crème de la crème basics to understand electrocardiographic analysis in an easy & simple way with some specifications to its use in Emergency medicine/clinical toxicology practice.
crème de la crème basics to understand electrocardiographic analysis in an easy & simple way with some specifications to its use in Emergency medicine/clinical toxicology practice.
Describe events in cardiac cycle.
Describe atrial, ventricular and aortic pressure changes during cardiac cycle.
Describe the changes in ventricular volume & stroke volume during cardiac cycle.
Relate ECG changes to the phases of cardiac cycle.
Describe the functions of cardiac valves and relate their state to the production of heart sounds during cardiac cycle.
med_students0
right ventricle internal and external features-
interior is divided into inflowing and outflowing parts (infundibulum)
inflowing part is rough due to trabeculae corneae, - ridges, bridges, pillars. Chordae tendineae- are attached to pillars and cusps of tricuspid valve.
outflowing part is smooth, semilunar valve guards opening of pulmonary valve
Sa nodal action potential, conducting system of heart and spread of cardiac i...Maryam Fida
SA NODE, AV NODE and Purkinje System are specialized cells of the heart having unstable phase IV.
SA Node has no role of Voltage gated sodium channels(although they are present in SA Node) and
so the depolarization in it occurs through voltage gated slow calcium channels
The membrane of SA Node is Inherently leaky to Sodium and Calcium Ions.
It is the Pre Potential Slope or spontaneous slow depolarization which accounts for the Pace maker activity of SA node i.e. Automaticity
It is caused by the inherent leakiness of SA Nodal membrane to Sodium and Calcium leading to influx of Na+ , causing a slow rise in the RMP in the positive direction.
Thus, the “resting” potential gradually rises between each two heartbeats.
When the potential reaches a threshold voltage of about -40 millivolts, the Sodium-Calcium channels become “activated,” thus causing the action potential.
It is the upstroke of action potential
When the membrane potential reaches the thresh hold level i.e. -40 mV, voltage gated slow calcium channels open up leading to influx of calcium causing depolarization
Voltage gated sodium channels has no role in SA nodal depolarization because at the level of -55 mV, the fast sodium channels mainly have already become “inactivated,” which means that they have become blocked.
The cause of this is that any time the membrane potential remains less negative than about -55 mV for more than a few milliseconds, the inactivation gates on the inside of the cell membrane that close the fast sodium channels become closed and remain so. Therefore, only the slow sodium-calcium channels can open (i.e., can become “activated”) and thereby cause the action potential.
Describe events in cardiac cycle.
Describe atrial, ventricular and aortic pressure changes during cardiac cycle.
Describe the changes in ventricular volume & stroke volume during cardiac cycle.
Relate ECG changes to the phases of cardiac cycle.
Describe the functions of cardiac valves and relate their state to the production of heart sounds during cardiac cycle.
med_students0
right ventricle internal and external features-
interior is divided into inflowing and outflowing parts (infundibulum)
inflowing part is rough due to trabeculae corneae, - ridges, bridges, pillars. Chordae tendineae- are attached to pillars and cusps of tricuspid valve.
outflowing part is smooth, semilunar valve guards opening of pulmonary valve
Sa nodal action potential, conducting system of heart and spread of cardiac i...Maryam Fida
SA NODE, AV NODE and Purkinje System are specialized cells of the heart having unstable phase IV.
SA Node has no role of Voltage gated sodium channels(although they are present in SA Node) and
so the depolarization in it occurs through voltage gated slow calcium channels
The membrane of SA Node is Inherently leaky to Sodium and Calcium Ions.
It is the Pre Potential Slope or spontaneous slow depolarization which accounts for the Pace maker activity of SA node i.e. Automaticity
It is caused by the inherent leakiness of SA Nodal membrane to Sodium and Calcium leading to influx of Na+ , causing a slow rise in the RMP in the positive direction.
Thus, the “resting” potential gradually rises between each two heartbeats.
When the potential reaches a threshold voltage of about -40 millivolts, the Sodium-Calcium channels become “activated,” thus causing the action potential.
It is the upstroke of action potential
When the membrane potential reaches the thresh hold level i.e. -40 mV, voltage gated slow calcium channels open up leading to influx of calcium causing depolarization
Voltage gated sodium channels has no role in SA nodal depolarization because at the level of -55 mV, the fast sodium channels mainly have already become “inactivated,” which means that they have become blocked.
The cause of this is that any time the membrane potential remains less negative than about -55 mV for more than a few milliseconds, the inactivation gates on the inside of the cell membrane that close the fast sodium channels become closed and remain so. Therefore, only the slow sodium-calcium channels can open (i.e., can become “activated”) and thereby cause the action potential.
