Coronary disorders Flashcards
What is the definition of heart failure?
Heart failure is defined as the inability of the heart to accommodate adequate systemic circulation to maintain the metabolic requirements to supply the organs of the body
What ejection fraction parameter defines preserved ejection fraction (HFpEF)?
Less than 50%
What is HFpEF affiliated with?
Reduction in diastolic function
What arrangement of muscle is configured by cardiomyocytes in HFpEF?
Concentric development
What state is ventricular muscle in during HfPEF?
Contractile state (Inability to relax
Why is there a reduction in cardiac output for preserved EFHf?
Ventricular diastole cannot proceed effectively, pressure gradient unable o be established (AV valves opening time has decreased)
Reduced EDV & preload
What are the causes of preserved EFHf?
Hypertension, increases afterload and thus the development cardiac muscle through hypertrophy
What ejection fraction parameter defines reduced EFHf?
Less than 40%
What is reduce EFHf associated with?
Reduction in systolic function
Why is there a reduction in cardiac output associated with reduced EFHf?
Left ventricle is more dilated, reduced contractility, and decreases ejection of blood (Laplaces law, high radius = greater wall stress, therefore lower pressures can be sustained = less contractility)
What are the underlying causes of Reduced EFHf?
Cardiac damage, ischaemia, myopathy, hypertension, valve disease
What are the ECG findings for heart failure?
Enlarged QRS complex
Why is there an enlarged QRS complex associated with heart failure?
Hypertrophy –> greater depolarisation of the muscle, (amplitude and width increases)
Time taken to depolarise all ventricular cells increases
What other diagnostic measures are used for Heart failure?
Echocardiography
Elevated ANP levels (Atrial-natriuereitc peptide)
What are the symptoms associated with heart failure?
Breathlessness, fatigue, fluid retention
What other non-specific findings coincide with heart failure ECGs?
Hypertrophy
Atrial fibrillation
What is dilated cardiomyopathy?
Cardiomegaly. and dilation of ventricular myocardiocytes
What is associated with dilated cardiomyopathy?
Hypo-contraction and systolic dysfunction, reducing stroke volume
What ECG findings reflect dilated cardiomyopathy?
Enlarged QRS complex
What is Tako-Tsubo Syndrome?
Left ventricular enlargement in a specific arrangement (Architecture expresses resemblance to pot), apical ballooning of the ventricles
Why does ventricular enlargement cause reduced cardiac output?
Reduced diastolic filling, and preload, this decreases the stroke volume.
Apical ballooning reduces contractility
Why does Tako-Tsubo syndrome cause myocardial infarction?
Coronary vessels arise from aortic sinuses, therefore reduction in coronary arteriole flow causes cardiac necrosis via ischaemic mechanism
What is the pathophysiology associated with Tako-Tsubo syndrome?
Stress induced event
Which demographic is more at risk of Tako-Tsubo Syndrome?
Widowed females
What ECG findings are associated with Tako-TS Syndrome?
ST-Segment Elevation (STEMI)
What is STEMI?
Early onset of depolarisation of ventricular cardiomyocytes in response to hypertrophy
What is the ST-segment?
The isoelectric line, the interval between depolarisation and depolarisation of ventricles
What can be associated with Tako-tsubo syndrome?
Chest pain
What is hypertrophic cardiomyopathy?
Unexplained left ventricular hypertrophy
Which ventricular feature does hypertrophic cardiomyopathy affect?
Interventricular septum
What type of inheritance pattern is demonstrated by hypertrophic cardiomyopathy?
Autosomal dominant
What can occur during exercise with patients suffering from hypertrophic cardiomyopathy?
Sudden death
What are the symptoms associated with hypertrophic cardiomyopathy?
Dyspnoea, fatigue
What are the ECG findings with Hypertrophic cardiomyopathy?
Enlarged QRS complex
What is a P wave?
Represents atrial depolarisation
What is the QRS complex?
Represents ventricular depolarisation, requires greater electrical amplitude (larger ventricular cardiac muscle)
When does ventricular contraction occur?
R wave
What is the ST segment?
Baseline, interval between ventricular depolarisation and repolarisation, it is isoelectric
What is the QT interval?
The total duration of ventricular depolarisation and repolarisation
What is the RR interval?
Duration between ventricular depolarisations (heart rate)
What is the T wave?
Represents the depolarisation of the ventricles
How is atrial Repolarisation shown on an ECG?
None, the QRS complex masks the atrial repolarisation
What is a segment on an ECG?
Defined as the regions between two waves
What is more clinically relevant the PR segment or PR interval?
PR interval
What is the PR interval?
Starts at the P wave, ends at the beginning of the QRS complex
What is the typical time for the PR interval?
120-200ms
What factors influence the PR segment?
Electrical conductance through the atrioventricular node
How would delayed impulse passage from SAN to AVN influence the ECG PR interval?
Longer PR interval
Which ECG lead results in the greatest QRS complex?
V5 (lateral view)
Which ECG leads provide a septal view?
V1 and V2
Which region of the heart generates electrical activity the fastest?
The sinoatrial node (SAN)
Why is it important that there is slower conduction of the electrical signal through the AV node (and its extension, the Bundle of His)?
The delay allows the atria to contract completely before a ventricular contraction begins.
Movement of depolarisation towards the lead will produce which type of deflection?
A wave of depolarization moving towards a lead produces a positive deflection (i.e., movement above isoelectric line). The magnitude of this deflection is greatest when the wave is moving directly towards the lead.
Movement of depolarisation away from the lead produced what type of deflection?
Depolarization away from the lead produces a negative deflection.
Which type of movement in comparison to the leads will lead to no deflection?
Perpendicular movements
Waves of repolarisation moving away from the lead will produce which type of deflection?
Positive deflection
Waves of repolarization produce a signal opposite to that seen with a depolarizing wave (e.g., a repolarizing wave moving away from the positive lead causes a positive deflection on the ECG trace
What is Einthoven’s Triangle?
Einthoven’s Triangle is a useful imaginary triangle spanning the trunk which can quickly give an idea about which lead will best show certain electrical activity.
What is the direction of lead one?
Left-arm –> Right arm
What is the direction of lead three?
Left arm –> Left foot
What is the direction of lead 2?
Left foot –> Right arm