Diagnosis and management of acute coronary syndromes - STEMI Flashcards
What is the pathology of a ST-elevation myocardial infarction
Plaque rupture leads to more complete, or complete thrombotic occlusion of coronary lumen and infarction of distal myocardium
What can be seen on an ECG of STEMI
ST elevation
What further problems arise due to coronary occlusion
Necrosis of myocardial tissue
Left ventricular damage
How can myocardial tissue be salvaged in a coronary occlusion and what are the treatment options
“open” infarct related artery
By Fibrinolysis or Primary PCI
What is the benefits of primary PCI over fibrinolytic therapy
Has a greater reduced risk of cardiac mortality, recurrent MI; and haemorrhagic stroke
PCI is most effective if delivered within 120 to 150 mins of the patient’s call for help
When would fibrinolytic therapy be the treatment of choice and What is the times of fibrinolytic therapy from the call and entering the hospital
when PCI cannot be performed
Aim to initiate within
(‘call-to-needle’) 90 mins of patient calling for help
(‘door-to-needle’) within 30 mins of hospital arrival
When is it best to perform PCI
If can be delivered in less than 90minutes from call for help and has more than 3 hours symptom onset
Cardiogenic shock or heart failure present
High bleeding risk
Diagnosis uncertain e.g coronary dissection
What is the general measures of secondary preventions put in place to reduces the risk of STEMI
General measures:
stop smoking, diet, exercise, control BP and glycemic
Statins
Angiotensin converting enzyme inhibitors - rampipril
- if left ventricular dysfunction
also:
Beta blocker
What is the dual medication therapy that must be taken for one year after STEMI as a prevention therapy
Aspirin and clopidogrel (for one year only)
What possible myocardial disfunction does an ECHO show
Size of wall motion abnormality
overall contractility
presence and degree of mitral regurgitation
presence of mural thrombus
LV ejection is the most important factor to investigate in MI survival, what does it show?
how well your left ventricle (or right ventricle) pumps blood with each heart beat - show if any LV dysfunction
How can ACS result in sudden cardiac death
As an ACS, the atherothrombotic event causes acute myocardial ischaemia and subsequent sufficient electrical disturbance to cause ventricular arrhythmia
ventricular Fibrillation tends to rapidly deteriorate into asystole - heart ceases to beat
What can be seen on an ECG of sudden cardiac death
Irregular, ineffectual ventricular fibrillating activity
Multiple wavelets of electrical activity
What is the appropriate plane when ventricular arrest happens (sudden cardiac death)
Resuscitation: Defibrillation with the best chance for success probably occurring in the first 3–4 minutes
What is the two main groups of immediately life threatening complications of acute MI,
Mechanical complications
Ventricular arrhythmic complications
What is a later complication of acute MI less threatening but still needs treatment
LV thrombus
What is the three main mechanical complications
Free Wall Rupture
Papillary Muscle Rupture
Ventral Septal defect
Where is free wall rupture most likely to occur and what is the outcome
Occurs at the edge of the infarcted area
haemopericardium - blood effuses into pericardium resulting in acute tamponade which compreses the heart due to fluid compression in the pericardium
What patients are more common to experience a mechanical complication after a AMI
Elderly, females, Patients with HBP Or patient who experienced an anterior MI Patients who have not been thrombolysed
What is the treatment if possible for a free wall rupture
urgent echo,
pericardiocentesis and drainage with pigtail catheter.
In what patients is it more likely for septal wall rupture (VSD) to occur
Patients with multi vessel CAD
When in papillary muscle rupture and Ventral septal defect most likely to occur
Generally within the first week of MI.
What is the symptoms of papillary muscle rupture and Ventral septal defect
Sudden severe breathlessness
Autonomic activation eg sweating, nausea & vomiting
Chest pain
What is the signs of papillary muscle rupture and Ventral septal defect
Shock, tachycardia, pulmonary oedema New harsh systolic murmur Right parasternal heave Palpable thrill elevated JVP.
What can occur as a result of papillary muscle rupture and worsen symptoms
Mitral valve regurgitation
What mechanical complication has the greatest elevation in JVP
Ventral Septal defect
What mechanical complication is most likely to develop an
Inferior MI
anterior MI
Papillary muscle rupture
Ventral septal defect
What does an echo show in investigation mechanical complication of an AMI and what can easily be missed
Prolapsing mitral leaflets
Missing chunks of muscle
a VSD can be easily missed
How does right heart catheterization confirm the diagnosis of mechanical complication
VSD - shown by a Step up in O2 sats
Acute mitral regurgitation - Large v waves on wedge
What is the purpose of catheterization
Establish coronary anatomy
Better localisation of pathology
What is the temporary medical management of papillary muscle rupture and VSD dependant on blood pressure
I.V. Nitrates if Systolic BP > 90mmhg
or
Inotropes if Systolic BP < 90mmhg
How does IABP (balloon pump) aid in the treatment of papillary muscle rupture and VSD
Reduce afterload, therefore increasing Diastolic BP
What is the Non pharmaceutical treatments for papillary muscle rupture and VSD
surgery
- coronary bypass if needed
- Miral valve replacemrnt
- VD repair with pericardial or synthetic patch
Balloon pump
What is examples of Ventricular arrhythmic complications
Ventricular tachycardia
Ventricular Fibrillation
What is the ECG characteristics that help define VTs:
Rapid, wide, and regular QRS complexes
Rate of 120 BPM or greater
The T-waves are large with deflections opposite the QRS complexes
P-waves are usually not visible, therefore the PR interval is not measurable
What is the medical treatment for VT
Cardioversion - electric shocks to your heart through electrodes placed on your chest
amiodarone -antiarrhythmic medication used to treat and prevent a number of types of irregular heartbeats
What can be seen in VF
P-waves and QRS complexes are not present
Heart rhythm is highly irregular
The heart rate is not defined (without QRS complexes)
multiple wavelets
What is the only possible medical treatment for VF
Defibrillation -the stopping of fibrillation of the heart by administering a controlled electric shock, to allow restoration of the normal rhythm
What is the general outcome of VF
asytole - difficult to restore cardiac output
What maintains VF
the multiple wavelets
What is the result of a LV thrombus
significant LV dysfunction
What is the treatment for LV thrombus
Anticoagulation for 6/12 with warfarin and repeat echo
