scholarly journals P1500 Reptilian heart in a man

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
E O Ozpelit ◽  
E E O Ozcan ◽  
M E O Ozpelit ◽  
N O Ozgul
Keyword(s):  
Human Evolution ◽  
Peak Velocity ◽  
Pulmonary Regurgitation ◽  
Maximum Velocity ◽  
Heart Model ◽  
Av Node ◽  
His Bundle ◽  
Diastolic Velocity ◽  
Qrs Duration ◽  
The One

Abstract 40 year old man admitted to hospital due to tachycardia episode. His normal ECG was consistent with RBBB with a QRS duration of 200msec. He had undergone a VSD operation when he was 6. He had a 3/6 systolic murmor . On TTE, there was a VSD patch and a residual tiny VSD with a L-R shunt. The maximum systolic gradient of VSD shunt was measured as 92mmHg .There was also moderate tricuspid regurgitation (TR) with a peak velocity of 5.1m/sec and estimated sPAP of 103mmHg. Considering the measured sPAP and the VSD shunt gradients, his systolic blood pressure (SBP)should approximately be equal to sum of those two ( 103+ 92 = 195mmHg). However his BP was 140/90mmHg.When we examined his heart for a possible explanation for this inconsistency, we noticed a systolic aliasing inside the RV with a maximum velocity of 3.1m/sec and systolic gradient of 38mmHg. However the chamber with lower pressure (P) was the one to which the VSD shunt was directed, and this chamber was in direct continuity with pulmonary artery. So to confirm the P in this chamber we also used pulmonary regurgitation flow and measured a peak diastolic velocity of 3.8m/sec, meaning a mean PAP of 60mmHg .Cardiac catheterization also confirmed a sPAP of 116mmHg and mPAP of 65mmHg. The systolic aortic P was 145mmHg and systolic LV P was 152mmHg. So the unexpectedly high gradient of VSD shunt was still a mystery for us. While searching the literature to explain this , we noticed that the patients’ heart was resembling the reptilian heart model. The reptilian heart has two atria and one ventricle with 3 segments seperated via muscular ridges. In our patients’ heart ,the small chamber with high P in the RV was the cavum venosum, the larger chamber of RV with VSD was the cavum pulmonale, and the left ventricle was the cavum arteriosum. (Fig) The reptilian hearts typically have noncompacted myocardium which was actually the case in our patient. The reptilian hearts also have unique conduction system with no AV node and His bundle, and slow depolarization of ventricle from left to right. When we performed EPS, we found that the patient had no AV node and His bundle. Bringing together all these findings, we conclude that the patient has a reptilian heart with all anatomical, electrical and physiological features. And the answer to the mystery of inconsistent P recordings was hidden in ECG. The RBBB with very long QRS duration causes a delay between contraction of ventricles resulting in a dynamic P gradient between ventricles. We demonstrated this dinamic bidirectional shunt on CW recording when we obtained a more optimal recording of the shunt flow.This case demonstrates us one more evidence of human evolution; arising from single cell and developing to fish, to reptiles and to mammals. The evolution takes place again and again during neonatal life. If there is an embryological arrest, as occured in our patient, we can easily see the clues of this amazing human evolution. Abstract P1500 Figure

scholarly journals Can atrioventricular node ablation be safely performed in patients with permanent His bundle pacing? Data from a multicentric registry

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
C Chaumont ◽  
N Auquier ◽  
A Mirolo ◽  
E Popescu ◽  
A Milhem ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Rate Control ◽  
Atrioventricular Node ◽  
Atrial Arrhythmia ◽  
Av Node ◽  
His Bundle ◽  
His Bundle Pacing ◽  
Ventricular Lead ◽  
Qrs Duration

