Heart Failure with Preserved Ejection Fraction

Heart failure is a disorder in which the heart cannot pump the blood to the body at a rate that is the needed . It is a clinical syndrome caused by a variety of cardiac diseases and causes characteristic symptoms of dyspnea and fatigue.  

Catagories of Heart Failure:

Clinically heart failure is divided into two broad categories heart failure with reduced ejection fraction and heart failure with preserved ejection fraction . In this article we will focus on heart failure with preserved ejection fraction which accounts for more than 50 percent of heart failure cases to better understand heart failure. 

2 Phases of heart:

We need to review the heart's function. The heart has two phases during each heartbeat filling which is diastole and pumping which is systole . Systolic function of the heart and the  resulting  a cardiac output is governed by four major determinants. 

These are the contractility of the heart muscle,  the preload of the ventricle and then the afterload , which is the force the ventricles must overcome to pump blood out and finally the heart rate .

Stroke Volume:

The cardiac output equation can be simplified nicely into stroke volume which is the amount of blood the ventricles pump out during each heartbeat multiplied by heart rate contractility . 

After load and preload all affect stroke volume . Low cardiac output is the main feature in heart failure , the heart fails to pump blood to the rest of the body . Cardiac output may be inadequate as a result of any alterations in the determinants we talked about.

Causes

Heart failure with preserved ejection fraction is a problem with diastolic function . A problem with heart filling typically the most common cause of heart failure with preserved ejection fraction is hypertension and less commonly aortic stenosis . These changes cause an increase in afterload which causes slow adaptations to the ventricles. 

Procedure:

An increase in afterload means stroke volume will decrease.  This means that the cardiac output will decrease . A reduced cardiac output will be picked up by baroreceptors .  

The baroreceptors will then trigger activation of the sympathetic nervous system which will subsequently increase contractility of the cardiac muscles increase.  

The heart rate as well as venous tone these are all done to help increase cardiac output long term.  However these changes causes ventricular remodeling and dysfunction , in addition to this reduced cardiac output means that there is reduced renal  profusion . 

 As a result the kidneys will activate what's called the renin angiotensin aldosterone system 

Concentric Remodeling:

This is in the hopes to also increase cardiac output however long term again causes ventricular remodeling the ventricular muscles of the heart specifically undergo what's called concentric remodeling and hypertrophy causing a smaller ventricular size. 

Condition of Arterial and Ventricular Pressure:

This means less blood in the ventricles the hypertrophied muscle cells fibros due to inadequate blood supply. As a result there is stiffness of the ventricles and reduced compliance so less blood filling the ventricle during diastole the reduced ventricular compliance. 

As a result of ventricular stiffness causes an increase in ventricular pressure which then will cause increase in arterial pressure and this can lead to pulmonary congestion .

Patients:

Majority of patients with heart failure with preserved ejection fraction suffers from pulmonary hypertension and as a result can develop right ventricular dysfunction , right-sided heart failure , of course we cannot forget there's also left-sided dysfunction as a result of the ventricular remodeling process . 

Diastolic Dysfunction:

As well overall there is diastolic dysfunction,  reduced volume of blood in the ventricles and therefore overall reduced stroke volume and cardiac output. However the ejection fraction which is the percentage of blood volume ejected by the heart during each cardiac cycle is normal and this is because the heart is still able to pump the small volume of blood during systole .

Hence why this heart failure is called heart failure with preserved ejection fraction.

Classification

So the pathological classification of heart failure is based on injection fraction patients with chronic heart failure can either be heart failure with reduced ejection fraction or heart failure with preserved ejection fraction.

Heart failure with reduced ejection fraction is where there is impaired systolic function impaired emptying represented by an ejection fraction less than 40 percent heart failure with preserved ejection fraction is an impairment in filling. But you have preserved ejection fraction of greater than 50 percent .

Distinction:

The distinction is important because the treatment of these two groups are different. Patients with ejection fraction of 41 to 49 percent are classified as preserved ejection fraction and their treatment is usually under this category as well . 

Heart failure with preserved ejection fraction previously known as diastolic heart failure accounts for approximately 50 percent of all heart failure cases.  

Common causes:

The most common cause is hypertension, less common aortic stenosis and then cardiomyopathy such as hypertrophic obstructive cardiomyopathy restrictive and infiltrative cardiomyopathies.  Heart failure with preserved ejection fraction is also associated with other conditions such as obstructive sleep apnea diabetes and obesity.

Clinical Signs

Clinical signs and symptoms of heart failure is easily classified into left-sided heart failure or right-sided heart failure . 

Symptoms of Left sided Heart Failure:

Left-sided heart failure have symptoms of low cardiac output and elevated pulmonary venous pressures or pulmonary congestion . Low cardiac output state causes pre-syncope fatigue and lethargy exertional dyspnea which will progress to orthopedia and paraxysmal nocturnal dyspnea .

Pulmonary edema causes shortness of breath and chest discomfort. Chronic, non-productive cough coarse crackles at the base and hypoxia. 

Symptoms of Right sided Heart Failure:

Right-sided heart failure causes congestion of peripheral tissue and this manifests as a raised jugular venous pressure . Liver congestion with a sustained poster liver right ventricular heave and lower limb pitting edema.

Treatment

Investigations to order include a braynatrotic peptide which is released by the ventricles and is a marker of ventricular distension or pressure electrocardiogram which may show arrhythmia echocardiogram . 

To detect the ejection fraction as well as to look for valvular problems specifically in the presence of right-sided heart failure,  For example chest x-ray which may show cardiomegaly cardiac MRI to look for infiltrated diseases .

Non Pharmacological Management:

As well as right or left cardiac catheterization can be done.  Treatment of heart failure with preserved ejection fraction is divided into non-pharmacological and pharmacological . 

Non-pharmacological approach includes reduced sodium intake,  stop alcohol,  stop smoking,  encourage weight loss , if overweight and exercise.

Pharmacological Management:

Pharmacological management of heart failure with preserved ejection fraction is limited as compared to heart failure with reduced ejection fraction . Pharmacotherapy used include frozamide , the loop diuretics , ace inhibitors or angiotensin receptor blockers spironolactone and sglt2 inhibitors.

Conclusion

In summary heart failure is a disorder in which the heart cannot pump blood to the body heart failure is classified into heart failure with reduced ejection fraction and heart failure with preserved ejection fraction heart failure with preserved ejection fraction accounts for 50 of all heart failure cases and causes concentric ventricular remodeling it is associated with diastolic dysfunction the most common cause is hypertension .