Evaluation of antioxidant status and lipid peroxidation in dogs with myxomatous mitral valve degeneration stage B1.

Myxomatous mitral valve degeneration (MMVD) is the most common naturally occurring heart disease in dogs. There is a lack of data on antioxidant status and oxidative damage in dogs with MMVD stage B1 according to the American College of Veterinary Internal Medicine (ACVIM B1). The aim of this study was to investigate antioxidant status (plasma vitamin E, lipid-standardized vitamin E (LS-VitE), antioxidant capacity of lipid-(ACL) and water-soluble antioxidants, whole blood glutathione peroxidase and erythrocyte superoxide dismutase), and lipid peroxidation [malondialdehyde (MDA)] in dogs with MMVD ACVIM B1. Serum cholesterol and triglyceride concentrations were measured to calculate LS-VitE. Fourteen dogs with MMVD ACVIM B1 and 12 control dogs were included in the study. Dogs with MMVD had significantly higher vitamin E, ACL, MDA, and cholesterol concentrations and significantly higher LS-VitE values than control dogs. No significant correlations between MDA and antioxidant parameters were determined in either group. In conclusion, oxidative damage to lipids is already present and the antioxidant status is altered but not depleted in dogs with MMVD ACVIM B1. The antioxidant response to increased oxidative damage consists mainly of the activation of fat-soluble antioxidants. Further research is needed to evaluate the efficacy and targets of early antioxidant supplementation to prevent or ameliorate oxidative stress and mitigate disease progression in dogs with early-stage MMVD.

Cardiac Virtual Noncontrast Images for Calcium Quantification with Photon-counting Detector CT.

Purpose: To assess the accuracy of aortic valve calcium (AVC), mitral annular calcium (MAC), and coronary artery calcium (CAC) quantification and risk stratification using virtual noncontrast (VNC) images from late enhancement photon-counting detector CT as compared with true noncontrast images. Materials and Methods: This retrospective, institutional review board-approved study evaluated patients undergoing photon-counting detector CT between January and September 2022. VNC images were reconstructed from late enhancement cardiac scans at 60, 70, 80, and 90 keV using quantum iterative reconstruction (QIR) strengths of 2-4. AVC, MAC, and CAC were quantified on VNC images and compared with quantification of AVC, MAC, and CAC on true noncontrast images using Bland-Altman analyses, regression models, intraclass correlation coefficients (ICC), and Wilcoxon tests. Agreement between severe aortic stenosis likelihood categories and CAC risk categories determined from VNC and true noncontrast images was assessed by weighted κ analysis. Results: Ninety patients were included (mean age, 80 years ± 8 [SD]; 49 male patients). Scores were similar on true noncontrast images and VNC images at 80 keV for AVC and MAC, regardless of QIR strengths, and VNC images at 70 keV with QIR 4 for CAC (all P > .05). The best results were achieved using VNC images at 80 keV with QIR 4 for AVC (mean difference, 3; ICC = 0.992; r = 0.98) and MAC (mean difference, 6; ICC = 0.998; r = 0.99), and VNC images at 70 keV with QIR 4 for CAC (mean difference, 28; ICC = 0.996; r = 0.99). Agreement between calcification categories was excellent on VNC images at 80 keV for AVC (κ = 0.974) and on VNC images at 70 keV for CAC (κ = 0.967). Conclusion: VNC images from cardiac photon-counting detector CT enables patient risk stratification and accurate quantification of AVC, MAC, and CAC.Keywords: Coronary Arteries, Aortic Valve, Mitral Valve, Aortic Stenosis, Calcifications, Photon-counting Detector CT Supplemental material is available for this article © RSNA, 2023.

Treatment of atrial tachycardia arising after superior transseptal approach mitral valve surgery: Insights from ultra-high-density mapping to prevent atrioventricular block.