Abstract Introduction Ventricular rate control is essential in the management of atrial fibrillation. Atrioventricular node ablation (AVNA) and ventricular pacing can be an effective option when pharmacological rate control is insufficient. However, right ventricular pacing (RVP) induces ventricular desynchronization in patients with normal QRS and increases the risk of heart failure on long term. His bundle pacing (HBP) is a physiological alternative to RVP. Observational studies have demonstrated the feasibility of HBP but there is still very limited data about the feasibility of AVNA after HBP. Purpose To evaluate feasibility and safety of HBP followed by AVNA in patients with non-controlled atrial arrhythmia. Methods We included in three hospitals between september 2017 and december 2019 all patients who underwent AVNA for non-controlled atrial arrhythmia after permanent His bundle pacing. No back-up right ventricular lead was implanted. AVNA procedures were performed with 8 mm-tip ablation catheter. Acute HBP threshold increase during AVNA was defined as a threshold elevation >1V. His bundle capture (HBC) thresholds were recorded at 3 months follow-up. Results AVNA after HBP lead implantation was performed in 45 patients. HBP and AVNA were performed simultaneously during the same procedure in 10. AVNA was successful in 32 of 45 patients (71%). Modulation of the AV node conduction was obtained in 7 patients (16%). The mean procedure duration was 42±24min, and mean fluoroscopy duration was 6.4±8min. A mean number of 7.7±9.9 RF applications (347±483 sec) were delivered to obtain complete / incomplete AV block. Acute HBC threshold increase occurred in 8 patients (18%) with return to baseline value at day 1 in 5 patients. There was no lead dislodgment during the AVNA procedures. Mean HBC threshold at implant was 1.26±[email protected] and slightly increased at 3 months follow-up (1.34±[email protected]). AV node re-conduction was observed in 5 patients (16% of the successful procedures) with a second successful ablation procedure in 4 patients. No ventricular lead revision was required during the follow-up period. The baseline native QRS duration was 102±21 ms and the paced QRS duration was 107±18 ms. Conclusion AVNA combined with HBP for non-controlled atrial arrhythmia is feasible and does not compromise HBC but seems technically difficult with significant AV nodal re-conduction rate. The presence of a back-up right ventricular lead could have changed our results and therefore would require further evaluation. Unipolar HBP after AV node ablation Funding Acknowledgement Type of funding source: None

P6020His bundle pacing in patients with abnormal versus intact atrioventricular conduction: from the IMAGE-HBP Study

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
J A Y Koneru ◽  
G O P I Dandamudi ◽  
F A I Z Subzposh ◽  
R K S Shepard ◽  
G K Kalahasty ◽  
...  
Keyword(s):  
Statistical Tests ◽  
Adverse Outcomes ◽  
Cardiac Conduction ◽  
Electrical Performance ◽  
Av Node ◽  
Bundle Branch Block ◽  
Right Ventricular Pacing ◽  
His Bundle ◽  
Av Conduction ◽  
Qrs Duration

Abstract Background Frequent right ventricular pacing causes ventricular dyssynchrony and adverse outcomes. His bundle pacing (HBP) offers a physiological alternative. HBP electrical performance characteristics with cardiac conduction system abnormalities are not well established. Purpose To compare HBP implant procedure related parameters in patients with abnormal atrioventricular (AV) conduction versus those with intact AV conduction. Methods Patients prospectively enrolled in the IMAGE-HBP study undergoing implant attempt with a SelectSecure 3830 lead placed at the putative His-bundle location were included in the analysis. Patients were divided into groups based on AV conduction status. Implant characteristics and electrical performance of the pacemaker were tabulated and compared between the two groups with formal statistical tests. Results Among 60 patients (age 74.7 years old and 60% male), 29 patients (48%) had abnormal AV conduction at or below the AV node (18 with AV block of which 5 also had bundle branch block (BBB), 6 with SND and BBB, and 5 with AV node ablation). The remaining 31 patients (52%) had intact AV conduction. Procedure times were not significantly different between the groups (P=0.26). Selective HBP was achieved in 20.7% of abnormal AV conduction patients and 45.2% of intact AV conduction patients (P=0.06); the remaining patients had non-selective HBP. There were no differences detected in pacing characteristics at implant and paced QRS durations by AV conduction status. Patient with intact AV conduction (N=31) Patients with abnormal AV conduction at or below AV node (N=29) Procedure time in minutes (mean ± SD, Median, IQR) 99±38; 87 [43, 180] 108±32; 108 [65, 182] Fluoroscopy time in minutes (mean ± SD, Median, IQR) 15±12; 11 [3, 50] 16±9; 13 [4, 36] Number of fixation attempts 3.0±2.2 2.2±2.0 sHBP PCT N=14 N=6 V at 0.5ms 1.8±0.9 1.7±1.2 V at 1.0ms 1.6±1.2 1.2±0.8 nsHBP PCT N=17 N=22 V at 0.5ms 2.2±1.9 1.7±1.3 V at 1.0ms 1.5±1.1 1.3±1.1 His signal recorded, number 30 (96.8%) 28 (96.6%) H-QRS interval, ms 46±7 48±13 His Injury of Current, N (%) 23 (74.2%) 18 (62.1%) Baseline Intrinsic QRS, ms 96±16 107±22 Paced QRS duration, ms (from HBP at 1.0ms) 119±23 121±19 Conclusions Selective and non-selective HBP are achievable in bradycardic patients with abnormal and intact AV conduction, including those with BBB. There were no major differences in HBP implant parameters between patients with abnormal AV conduction and those with intact AV conduction.

