Ventricular activation process and genesis of QRS complex in the goat

1961 ◽  
Vol 200 (2) ◽  
pp. 223-228 ◽  
Author(s):  
Robert L. Hamlin ◽  
Allen M. Scher

The pathways of ventricular excitation in the interventricular septum and the free walls of the ventricles were determined in the goat. During the first 5 msec. of the QRS complex, activity occurs in a cup-shaped zone formed around the apex of the left ventricular cavity, consisting of the left endocardial portions of the septum and the endocardium of the free wall. Within the next 10 msec. of the QRS, the apical third of the septum is excited, simultaneously, from both the left and the right ventricular endocardial surfaces. Also, all of the ventricles, except the bases and a small epicardial apical area of the left ventricle, are excited with almost a single burst of depolarization. During the next 3–5 msec. the ventricular bases and the small apical epicardial area are excited along with the middle third of the interventricular septum. The final 15 msec. of the QRS and approximately 3 msec. of the following isoelectric period are inscribed during activation of the basilar third of the septum.

2020 ◽  
Vol 4 (3) ◽  
pp. 1-5
Author(s):  
Mandeep Singh Sondh ◽  
Rohit Tandon ◽  
Rajiv Gupta ◽  
Gurpreet Singh Wander

Abstract Background Aneurysms of the sinus of Valsalva (SOV) are thin-walled outpouchings most commonly involving the right or non-coronary sinuses. Because they are asymptomatic, they are rarely discovered before they rupture and form an aorto-cardiac fistula. We present a rare case of unruptured aneurysm of the right coronary SOV burrowing into the interventricular septum with severe aortic incompetence and left ventricular dysfunction. To our knowledge, burrowing of the SOV aneurysm (SVA) into the interventricular septum and its large sac-like appearance has never been described using three dimensional (3D) echocardiography before. Case summary A 37-year-old man presented to the cardiology outpatient department with complaints of dyspnoea and palpitations (New York Heart Association Class II–III) for the last 6 months. He was evaluated with transthoracic echocardiography which showed a large mobile sac-like structure with irregular borders bulging and prolapsing into the left ventricular cavity with each cardiac cycle along with severe aortic incompetence. On transoesophageal echocardiogram, the right coronary cusp showed malcoaptation with deformed aortic sinus causing severe aortic incompetence. Cardiac computed tomography showed sparing of right coronary artery at the origin. A diagnosis of SVA was made. The patient underwent aortic valve replacement along with partial resection of the aneurysm. The patient had an uneventful postoperative course. Follow-up echocardiography after 4 weeks showed well-seated aortic valve prosthesis with residual SVA. The ejection fraction decreased from 46–48% to 36–38%. Discussion Comprehensive multimodality imaging can be used for management strategy of SVA.


2005 ◽  
Vol 129 (9) ◽  
pp. 1155-1158
Author(s):  
Brendan P. Lucey ◽  
Caroline Bedell Thomas ◽  
Grover M. Hutchins

Abstract A 14-year-old adolescent girl presented with severe congestive heart failure, progressive throughout 3 months. A precordial thrill, machinery-like murmur, and right bundle branch block were noted. Death occurred despite digitalis and diuretic therapy and removal of pleural and ascitic fluid. The autopsy revealed 2 multilocular cystic structures in the interventricular septum consistent with being spontaneously drained valve ring abscesses. One of these lesions formed a fistulous communication that penetrated through the interventricular septum between the right aortic sinus of Valsalva and the crista supraventricularis that connected to the right ventricle. Another lesion, an adjacent separate but similar cystlike structure, communicated only with the left ventricular cavity. Although the cause of these lesions is uncertain, it seems probable that they are the residue of spontaneously drained and healed valve ring abscesses. Max Brödel, a medical illustrator and the first director of the Department of Art as Applied to Medicine at The Johns Hopkins University, drew previously unpublished figures of this patient's cardiac lesions. These illustrations exhibit Brö del's superb command of both art and medicine essential to his ability to make complex anatomic relationships demonstrable. We discuss Brödel's career and his influence on both the art and science of medicine.


