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CARDIAC FAILURE

Heart failure is defined as a state in which the heart cannot maintain an adequate cardiac output or can do so at elevated filling pressure.

Heart failure is a syndrome caused by cardiac dysfunction, generally resulting from myocardial muscle dysfunction or loss & charactersied by either LV dilation or hypertrophy or both.

CLINICAL FEATURES

• Dyspnea at rest or on exertion

• Reduction in exercise capacity

• Orthopnea/PND

• Edema

• Ascites/ scrotal edema

LESS SPECIFIC

• Early satiety, nausea & vomiting

• Abdominal discomfort

• Wheezing, cough

• Unexplained fatigue

• Confusion, delirium

• Depression, weakness

Orthopnea

• Orthopnea is defines as dyspnea occuring in recumbent position. It is later manifestation of HF than exertional dyspnea. It is due to redistribution of fluid from splanchic circulation & lower extremities into central circulation during recumbency with a resultant increase pulmonary capillary pressure.

PND

• Refers to acute episodes of severe shortness of breath & coughing that generally occur at night & awaken the patient from sleep, usually 1-3hrs after patient retires. They may manifest by coughing or wheezing, possibly due toincreased pressure in bronchial artery leading to airway compression, along with interstitial pulmonary oedema.

SIGNS

FRAMINGHAM HEART STUDY CRITERIA

Diagnosis of CHF requires the simultaneous presence of at least 2 major criteria or 1 major criterion in conjunction with 2 minor criteria.

Major criteria:

1. Paroxysmal nocturnal dyspnea

2. Neck vein distention

3. Rales

4. Radiographic cardiomegaly (increasing heart size on chest radiography)

5. Acute pulmonary edema

6. S3 gallop

7. Increased central venous pressure (>16cm H2O at right atrium)

8. Hepatojugular reflux

9. Weight loss > 4.5 kg in 5 days in response to treatment

Minor criteria:

1. Bilateral ankle edema

2. Nocturnal cough

3. Dyspnea on ordinary exertion

4. Hepatomegaly

5. Pleural effusion

6. Decrease in vital capacity by one third from maximum recorded

7. Tachycardia (heart rate>120 beats/min.)

NYHA CLASSIFICATION

I CLASS: No symptoms and no limitation in ordinary physical activity, e.g. shortness of breath when walking, climbing stairs etc.

II CLASS: Mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary activity.

III CLASS: Marked limitation in activity due to symptoms, even during less-than-ordinary activity, e.g. walking short distances (20–100 m).
Comfortable only at rest.

IVCLASS: Severe limitations. Experiences symptoms even while at rest. Mostly bedbound

patients.

TYPES OF HEART FAILURE

• Left sided heart failure : There is reduction in left ventricular output and an increase in the left atrial or pulmonary venous pressure. An acute increase in left atrial pressure leads to pulmonary congestion & pulmonary odema.

• Right side heart failure: There is a reduction in right ventricular output for any given right atrial pressure. It may be due to Cor pulmonale, multiple pulmonary emboli, pulmonary valvular stenosis.

• Biventricular heart failure: Dialted cardiomyopathy, IHD, pulmonary valvular stenosis, multiple pulmonary emboli.

• Diastolic & systolic dysfunction: Heart failure can occur due to impaired myocardial contraction (systolic dysfunction) but can also be due to poor ventricular filling & high filling pressure caused by abnormal ventricular relaxation(Diastolic dysfunction) . In CAD both can co exist.

• High output heart failure : Large AV shunt, beri beri, severe anemia, thyrotoxicosis can occasionally cause heart failure due to an excessively high cardiac output.

INVESTIGATION

• ECG : LV hypertrophy , prior MI.

• X-ray : Pulmonary oedema, cardiomegaly

• ECHO :Assesing LV function

• BNP

• Electrolytes : Potassium, magnesium,

• Hb: to rule out anemia

• S. creatinine : To rule out renal failure

• TFT

  MANAGEMENT

GENERAL MEASURES

• Stop smoking & limit alcohol consumption, stop in alcohol induced cardiomyopathy

• Modest, routine, isotonic exercise such as walking or riding a stationary bikecycle as tolerated is encouraged.

• Sodium restriction <2-3 gm/dl

• Fluid restriction <2l/day , if there is hyponatremia.

• Pneumococcal vaccine and annual influenza vaccination are recommended in all patients with HF in the absence of known contraindications.

DIURETICS

• Moderate to severe HF results from excessive salt & water retention.

• They act at the loop of henle by reversibly inhibiting the absorption of Na+ ,K+, Cl- from the ascending loop of henle.

• Pottasium sparing diuretics acts at the level of collecting duct. Metalazone reduces the absorption of Na+ & Cl- in the first half of DCT.

• It is used to restore & maintain normal volume status in patients with congestive symptoms or signs of elevated filling pressure.

• It is started at a low dose & titrated upwards to attain the dry weight of the patient.

• Metalazone is used in persistent fluid retention but chronic daily use is not recommended.

ACE INHIBITORS

• Since cardiac failure is due to neurohumeral activation (Renin- angitensin aldosterone system) ACEI has to be used to inhibit the RAAS by inhibitng the enzyme which converts angiotensin 1 to angiotensin 2 . There by preventing salt & water retention , peripheral arterial & venous congestion & activation of sympathetic nervous system.

• They also inhibit kinase II and leads to upregulation of bradykinin

• Majority of benefit of ACEI in heart failure is due to reduction in afterload, it also reduce preload & cause a modest rise in plasma potassium concentration.

