Article

Ruptured chordae tendineae in the dog.

Journal of the American Veterinary Medical Association (Impact Factor: 1.72). 09/1969; 155(3):535-46.
Source: PubMed
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    ABSTRACT: Myxomatous mitral valve disease causing mitral regurgitation (MR) is a common cause of heart failure in dogs. However, many aspects of pathophysiology affecting diagnostic measurements are poorly defined. The objective of this study was to add to the knowledge of different pathophysiological processes affecting measures used. Focus was put on plasma parameters, including N-terminal pro A-type natriuretic peptide (NT-proANP) and nitric oxide (NO), and first pass radionuclide angiocardiography to evaluate heart pump function and possible right sided heart enlargement associated with pulmonary hypertension. Echocardiography and thoracic radiographs were used as reference methods. Results. In normal dogs both NT-proANP (P=0.002) and NO (P=0.01) increased with age. Plasma NT-proANP concentrations for dogs under 5.9 years of age were lower than for dogs older than 5.9 years (inter quartile range 190–270 pmol/l vs. 307–530, respectively), with no overlap between groups. This discrimination was not seen for NO. In healthy dogs heart rate normalized blood pulmonary transit time (nPTT) was 4.4±0.6, dogs with asymptomatic MR 6.3±1.6, and dogs with CHF 11.8±3.4 (P<0.001). The size of the right heart chambers increased only late in MR. Pulmonary blood volume (PBV) was associated with nPTT (R2=0.85, P<0.0001) but not with forward stroke volume. Increase in PBV appeared late in the phase before CHF. The hazard ratio for NT-proANP was 1.21 (per 100 pmol/l; P<0.0002). The median time to failure was 11 months for dogs with NT-proANP concentrations >1000 pmol/l and 54 months for dogs with concentrations ≤1000 pmol/l (P<0.0001). Dogs that developed CHF had a lower mean plasma level of NO than dogs not reaching CHF (mean 23 vs. 28 µmol/l (as nitrite), P=0.016). Increased heart rate (>130 beats/min, P<0.001) and heart murmur (3-6/6 vs. 1-2/6, P<0.001) increased risk. Conclusions. Specific normal values for natriuretic peptides should be established for different age groups of dogs. Heart rate, murmur and NT-proANP can be used to predict risk of and time to heart failure in dogs with MR. Heart rate normalized PTT (nPTT) is a robust measure of heart pump function in MR. Both nPTT and pulmonary blood volume increase before onset of CHF. Apparent right-sided heart enlargement on radiographs is due to them being displaced by left heart chambers as they enlarge only in severe MR.
    11/2013, Degree: PhD
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    ABSTRACT: Background:Degenerative mitral valve disease (MVD) is the most common heart disease in small breed dogs, and chordae tendineae rupture (CTR) is a potential complication of this disease. The survival time and prognostic factors predictive of survival in dogs with CTR remain unknown.Hypothesis:The prevalence and prognosis of CTR in dogs with MVD increases and decreases, respectively, with heart failure class.Animals:This study used 706 dogs with MVD.Methods:The diagnosis of CTR was based on a flail mitral leaflet with the tip pointing into the left atrium during systole, which was confirmed in several 2-dimension imaging planes using the left and right parasternal 4-chamber views.Results:CTR was diagnosed in 114 of the 706 dogs with MVD (16.1%) and most of these (106/114, 93%) had severe mitral valve regurgitation as assessed by color Doppler mode. CTR prevalence increased with International Small Animal Cardiac Health Council (ISACHC) clinical class (i.e., 1.9, 20.8, 35.5, and 69.6% for ISACHC classes Ia, Ib, II, and III, respectively [P < .05]). Long-term follow-up was available for 57 treated dogs (angiotensin-converting enzyme inhibitors and diuretics) and 58% of these (33/57) survived > 1 year after initial CTR diagnosis (median survival time, 425 days). Clinical class, the presence of ascites or acute dyspnea at the time of diagnosis, heart rate, plasma urea concentration, and left atrial size were predictors of survival.Conclusions and Clinical Relevance: CTR is associated with a higher overall survival time than previously supposed. Its prognosis mostly depends on a combination of clinical and biochemical factors.
    Journal of Veterinary Internal Medicine 02/2008; 21(2):258 - 264. · 2.06 Impact Factor
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    ABSTRACT: Degenerative mitral valve disease (MVD) is the most common heart disease in small breed dogs, and chordae tendineae rupture (CTR) is a potential complication of this disease. The survival time and prognostic factors predictive of survival in dogs with CTR remain unknown. The prevalence and prognosis of CTR in dogs with MVD increases and decreases, respectively, with heart failure class. This study used 706 dogs with MVD. The diagnosis of CTR was based on a flail mitral leaflet with the tip pointing into the left atrium during systole, which was confirmed in several 2-dimension imaging planes using the left and right parasternal 4-chamber views. CTR was diagnosed in 114 of the 706 dogs with MVD (16.1%) and most of these (106/114, 93%) had severe mitral valve regurgitation as assessed by color Doppler mode. CTR prevalence increased with International Small Animal Cardiac Health Council (ISACHC) clinical class (i.e., 1.9, 20.8, 35.5, and 69.6% for ISACHC classes Ia, Ib, II, and III, respectively [P < .05]). Long-term follow-up was available for 57 treated dogs (angiotensin-converting enzyme inhibitors and diuretics) and 58% of these (33/57) survived > 1 year after initial CTR diagnosis (median survival time, 425 days). Clinical class, the presence of ascites or acute dyspnea at the time of diagnosis, heart rate, plasma urea concentration, and left atrial size were predictors of survival. CTR is associated with a higher overall survival time than previously supposed. Its prognosis mostly depends on a combination of clinical and biochemical factors.
    Journal of Veterinary Internal Medicine 21(2):258-64. · 2.06 Impact Factor