Chest pain and breathlessness

Re. Q 2 it's simply that the heart cannot work hard enough to supply tissue with oxygen. So he's breathing harder but it's not sufficient. Doesn't necessarily have to be a separate disease, could well be a symptom of the CHF.

You have to take the problem and apply it to the whole body. He has a heart which is not working very well. Doing exercise increases the amount of oxygen your body demands. The heart needs to circulate this oxygen to the muscles, but is not doing it very well. Carbon dioxide is also building up and not being removed quickly enough because the circulation can't cope. Therefore to attempt to increase the amount of oxygen entering, he breathes harder to oxygenate more the blood which is circulating. It's basically the same as why we get out of breath when we exercise, except that if you've got heart failure your oxygen delivery is compromised so you'll get out of breath more easily.

Ok... makes sense... bad heart -> PCO2 increasing / PO2 decreasing / pH decreasing -> chemoreceptors stimulated -> increased breathing -> but this increase is insufficient so you get breathless

Thanks!

With that history the primary differential would definately be class III/IV angina. having said that the patient's age would alter that if he was young.

It is usually caused by:
a) A decrease in myocardial blood supply due to increased coronary resistance in large and small coronary arteries. This is commonly due to significant coronary atherosclerotic lesion in the large epicardial coronary arteries with at least a 50% reduction in arterial diameter OR coronary spasm

b)Increased extravascular forces, such as severe LV hypertrophy caused by hypertension, aortic stenosis, or hypertrophic cardiomyopathy, or increased LV diastolic pressures

c)Reduction in the oxygen-carrying capacity of blood, such as elevated carboxyhemoglobin or severe anemia (hemoglobin, <8 g/dL)

Chest radiograph findings are usually normal in patients with angina pectoris. However, they may show cardiomegaly in patients with previous MI, ischemic cardiomyopathy (Dyspnoea largely is a consequence of elevated LV diastolic filling pressures. The elevated LV filling pressures principally are caused by impaired diastolic compliance as a result of marked hypertrophy of the ventricle), pericardial effusion, or acute pulmonary oedema.

Q1. I would say that is pretty much correct, plus preload is increased due to smaller LV chamber size due to the hypertrophy from ischaemic changes.

Q2. Angina can directly cause exertional breathlessness (SOBOE). Other differentials for SOBOE and chest pain would be pulmonary oedema (due to CHF, effusion, infection - though oedema is unlikely to be missed on CXR), pericarditis (more likely to be dyspnoea rather than breathlessness), acid reflux/gastritis (though wouldn't cause enlarged heart and is unlikely to correlate with exercise), pneumothorax (usually more spontaneous and severe - and also persists at rest), pulmonary embolism (as for pneumothorax).

Q3. myocardial ischaemia, due to lack of oxygenation to the tissues of the heart, which is often due to atherosclerosis, but can be due to spasm, anaemia, congenital malformations, etc

It is likely to be mixed metabolic and respiratory acidosis, i.e:

heart failure -> low O2 delivery -> decreased perfusion -> lactic acidosis

AND HF -> increased CO2 retention -> resp acidosis

As a result pH drops, chemoreceptors are stimulated, resp rate increases to try to compensate by blowing off CO2. Also bicarbonate is likely to be retained by the kidneys to correct the acidosis.

Edit: surely asthma / emphysema could cause breathlessness as well though...?

Yeah, but both are less likely to cause chest pain, and are also not usually associated with mild exercise

The most likely candidates (assuming this is a middle aged/elderly person) are angina, CHF (specifically LVF), or silent MI (which I didn't put in my earlier list as it is more common in diabetics, but could also be a candidate if the person is old)