2021 ◽  
Vol 29 (2) ◽  
pp. 239-244
Author(s):  
Vadim S. Petrov ◽  
Alexander A. Nikiforov ◽  
Elena A. Smirnova

AIM: This study aimed to identify the associations of CYP3A4 isoenzyme gene polymorphism with the parameters of echocardiography (EchoCG), spirometry, and endothelial function of patients with chronic rheumatic heart disease (CRHD). MATERIALS AND METHODS: A total of 128 patients with CRHD (15.6% men and 84.4% women) were examined. A392A, A392G, and G392G polymorphic markers were genotyped through polymerase chain reaction (PCR) with an SNP-EXPRESS electrophoretic scheme (NPF Litekh, Russia) to detect results after DNA was isolated from leukocytes in venous blood. EchoCG was implemented on an Affinity 50 apparatus (Philips, the Netherlands), endothelial function was assessed with an AngioScan01 apparatus (AngioScan-Electronics, Russia), and respiratory function was examined using a SpiroLab II spirometer (MIR Medical, Italy). RESULTS: The distance in a 6 min walk test did not show any significant differences among the groups: A392A 327.47 6.71 m, A392G 303.63 26.19 m, G392G 338.87 20.12 m (p=0.505). The area of the mitral opening was as follows: A392A 1.74 (1.67; 1.81) cm2, A392G 1.68 (1.45; 1.92) cm2, and G392G 1.65 (1.67; 1.81) cm2 (p = 0.214). As for the EchoCG parameters, the group of G392G homozygotes had the lowest linear dimensions of the left ventricle (the end diastolic dimension 4.83 (4.72; 4.95) cm, the end systolic dimension 2.97 (2.79; 3.14) cm, the right ventricle (2.45 [2.32; 2.58] cm), of the right atrium (4.09 [3.56; 4.62] cm), and the criteria of left ventricular hypertrophy (thickness of the interventricular septum 0.88 [0.81; 0.95] cm, and the posterior wall 0.88 (0.81; 0.95 cm). No statistically significant differences were found in the occlusion index amplitude among the groups, that is, single nucleotide replacements of CYP3A4 had no influence on the system of low-resistance arteries. Conversely, the values of the phase shift between channels (reflecting the condition of large arteries) significantly differed. The G392G polymorphism showed the worst parameters, and minimal changes were observed in the A392A group. Contour analysis demonstrated the highest augmentation index values in the G392G group, reflecting the maximal stiffness of vessels. The CYP3A4 polymorphism had no effect on the parameters of respiratory function in the studied cohort of patients. Spirometry revealed that the obstructive and restrictive parameters were not significant although homozygotes demonstrated the highest forced vital capacity of the lungs (76.5% [71.1% and 82.0%]) and forced expiratory volume for 1 s (84.6% [79.0% and 90.3%]). The maximal parameter of the vital capacity of the lungs in homozygotes for A392A (85.6% [82.3% and 88.8%]). CONCLUSION: Patients with CRHD homozygous for G392G had the minimum parameters of hypertrophy and dimensions of the left ventricular cavity. They also had the lowest values for the cavities of the right heart. CYP3A4 polymorphism had no effect on the parameters of respiratory function in the studied patients with CRHD.


1964 ◽  
Vol 207 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Robert L. Hamlin ◽  
David L. Smetzer ◽  
C. Roger Smith

A semiorthogonal lead system for recording electrocardiograms from horses was designed. The X, Y, and Z axes of the body were monitored by leads I, aVF, and V10 (the unipolar lead taken from the dorsal spinous process of the seventh thoracic vertebra), respectively. Records were taken from 15 standing horses. Ventricular premature beats were elicited by pricking foci on the right and left ventricular epicardium. For normally conducted beats, two major vectors represented forces generating the QRS complex. Vector 1, probably representing excitation of the apical third of the interventricular septum from left to right, was relatively low in magnitude, and was oriented dextrad, ventrad, and craniad. Vector 2, probably representing depolarization of the basilar third of the interventricular septum from left to right and in an apicobasilar direction, was of greater magnitude and was oriented ventrad, sinistrad, and craniad. Occasionally a vector intermediate between vectors 1 and 2 was oriented caudad and dorsad. The origin of this vector is equivocal. Left ventricular premature beats generated vectors of great magnitude oriented dextrad and craniad. Right ventricular premature beats generated vectors of magnitude between those of sinus or left ventricular origin, and directed predominantly sinistrad.


2021 ◽  
Vol 10 (4) ◽  
pp. 822
Author(s):  
Luuk I.B. Heckman ◽  
Justin G.L.M. Luermans ◽  
Karol Curila ◽  
Antonius M.W. Van Stipdonk ◽  
Sjoerd Westra ◽  
...  