Adrenergic potentiation on spontaneous activity of canine paranodal fibers

1984 ◽  
Vol 247 (3) ◽  
pp. H415-H421
Author(s):  
W. W. Tse
Keyword(s):  
Spontaneous Activity ◽  
Tricuspid Valve ◽  
Action Potentials ◽  
Smooth Transition ◽  
Convex Side ◽  
Av Node ◽  
Junctional Tachycardia ◽  
His Bundle ◽  
Spontaneous Rate

The present study, using in vitro preparations, was designed to determine the anatomic, histological, and automatic properties of canine paranodal fibers. This tissue, together with the atrioventricular (AV) node and His bundle, constituted the three major tissues in the AV junction. The fascicles of the paranodal fibers ran parallel and adjacent to the base of the septal cusp of the tricuspid valve. The distal end of the paranodal fibers joined the lower half of the compact AV node on its convex side. Paranodal fibers when isolated were able to initiate spontaneous activity. Action potentials of many of these fibers showed primary pacemaker characteristics, i.e., a prominent phase 4 depolarization and smooth transition from phases 4 to 0. In 14 preparations, epinephrine (2.0 micrograms injected into the tissue bath) potentiated spontaneous rates to 144 +/- 6.0 beats/min from 61 +/- 5.0, an increase of 136%. Also, under the influence of epinephrine, paranodal fibers consistently generated a spontaneous rate higher than that of the AV node or His bundle, whether they were functionally connected or separated. These findings provide a basis for explaining the junctional tachycardia that occurs under adrenergic influence and demonstrate the presence of three major automatic tissues: the paranodal fibers, AV node, and His bundle in the canine AV junction.

scholarly journals Echobiometrics kidney and renal artery triplex doppler of canine fetuses

2014 ◽  
Vol 66 (2) ◽  
pp. 445-449 ◽  
Author(s):  
M.A.R. Feliciano ◽  
D.J. Cardilli ◽  
A.C. Nepomuceno ◽  
R.M. Crivalero ◽  
M.A.M. Silva ◽  
...  
Keyword(s):  
Renal Artery ◽  
Fetal Development ◽  
Pulsatility Index ◽  
Peak Velocity ◽  
Renal Arteries ◽  
Renal Development ◽  
Diastolic Velocity ◽  
Renal Abnormalities ◽  
Time Point

The aim of this study was to assess the sogographic parameters and biometry of canine fetal kidneys using the B mode, and to determinate the vascular index of the fetal renal arteries using the Doppler Triplex. Twenty four Shi-tzu and Pug, weighting between 4 and 10kg, aging between 4 and 6 years old were evaluated. The B mode, the fetal renal echobiometry and regularity of the renal surface, echotexture and cortex:medular ratio were evaluated during the 5th, 6th, 7th and 8th weeks of pregnancy. At the same time point of the B mode evaluation, the Doppler Triplex was carried out to assess the sistolic peak velocity (SPV), end diastolic velocity (EDV), vascular resistive (RI) and pulsatility index (PI). B mode revealed no fetal renal abnormalities and echobiometry showed important measurements during fetal development (P<0.0001). The values of the fetal renal arteries index (PSV and EDV) increased during the course of the pregancy (P<0.05) and remained constant for PI and RI (P>0.05). B mode and Doppler Triplex were important tools for the assessment of fetal renal development, using echobiometry and renal arterial index in canie fetuses.

P508Biventricular pacing versus His bundle pacing after atrioventricular node ablation in heart failure patients with permanent atrial fibrillation and narrow QRS

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
D Zizek ◽  
B Antolic ◽  
D Zavrl-Dzananovic ◽  
L Klemen ◽  
M Jan ◽  
...  
Keyword(s):  
Heart Failure ◽  
Rate Control ◽  
Atrioventricular Node ◽  
Short Term ◽  
Av Node ◽  
Permanent Atrial Fibrillation ◽  
Narrow Qrs ◽  
Qrs Duration ◽  
Lv Ejection Fraction

