scholarly journals His bundle has shorter chronaxie than adjacent ventricular myocardium: Implications for pacemaker programming

2019 ◽  
Author(s):  
Marek Jastrzębski ◽  
Paweł Moskal ◽  
Agnieszka Bednarek ◽  
Grzegorz Kiełbasa ◽  
Pugazhendhi Vijayaraman ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Safety Margin ◽  
Ventricular Myocardium ◽  
His Bundle ◽  
First Time ◽  
Distance Zone ◽  
Current Drain

AbstractBackgroundStrength-duration curves for permanent His bundle (HB) pacing are potentially important for pacemaker programming.ObjectiveWe aimed to calculate strength-duration curve and chronaxie of the His bundle (HB) and of the adjacent right ventricular (RV) working myocardium and to analyze zones of selective HB capture and battery current drain when pacing at different pulse durations (PDs).MethodsConsecutive patients with permanent HB pacing were studied. The RV and HB capture thresholds were assessed at several PDs. Battery current drain and zones of selective HB capture at PDs of 0.1, 0.2, 0.4 and 1.0 ms were determined.ResultsIn the whole group (n =127) the HB chronaxie was shorter than the RV chronaxie. This difference was driven by patients with selective HB pacing (HB chronaxie of 0.47 vs RV chronaxie of 0.79 ms). Strength-duration curve for HB had lower rheobase and its steep portion started at shorter PDs thus creating wider distance - zone of programmable selective HB pacing - between the HB and RV strength-duration curves at shorter PDs. The battery current drain was lower with pacing at PDs of 0.1 - 0.4 ms vs 1.0 ms. Chronaxie adjusted PDs offered lowest current drain.ConclusionFor the first time the strength-duration curves for permanent selective and non-selective HB pacing were determined. Selective HB capture and battery longevity can be promoted by shorter PDs (0.2 ms). Longer PDs (1.0 ms) offer bigger safety margin for RV capture and may be preferable if simultaneous RV capture during HB pacing is desired.

P6547The energy cost of His bundle pacing can be curtailed

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
F Zanon ◽  
L Marcantoni ◽  
G Pastore ◽  
E Baracca ◽  
C Picariello ◽  
...  
Keyword(s):  
Pulse Duration ◽  
Safety Margin ◽  
Significant Saving ◽  
His Bundle ◽  
His Bundle Pacing ◽  
On Demand ◽  
Mild Reduction ◽  
Ventricular Activation ◽  
The Individual ◽  
Current Drain

Abstract Introduction His bundle pacing (HBP) allows physiological ventricular activation and prevents the electrical and mechanical desynchronization generally induced by myocardial stimulation, which can increase the risk of atrial fibrillation and heart failure. On the other hand, reliable HBP capture often requires higher energy than conventional myocardial pacing. This reduces the expected life of the stimulator and might limit the diffusion of HBP in the clinical practice. Purpose Decreasing HBP current drain by careful management of stimulation safety margin and pulse duration. Methods In 28 patients undergoing DDD pacing with HBP, a third lead was implanted in RV apex to provide back-up pacing on demand. HBP and apical leads were connected, respectively, to the V1 and V2 channels of a 3-chamber stimulator. When HBP was effective, apical sensing occurred within the VV delay and prevented V2 stimulation. In contrast, in case of HBP failure, V2 sensing was missing and apical back-up pacing was promptly delivered at the end of the VV delay. The availability of a back-up pulse on demand allowed reducing the HBP safety margin with no risk. Furthermore, the individual HBP strength-duration curve was derived in the aim of optimizing the Hisian pulse parameters, which are the major determinants of the device current drain. Results Correct back-up inhibition by successful HBP and stimulation in the event of capture loss was achieved in all the patients. The latency from Hisian pacing to apical sensing averaged 96±14 ms. According to the pacemaker counters, no back-up pulse was delivered in daily life in 59% of patients. In the remaining, the prevalence of back-up stimulation never exceeded 15% of paced ventricular cycles. The high HBP threshold was essentially due to an increased rheobase (1.2±0.6 V), while the chronaxie ranged from 0.30 to 0.53 ms in 71% of patients (median 0.44 ms), exceeding 0.6 ms only in 29% of the cases. An average current saving of 5.4±3.0 μA was obtained at the expense of a mild reduction in HBP safety margin (from 1.6±0.2 to 1.4±0.1 times). HBP and apical back-up Conclusions Back-up stimulation on demand is a reliable option to decrease HBP current drain and prolong the stimulator service life with full safety. In most of the cases, significant saving can be achieved by pulse shortening, as the chronaxie time is in the same range as with myocardial stimulation and longer pulses are not required. A pulse duration exceeding 0.6 ms is indicated in less than 1/3 of the implants.