Aortic stenosis is a valvular heart disease resulting in reduction of blood flow to the body and making the heart work harder. The heart may weaken causing chest pain, fatigue and shortness of breath.
ventricular premature complexes and idioventricular rhythm identification is important in the ICU ..they may run into arryhthmias..look over my seminar...
any queries...
a cardiac surgery presentation about Atrioventricular septal defect,Definition, Prevalence,Anatomy,Classification,presentation ,diagnosis and management
What separates an accomplished cardiac surgeon from the reat is the right patient selection for surgery. This PPT will give insight when its best not to opearte on a mitral valve
This presentation is no way to discredit TAVI or bring the positives of SAVR. Its about trials when short term outcomes of TAVI are compared to long term benefits of surgery.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
3. The primitive cardiac tube has five zones:
the arterial trunk
the bulbus cordis )
the ventricle
the atrium
and the sinus venosus
The arterial trunk will divide to separate the pulmonary and systemic supply.
The bulbus and the ventricle will differentiate into the right and left ventricles
5. The cardiac tube grows at a greater
longitudinal rate then the rest of the
embryo, causing it to fold. As it does this
it falls to the right. This is known as
d-looping. It may fall to the left in an
l-loop: this will lead to a malformed heart.
.
normal d-loop
l-loop
6. The Tube Bends
V
B
D
A
V
SV
The tube, as it grows, cannot be accommodated within the pericardial cavity and undergoes
bending.
8. The Conduction System
The heart is controlled by the ANS – it
increases/decreases contraction, but it
does NOT initiate it.
The heart has its own regulating system =
conduction system
The conduction system is composed of
specialized muscle tissue that generates
action potentials within cardiac tissue.
9. Conduction system
The specialized heart cells of the cardiac
conduction system generate and coordinate the
transmission of electrical impulses to myocardial
cells
The result is sequential atrioventricular
contraction which provides for the most effective
flow of blood , thereby optimizing cardiac out put
10. Characteristics of Cardiac
Conduction Cells
Automaticity: ability to initiate an electrical
impulse
Excitability: ability to respond to an electrical
impulse
Conductivity: ability to transmit an electrical
impulse from one cell to another
11. CONDUCTION SYSTEM OF THE HEART
1. SINO ATRIAL NODE
2. INTERNODAL ATRIAL
PATHWAY
3. ATRIOVENTRICULAR
NODE
4. BUNDLE OF HIS
5. PURKINJEE SYSTEM
20. SA NODE of Keith & Flack
Pacemaker of the heart
Lies- Junction of right atrial appendage with SVC
- underlies uppermost part of Sulcus terminalis
Dimensions – 10 to 20 mm X 1 mm X 3mm wide
Composition – Specialised branching myocardial
fibres embedded in dense matrix of fibrous tissue.
Artery to SA node – 55% - Right coronary artery
- 45% - Circumflex branch of LCA
21.
22. WHY SA NODE LEADS THE HEART?
TISSUE
RATE OF IMPULSE
GENERATION
SA NODE
70-80/MIN
AV NODE
40 – 60/MIN
BUNDLE OF HIS
40/MIN
PURKINJE SYSTEM
24/MIN
23. Depolarization of SA Node
SA node - no stable resting membrane potential
Pacemaker potential
– gradual depolarization from -60 mV, slow influx of Na+
Action potential
– at threshold -40 mV, fast Ca+2 channels open, (Ca+2 in)
– depolarizing phase to 0 mV, K+ channels open, (K+ out)
– repolarizing phase back to -60 mV, K+ channels close
Each depolarization creates one heartbeat
– SA node at rest fires at 0.8 sec, about 75 bpm
27. INTERNODAL CONDUCTION
PATHS
Special pathways in atrial wall
Mixture of purkinje fiber and ordinary cardiac muscle
cells
Function to transmit impulses rapidly from SA node
to AV node
•ANTERIOR-------- BACHMAN
•MIDDLE-------------WENCKEBACH
•POSTERIOR-------THOREL
28. ANTERIOR INTERNODAL TRACT
Bachmann’s Bundle
BEGINNING -leaves the anterior end of the
sinuatrial node
COURSE -passes anterior to the superior vena
caval opening -descends on the atrial septum
TERMINATION - in the atrioventricular node.
Tract composed of both ordinary Myocardial &
Purkinje fibres
29. MIDDLE INTERNODAL
PATHWAY of Wenkebach
BEGINNING -leaves the posterior end of the
sinuatrial node
COURSE
passes posterior to the superior vena caval
opening descends on the atrial septum
TERMINATION - upper end of atrioventricular
node.
30. POSTERIOR INTERNODAL PATHWAY
of Thorel
BEGINNING -Leaves the posterior part of the
sinuatrial node
COURSE -descends through the crista terminalis
and the valve of the inferior vena cava
TERMINATION - Atrioventricular node.
