Heart Failure: Difference between revisions

Basically, HF is caused by a loss of cardiac pump function or a structural abnormality which both can have multiple underlying mechanisms. The most common causes or pathophysiological mechanisms are a loss and/or weakness of myocardial tissue, a (long-lasting) increased vascular resistance and tachyarrhythmias.  

The most important cause (65-70% of the cases) of HF in the Western world is ischaemic heart disease including myocardial infarction (vd wall). These patients mainly suffer systolic HF due to wall motion abnormalities of the affected and remodeling of the non-affected parts of the myocardium.  

In patients with a high blood pressure (BP), the heart faces an increased afterload (a higher workload pumping the blood against the increased vascular resistance). At longer duration, this will lead to hypertrophy of the cardiac myocardium. This thicker, stiffer myocardium has a decreased pump function compared with non-hypertrophic  myocardium. Moreover, (chronic) hypertension is a risk factor for (coronary) atherosclerosis and thereby increases the risk of myocardial infarction and subsequent HF. In as much as 60-70% of patients suffering HF, hypertension is the primary or secondary cause. (vd wall)

Atrial fibrillation is a common rhythm disorder in the elderly. With this condition, the atria do not contract in the coordinated fashion unlike when in normal sinus rhythm, and therefore the atria never optimally empty. Normally, this ‘atrial kick’ contributes to around 15% of the LVEF. The absence of the atrial kick during atrial fibrillation can contribute to a reduced LVEF. Less frequently, , blood can stagnate in the atria during fibrillation which is prone to thrombus formation and embolisation to the coronary arteries with myocardial infarction and HF as possible consequences.

Valvular disease, especially mitral- or aortic, can cause volume overload of the heart. This overload causes dilation of the ventricle which makes the pump function less pristine.

Dilated cardiomyopathy (DCM) is characterized by diffuse dilatation of one or more of the chambers of the heart, with a general decrease in contractility and consequently a decreased pump function. In about 30% of the cases, DCM is hereditary. (boek vd wall) Hypertrophic cardiomyopathy (see also Hypertension), restrictive cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy  and peripartum cardiomyopathy can be malefactors causing HF.

Tamponade can be the cause of diastolic HF when relaxation and filling of the heart is impaired by blood or fluid in the pericardium.  

β-blockers, calcium antagonist, antiarrhythmics, cytotoxic agents.

Alcohol, medication, cocaine, trace elements (mercury, cobalt, arsenic).

Diabetes mellitus, hypo- or hyperthyroidism, Cushing syndrome, adrenal insufficiency, excessive growth hormone, phaeochromocytoma.

Deficiency of thiamine, selenium, or camitine, obesity, cachexia.

Sacroidosis, amyloidosis, haemochromatosis, connective tissue disease.

Chaga’s disease, HIV infection,  end-stage renal failure.