Left Ventricular Failure

Congestive left heart failure

Left Ventricular Failure

• A life-threatening condition• The left side of the heart receives oxygenated blood

from the lungs and pumps it to the remainder of the body.

• As the ability to push blood forward from left side decreases, the body does not receive enough oxygen, resulting in fatigue.

• It also causes congestion of the pulmonary vasculature so the symptoms are predominantly respiratory in nature.

Classification• There are many different ways to categorize heart failure,

including:– the side of the heart involved (left heart failure versus right heart

failure). Right heart failure compromises pulmonary flow to the lungs. Left heart failure compromises aortic flow to the body and brain. Mixed presentations are common; left heart failure often leads to right heart failure in the longer term.

– whether the abnormality is due to insufficient contraction (systolic dysfunction), or due to insufficient relaxation of the heart (diastolic dysfunction), or to both.

– whether the problem is primarily increased venous back pressure (preload), or failure to supply adequate arterial perfusion (afterload).

– whether the abnormality is due to low cardiac output with high systemic vascular resistance or high cardiac output with low vascular resistance (low-output heart failure vs. high-output heart failure).

New York Heart Association• Functional classification generally relies on the New York Heart

Association functional classification. The classes (I-IV) are:– Class I: no limitation is experienced in any activities; there are no

symptoms from ordinary activities.– Class II: slight, mild limitation of activity; the patient is comfortable at

rest or with mild exertion.– Class III: marked limitation of any activity; the patient is comfortable

only at rest.– Class IV: any physical activity brings on discomfort and symptoms

occur at rest.• This score documents severity of symptoms, and can be used to

assess response to treatment.

Etiology• Coronary artery disease• Hypertension• Abnormal heart valves• Cardiomyopathy• Myocarditis• Congenital heard defects• Severe lung disease• Diabetes• Anemia• Hyperthyroidism• Arrhythmias

Pathophysiology of LVFNeurohormonal: sympathetic activity activated

Cellular changes: increase in fibrous tissue

Reduced contractility due to overloading of the ventricle: reduced ability to cross-link actin and myosin filaments in over-stretched myocardium

Reduced stroke volume

Increased end systolic volume: due to decreased contractility

Decreased end diastolic volume: impaired ventricular filling

Hypertrophy of myocardium: due to terminally differentiated heart muscle fibers increasing in size to improve contractility

May increase stiffness and decrease ability to relax during diastole

Reduced cardiac output and increase strain on the heart: increase risk of cardiac arrest.

Symptoms

• Cough – frothy or blood tinged mucus• Decreased urine output• Orthopnea• Fatigue• Tachycardia• Palpitations• Exertional Dyspnea• Paroxysmal nocturnal dyspnea• Edema

Signs• Restless, cold clammy palms• Dyspnea and tachypneac• Central cyanosis• Hypotension• Tachycardia ± arrhythmias• Displaced apex beat• Gallop rhythms• S3 and S4 heart sounds• Functional Mitral regurgitation• Bibasal crepitations• Pleural effusions• Decreased urine output

Diagnosis• Echocardiography – supports clinical diagnosis of HF to

determine the stroke volume and end diastolic volume.• Chest X-rays – shows visible enlargement of the heart,

vascular redistribution, cuffing of areas around the bronchi and interstitial edema.

• Electrocardiogram (ECG) – used to identify IHD, left and right hypertrophy and presence of conduction delay or abnormalities.

• Blood test – an elevated B-type natriuretic peptide (BNP) is a specific test indicative of heart failure, BNP can be used to differentiate causes of dyspnea due to heart failure.

Framingham criteria• By the Framingham criteria, diagnosis of congestive heart failure (heart

failure with impaired pumping capability) requires the simultaneous presence of at least 2 of the following major criteria or 1 major criterion in conjunction with 2 of the following minor criteria:

• Major criteria:– Cardiomegaly on chest radiography– S3 gallop (a third heart sound)– Acute pulmonary edema– Paroxysmal nocturnal dyspnea– Crackles on lung auscultation– Central venous pressure of more than 16 cm H– 2O at the right atrium– Jugular vein distension– Positive abdominojugular test– Weight loss of more than 4.5 kg in 5 days in response to treatment (sometimes

classified as a minor criterion)

• Minor criteria:– Tachycardia of more than 120 beats per minute– Nocturnal cough– Dyspnea on ordinary exertion– Pleural effusion– Decrease in vital capacity by one third from maximum recorded– Hepatomegaly– Bilateral ankle edema

• Minor criteria are acceptable only if they can not be attributed to another medical condition such as pulmonary hypertension, chronic lung disease, cirrhosis, ascites, or the nephrotic syndrome.

Treatment

• Medications– First-line therapy for all heart failure patients is angiotensin-

converting enzyme (ACE) inhibition. ACE inhibitors improve survival and quality of life in heart failure patients

– Oral loop diuretics– Beta-blockers– ACE inhibitors – Angiotensin receptor blockers– Vasodilators– In severe cardiomyopathy aldosterone receptor antagonists

References • http://www.nhs.uk/Conditions/Heart-failure/Pages/

Introduction.aspx• http://www.heartfailureguideline.org/_assets/

document/Guidelines.pdf• http://www.sign.ac.uk/pdf/sign95.pdf• http://www.heart.org/idc/groups/heart-public/@wcm/

@hcm/documents/downloadable/ucm_300315.pdf• https://www.ghc.org/all-sites/guidelines/heart-failure.pdf• http://www.nlm.nih.gov/medlineplus/tutorials/

congestiveheartfailure/ct129106.pdf