Formed mainly of Purkinje type fibres
32. AV Node
Node of Tawara
Lies- Subendocardially in medial wall of Rt atrium
- 1cm above the opening of coronary sinus
- basal attachment of septal cusp of tricuspid valve
Histologically – “An entanglement ” – fine poorly striated
branching specialised myocardial fibres. No dense fibrous
matrix.
Artery to AV node – 90% - Right coronary artery
- 10 % - Circumflex branch of LCA
Delay of about 0.12 sec in conduction through AV node
33.
34.
35. AV bundle of His
No sharp demarcation
2-3 cm long- passes into the substance of
central fibrous body- to reach lower margin of
membranous part of the Ventricular septum.
Vulnerability – surgical repair of VSD.
Accessory conducting bundle- WPW Syndrome
36.
37. RIGHT BUNDLE BRANCH
Considered continuation of AV bundle.
Compact bundle- 1 mm thick
Its intramyocardial course varies in length
before it reaches subendocardium on the right
side.
Principal branch of the right bundle passes into
the moderator band- septomarginal trabecula
Becomes continuous with fibers of Purkinje
fibers
38.
39. LEFT BUNDLE BRANCH
Pierces the interventricular septum
Passes down on its left side beneath the
endocardium
Divides into two branches -Anterior /Posterior
Eventually become continuous with the fibers of
the purkinje plexus of the left ventricle.
41. •ATRIAL DEPOLARIZATION COMPLETES
0.1 S
AV NODAL DELAY 0.1 SEC
SPREADING OF DEPOLARIZATION
PURKINJE FIBERS – VENTRICLE
0.08 – 0.1 S
DEPOLARIZATION WAVE MOVES
FROM LEFT TO RIGHT THROUGH SEPTUM
THE LAST PART OF THE HEART TO BE
DEPOLARIZED
POSTERO BASAL PORTION OF THE LV
PULMONARY CONUS
ARP
RRP
UPPER MOST PORTION OF THE SEPTUM
45. Conduction disturbances
First Degree AV block
Most commonly due to fibrosis of AV node or
toxicity of medications such as beta blockers or
calcium channel blockers
Other causes include edema of AV node region
after mitral and aortic valve replacement
Electrolyte disturbances
46.
47. Conduction disturbances
Second-Degree AV block
Mobitz Type II & I blocks are common after
valve replacement surgery
Drug effect or toxicity should be excluded as
potential causes
Temporary pacing may be needed depending on
degree of AV block and HR
48.
49. Conduction disturbances
Complete AV block
May be secondary to cardioplegia washout
during immediate postoperative period or as a
consequence of antiarrhythmic drug therapy
It may be seen after valve replacement
secondary to trauma of surgical manipulation in
the area of AV node or bundle of HIS
50. Conduction disturbances
Complete AV block
Factors which predict low likelihood of recovery
include -calcified Aortic valve
-delayed appearance of AV block
-significant preop conduction defect
54. Atrial Septal Defect
There are 3 major types:
Secundum ASD – at the Fossa Ovalis, most
common.
• Primum ASD – lower in position & is a form of AVSD,
MV cleft.
• Sinus Venosus ASD – high in the atrial septum,
associated w/partial anomalous venous return & the
least common.
55. ASD
ECG can be helpful in differentiating a primum ASD from the other forms of
ASD.
Because the triangle of Koch where the AV node and bundle of His are
usually located is absent in the setting of a primum ASD, the bundle must
pass in a more inferior direction to gain access to the ventricular septum.
This is associated with left axis deviation and a counterclockwise loop.
It is extremely rare for there to be left axis deviation with a secundum ASD
where the axis is more likely to be rightward than leftward depending on the
degree of right ventricular hypertrophy.
It is not uncommon to see a partial right bundle branch block reflecting right
ventricular intraventricular conduction delay
57. SURGICAL IMPLICATIONS
Surgery for sinus venosus ASD is a rather complex undertaking
to avoid atrial arrhythmias.
When the sinus venosus defect is associated with an
anomalous pulmonary vein low in the superior vena
cava, usually one atrial incision away from the sino-atrial node
can provide enough exposure to safely close the ASD and
avoid conduction problems.
If the anomalous pulmonary veins drain high in the superior
vena cava, then an alternative operation is necessary. The
operation is called a Warden operation
58. VSD
Isolated VSD comparable to TOF
Perimembranous defect- Non branching
bundle can be considerably long- directly
underneath the septal remnant
Posteroinferior area of the rim is most critical
area
Muscular outlet defects – away from
conduction bundle
Muscular inlet defects-conduction axis at
antero superior quadrant
59. VSD
The perimembranous VSD is intimately
associated with the bundle of His which in
a d-loop heart passes through the tricuspid
annulus at the posterior and inferior corner
of the VSD.
