Intra-aortic balloon pump (IABP) purpose is to act as an LV assist device to support a patient.
It is typically used in critically ill patients, patients in theatre or in patients who are
undergoing a cath lab procedure. The whole concept of the IABP is that it improves the LV
performance and reduces workload. In the clinical context this is not a cure, this is a short
term/ temporary support mechanism for the left ventricle (theatre, cath lab, post cath lab,
ITU as necessary). - ANSWER What is the purpose of the intra-aortic balloon pump?
Mean Arterial Pressure (MAP) is the pressure that blood propels out of the heart. Diastole
lasts twice as long as systole, so MAP is not simply a mean between systole and diastole. It is
a mean between two diastolic values and one systolic value. - ANSWER What is the mean
arterial pressure?
Ischemia is caused by unbalancing the supply and demand of oxygenated blood.
Supply -
• coronary artery disease (CAD) - if there is CAD present, this reduces the flow of blood
through the coronary artery which reduces the supply of oxygenated blood to the
myocardium
• diastolic pressure
• diastolic time - reduces with increased heart rates
• oxygen extraction - haemoglobin and PaO2 - there is only a limited oxygen that the heart
can extract. Therefore to increase oxygen extraction we need to increase blood flow.
Demand -
• heart rate - the heart rate can increase if there is not enough oxygen to compensate (the
demand for oxygen is high)
• afterload - refers to the pressure against which the heart has to work to eject blood out of
the ventricle. The bigger the afterload, the harder the heart has to work and therefore it
1
, requires a lot more oxygen to produce a more forceful contraction (increase demand). Wit -
ANSWER What is meant by ischemia? Explain the determinants of myocardial supply and
demands.
The coronary Ostia is just above the aortic valve from the ascending aorta. The coronary
arteries branch off from the coronary Ostia to form two openings in the aortic sinus that
marks the left main coronary artery (LMCA) and the right coronary artery (RCA).
The coronary Ostia is where the balloon for the intra aortic balloon pump plays an important
part. - ANSWER What is the coronary Ostia ?
The majority of cardiac perfusion occurs during diastole
It becomes more critical when people have poorly functioning hearts or when pathology is
present
There is not a huge change in coronary perfusion in the right coronary artery because there
is lower coronary blood flow during diastole and systole in the right coronary artery
However -
In the left coronary artery diastole plays a key role.
In left coronary artery - the blood flow is much lower in systole than in diastole.
Left coronary artery and diastole is important. - ANSWER Where does the heart get its
blood supply from? In which part of the cardiac cycle does the heart receive oxygenated
blood?
The heart rate is under the influence of the autonomic nervous system (ANS). We know that
if we increase the heart rate this will reduce the diastolic time but the systolic time will
remain roughly the same. The heart rate can be impacted clinically by other factors other
than the ANS such as pain and drugs - and this will have an impact on the cardiac output and
2
It is typically used in critically ill patients, patients in theatre or in patients who are
undergoing a cath lab procedure. The whole concept of the IABP is that it improves the LV
performance and reduces workload. In the clinical context this is not a cure, this is a short
term/ temporary support mechanism for the left ventricle (theatre, cath lab, post cath lab,
ITU as necessary). - ANSWER What is the purpose of the intra-aortic balloon pump?
Mean Arterial Pressure (MAP) is the pressure that blood propels out of the heart. Diastole
lasts twice as long as systole, so MAP is not simply a mean between systole and diastole. It is
a mean between two diastolic values and one systolic value. - ANSWER What is the mean
arterial pressure?
Ischemia is caused by unbalancing the supply and demand of oxygenated blood.
Supply -
• coronary artery disease (CAD) - if there is CAD present, this reduces the flow of blood
through the coronary artery which reduces the supply of oxygenated blood to the
myocardium
• diastolic pressure
• diastolic time - reduces with increased heart rates
• oxygen extraction - haemoglobin and PaO2 - there is only a limited oxygen that the heart
can extract. Therefore to increase oxygen extraction we need to increase blood flow.
Demand -
• heart rate - the heart rate can increase if there is not enough oxygen to compensate (the
demand for oxygen is high)
• afterload - refers to the pressure against which the heart has to work to eject blood out of
the ventricle. The bigger the afterload, the harder the heart has to work and therefore it
1
, requires a lot more oxygen to produce a more forceful contraction (increase demand). Wit -
ANSWER What is meant by ischemia? Explain the determinants of myocardial supply and
demands.
The coronary Ostia is just above the aortic valve from the ascending aorta. The coronary
arteries branch off from the coronary Ostia to form two openings in the aortic sinus that
marks the left main coronary artery (LMCA) and the right coronary artery (RCA).
The coronary Ostia is where the balloon for the intra aortic balloon pump plays an important
part. - ANSWER What is the coronary Ostia ?
The majority of cardiac perfusion occurs during diastole
It becomes more critical when people have poorly functioning hearts or when pathology is
present
There is not a huge change in coronary perfusion in the right coronary artery because there
is lower coronary blood flow during diastole and systole in the right coronary artery
However -
In the left coronary artery diastole plays a key role.
In left coronary artery - the blood flow is much lower in systole than in diastole.
Left coronary artery and diastole is important. - ANSWER Where does the heart get its
blood supply from? In which part of the cardiac cycle does the heart receive oxygenated
blood?
The heart rate is under the influence of the autonomic nervous system (ANS). We know that
if we increase the heart rate this will reduce the diastolic time but the systolic time will
remain roughly the same. The heart rate can be impacted clinically by other factors other
than the ANS such as pain and drugs - and this will have an impact on the cardiac output and
2
