Heart disease Flashcards
myocardial infarction
when blood flow is decreased or stop to part of the heart causing damage to the muscle. Occur to due to coronary heart disease. Muscle is unable to receive the O2 and nutrients it needs to respire and therefore dies causing the heart not to pump blood properly
most cardiac markers are
enzymes
cardiac biomarkers
-creatine kinase
-cardiac troponin T ned I
-myogloblin
Natriuteritc peptides
creatine kinase
Creatine kinase
Myocardial muscle creatine kinase is found mainly in the heart
Levels increase within 3-12 hours of onset of chest pain and reach peak values at 24 hours
Not as sensitive or specific as troponin levels
cardiac troponin T and I
Troponin is a protein released from myocytes when irreversible myocardial damage occurs- highly specific to cardiac tissue
Troponin level is dependent on infarct size- providing an indicator or prognosis
Use of sensitive assays- more patients with angina will be classified as having non ST elevation myocardial infarction.
May not be detectable for 6 hours after attack- most sensitive early marker is myoglobin
why is cardiac troponin T and I the preferred marker for myocardial injury
highest snesiitvites and spceiificities for diagnosis of acute myocardial infation
myogloblin
- found in cardiac and skeletal muscle
- more rapidly released for infarcted myocardium than troponin
- high sensitivity but poor speciifcity
natriuretic peptides
elevated BNP are independently associated with adverse outcomes-mortality
symptoms of myocardial infarction
Pressure, tightness, or squeezing in chest or arm
Nausea, indigestion, heartburn, abdominal pain
Shortness of breath
Cold sweats
Fatigue
Dizziness.
diagnosis of MI
- symptoms of ischaemia
- biomarkers
- ECG changes indicative of new ischaemia
- imaging evidence of new loos off viable myocardium
which wave if the ECG will change
Q wave
MI simple
Irreversible necrosis of a heart muscle due to a prolonged lack of oxygen supply (ischemia).
angina
narrowing of the arteries caused by plaques
full occlusion by plaque
MI
half of the salvageable myocardium is lost within
1 hour. 2/3 lost within 3
Myocardial myopathy
disease of the heart tissue- muscle becomes thick, rigid and enlarged
three types of myocardial myopathy
- ARVC
- HCM
- DCM
Hypertrophic cardiomyopathy (HCM)
a portion of theheartbecomes thickened without an obvious cause. This results in theheart is less able to pump blood effectively. Symptoms vary from none to feeling tired, leg swelling, and shortness of breath. It may also result in chest pain or fainting.
HCM is
autosomal dominant, 1 in 500
- over 400 mutations in 9 genes
HCM mutations
42% cardiac MyBP-C gene
40% cardiac beta myosin heavy chain
-around 50 down mutations
diagnosis of HCM
- ECG
- Echocardiogram
- stress testing
treatment for HCM
B blockers
Diuretics
Disopyramide
Arrthymogenic right ventricular cardiomyopathy
Does not effect the muscle of the atria
Cells of the heart are held together by proteins
Thought that people with ARVC cannot keep the heart muscle cells together when under stress
Cells become detached and die
These cells become fibrous and cause scarring
Fatty deposits build up
result of ARVC
walls of ventricles become thin and stretch and therefore cannot pump effectively
-also itnerups electrical impulses causing arrhythmias and sudden cardia death
Naxos
a recessive association of ARVC with wooly hair and palmoplantar kertoderma.
- mutation in gene encoding desmosome associated protein plakoglobin
