VALVULAR HEART DISEASE
Aortic RegurgitationEtiology of Chronic AR
Cusps defects Congenital -Bicuspid aortic valve Rheumatic Collagen vascular diseases Degenerative aortic valve diseas Aortic root dilatation Marfan syndrome Idiopathic aortic dilation Syphilitic aortitisPathophysiology of AR
Combined pressure AND volume overload Diastolic reflux through the aortic valve can lead to progressiuve left ventricular dilatation as a compensatory mechanism with LVH (asymptomatic). Eventually, the LV reaches its maximal diameter and diastolic pressure begins to rise, resulting in symptoms (dyspnea) that may worsen during exercise..Symptoms
1. Asymptomatic until 4th or 5th decade 2. Progressive Symptoms include: - Dyspnea: exertional, orthopnea, and paroxsymal nocturnal dyspnea Nocturnal angina. Palpitations: due to increased force of contraction. 3. Complications: Sudden cardiac death ,IEPulses : Large volume or ‘collapsing’ pulse.Increased pulse pressureCapillary pulsation in nail bedsApex : Hyperdynamic and displaced (Thrusting).Auscultation Characterstic murmurHigh pitched, blowing diastolic murmur at LSB. Signs
Central Signs Apex : Hyperdynamic and displaced apical impulse(Thrusting). Diastolic thrill may be felt. Auscultation Characterstic murmur High pitched, blowing,decrescendo diastolic murmur at LSB, best heard at end-expiration & leaning forw ard. Other murmurs -Austin-Flint murmur indicates severity (mid to late diastolic murmur). Systolic murmur related to high flow state.
Investigations
ECG Initially normal, later left ventricular hypertrophy .. Chest X-ray Cardiomegaly, maybe aortic dilatation Echocardiogram Cardiac catheterisationManagement of AR
General: IE prophylaxis in dental procedures with a prosthetic AV or history of endocarditis. Medical: Vasodilators (ACEI’Diuretics, are sometimes used to help control symptoms in patients with AR,.Surgical Treatment: Definitive Tx (AVR)Tricuspid stenosis Tricuspid stenosis is almost always rheumatic in origin and is generally accompanied by mitral and aortic valve involvement. Tricuspid regurgitation Most common cause is annular dilatation due to RV failure (functional) but rarely primary. Pulmonary stenosis Most common cause of pulmonary valve stenosis is congenital heart disease. Pulmonary regurgitation Most common cause is ring dilatation due to pulmonary hypertension.
Infective endocarditis
Endocarditis: DefinitionInfective Endocarditis: a microbial infection of the endocardial surface of the heart commonly due to streptococcal viridance. Common site: heart valve, but may occur at septal defect, on chordae tendinae or in the mural endocardium Classification: acute or subacute on temporal basis, severity of presentation and progression By organism
Bacteraemia Transient bacteraemia occurs when a heavily colonised mucosal surface is traumatised Dental extraction Periodontal surgery Tooth brushing Tonsillectomy Operations involving the respiratory, GI or GU tract mucosa Oesophageal dilatation Biliary tract surgery
More common lesions now: Mitral valve prolapse Degenerative calcific valvular stenosis Bicuspid aortic valve Prosthetic valves Congenital defects
Clinical symptoms
1. This should be suspected when a patient with congenital or valvular heart disease develops a persistent fever. 2. Unusual tiredness, night sweats or weight loss, or develops new signs of valve dysfunction or heart failure. 3. New changing regurgitant murmur is the hallmark of IE 4. Less often, it presents as an embolic stroke or peripheral embolism. 5. Other features include purpura and petechial haemorrhages in the skin and mucous membranes, and splinter haemorrhages under the fingernails or toe nails. Digital clubbing is a late sign. 6. The spleen is frequently palpableSplinter Haemorrhages
InvestigationsBlood culture Echocardiograph CBC/ESR/CRP MSU Chest x ray
Diagnosis
Duke criteriaMajor criteria
Blood culture positive for typical IE-causing microorganism Evidence of endocardial involvement(Vegitation)
Minor criteria
Predisposition – heart condition or i.v. drug abuseFever – temp. >38 °CVascular phenomena – arterial emboli etc.Immunologic phenomena – glomerulonephritis, Osler’s nodes, Roth’s spotsMicrobiological evidence – positive blood cultures but do not meet major criteria Diagnosis 2 major criteria 1 major and 3 minor 5 minor criteria
Treatment basics - continued
. Empirical treatment depends on the mode of presentation, the suspected organism, and whether the patient has a prosthetic valve or penicillin allergy If the presentation is acute, flucloxacillin and gentamicin are recommended, while for a subacute or indolent presentation, benzyl penicillin and gentamicin are preferred.Those with penicillin allergy, a prosthetic valve or suspected meticillin-resistant Staph. aureus (MRSA) infection, triple therapy with vancomycin, gentamicin and oral rifampicin should be considered. SURGERY indicated in Heart failure due to valve damage •