Background: Left bundle branch area pacing (LBBAP) has recently been introduced as a novel physiological pacing strategy. Within LBBAP, distinction is made between left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP, no left bundle capture). Objective: To investigate acute electrophysiological effects of LBBP and LVSP as compared to intrinsic ventricular conduction. Methods: Fifty patients with normal cardiac function and pacemaker indication for bradycardia underwent LBBAP. Electrocardiography (ECG) characteristics were evaluated during pacing at various depths within the septum: starting at the right ventricular (RV) side of the septum: the last position with QS morphology, the first position with r’ morphology, LVSP and—in patients where left bundle branch (LBB) capture was achieved—LBBP. From the ECG’s QRS duration and QRS morphology in lead V1, the stimulus- left ventricular activation time left ventricular activation time (LVAT) interval were measured. After conversion of the ECG into vectorcardiogram (VCG) (Kors conversion matrix), QRS area and QRS vector in transverse plane (Azimuth) were determined. Results: QRS area significantly decreased from 82 ± 29 µVs during RV septal pacing (RVSP) to 46 ± 12 µVs during LVSP. In the subgroup where LBB capture was achieved (n = 31), QRS area significantly decreased from 46 ± 17 µVs during LVSP to 38 ± 15 µVs during LBBP, while LVAT was not significantly different between LVSP and LBBP. In patients with normal ventricular activation and narrow QRS, QRS area during LBBP was not significantly different from that during intrinsic activation (37 ± 16 vs. 35 ± 19 µVs, respectively). The Azimuth significantly changed from RVSP (−46 ± 33°) to LVSP (19 ± 16°) and LBBP (−22 ± 14°). The Azimuth during both LVSP and LBBP were not significantly different from normal ventricular activation. QRS area and LVAT correlated moderately (Spearman’s R = 0.58). Conclusions: ECG and VCG indices demonstrate that both LVSP and LBBP improve ventricular dyssynchrony considerably as compared to RVSP, to values close to normal ventricular activation. LBBP seems to result in a small, but significant, improvement in ventricular synchrony as compared to LVSP.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Agata Popielarz-Grygalewicz ◽  
Jakub S. Gąsior ◽  
Aleksandra Konwicka ◽  
Paweł Grygalewicz ◽  
Maria Stelmachowska-Banaś ◽  
...  

To determine whether the echocardiographic presentation allows for diagnosis of acromegalic cardiomyopathy. 140 patients with acromegaly underwent echocardiography as part of routine diagnostics. The results were compared with the control group comprising of 52 age- and sex-matched healthy volunteers. Patients with acromegaly presented with higher BMI, prevalence of arterial hypertension, and glucose metabolism disorders (i.e., diabetes and/or prediabetes). In patients with acromegaly, the following findings were detected: increased left atrial volume index, increased interventricular septum thickness, increased posterior wall thickness, and increased left ventricular mass index, accompanied by reduced diastolic function measured by the following parameters: E’med., E/E’, and E/A. Additionally, they presented with abnormal right ventricular systolic pressure. All patients had normal systolic function measured by ejection fraction. However, the values of global longitudinal strain were slightly lower in patients than in the control group; the difference was statistically significant. There were no statistically significant differences in the size of the right and left ventricle, thickness of the right ventricular free wall, and indexed diameter of the ascending aorta between patients with acromegaly and healthy volunteers. None of 140 patients presented systolic dysfunction, which is the last phase of the so-called acromegalic cardiomyopathy. Some abnormal echocardiographic parameters found in acromegalic patients may be caused by concomitant diseases and not elevated levels of GH or IGF-1 alone. The potential role of demographic parameters like age, sex, and/or BMI requires further research.


2019 ◽  
Author(s):  
Safir Soukaina

Rhabdomyoma represent a rare cardiac tumor often associated with tuberous sclerosis however is often remains asymptomatic with a regressive pattern of evolution throughout childhood. We report a rare case of an infant of 1 year old from a uneventful pregnancy and delivery,with normal developmental milestones, whose mother noticed two episodes of brief period of loss of consciousness and muscle tone upon pediatric consultation clinical examination reveal a conscious child able to stand without support with hypopigmented skin lesion a CT scan revealed periventricular calcifications with subcortical intraparenchymal hypodense plaque an EEG without signs of epileptic pattern EKG didn’t reveal signs of arrythmias and transthoracic echogardiogram showing multiple hyperechogenic homogenous tumors one attached to the interventricular septum with intermittant left ventricular outflow tract obstruction due to motion second near to the tricuspid valve with no signs of obstruction and a third attached to the free wall of the right ventricle. Tuberous sclerosis was retained as a diagnosis with rhabdomyoma and the management was based on regular cardiac monitoring with marked regression of tumor size and no recurrence of syncope episodes.