INTRODUCTION: Mitral valve surgery employing a superior transseptal approach (STA) is associated with arrhythmogenicity and intra-atrial conduction delay, despite being optimal for visualization of the surgical field. It is sometimes difficult to treat atrial tachycardias (AT) that arise after STA. To investigate AT circuits that arise after STA in detail in order to identify the optimal ablation line, using ultra-high-resolution mapping (UHRM). METHODS: We retrospectively analyzed 12 AT from 10 patients (median age 70 years, nine males) who had undergone STA surgery. The tachycardias were mapped using the Rhythmia mapping system (Boston Scientific, Natick, Massachusetts). RESULTS: The 12 STA-related AT (STA-AT) circuits were classifiable as follows according to location of the optimal ablation line: (1) peri-septal incision STA-AT (n = 3), (2) cavotricuspid isthmus (CTI) dependent STA-AT (n = 7), and (3) biatrial tachycardia (n = 2). Radiofrequency (RF) application terminated 11 of the 12 STA-AT. We found that difference in STA-AT circuit type was due to characteristics of the septal incision line made for STA. UHRM was important in identifying optimal ablation sites that did not create additional conduction disturbances in the right atrium (RA). CONCLUSIONS: ATs after STA involve complex arrhythmia circuits due to multiple and long incision lines in the RA. Accurate understanding of the arrhythmia circuit and sinus conduction in the RA after STA is recommended for treating post-surgical tachycardia in a minimally invasive manner.

Effects of Coenzyme Q10 Supplementation on Oxidative Stress Markers, Inflammatory Markers, Lymphocyte Subpopulations, and Clinical Status in Dogs with Myxomatous Mitral Valve Disease.

Scarce data exist on the effects of coenzyme Q10 (CoQ10) supplementation in dogs with myxomatous mitral valve disease (MMVD). The purpose of this study was to investigate the effect of CoQ10 supplementation on oxidative stress markers (glutathione peroxidase, F2-isoprostanes), markers of inflammation (tumor necrosis factor-α, TNF soluble receptor II, leucocytes, and their subtypes), lymphocyte subpopulations (T helper and cytotoxic T lymphocytes, including activated T lymphocytes, and B lymphocytes), and echocardiographic and clinical parameters in dogs with MMVD. In this randomized, controlled, double-blind, longitudinal study, 43 MMVD dogs in stages ACVIM (American College of Veterinary Internal Medicine classification) B2 and ACVIM C and D (congestive heart failure (CHF)) received water-soluble coenzyme Q10 (100 mg twice daily) or placebo for 3 months, and 12 non-supplemented healthy dogs served as controls. All parameters were measured before and after supplementation in MMVD dogs and once in healthy dogs. CoQ10 supplementation had a positive impact on neutrophil percentage, lymphocyte percentage, and lymphocyte concentration in our cohort of dogs with CHF (ACVIM C and D). Conclusion: CoQ10 as an oral supplement may have benefits in terms of decreasing inflammation in dogs with MMVD and CHF.

Overview of mitral valve replacement versus mitral valve repair due to ischemic papillary muscle rupture: A meta-analysis inspired by a case report.

BACKGROUND: Papillary muscle rupture (PMR) is an infrequent but catastrophic complication after myocardial infarction (MI). Surgical procedure is considered the optimal treatment, despite high risk. However, the gold standard technique is still a major dilemma. Therefore, a meta-analysis was carried out to assess and provide an overview comparing mitral valve replacement (MVR) and mitral valve repair (MVr) for PMR post-MI. METHODS: A systematic literature search was performed. Data were extracted and verified using a standardized data extraction form. Meta-analysis was realized mainly using RevMan 5.4 software. RESULTS: From four observational studies 1640 patients were identified; 81% underwent MVR and 19% MVr. Operative mortality results were significantly higher in MVR group than the MVr group. MVR was performed under emergency conditions and patients admitted in cardiogenic shock or who required the use of mechanical cardiac support underwent MVR. MVr had shorter time of hospitalization and similar incidence of postoperative complications than MVR. No significant differences existed between the two procedures regarding cardiopulmonary bypass time. CONCLUSIONS: Mitral valve repair appears to be a viable alternative to MVR for post-MI PMR, given that it has lower operative mortality, shorter time of hospitalization and similar incidence of short-term postoperative complications than MVR. However, it needs to be pointed out that MVR was associated with the most critical clinical condition following PMR. There is uncertainty regarding the overall survival and improvement of the quality of life between the procedures. Nevertheless, further completed investigation is required.