Abstract Background Atrioventricular (AV) node ablation with biventricular (BiV) pacemaker implantation is a feasible rate control strategy for symptomatic permanent atrial fibrillation (AF) with rapid ventricular response and tachycardia-induced heart failure (HF). However, certain controversy exists since BiV pacing delivers non-physiological ventricular resynchronization and does not return left ventricular (LV) activation times to those seen in individuals with intrinsically narrow QRS. Permanent His bundle pacing (HBP) is a physiological alternative to conventional and BiV pacing. By capturing the native conduction system, depolarization of the ventricles through the His-Purkinje system induces normal synchronous ventricular activation. Purpose The aim of the study was to compare short-term outcomes between BiV pacing and HBP after AV node ablation in HF patients with symptomatic permanent AF and narrow QRS. Methods A total of 25 consecutive HF patients with permanent AF and narrow QRS (≤110 ms) who underwent AV node ablation in conjunction with BiV pacing or HBP in our centre were enrolled. Post-implant QRS duration, echocardiographic data, and New York Heart Association (NYHA) functional class were assessed in short-term follow-up. Results Among 25 HF patients (aged 68 ± 7 years, 52% female, QRS 96 ± 9 ms, LVEF 37 ± 7%, NYHA II-IV), 13 received BiV pacing and 12 HBP. Implant and ablation procedures were acutely successful in both groups. In BiV group 1 patient had a LV lead dislodgement and 1 patient in the HBP group had an acute HB lead threshold increase after AV node ablation. In HBP group post-implant QRS duration was shorter compared to BiV (103 ± 15 ms vs. 177 ± 13 ms, p &lt; 0.001). At a median follow-up of 6 months, patients treated with HBP had greater increase in LV ejection fraction compared to BiV (44 ± 10 vs. 37 ± 6, p = 0.045). A trend toward greater reduction of LV volumes (EDV 119 ± 54 ml vs. 153 ± 33 ml, p = 0.07; ESV 75 ± 34 ml vs. 97 ± 26 ml, p = 0.09) and improvement of NYHA class (2.1 ± 0.7 vs. 2.7 ± 0.8, p = 0.08) was also observed in HBP group compared to BiV group. Conclusion In rate control refractory HF patients with permanent AF and narrow QRS atrioventricular node ablation in conjunction with HBP demonstrated superior electrical resynchronization and greater increase in LV ejection fraction compared to BiV pacing. Larger prospective studies are warranted to address clinical outcomes between both pace and ablate strategies.

Effects of hypoxia on atrioventricular node of adult and neonatal rabbit hearts

1989 ◽  
Vol 256 (5) ◽  
pp. H1337-H1343 ◽  
Author(s):  
M. L. Young ◽  
R. C. Tan ◽  
B. M. Ramza ◽  
R. W. Joyner
Keyword(s):  
Cycle Length ◽  
Atrioventricular Node ◽  
The Other ◽  
Adult Rabbit ◽  
Atrial Pacing ◽  
Isolated Perfused Heart ◽  
Heart Model ◽  
Perfused Heart ◽  
Av Node ◽  
The Difference

We used an isolated perfused heart model to assess the effects of graded hypoxia (95, 45, 20, 10, or 0% O2, exposure for 5 min) on the adult and neonatal (0-3 days) rabbit atrioventricular (AV) node. The AV nodal function was assessed by measuring the A-H interval at a constant atrial pacing cycle length, the longest pacing cycle length resulting in Wenckebach periodicity [Wenckebach cycle length (WCL)] and the AV nodal effective refractory period (AVNERP). The A-H intervals remained stable in neonatal hearts until O2 saturation was decreased to 10%. On the other hand, the A-H intervals began to increase in adult rabbit hearts at 20% O2. In 95% O2, the AV nodal WCL was longer in adult hearts than in the neonatal hearts (165 +/- 8 ms vs. 142 +/- 7 ms). The effect of hypoxia on the AV nodal WCL was significantly greater in adult hearts than in neonatal hearts when the O2 saturation was decreased to 20% (a 54% increase in adults vs. a 14% increase in neonates, P = 0.02). The difference was greater at lower levels of O2. In 95% O2 at comparable basis driving cycle length (240 ms), the A-H intervals were equal in neonatal and adult hearts (43 +/- 3 vs. 43 +/- 7 ms), but the AVNERP of the neonates was significantly longer than that of the adults (133 +/- 21 vs. 97 +/- 19 ms, P = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of AV nodal and Hisian conduction by changes in extracellular space

