Pathophysiology of Valvar Heart Disease

Pierpont, Gordon L.; Talley, Robert C.

doi:10.1001/archinte.1982.00340180156027

Cited by 4 publications

(1 citation statement)

References 25 publications

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“…Both these factors are labile. 25 The size of the regurgitant orifice is determined by the structure of the mitral valves26 and the size of the left ~entricle.~' Chronic valvular disease induces a progressive thickening and contraction of the atrioventricular valves''.26 and the increase in left ventricular size enlarges the mitral ann~lus.~' The pressure gradient between the left atrium and ventricle is influenced by the atrial pressure, ventricular force of contraction, and systemic vascular resistance. *' These factors vary with the severity of mitral regurgitation and the ability of the left atrium and ventricle to compensate for the hemodynamic changes.…”

Section: Discussionmentioning

confidence: 99%

Heart Sounds and Murmurs: Changes Related to Severity of Chronic Valvular Disease in the Cavalier King Charles Spaniel

Häggström

Kvart

Hansson

1995

Veterinary Internal Medicne

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Auscultatory, phonocardiographic (PCG), radiographic, and echocardiographic evidence of chronic valvular disease (CVD) were studied in 79 Cavalier King Charles Spaniels with a mean age of 7.6 years (SD 2.6). Cardiac murmurs were present in 59 of the dogs and the intensity of the systolic cardiac murmur, assessed by auscultation (grade 1-6). was correlated (P < .001) t o the severity of CVD (heart failure class) and t o the echocardiographical dimensions of the heart (left atrial ratio, La/Ao-d, and left ventricular end diastolic diameter, LVEDD) (both P < .001).The heart sounds and duration of electromechanical systole (042) were investigated in all dogs using measurements obtained from PCG recordings. Normal regression equations describing the relation between heart rate and systolic intervals (Q-Sl, Q-S2 and Sl-S2) were established based on observations in 1 1 normal control Cavalier King Charles Spaniels. The total electromechanical systole (Q-S2). 0-S1, and S1 -S2 intervals in the 59 dogs were related to the corresponding normal regression equation. A shortening of Q-S2 and S1 -S2 intervals were found in dogs belonging t o heart failure class I (Q-S2; P < .01 and S1 -S2; P < .05), class II, and classes Ill and IV (both P < ,001). The ratio of the amplitudes of the first (SI) and second heart hronic valvular disease (CVD) is commonly ob-C served in old dogs of small to medium size breeds.'-3 Lesions associated with CVD start with a progressive thickening and contraction of the atrioventricular valves leading to insufficient coaptation of the leaflets. This causes an increasing regurgitation of blood with accompanying enlargement of the atrium and ventricle. The areas of contact along the free border of the mitral cusps and corresponding chordae tendineae are commonly a f f e~t e d ,~ but the tricuspid valves can also display pathological changes; the pulmonary and aortic valves are seldom affe~ted.~ The animal can compensate for the valvular insufficiency for a period of time, but decompensation and, usually, left-sided congestive heart failure may ultimately desounds (S2) measured on the PCG recordings was found t o be increased in dogs belonging t o class I (P < .Ol), class II, and classes 111 and IV (both P < .OOl). The relationship between cardiac dimensions (LVEDD and La/Ao-d) and Sla/ S2a ratio was described by quadratic regression and found to be significant for both parameters (LVEDD; P < .001, R2 = .54 and La/Ao-d; P < .001, R2 = .63). The presence of a third heart sound (S3) was detected, using PCG, in 21 of the 68 dogs. The proportion of dogs exhibiting S3 increased with heart failure class (and increasing cardiac dimensions) (P < ,001 ). These findings were confirmed by observations in 13Cavalier King Charles Spaniels with cardiac failure progressing from heart failure class I toclass II (Mean LVEDDfrom Ao-d from 1.09 t o 1.43). An increase in intensity of the heart murmur, assessed by auscultation, increase in the ratio of the amplitudes of S1 and S2, as well as a shortening in Q-S2 and S1 -S2 in...

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Section: Discussionmentioning

confidence: 99%