Congestive Heart Failure
Definition:
Heart failure is the inability of the heart to maintain an output adequate to meet the metabolic demands of the body. It is an increasingly common condition that affects millions of people. It is also associated with high morbidity and mortality. Consider it a syndrome, not a disease.
Pathophysiology:
- Heart failure is manifested as organ hypoperfusion and inadequate tissue oxygen delivery due to low cardiac output and decreased cardiac reserve, as well as pulmonary and systemic vascular congestion. A variety of “compensatory adaptations” occur, including (1) increased left ventricular volume dilatation and hypertrophy, (2) increased systemic vascular resistance (SVR) secondary to enhanced activity of the sympathetic nervous system and elevated levels of catecholamines, (3) activation of the rennin-angiotensin-aldosterone and ADH (anti-diuretic hormone) systems. These mechanisms, with pump failure, play an important role in heart failure.
- Most patients present left heart failure that progresses to right heart failure. The most common cause of right heart failure is left heart failure but it can also be caused by pulmonary hypertension (cor pulmonale) or disease that effect the RV>LF (like EMF).
- Heart failure can be either compensated (when the patient is stable) or decompensated (when the patient suddenly gets worse)
Etiology of CHF:
Systolic dysfunction (inability to expel blood) Diastolic dysfunction (abnormal filling)
-hypertension * -hypertension
-ischemic heart disease -fibrosis
-idiopathic cardiomyopathy (like HIV) * -ischemia
-valvular disease * -aging process
-alcoholic cardiomyopathy -constrictive pericarditis (like TB) *
-drug associated cardiomyopathy -restrictive cardiomyopathy (like EMF) *
-myocarditis -hypertrophic cardiomyopathy
* the most common causes in our setting
Degrees of CHF (NYHA Classification) – Defined by condition of patient when they are in compensated heart failure (not decompensated)
- Class I: patients with no limitations of activities; they suffer no symptoms from ordinary activities; symptoms only with extreme exertion
- Class II: patients with mild limitation of activity; they are comfortable with rest or with mild exertion; symptoms with moderate exertion
- Class III: patients with marked limitation of activity; they are comfortable only at rest; symptoms with mild exertion
- Class IV: patients who should be at complete rest, confined to a bed or chair; any physical activity brings on discomfort and symptoms occur at rest; symptoms at rest
Symptoms/Signs:
Heart failure manifests as fatigue, exercise intolerance, decreased peripheral perfusion. Extreme deterioration in cardiac output and elevated SVR result in hypoperfusion of vital organs, so patients can present with encephalopathy (confusion and lethargy), acute renal failure (decreased urine output) and ultimately cardiogenic shock.
Of note,
Left sided failure -> dyspnea, orthopnea, paroxysmal nocturnal dysnpnea
Right sided failure -> peripheral edema, RUQ discomfort
Diagnosis:
Made based on clinical presentation. Echocardiography will assess for depressed ventricular function. Always look for abnormalities on ECG.
Framingham Criteria for CHF: validated CHF with 2 major criteria or 1 major and 2 minor criteria
Major Minor
-PND or orthopnea -peripheral edema
-elevated JVP -nighttime cough
-pulmonary rales -dyspnea on exertion (DOE)
-S3 -hepatomegaly
-cardiomegaly on CXR (unreliable) -pleural effusion
-pulmonary edema on CXR -HR > 120
-weight loss > 4.5 kg in 5 days with
diuresis
Also note,
Left sided heart failure presents with pulmonary edema. Right sided heart failure presents with increased JVP, hepatomegaly, peripheral edema.
Causes of CHF exacerbation/decompensation: FAILURE
F: forgot to take medication, ran out of medication
A: arrhythmias (especially atrial fibrillation)
I: ischemia / infarction / infection
L: lifestyle (poor diet)
U: up-regulation (high cardiac output states i.e. pregnancy, thyroid)
R: renal failure (fluid overload)
E: embolism / endocarditis
Treatment:
Non-pharmacologic therapy: weight loss in obese patients, dietary sodium restriction ( < 2 grams a day), fluid restriction, administration of oxygen if needed, exercise as tolerated for class I and II
Pharmacologic therapy:
- Vasodilator therapy: mainstay of chronic therapy; reduces mortality
- ACE inhibitors (1st line) – but must follow renal function
- Hydralazine (rarely used)
- Beta-blockers: for chronic therapy in patients with non-valvular CHF; not acute, decompensated heart failure; reduces mortality
- Carvedilol (best), metoprolol, atenolol
- Digoxin
- for Class II-III
- improves symptoms, does not reduce mortality
- Diuretics
- Loop diuretics (lasix) for diuresis are the primary treatment of decompensated heart failure but do not reduce mortality
- Aldactone – useful in chronic therapy of patients with Class III-IV; reduces mortality but also greatly increases risk of hyperkalemia in patients who are also taking ACE inhibitors!
Congestive Heart Failure Clinical Cases
Case 1:
50 yo female h/o HTN presents with 6 month history of fatigue and shortness of breath with exertion. She noticed that before she was able to walk 10 blocks without any problems and now she can walk 5 blocks and has to stop to rest which makes her feel better. She does wake up at night feeling short of breath. The patient also noticed that she thinks she has gained weight in the past few months.
- What is the most likely etiology of her heart failure?
-hypertension
- What class of heart failure is this?
-Class II
- What imaging study would best help you evaluate her heart function?
-echocardiogram
She is not taking any medications for her blood pressure and you note that her blood pressure in the office is 150/90 and her HR is 82.
1. Would you start a blood pressure medication?
-yes
2. If yes, what medication?
-ACE inhibitor
3. What blood work would you like to check if any?
-creatinine
You decided to start her on a blood pressure medication and she has then been doing well at home. 6 months later, she comes to the hospital again complaining of increased peripheral edema and right sided abdominal pain. She is admitted to the hospital for heart failure exacerbation.
1. What kind of heart failure is she describing: left sided or right sided?
-right sided
2. What physical exam findings would likely be positive in this patient?
-parasternal heave, pronounced P2, elevated JVP, hepatomegaly, lower extremity edema
3. What medication do you want to give her in the hospital to help with peripheral edema?
-loop diuretics (furosemide)
4. What other tests do you want while she is admitted to the hospital to complete heart failure workup?
-ECG, CXR, echocardiogram, creatinine, cholesterol, abdominal ultrasound
You order a CXR which shows cardiomegaly and no pleural effusions. Her ECG shows a new atrial fibrillation. The patient confirms that she has been taking her blood pressure medication. Her BP on admission is 146/90 and HR 82.
1. What is the most likely cause of her heart failure exacerbation?
-new arrhythmia of atrial fibrillation
2. What medications do you want to discharge her on?
-ACE inhibitor, beta blocker, warfarin
