Some of the most common cardiovascular diseases are:

Arrhythmia

Arrhythmia is a cardiovascular disease which is characterized by an abnormal heart rate. There are different types of arrhythmias, the heart can beat too fast (tachycardia), too slow (bradycardia) or simply irregularly.

• It is considered bradycardia when the resting pulse of a person is permanently lower than 60 bpm.

• It is considered tachycardia when the resting pulse of a person is permanently higher than 100 bpm.

Failing aortic valve

Sometimes, some of the valves of the heart may misfunction. This can be, failing to close properly or not opening as much as necessary.

• The aortic valve may not open as much as necessary due to a medical condition called "aortic valve stenosis". This happens when the flaps of the valve have become thicker and stiffer. Aortic valve stenosis will cause decreased stroke volume and, consequently, decreased cardiac output.

• When the aortic valve fails to close properly, regurgitation might happen. Regurgitation is the blood flow back into the ventricle after been pumped out of the heart. This can cause lower stroke volume and cardiac output (since part of the blood is going back into the ventricle). This forces the heart to increase the force of contraction, increasing the systolic pressure, and since the blood leaves the aorta faster, it decreases the diastolic blood pressure.

Previous heart attack affecting the left ventricle

A heart attack consists of the interruption of the blood flow towards the heart, usually caused by a blood clot. The interruption in the blood flow may cause the death of certain part of the heart tissue, leading a to a weaker heart. Once recovered from a heart attack, if for example, the left ventricle suffered damage, this would cause a decrease in the amount of blood pumped by the heart into the aorta (stroke volume) and consequently in the cardiac output.