• They stabilises LV remodelling, reduces symptoms , hospitalisation & prolongs life.

• It should be used in asymptomatic & symptomatic patients with LVEF <40%. It should be used in combination with beta blocker.

• Renal function must be monitored and should be checked after 1-2 weeks after starting therapy.

ARB

• It is used when patient cannot tolerate ACEI due to cough & also in angioedema as it is infrequent with ARB.

• Individual ARBs may be considered as initial therapy rather than ACE inhibitors for patients with the following conditions: HF Post-MI & Chronic HF and reduced LVEF .

β- Blocker

• β- blocker helps to counteract the deleterious effects of enhanced sympathetic stimulation & reduce the risk of arrythmia & sudden cardiac death.

• They reverses LV remodelling, reduces symptoms , hospitalisation & prolongs life.

• It is recommended that beta blocker should be given to all patients with heart failure & LVEF<40% in combination with ACEI.

• When given in small incremental dose they can increase ejection fraction, reduce the symptoms and frequency of hospitalisation & mortality.

  
  Note:

• It is recommended that beta blocker therapy be continued in most patients experiencing a symptomatic exacerbation of HF during chronic maintenance treatment, unless they develop cardiogenic shock, refractory volume overload, or symptomatic bradycardia .

• In such case a temporary dose reduction can be done. It should not be stopped abruptly .

Aldosterone antagoinist

• ACEI inhibitors cause only transient reduction of aldosterone levels as studies have shown rapid rise of aldosterone to previous level due to other stimuli.

• Administration of an aldosterone antagonist is recommended for patients with NYHA class IV (or class III, previously class IV) HF from reduced LVEF (<35%) while receiving standard therapy, including diuretics.

• Administration of an aldosterone antagonist should be considered in patients following an acute MI, with clinical HF signs and symptoms or history of diabetes mellitus, and an LVEF !40%. Patients should be on standard therapy, including an ACE inhibitor (or ARB) and a beta blocker.

• Aldosterone antagonists are not recommended when creatinine is >2.5 mg/dL (or creatinine clearance is <30 ml/min) or serum potassium is >5.0 mmol/L or in conjunction with other potassium-sparing diuretics .

• In the absence of persistent hypokalemia (<4.0 mmol/L), supplemental potassium is not recommended in patients taking an aldosterone antagonist.

DIGOXIN

• It can be used in patients LV dysfunction with concamitant AF.

• Digoxin may be considered to improve symptoms in patients with reduced LVEF (LVEF <40%) who have signs or symptoms of HF while receiving standard therapy, including ACE inhibitors and beta blockers: NYHA class II-III & NYHA class IV.

• It is recommended that the dose of digoxin, which should be based on lean body mass, renal function, and concomitant medications, should be 0.125 mg daily in the majority of patients and the serum digoxin level should be <1.0 ng/mL, generally 0.7-0.9 ng/mL

AMIODARONE

• Antiarrhythmic agents, including amiodarone, are not recommended for the primary prevention of sudden death in patients with HF .

• It is recommended that when amiodarone therapy is initiated, the potential for interactions with other drugs be reviewed. The maintenance doses of digoxin, warfarin, and some statins should be reduced when amiodarone is initiated and then carefully monitored. Adjustment in doses of these drugs and laboratory assessment of drug activity or serum concentration after initiation of amiodarone is recommended.

Recommendations for Anticoagulation and Antiplatelet Drugs

• Patients with HF are recognized to be at increased risk for arterial or venous thromboembolic events. In addition to atrial fibrillation and poor ventricular function, which

  promote stasis and increase the risk of thrombus formation, patients with HF have other manifestations of hypercoagulability.

• Treatment with warfarin (goal international normalized ratio [INR] 2.0-3.0) is recommended for all patients with HF and chronic or documented paroxysmal, persistent, or long-standing atrial fibrillation or a history of systemic or pulmonary emboli, including stroke or transient ischemic attack unless contraindicated.

• Long-term treatment with an antiplatelet agent, generally aspirin in doses of 75 mg, is recommended for patients with HF due to ischemic cardiomyopathy, CAD.

DEVICE THERAPY

Cardiac resynchronisation

• Appoximately 1/3rd with depresses EF & symptomatic HF manifest QRS >120ms.

• ECG : Abnormal inter or intra ventricular conduction delay suggestive of dyssynchronus ventricular contraction.

• Consequence of dysynchronous contraction : Suboptimal ventricular filling, a reduction in LV contractility, paradoxical septal wall motion, increased duration of MR.

• Biventricular pacing also termed as cardiac resynchronisation therapy stimulates both ventricle nearly simultaneous thereby improving the coordination of ventricular contraction and reducing the severity of MR.

• CRT is recommended in patients with sinus rhythm with an EF <35% & QRS >120ms & those who are symptomatic despite optimal medical therapy.

Implantable cardiac defibrillators

• ICD is considered for patients with NYHA class II – III HF with a depressed EF of <35% who are optimal medical therapy.

Updated on 29/01/13

Reference :

• HFSA : 2010 guidelines

• Harrisons internal medicine : 18^th edition

• Davidson

At the end of the day A patient with established heart failure should be on ACEI/ ARB + β Blocker.

Aldosterone antagonist may be added.

Diuretics : loop diuretics for fluid retention.

Aspirin,Clopidogrel & Statins : especially in CAD.

Calcium channel blocker (Amlodipine) for HTN.

Warfarin

Digoxin in class 3 or 4 HF.