What is Congestive Heart Failure?
Congestive heart failure means that the heart’s pumping power is weaker than normal. With Congestive heart failure blood moves through the heart at a slower rate. This increases the pressure and the volume in the heart, therefor the heart becomes congested. As the result, the heart cannot pump enough blood, oxygen and nutrients to meet the body’s demand.
Heart failure is a major health problem in the United States, affecting about 5.7 million Americans. About 550,000 new cases of heart failure occur each year. It’s the leading cause of hospitalization in people older than 65.
We can divide Congestive heart failure into the left sided heart failure, and the right sided heart failure. The left sided heart failure includes the left atrium and ventricle and the right sided heart failure includes the right atrium and ventricle.
Congestive heart failure can be either due to systolic dysfunction, which is the inability of the heart to contract and pump out the blood, or diastolic dysfunction, which is the inability for the heart to relax.
Risk Factors for Congestive Heart Failure:
In the 1970s, hypertension and coronary disease, particularly myocardial infarction (MI), were the primary causes of heart failure in the United States and Europe. However, coronary disease and diabetes mellitus have become increasingly responsible for heart failure while hypertension and valve disease have become less common because of improvements in detection and therapy. Over four decades of observation in the Framingham Study, the prevalence of coronary disease as a cause of heart failure increased 41% per calendar decade in men and 25% in women; the prevalence of diabetes as a contributing cause increased by more than 20% per decade.
Epidemiologically, the impact of the various predisposing conditions for heart failure is best determined by the population attributable risk (PAR) that takes into account both the hazard ratio and the prevalence of the predisposing condition in the population. As an example, the First National Health and Nutrition Examination Survey (NHANES I) of 13,643 men and women who were followed for 19 years found that the risk factors for heart failure and their PAR were as follows:
- Coronary heart disease: relative risk 8.1; overall PAR 62%, 68% in men and 56% in women. In coronary heart disease the major blood vessels that supply the heart muscles with blood and oxygen become narrowed or diseased, leading to ischemic damage to the heart muscles.
- Cigarette smoking: relative risk 1.6, PAR 17%.
- Hypertension: relative risk 1.4, PAR 10%. Hypertension can lead to left ventricular hypertrophy, which makes it harder to oxygenate the hypertrophied heart muscles and can eventually lead to ischemic damage to the heart muscles.
- Obesity: relative risk 1.3, PAR 8%; the importance of obesity was also demonstrated in a long-term follow-up from the Framingham Heart Study that estimated that approximately 11% of cases of heart failure in men and 14% in women are attributable to obesity alone.
- Diabetes: relative risk 1.9, PAR 3%.
- Valvular heart disease: relative risk 1.5, PAR 2%; however, valve disease is an increasingly common cause of heart failure at older ages, with calcific aortic stenosis being the most common disorder requiring surgery. Heart valve disease such as aortic stenosis which can eventually lead to left ventricular hypertrophy and ischemic changes similar to Hypertension.
Clinical Features of Left sided Congestive heart failure:
Even though both the left and the right sided heart failure pretty much have the same clinical features. The left sided heart failure presents with symptoms associated with Pulmonary edema, which is due to failure of the left ventricle to sufficiently remove blood from the pulmonary circulation. This leads to fluid accumulation in the lugs and the clinical features such as:
- Dyspnea (difficult or labored breathing), specially with exertion and exercise,
- Paroxysmal nocturnal dyspnea (PND), which is a sensation of shortness of breath that awakens the patient, often after 1 or 2 hours of sleep, and is usually relieved in the upright position,
- Orthopnea, which is the sensation of breathlessness that occurs when laying flat and improves when sitting up or standing.
Also since the heart is not pumping out enough blood, there is going to be decreased in forward perfusion. This leads to activation of Renin Angiotensin Aldosterone system, which causes fluid retention and worsens the symptom of Congestive heart failure.