CONDITION OF HEMODYNAMICS IN THE PULMONARY CIRCULATION OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) CONCURRENT WITH METABOLIC SYNDROME WITH HYPERTROPHY AND ATROPHY OF THE MYOCARDIUM

2019 ◽  
Vol 72 (8) ◽  
pp. 1491-1493
Author(s):  
Viktor P. Boriak ◽  
Svitlana V. Shut’ ◽  
Tetiana A. Trybrat ◽  
Olena V. Filatova
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Metabolic Syndrome ◽  
Right Ventricular ◽  
Pulmonary Disease ◽  
Pulmonary Circulation ◽  
Contractile Function ◽  
Ventricular Myocardium ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
The Right

Introduction: In recent years, COPD is observed as not an isolated, but an associated pathology, in particular, concurrent with metabolic syndrome. The aim of the research is to identify the differences in changes of the rheopulmonography parameters (RPG) depending on the presence of hypertrophy or atrophy of the right ventricular myocardium in patients with COPD concurrent with metabolic syndrome.. Materials and methods: We studied changes in rheopulmonography (RPG) in 145 patients with chronic obstructive pulmonary disease (COPD) concurrent with metabolic syndrome. Results: We detected precapillary hypertension of the pulmonary circulation in patients with right ventricular myocardial hypertrophy: anacrotism serration; flattened peak of the systolic wave; decreased Vcp; high placement of incisura; horizontal course of catacrotism; decreased amplitude of the systolic wave (in this case, due to a greater increase in the resistance of the blood flow in the pulmonary vessels than the decreased impact volume of the right ventricle); prolonged Q-a (in this group of patients, it depends more on hypertension of the pulmonary circulation than on the reduction of contractile function of the myocardium). In atrophy of the right ventricular myocardium, the following changes in the RPG were revealed: decreased systolic wave at its dramatic rise; prolonged Q-a (in this case, due to the weakened heart contraction); Vmax reduction (it reflects the reduction of myocardial contractility); in hypertrophy of the myocardium, Vcp., unlike RPG, does not decrease, which is explained by the decrease in the pressure of the pulmonary circulation. Conclusions: We believe that these changes in RPG allow differentiating hypertrophy and right ventricular myocardial atrophy along with established diagnostic criteria, and can be used as markers for the diagnosis and treatment of COPD concurrent with metabolic syndrome.

Evidence-based management of arrhythmogenic right ventricular cardiomyopathy in pregnancy

2020 ◽  
Author(s):  
Jagjit Khosla ◽  
Reshma Golamari ◽  
Alice Cai ◽  
Jamal Benson ◽  
Wilbert S Aronow ◽  
...  
Keyword(s):  
Heart Failure ◽  
Right Ventricular ◽  
Retrospective Studies ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Genetic Disorder ◽  
Ventricular Myocardium ◽  
Evidence Based ◽  
Ventricular Cardiomyopathy ◽  
Genes Encoding ◽  
In Pregnancy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder resulting in fibrofatty replacement of the myocardium. Genetic mutations in genes encoding for desmosome proteins result in a ventricular myocardium prone to arrhythmias and heart failure. Although ARVC is known for a few decades, most of the outcomes in pregnancy are reported recently. Pregnancy leads to significant physiological changes with excess mechanical stress on the myocardium. All the retrospective studies suggest that pregnancy is well tolerated in these patients despite the high risk of arrhythmias and heart failure. Our review focuses on the most up-to-date evidence on the management of ARVC patients during the antepartum and postpartum period.

Magnetic resonance imaging in the diagnosis of non-compact right ventricular myocardium complicated by pulmonary embolism

Therapy ◽  
2021 ◽  
Vol 6_2021 ◽  
pp. 104-108
Author(s):  
Oleynikov V.E. Oleynikov ◽  
Donetskaya N.A. Donetskaya ◽  
Vdovkin A.V. Vdovkin ◽  
◽  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Pulmonary Embolism ◽  
Magnetic Resonance ◽  
Right Ventricular ◽  
Ventricular Myocardium ◽  
Resonance Imaging

Stress-induced ischemia in the right ventricular myocardium on 99mTc-MIBI myocardial perfusion scintigraphy in a rare case of double-chambered right ventricle

2018 ◽  
Vol 26 (6) ◽  
pp. 2148-2150
Author(s):  
Shelvin Kumar Vadi ◽  
Palanivel Rajan ◽  
Ashwani Sood ◽  
Manoj Kumar Rohit ◽  
Madan Parmar ◽  
...  
Keyword(s):  
Myocardial Perfusion ◽  
Right Ventricle ◽  
Right Ventricular ◽  
Rare Case ◽  
Myocardial Perfusion Scintigraphy ◽  
Ventricular Myocardium ◽  
Perfusion Scintigraphy ◽  
99Mtc Mibi ◽  
The Right

scholarly journals Post-Translational Modifications of Myofilament Proteins Involved in Length-Dependent Prolongation of Relaxation in Rabbit Right Ventricular Myocardium

2012 ◽  
Vol 102 (3) ◽  
pp. 614a
Author(s):  
Michelle M. Monasky ◽  
Domenico M. Taglieri ◽  
Alice K. Jacobson ◽  
Kaylan M. Haizlip ◽  
R John Solaro ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Ventricular Myocardium ◽  
Post Translational Modifications
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