The bundle soon branches into the right
and left bundle branch
60.
61. Shallow Stitching Close to the Rim of the Ventricular
Septal Defect Eliminates Injury to the Right Bundle Branch
62. CORRECTED TGA
Since the right atrium must connect with the left ventricle (i.e.
atrioventricular discordance), it is not surprising that the
conduction system is abnormal. Pioneering work in this area
was undertaken by Anderson and colleagues.
In corrected transposition (C-TGA), the functional
atrioventricular node arises anteriorly and superiorly and is
usually lodged between the annulus of the mitral valve .
This functional AV node is therefore superior to the usual
location of the AV node which may be present as an
accessory node.
63. CORRECTED TGA
Often there is a posterior atrioventricular node in its usual
position within the triangle of Koch, but it is usually
disconnected from the remainder of the conduction tissue.
The conduction system in C-TGA is more tenuous than that of
normal hearts. Fibrosis of the junction between the
atrioventricular node and the atrioventricular bundle has been
seen in older patients
Artrial switch operation- Post operative arrhythmia less
compared to Mustard and Senning operation.
64. Tetrolgy of Fallot
4 components
VSD – PERIMEMBRANOUS/ MUSCULAR
Post op- RBBB
- SA node dysfunction
- Ventricular arrhythmias
- Complete heart block
Sudden Death – Fatal ventricular arrhythmias
Surgical approach – Right atrial vs right
ventricular
65. UNIVENTRICULAR HEART
Categorised – Left or right – based on
morphological operative single ventricle
Single right ventricle- no conduction
disturbances.
Single left ventricle- AV node is hypoplastic
- Prolonged PR interval
culminating in complete heart block
67. Tricuspid atresia with / with out
transposition
SA node is normal.
Posterior small AV node originates in close
relation to Tendon of Todaro.
Occasionally, the branching bundle may
be in close proximity to the posteroinferior rim
of the foramen and the right bundle-branch may
lie subendocardially in the rim of the defect.
68. Surgical implication
It is important, therefore, to appreciate
that the atrioventricular node is in close relation
to the tendon of Todaro, which is a readily
identifiable landmark during surgical exposure.
Closure of the foramen should usually be
accomplished safely provided that
deep sutures are not placed in the
posteroinferior quadrant.
69. POST OP ARRHYTHMIAS
Usual type of arrythmias with Atrial surgery are
SVT of which AF, Atrial flutter and junctional
rhythms are most common.
In large ostium primum type defect because of
posteriorly displaced AV node , it is frequently
associated with prolonged AV conduction.
Small osteum secundum defect causes no
problem during repair.
70. Hypothermia, ischemic arrest , direct injury to
conduction system, haematoma, injury to SA
nodal artery , oedema , forign body reaction to
suture material all are responsible for
arrhythmias
The most common conduction disturbance that
occurs after ventricular surgery is RBB block .
RBBB can be due to direct injury to main RBB
or right ventriculotomy ( in fallots tetrology
surgery ) by disrupting the right ventricular
subendocardial purkinje network
71. Post cardiac surgery
arrhythmias
Potential causes and precipitating factors
•Myocardial ischemia or infarction
•Hemodynamic instability
•Electrolyte abnormalities
a) Hypokalemia, b) Hypomagnesemia
•Metabolic disturbances
a) Acidosis, b) Alkalosis, c) Hypoxemia
•Drugs
a) Sympathomimetics, b) Antiarrhythmics, c) Anesthetic
•Reperfusion effect
•Tissue trauma or inflammation, indwelling catheters
•Increase in catecholamines
75. GENE MAPPING
.
Mutations of Nkx2.5 - lead not only to structural
cardiac abnormalities
But also to progressive atrioventricular block.
FAMILIAL
Atrial septal defects and cardiac conduction
abnormalities - shown to have mutations of Nkx2.5
76. Kearns-Sayre Syndrome
Kearns-Sayre Syndrome is disorder characterized by external
opthalmoplegia, pigmentary degeneration of the retina,
premature dementia, and a dilated cardiomyopathy, often with
progressive conduction defect.
Most cases represent new deletions but there are reports of
familial transmission of the disorder.
Depending on the exact size and location of the mitochondrial
DNA deletion, patients may also exhibit weakness of facial,
pharyngeal, trunk and extremity muscles, deafness, short
stature, and markedly increased cerebrospinal fluid proteins.
77. Progressive Cardiac Conduction Defect
Progressive cardiac conduction defect (PCCD), also called
Len`egre or Lev disease,
It is characterized by progressive slowing of conduction
through the His-Purkinje system leading to right or left bundle
branch block and, ultimately, to complete atrioventricular
block, syncope, and sudden death.
Several familial cases of PCCD have been described,
Gene responsible for the disorder has been localized to
chromosome 19q13.3