBCL), and AVN effective refractory period (AVNERP) were measured. Cesium (2 mM) was used to block hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, while ryanodine (2 μM) was used to block ryanodine 2 (RyR2) channels. Protein expression from different regions of the AVJ was studied using immunofluorescence. The expression of connexins (connexin 43 and connexin 40), ion channels (Hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4), voltage sensitive sodium channel (Na v 1.5), and L-Type calcium channel (Ca v 1.3)), and calcium handling proteins (RyR2 and sarco/endoplasmic reticulum calcium ATPaset type 2a (SERCA2a)) were measured. Morphological characteristics were studied with histology. Results Without drugs to block HCN and RyR2 channels, there was prolongation of the AH Interval, WBCL, and AVNERP ( P P P v 1.5, and RyR2 downregulate in the regions of the AVJ and connexin 40, SERCA2a, and Ca v 1.3 upregulate ( P Conclusion Heterogeneous ion channel expression changes were observed in the AVJ with aging. For the first time, we have shown that HCN and RyR2 play an important role in AVN dysfunction with aging.

  • Structural and functional remodeling of the atrioventricular node with aging in rats: The role of hyperpolarization-activated cyclic nucleotide-gated and ryanodine 2 channels.
    Heart rhythm, 2017
    Co-Authors: Yawer Saeed, Ian P. Temple, Zoltan Borbas, Andrew Atkinson, Joseph Yanni, Michal Maczewski, Urszula Mackiewicz, Mariam Aly, Sunil Jit R. J. Logantha, Clifford J. Garratt
    Abstract:

    Background Aging is associated with an increased incidence of atrioventricular nodal (AVN) dysfunction. Objective The aim of this study was to investigate the structural and functional remodeling in the atrioventricular junction (AVJ) with aging. Methods Electrophysiology, histology, and immunohistochemistry experiments on male Wistar Hannover rats aged 3 months (n = 24) and 2 years (n = 15) were performed. Atrio-His (AH) Interval, Wenkebach cycle length (WBCL), and AVN effective refractory period (AVNERP) were measured. Cesium (2 mM) was used to block hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, while ryanodine (2 μM) was used to block ryanodine 2 (RyR2) channels. Protein expression from different regions of the AVJ was studied using immunofluorescence. The expression of connexins (connexin 43 and connexin 40), ion channels (Hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4), voltage sensitive sodium channel (Nav1.5), and L-Type calcium channel (Cav1.3)), and calcium handling proteins (RyR2 and sarco/endoplasmic reticulum calcium ATPaset type 2a (SERCA2a)) were measured. Morphological characteristics were studied with histology. Results Without drugs to block HCN and RyR2 channels, there was prolongation of the AH Interval, WBCL, and AVNERP (P Conclusion Heterogeneous ion channel expression changes were observed in the AVJ with aging. For the first time, we have shown that HCN and RyR2 play an important role in AVN dysfunction with aging.

Jin Long Huang - One of the best experts on this subject based on the ideXlab platform.

  • atrioventricular node reentrant tachycardia in patients with a prolonged AH Interval during sinus rhythm clinical features electrophysiologic characteristics and results of radiofrequency ablation
    Journal of Interventional Cardiac Electrophysiology, 1997
    Co-Authors: Shih Huang Lee, Shihann Chen, Ching Tai Tai, Chern En Chiang, Zu Chi Wen, Yi Jen Chen, Ann Ning Fong, Jin Long Huang, Jun Jack Cheng, Mausong Chang
    Abstract:

    Among a consecutive series of 600 patients who underwent radiofrequency catheter ablation for AV node reentrant tachycardia, 14 patients (age 29-76 years) had a prolonged AH Interval during sinus rhythm (172±18 ms, range 140 to 200). Seven of them had unsuccessful ablation during the previous ablation sessions. Eight patients with anterograde dual AV node pathway physiology received anterograde slow pathway ablation, and the other 6 patients without dual-pathway physiology received retrograde fast pathway ablation. All patients had successful elimination of AV nodal reentrant tachycardia after a mean of 4±4 radiofrequency applications, power level 36±6 watts and a pulse duration of 42±4 seconds. The postablation AH Interval remained unchanged. During a follow-up period of 25±13 months, one patient who received slow pathway ablation developed 2:1 AV block with syncope. As compared with the other 586 patients without a prolonged AH Interval, these 14 patients had significantly poorer anterograde AV nodal function and lower incidence of anterograde dual AV node physiology (P<0.01). We concluded that slow pathway ablation in patients with dual pathway physiology, and retrograde fast pathway ablation in patients without dual pathway physiology were effective and safe in patients with a prolonged AH Interval. However, delayed onset of symptomatic AV block is possible and careful follow-up is necessary.

  • Atrioventricular Node Reentrant Tachycardia in Patients With a Prolonged AH Interval During Sinus Rhythm: Clinical Features, Electrophysiologic Characteristics and Results of Radiofrequency Ablation
    Journal of Interventional Cardiac Electrophysiology, 1997
    Co-Authors: Shih Huang Lee, Shihann Chen, Ching Tai Tai, Chern En Chiang, Zu Chi Wen, Yi Jen Chen, Ann Ning Fong, Jin Long Huang, Jun Jack Cheng, Mausong Chang
    Abstract:

    Among a consecutive series of 600 patients who underwent radiofrequency catheter ablation for AV node reentrant tachycardia, 14 patients (age 29-76 years) had a prolonged AH Interval during sinus rhythm (172±18 ms, range 140 to 200). Seven of them had unsuccessful ablation during the previous ablation sessions. Eight patients with anterograde dual AV node pathway physiology received anterograde slow pathway ablation, and the other 6 patients without dual-pathway physiology received retrograde fast pathway ablation. All patients had successful elimination of AV nodal reentrant tachycardia after a mean of 4±4 radiofrequency applications, power level 36±6 watts and a pulse duration of 42±4 seconds. The postablation AH Interval remained unchanged. During a follow-up period of 25±13 months, one patient who received slow pathway ablation developed 2:1 AV block with syncope. As compared with the other 586 patients without a prolonged AH Interval, these 14 patients had significantly poorer anterograde AV nodal function and lower incidence of anterograde dual AV node physiology (P

  • Complex Electrophysiological Characteristics in Atrioventricular Nodal Reentrant Tachycardia With Continuous Atrioventricular Node Function Curves
    Circulation, 1997
    Co-Authors: Ching T. Tai, Shih Huang Lee, Shih A. Chen, Chern E. Chiang, Zu C. Wen, Chuen Wang Chiou, Kwo Chang Ueng, Yi J. Chen, Jin Long Huang
    Abstract:

    Background Although typical atrioventricular nodal reentrant tachycardia (AVNRT) with discontinuous AV node function curves has been well studied, there has been a lack of any significant information about AVNRT without evidence of dual AV nodal pathway physiology during atrial extrastimulus testing or atrial pacing. Methods and Results Group 1 included 9 patients with continuous curves during atrial extrastimulus testing but without a jump (≥50 ms) of the atrial–His bundle (AH) Interval during incremental atrial pacing. The maximal AH Interval during atrial pacing (266±61 versus 168±27 ms, P=.007) or extrastimulus testing (290±60 versus 176±18 ms, P=.005) shortened significantly after ablation. Antegrade and retrograde AV node properties were similar before and after ablation. Group 2 included 14 patients with continuous curves and a jump of the AH Interval during incremental atrial pacing. The atrial pacing cycle length with 1:1 AV conduction and effective refractory period (ERP) of the antegrade AV nod...

Keisuke Fujii - One of the best experts on this subject based on the ideXlab platform.

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