Author(s):  
Joseph Hadaya ◽  
Una Buckley ◽  
Nil Z. Gurel ◽  
Christopher A. Chan ◽  
Mohammed A Swid ◽  
...  

Maladaptation of the sympathetic nervous system contributes to the progression of cardiovascular disease and risk for sudden cardiac death, the leading cause of mortality worldwide. Axonal modulation therapy (AMT) directed at the paravertebral chain blocks sympathetic efferent outflow to the heart, and may be a promising strategy to mitigate excess disease-associated sympathoexcitation. The present work evaluates AMT, directed at the sympathetic chain, in blocking sympathoexcitation using a porcine model. In anesthetized porcine (n=14), we applied AMT to the right T1-T2 paravertebral chain and performed electrical stimulation of the distal portion of the right sympathetic chain (RSS). RSS-evoked changes in heart rate, contractility, ventricular activation recovery interval (ARI), and norepinephrine release were examined with and without kilohertz frequency alternating current block (KHFAC). To evaluate efficacy of AMT in the setting of sympathectomy, evaluations were performed in the intact state and repeated after left and bilateral sympathectomy. We found strong correlations between AMT intensity and block of sympathetic stimulation-evoked changes in cardiac electrical and mechanical indices (r=0.83-0.96, effect size d=1.9-5.7), as well as evidence of sustainability and memory. AMT significantly reduced RSS-evoked left ventricular interstitial norepinephrine release, as well as coronary sinus norepinephrine levels. Moreover, AMT remained efficacious following removal of the left sympathetic chain, with similar mitigation of evoked cardiac changes and reduction of catecholamine release. With growth of neuromodulation, an on-demand or reactionary system for reversible AMT may have therapeutic potential for cardiovascular disease-associated sympathoexcitation.


EP Europace ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 1234-1239
Author(s):  
Wei Ji ◽  
Xueying Chen ◽  
Jie Shen ◽  
Diqi Zhu ◽  
Yiwei Chen ◽  
...  

Abstract Aims As a physiological pacing strategy, left bundle branch pacing (LBBP) were used to correct left bundle branch block (LBBB), however, there is no relevant report in children. We aimed to evaluate the feasibility of LBBP in children. Methods and results Left bundle branch pacing was performed in a 10-year-old girl with a second-degree atrioventricular and LBBB. Under the guide of fluoroscopy, the pacing lead was deeply screwed into the interventricular septum to gain right bundle branch block (RBBB) pattern of paced QRS. Selective LBBP was achieved with a typical RBBB pattern of paced morphology and a discrete component between stimulus and ventricular activation in intracardiac electrogram and reached the standard of the stimulus to left ventricular activation time of 56 ms. At a 3-month follow-up, the LBBP acquired the reduction of left ventricular size and enhancement of left ventricular ejection fraction. Conclusion The application of LBBP in a child was first achieved with inspiring preliminary results. The LBBP can be carried out in children by cautiousness under the premise of strict grasp of indications.


1986 ◽  
Vol 251 (5) ◽  
pp. H1062-H1075 ◽  
Author(s):  
B. K. Slinker ◽  
S. A. Glantz

Right ventricular volume affects left ventricular volume via direct interaction across the interventricular septum and series interaction because the right and left hearts are connected in series through the lungs. Because it is difficult to sort out complex physiological mechanisms in the intact circulation, the relative importance of these two effects is unknown. We used statistical analyses of transient changes in left and right ventricular pressures and dimensions following pulmonary artery and venae caval constrictions to separate and quantitate the direct (immediate) from the series (delayed) interaction effects on left ventricular size at end systole and end diastole. With the pericardium closed, direct interaction was one-half as important as series interaction at end diastole and was one-third as important at end systole. With the pericardium removed, direct interaction was one-fifth as important as series interaction at end diastole and one-sixth as important at end systole. These results suggest that differences between transient and steady-state end-systolic pressure-volume relationships are largely explained by direct interaction and that direct end-systolic interaction is important for maintaining balanced right and left heart outputs.


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