Short-term melatonin supplementation decreases oxidative stress but does not affect left ventricular structure and function in myxomatous mitral valve degenerative dogs.

BACKGROUND: Cardiac wall stress and high oxidative stress are often found in cases of myxomatous mitral valve degenerative (MMVD) disease and can lead to myocardial injuries and cardiac dysfunction. Melatonin, an antioxidant, has been shown to exert cardioprotection in laboratory animal models. However, its effect on metabolic parameters and left ventricular (LV) adaptation in MMVD dogs has rarely been investigated. This clinical trial hypothesized that a melatonin supplement for 4 weeks would improve metabolic parameters, LV structure (diameters and wall thickness), and LV function in MMVD dogs. Blood profiles, echocardiograms, and oxidative stress levels were obtained from 18 dogs with MMVD stage B2 and C at baseline and after prescribed Melatonin (2 mg/kg) for 4 weeks. Eleven dogs with MMVD stage B2 and C, which received a placebo, were evaluated as a control group. RESULTS: In this clinical trial, the baseline plasma malondialdehyde (MDA) was no different between the treatment and placebo groups. The post-treatment plasma MDA levels (4.50 ± 0.63 mg/mL) in the treatment group was significantly decreased after 4 weeks of melatonin supplementation compared to pre-treatment levels (7.51 ± 1.11 mg/mL) (P = 0.038). However, blood profiles and LV structure and function investigated using echocardiography were found not to different between pre-and post-treatment in each group. No adverse effects were observed following melatonin supplementation. CONCLUSIONS: This clinical trial demonstrated that a melatonin supplement for 4 weeks can attenuate oxidative stress levels in MMVD dogs, especially in MMVD stage C, but does not result in LV structural changes or LV function in MMVD dogs of either stage B2 or stage C.

Do alternative approaches work in surgical septal myectomy?

Trans-aortic septal myectomy is the gold standard for septal reduction therapy. This technique has low peri-procedural mortality and excellent long-term survival. Moreover, it relieves the heart failure symptoms and improves the quality of life. Secondary chordal cutting along with septal myectomy has shown to improve the outcome but can potentially cause deterioration of left ventricular function. In patients with relatively thin inter-ventricular septum, abnormalities of mitral valve apparatus may be the main reason for systolic anterior motion and left ventricular outflow tract obstruction. These patients may require additional procedures on the mitral valve to shift the coaptation plane away from outflow tract. Mitral valve replacement should be performed only in patients with intrinsic mitral valve abnormalities that are not suitable for repair and its routine use along with limited septal myectomy should be discouraged. Minimal access surgery although attractive in concept requires more robust data before universal application.

Macro-reentrant atrial tachycardia after tricuspid or mitral valve surgery: is there difference in electrophysiological characteristics and effectiveness of catheter ablation?

