My Heart Skipped a Beat
Finding of X-Ray on Arrhythmia Patients
What to Assess
Position of Heart: 1/3 to right 2/3 to left, apex pointing to left
Heart Size: <50% chest diametre, normal ventricle/atrium size
Aortic Knuckle: on the left
What can be shown on X-Ray for patients with Arrhythmias
Enlargemnt of Ventricles
Bilateral Plueral Effusion
Enlargment of Atriums
Connection Between Valvular Heart Disease and Arrhythmias
Problem with valve --> Stenosis/Regurgitation --> Blood doesn't flow normally to ventricles --> Irregular Heartbeat
Hemodynamic Affects of Arrhythmia
Tachycardia
Reduced Cardiac Output
Reduced Ejection Fraction
Reduced Stroke Volume
Increased Myocardial Oxygen Demand
Atrial Fibrillation
Reduced Ventricular filling by around 10% at rest
Reduced Ventricular filling by around 40% during exercise
Ventricular Fibrillation
Most Severe
Can cause 0 cardiac output
Digoxin Toxicity
Brain
Eyes
GIT
Heart
Lack of appetite
Vomitting
Nausea
Headache
Confusion
Anxiety
Blurred vision
Seeing halos around bright objects
Irregular heart beat
Palpitations
AV Block
Definition
interruption of electrical conduction from the atria to ventricle due to conduction system abnormalities.
Causes
Post cardiac operation
Hypertension medication
Age
Degrees
1st
Electrical Impulses are slow
2nd
Type1
atrial impulses is blocked in AV node and fails to conduct to the ventricle
Type 2
the episodic atrial impulses are blocked in the diseased AV node.
3rd
Atrial impulses are completely blocked from reaching the ventricles.
Epidemiology
In UK, atrial fibrillation affecting up to 5% people aged 75 or over.
In Qatar, there is significant high incidence of atrial fibrillation during 1993-1997, it might be attributed to the environmental factor and pollution.
ECG
Definition
A machine that records the electrical signals in the heart
Electrodes
Conductive pads that are attached to the skin
10 electrodes will be placed at specific spots on the patient
RL electrode used as a reference electrode
Leads
Electrical potential difference between two electrodes
12 Leads gives a view of the heart electrical activity from two planes frontal (limb) and horizontal (pericardial)
Frontal Plane
Unipolar vectors
Bipolar Leads
aVR, aVF and aVL
I, II and III
Horizontal Plane
They include: V1, V2, V3, V4, V5 and V6
Unipolar leads
Six leads give a view of the heart
Readings
Depolarization
Repolarization
Interpretation
Changes the membrane potential from negative to positive
Goes from the – pole to the + pole
Changes the membrane potential from positive to negative
Atrium: first cell to be depolarized is the first to be repolarized
Ventricles: first cell to be depolarized is the last to be repolarized
P wave: Atrial repolarization
QRS interval: ventricular depolarization
T wave: Ventricular repolarization
Atrial Fibrillation
Causes may be problem with the heart structure, Coronary heart arteries, Heart attack, CHD.
Accumulation of blood in the atrium may form blood clots
Uncoordinated electrical impulses suddenly start firing in the atria
The heartbeat is around >350 bpm
Atrial Flutter
Caused by problems in the heart conductive system
Increases the risk of stroke and heart failure
It’s a type of arrhythmia
The heartbeat is around 250-350 bpm
The atriums beat too quickly, this causes the heart to beat in a fast, but usually in a regular rhythm
Patients could be asymptomatic
Supraventricular Tachycardia
it’s as an irregularly fast or erratic heartbeat (arrhythmia) that affects the heart's upper chambers
The heart beats about 150 to 220 bpm
Prognosis
Factors Affecting AFib prognosis
Health Conditions
Medication
Gender
Treatment and lifestyle
Age
Pacemaker
Definition
a small device implanted in the chest to help control the heartbeat
How it works
: it contains a pulse generator and leads which send electrical signals to correct the beat when needed
Implantable cardioverter-defibrillator
small battery powered device placed in the chest to detect and stop arrhythmias by sending electric shocks
AI Application
Deep learning model
Cycle-GAN
uses the “deep neural network” algorithm to learn by itself how to interpret data by analyzing large amounts of data and coming up with its own interpretation patterns (can be used to identify PQRST waves and any abnormalities)
can be used to restore ECGs in order to better identify the electrical waves and find any abnormalities in the signal
Wearable Devices
Come in a variety of shapes and sizes like watches (apple watch, fitbit), rings (oura ring), bands (kardiaband), and patches
Most are used to monitor HR, pulse, rhythm, BP, body temp, sleep, fitness, weight and BMI, risk of falling
Conducting System in the heart
Signal Flows through contraction progress
- SA Node 2. AV Node 3. Bundle of HIS 4. Left/Right Bundle Branches 5. Purkinje Fibers
Cardiac action Potential
Phase 0
Rapid Na+influx through open fast Na+channels
Phase 1
Transient K+channels open and K+efflux begins to return the membrane potential to 0 mV
Phase 2
Influx of Ca2+through Ca2+ channels balances the K+efflux to create the plateau phase.
Phase 3
Ca2+ channels close and rectifier K+channels remain open to return the membrane potential to -90 mV
Phase 4
Na+and Ca2+channels are closed, while open K+rectifier channels maintain the negative resting potential
Heart Arrhythmia
Definition
A heart arrhythmia is an irregular heartbeat. Heart rhythm problems (heart arrhythmias) occur when the electrical signals that coordinate the heart's beats don't work properly.
Types
Atrial flatter
Ventricular tachycardia
Atrial fibrillation
Ventricular fibrillation
Relationship between cardiac arrest and arrhythmias
Can happen when
Heart beats dangerously fast.
Ventricles may flutter or quiver (ventricular fibrillation).
Heart’s electrical system malfunctions and suddenly becomes irregular.
Pharmacological Treatment of Arrhythmias
Vaughan-Williams Calssification
Class III
Class IV
Class II
Class V
Class I
Voltage gated Na+ channel blockers
B-adrenergix receptor blockers
Voltage gated K+ channel blockers
Voltage gated Ca2+ channel blockers
Various