Clinical Features of Right sided Congestive heart failure:
The most common cause of right-sided heart failure is actually left-sided heart failure (either systolic or diastolic heart failure) and the common clinical features include,
- Dyspnea, since the right heart is unable to pump blood into the lungs to get oxygenated.
- Elevated Jugular Venous Pressure and Jugular Venous Distention, since the jugular veins can not empty their blood into the congested right atrium.
- Pitting edema, which occurs when excess fluid builds up in the body, causing swelling; when pressure is applied to the swollen area, a “pit”, or indentation, will remain.
- Ascites, which is due to excess fluid accumulation in the peritoneal cavity causing abdominal swelling.
- Congestive hepatopathy, also known as nutmeg liver, which is due to chronic passive congestion of the liver and it resembles a cut nutmeg.
Diagnosis of Congestive heart failure:
- Distinguishes Systolic from Diastolic dysfunction by measuring, Ejection Fraction, which is the total amount of blood in the left ventricle that is pushed out with each heartbeat.
- Determine if Acute Myocardial Ischemia is the precipitating cause, by showing abnormal wall motion (hypokinesia) or absent wall motion (akinesia).
- Identifies Valve diseases.
- Right heart catheterization:
- Right heart (eg, pulmonary artery) catheterization can be helpful to measure intracardiac pressures and determine eligibility for advanced heart failure therapies. Abnormal hemodynamics are generally necessary for the diagnosis, although the precise pattern and severity of hemodynamic dysfunction may vary greatly from patient to patient, and abnormal hemodynamics, per se, are not sufficient for the diagnosis of advanced heart failure. Typically, there is persistently elevated left- and right-sided filling pressures (pulmonary capillary wedge pressure >20 mmHg, right atrial pressure ≥12 mmHg) and/or decreased cardiac index (≤2.2 L/min/m2) despite optimal medical therapy is concerning for advanced heart failure. Right heart catheterization is most informative when performed after volume status has been optimized.
- B-type natriuretic peptide (BNP):
- Secreted by the ventricles of the heart in response to excessive stretching of heart muscle cells.
- Differentiate between causes of dyspnea due to heart failure from other causes of dyspnea.
- Chest X-rays:
- May show cardiomegaly (enlargement of the heart) and fluid collection in the lungs.
- Identify arrhythmias, ischemic heart disease, right and left ventricular hypertrophy, and presence of conduction delay or abnormalities (e.g. left bundle branch block).
- Blood tests:
- Blood tests routinely performed include electrolytes (sodium, potassium), measures of renal function, liver function tests, thyroid function tests, a complete blood count, and often C-reactive protein if infection is suspected. An elevated B-type natriuretic peptide (BNP) is a specific test indicative of heart failure. Additionally, BNP can be used to differentiate between causes of dyspnea due to heart failure from other causes of dyspnea. If myocardial infarction is suspected, various cardiac markers may be used.
Treatment for Congestive heart failure:
In order to prevent Congestive heart failure we must first focus on the modifying the patients life style by encouraging the patient to:
- Loose weight,
- Stop smoking,
- Start exercising,
- Adhere to medications and dietary restrictions (such as salt or fluid and alcohol intake restriction),
- have a healthier diet.
These are all equally effective in preventing and reducing he risk of progression of diastolic and systolic heart failure.
The pharmacological management for Systolic dysfunction heart failure includes:
- ACE inhibitors and or Angiotensin Receptor Blockers,
- Digoxin which is given if nothing else works.
Pharmacological management for diastolic dysfunction heart failure are not as well defined as therapies for systolic heart failure. Some of the medications that are used include:
- Beta-blockers are the first-line therapy as they induce bradycardia and give time for ventricles to fill.
- Calcium channel blocker drugs may be beneficial in reducing ventricular stiffness and lowering the heart rate.
- ACE inhibitors may be beneficial due to their effect on preventing ventricular remodeling but under control to avoid hypotension.
- Diuretics are useful, as these patients develop significant congestion. But they must be monitored because they frequently develop hypotension.