1999 ◽  
Vol 276 (3) ◽  
pp. H953-H960
Author(s):  
Keith G. Lurie ◽  
Atsushi Sugiyama ◽  
Scott McKnite ◽  
Paul Coffeen ◽  
Keitaro Hashimoto ◽  
...  
Keyword(s):  
Extracellular Space ◽  
Left Ventricular ◽  
Conduction Time ◽  
Av Node ◽  
Total Blood ◽  
His Bundle ◽  
Induced Changes ◽  
Total Blood Flow ◽  
Dose Dependent Increase ◽  
Dose Dependent

Previous studies have demonstrated that the extracellular space (ECS) component of the atrioventricular (AV) node and His bundle region is larger than the ECS in adjacent contractile myocardium. The potential physiological significance of this observation was examined in a canine blood-perfused AV nodal preparation. Mannitol, an ECS osmotic expander, was infused directly into either the AV node or His bundle region. This resulted in a significant dose-dependent increase in the AV nodal or His-ventricular conduction time and in the AV nodal effective refractory period. Mannitol infusion eventually resulted in Wenckebach block ( n = 6), which reversed with mannitol washout. The ratio of AV nodal to left ventricular ECS in tissue frozen immediately on the development of heart block ( n = 8) was significantly higher in the region of block (4.53 ± 0.61) compared with that in control preparations (2.23 ± 0.35, n = 6, P < 0.01) and donor dog hearts (2.45 ± 0.18, n = 11, P < 0.01) not exposed to mannitol. With lower mannitol rates (10% of total blood flow), AV nodal conduction times increased by 5–10% and the AV node became supersensitive to adenosine, acetylcholine, and carbachol, but not to norepinephrine. We conclude that mannitol-induced changes in AV node and His bundle ECS markedly alter conduction system electrophysiology and the sensitivity of conductive tissues to purinergic and cholinergic agonists.

Haemodynamic changes with the use of neuromuscular electrical stimulation compared to intermittent pneumatic compression

2014 ◽  
Vol 30 (5) ◽  
pp. 365-372 ◽  
Author(s):  
KJ Williams ◽  
HM Moore ◽  
AH Davies
Keyword(s):  
Electrical Stimulation ◽  
Healthy Subjects ◽  
Peak Velocity ◽  
Neuromuscular Electrical Stimulation ◽  
Haemodynamic Effect ◽  
Maximum Velocity ◽  
Intermittent Pneumatic Compression ◽  
Laser Doppler ◽  
Thrombosis Prophylaxis ◽  
Electrical Stimulator

Introduction Enhancement of peripheral circulation has been shown to be of benefit in many vascular disorders, and the clinical effectiveness of intermittent pneumatic compression is well established in peripheral vascular disease. This study compares the haemodynamic efficacy of a novel neuromuscular electrical stimulation device with intermittent pneumatic compression in healthy subjects. Methods Ten healthy volunteers (mean age 27.1 ± 3.8 years, body mass index 24.8 ± 3.6 kg/m2) were randomised into two groups, in an interventional crossover trial. Devices used were the SCD Express™ Compression System, (Covidien, Ireland) and the geko™, (Firstkind Ltd, UK). Devices were applied bilaterally, and haemodynamic measurements taken from the left leg. Changes to haemodynamic parameters (superficial femory artery and femoral vein) and laser Doppler measurements from the hand and foot were compared. Results Intermittent pneumatic compression caused 51% ( p = 0.002), 5% (ns) and 3% (ns) median increases in venous peak velocity, time-averaged maximum velocity and volume flow, respectively; neuromuscular electrical stimulator stimulation caused a 103%, 101% and 101% median increases in the same parameters (all p = 0.002). The benefit was lost upon deactivation. Intermittent pneumatic compression did not improve arterial haemodynamics. Neuromuscular electrical stimulator caused 11%, 84% and 75% increase in arterial parameters ( p < 0.01). Laser Doppler readings taken from the leg were increased by neuromuscular electrical stimulator ( p < 0.001), dropping after deactivation. For intermittent pneumatic compression, the readings decreased during use but increased after cessation. Hand flux signal dropped during activation of both devices, rising after cessation. Discussion The neuromuscular electrical stimulator device used in this study enhances venous flow and peak velocity in the legs of healthy subjects and is equal or superior to intermittent pneumatic compression. This warrants further clinical and economic evaluation for deep venous thrombosis prophylaxis and exploration of the haemodynamic effect in venous pathology. It also enhances arterial time-averaged maximum velocity and flow rate, which may prove to be of clinical use in the management of peripheral arterial disease. The effect on the microcirculation as evidenced by laser Doppler fluximetry may reflect a clinically beneficial target in microvascular disease, such as in the diabetic foot.

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