week 7-L1 cardiovascular disorders Flashcards
(30 cards)
define cardiomyopathies and give examples
disorders affecting cardiomyocytes or cardiac muscle function
E.g. heart failure, dilated cardiomyopathy, take stub syndrome and hypertrophic cardiomyopathy
define heart failure and which types exist
heart unable to maintain adequate circulation for metabolic requirements
divided into PRESERVED EJECTION FRACTION and REDUCED EJECTION FRACTION
describe preserved ejection fraction
EF>50% and reduced diastolic function resulting from concentric muscle growth
inability to relax but still pumping the quantity of blood however less blood fills the ventricles due to valves semi closed.
no particularly good outcome form pharmaceutical
describe reduced ejection fraction
EF>40% and reduced systolic function resulting from eccentric muscle development
inability to pump out the blood quantity required due to weakened heart muscles, pharmaceutical outcome good
underlying causes of heart failure
secondary to cardiac damage- ischaemia or myopathy
hypertension
valve disease
effects of heart failure on cardiac output and life expectancy
decrease cardiac output and venous blood accumulation
poor prognosis-50% mortality rate <5 years
heart failure ECG and findings
non-specific multiple potential ECG abnormalities-hypertrophy or atrial fibrillation,
Diagnosis: elevated echocardiography and elevated natriuretic peptides
symptoms of heart failure
breathlessness
fatigue
fluid retention caused by cardiac dysfunction
types of muscular cardiovascular disorders
dilated
hypertrophic
tako tsubo
define Dilated cardiomyopathy
pathophysiology: causes and effects on cardiac output and life expectancy
investigations
cardiomegaly and dilation, systolic dysfunction with hypo-contraction
causes mainly inheritance familial secondary to anterior myocardial infarction leading to reduced Q phase and ejection fraction < 40%, mortality rate 10-50%
symptoms: dysnopnea, fatigue, genetic testing
no ECG findings since abnormalities similar to LVH
define hypertrophic cardiomyopathy
pathophysiology: causes and effects on cardiac output and life expectancy
investigations
unexplained left ventricular hypertrophy-primarily affects the inter-ventricular septum
autosomal dominant inheritance, decrease in Q and can cause sudden cardiac death during exercise
dysnopnea, fatigue, genetic testing
no ECG findings since abnormalities similar to LVH
define Tako tsubo syndrome
pathophysiology: causes and effects on cardiac output and life expectancy
investigations
left ventricular dysfunction where the apex balloons and symptoms mimic myocardial infarction aka broken heart syndrome
stressful event mainly women
decrease in Q, ejection fraction about 40% with 5% mortality rate
symptoms: chest pain, increase cardiac biomarkers normal blood vessel and ST segment elevation
NB shape left ventricle post contraction is like octopus in pot
define conduction abnormalities
disorders affecting bioelectrical transmission along the heart
name some conduction abnormalities
atrial arrhythmias-atrial fibrillation and WPW
ventricular arrhythmias-ventricular fibrillation and torsade de pointes
tachycardias-sinus and atrial
conduction block-AV block type 1,2,3 and bundle branch block
define ECG in atria
P-wave which shows atrial contraction
define ECG conduction
P-R interval showing conduction in the AV node-120-200ms
NB conduction stops at AV node
define ECG ventricular
QRS complex-ventricular depolarisation< 120ms
ST segment-plateau phase-isoelectric baseline
QT interval-total duration of ventricular depolarisation and repolarisation-HR incr means QT decr
R-R interval- duration between ventricular depolarisation aka HB
define ECG positional
cardiac axis normally between -30 and +90 degree
define atrial arrhythmias- atrial fibrillation
pathophysiology
investigations
disorganised electric activity and contraction resulting in blood accumulation and clot in atria
caused by-spontaneously active cells throughout atria leading to small decline in Q and incr heart failure and stroke
checked by- palpitations and chest pain
ECG showing- absent P-waves, irregularly irregular rhythm and fibrillary waves
define atrial arrhythmias- Wolff Parkinson white
pathophysiology
investigations
cause of tachycardia and abnormal cardiac electrical conductance-another route beside AVN to ventricles
cause- accessory conduction pathway
Q unchanged and normal life expectancy
investigation-palpitations and chest pain
preexcitation- QRS complex ECG is biphasic/inverted-T wave of ECG
Cardiovascular disorders conduction
Ventricular arrhythmias
tachycardias
conduction block
ventricular arrhythmias-fibrillation
originate from His-Purkinje system or ventricular myocytes with ventricles contracting at 150-400 bpm
cause- structural heart disease, MI or congenital leading to complete loss of Q and cardiac output from seconds to minutes
investigations- syncope and ECG irregular deflections and difficulties identifying PQRST waves
ventricular arrhythmias- Torsade de pointes
polymorphic ventricular tachycardia occurring due to long QT interval
congenital or acquired QT prolongation leading to reduced repolarisation
reduced Q either auto resolves or progress to deadly V fib
investigations- chest pain, syncope with twisting around the point
tachycardias- Sinus (STach) and atrial (ATach)
characteristic atrial rate between 100-250 bpm
STach-P waves followed by QRS complexes
physiological with normal ECG
ATach-P waves not always followed by QRS complex
ectopic source of atrial beat with ECG solitary p-waves dependent on level of block
effects for both-unchanged or slightly decreased Q
