Different Parts Of Heart Research Articles

Implementation of cardiac Purkinje Fiber cells Model: High speed and low cost hardware

Purkinje fibers (PFs) permit the heart's conduction system to produce synchronized contractions of its ventricles, critical for continuing a reliable heart rhythm. Hardware realization of different parts of heart is done to simulate or dealing with some of diseases and deficiencies. PF performance can be described by models including a set of differential equations. In this paper the Noble model is modified for implementing a hardware to mimic the PF performance. The original model includes non-linear terms which are low speed and high cost regarding the hardware resources because of need to use the units such as multipliers. In modified model, the non-linear terms are converted to 2x terms to be implemented by low cost and high speed digital hardware such as logical SHIFTs, ADDs, and SUBs. The dynamic behavior of proposed model is close to the original model. A digital platform, Spartan 3xc3s50 tq144 Field Programmable Gate Arrays (FPGA) is used to certify the precision and feasibility of proposed model. The results show that the proposed model is easily implemented on this board and is able to produce different PF patterns at the maximum frequency of 162.273 MHz meanwhile the original model is not implementable because of its non-linear elements.

ACCURATE DETECTION AND CASSIFICATION OF VENTRICULAR ABNORMAMLITIESS USING MORPHOLOGICAL FEATURES

Electrocardiogram (ECG) is a bioelectrical signal which presents the electrical activity of different parts of heart in time domain. The accurate study of this signal leads to precise detection of ventricular arrhythmias that are serious problems in today's world and might lead to Sudden Cardiac Death (SCD). This research attempts to achieve accurate and fast detection and classification of ventricular abnormalities from morphological features using cross correlation between normal sinus beat and abnormal beats. Cross correlation between RR intervals and TT intervals in zero lag was used because of separation between normal sinus rhythm and T wave alternans. Specific morphological features were attained for T wave alternans and normal sinus rhythm signals. The classification accuracy of normal sinus rhythm with ventricular tachycardia, ventricular flutter, ventricular fibrillation, premature ventricular contraction and escape beat rhythm were obtained as 100%, 92.8%, 86.8%, 90.81%, 96.28% and 91.8%, respectively. Classification accuracy of T wave alternans was achieved as 95.03%.

0174 : RadiothErapy for BrEast Cancer and early detection of CArdiotoxicity (REBECCA): a prospective cohort study

Breast radiotherapy (RT) techniques used until the 1990s were responsible for increased mortality due to long term cardiac complications. Since the 2000s, improved techniques of RT have appeared leading to different dose distributions to organ at risks such as heart. But up to now, little is known on their cardiac toxicity. The aim of the REBECCA study is to evaluate whether helical tomotherapy (HT) induces cardiac toxicity that could be detected in the first two years after treatment based on analysis of subclinical functional and anatomical cardiac lesions at myocardial and coronary levels and evolution of circulating biomarkers. REBECCA study is a prospective cohort study that will include 120 women treated with adjuvant HT for breast cancer at the Institut Universitaire du Cancer Toulouse-Oncopole (IUCT), and followed up for 2 years after RT. Women aged 40 to 70 years, surgically treated at IUCT for breast cancer and for whom adjuvant RT with HT is indicated, without chemotherapy will be eligible for the study. Follow-up will include measures of a panel circulating biomarkers, coronary plaque index based on Coronary computed tomography angiography and myocardial strain based on 2D-speckle tracking echocardiography. Absorbed doses will be evaluated for the whole heart and for each different parts of heart, in particular coronary arteries. Analysis will focus on dose-response relationship between subclinical cardiac lesions, biomarkers, and different organ absorbed doses. Furthermore, this study aims to create a bio-bank of plasma and blood of this cohort for future investigations. This clinical research study is a novel approach to early detect cardiotoxicity of current breast RT, combining anatomical and functional heart consequences based on cardiac imaging, a panel of circulating biomarkers and a detailed heart dosimetry. With this approach, REBECCA aims to improve understanding of the mechanisms and circumstances that underlie the development of potential heart side effects and sequelaes.

Is there a significant transmural gradient in repolarization time in the intact heart?

Is there a significant transmural gradient in repolarization time in the intact heart?

Coenzyme Q10 content in different parts of the normal human heart.

Coenzyme Q10 (CoQ10) and citrate synthase (CS) activities were analysed in the myocardium of brain-dead organ donors (14-40 years). Different parts of the heart were studied: right and left auricular appendage, right and left atrium, right ventricle (septum and free wall) and left ventricle (septum, free wall, and papillary muscle). Freeze-dried, dissected myocardial samples were analysed for CoQ10 content by HPLC and CS activity by fluorometric technique. CoQ10 content in the normal human myocardium was lowest in auricular appendages and atria (0.25 +/- 0.06 mg X g-1 dry muscle), intermediate in right ventricle (0.37 +/- 0.05 mg X g-1 dm) and highest in left ventricle (0.42 +/- 0.07 mg X g-1 dm). CS activity showed the same relationship between these locations as CoQ10. The results suggest that there exist differences in CoQ10 content between different parts of the normal human myocardium. These differences were closely related to the differences in CS activity between corresponding parts. The differences between different parts of the heart may be related to divergent work demand, and the constant relationship between CS and CoQ10 may be related to their coupling to the mitochondrial oxidative metabolism.

Study of the PG E 2 synthetase activity of different regions of dog and rabbit hearts

Prostaglandin E 2 synthetase activity of the microsomal fraction from different parts of dog and rabbit heart was tested with 3H-arachidonic acid as substrate. PG E 2 synthesized was separated and purified by TLC and determined by the radiometric method or by bioassay. In the experimental conditions adopted, it was shown that the heart tissue is endowed with an enzyme system capable of synthesizing PG E 2 but this PG E 2 synthetase activity is not uniformly distributed in the different parts of the heart. It is highest in the right atrium and the activity of the atria is higher than that of the ventricles. It is species-dependent. The closely similar repartition of PG E 2 synthetase activity and sympathetic nerve endings strongly suggests that PG E 2 modulates adrenergic neurotransmission in the heart.