BACKGROUND: Macro-reentrant atrial tachycardias (MATs) are a common complication after cardiac valve surgery. The MAT types and the effectiveness of MAT ablation might differ after different valve surgery. Data comparing the electrophysiological characteristics and the ablation results of MAT post-tricuspid or mitral valve surgery are limited. METHODS: Forty-eight patients (29 males, age 56.1 ± 13.3 years) with MAT after valve surgery were assigned to tricuspid valve (TV) group (n = 18) and mitral valve (MV) group (n = 30). MATs were mapped and ablated guided by a three-dimensional navigation system. The one-year clinical effectiveness was compared in two groups. RESULTS: Nineteen MATs were documented in TV group, including 16 cavo-tricuspid isthmus (CTI)-dependent AFL and 3 other MATs at right atrial (RA) free wall, RA septum and left atrial (LA) roof. Thirty-nine MATs were identified in MV group, including15 CTI-dependent AFL, 8 RA free wall scar-related, 2 RA septum scar-related, 8 peri-mitral flutter, 3 LA roof-dependent, 2 LA anterior scar-related, and 1 right pulmonary vein-related MAT. Compared with TV group, MV group had significantly lower prevalence of CTI-dependent AFL (38.5% vs. 84.2%), higher prevalence of left atrial MAT (35.9 vs.5.3%) and higher proportion of patients with left atrial MAT (40 vs. 5.6%), P = 0.02, 0.01 and 0.01, respectively. The acute success rate of MAT ablation (100 vs. 93.3%) and the one-year freedom from atrial tachy-arrhythmias (72.2 vs. 76.5%) was comparable in TV and MV group. No predictor for recurrence was identified. CONCLUSION: Although the types of MATs differed significantly in patients with prior TV or MV surgery, the acute and mid-term effectiveness of MAT ablation was comparable in two groups. TRIAL REGISTRATION: This study was registered as a part of EARLY-MYO-AF clinical trial at the website ClinicalTrials. gov (NCT04512222).

Current Perspectives on Contemporary Rheumatic Mitral Valve Repair.

The surgical management of rheumatic mitral valve disease remains a challenge for cardiac surgeons. Durability of mitral valve repair (MVr) is likely compromised not simply due to high technical demand, but surgeon reluctance, despite boasting copious advantages over MV replacement. This comprehensive review aims to evoke a deeper understanding of MVr concepts necessary to abate these limitations and shift mindset towards a more holistic approach to repair. Details of commonly utilized techniques in contemporary MVr for rheumatic heart disease will be discussed. Of importance, the reparative procedures will be mapped to an in-depth physiological exploration of the mitral complex-dynamism and rheumatic interplay. This is further emphasized by outlining the current "aggressive" resection strategy in contemporary rheumatic MVr.

Percutaneous mitral valve repair in recurrent severe mitral valve regurgitation after mitral annuloplasty : MitraClip-in-the-ring as a complementary strategy.

BACKGROUND: Patients with reduced left ventricular (LV) function undergoing coronary artery bypass graft surgery or/and aortic valve replacement occasionally show severe mitral valve (MV) regurgitation and thus also undergo surgical mitral annuloplasty. Over time, further deterioration of LV function and additional ischemic events cause recurrence of severe MV regurgitation due to the Carpentier IIIb morphology of the MV that is not adequately addressed by the previously implanted annuloplasty ring. METHODS: Seven patients (Society of Thoracic Surgeons score: 7.5 ± 1.5%) with Carpentier type-IIIb recurrent severe MV regurgitation, having undergone prior cardiothoracic surgery (median: 40 months) including mitral annuloplasty, were treated with the MitraClip device. RESULTS: MitraClip implantation resulted in significantly reduced MV regurgitation and improved New York Heart Association functional state, translating into an increased exercise capability and improved cardiac biomarkers. The morphology of the MV was adequately addressed without causing relevant MV stenosis, while the MV annulus area remained unaltered. The procedure was safe with a 30-day mortality rate of 0%. CONCLUSION: MitraClip-in-the-ring is feasible and in principle safe for treating Carpentier type IIIb severe MV regurgitation after surgical MV repair using mitral annuloplasty. MitraClip-in-the-ring resulted in immediate amelioration of clinical symptoms and increased physical exercise capacity.

Early Experience With a Novel Transfemoral Mitral Valve Implantation System in Complex Degenerative Mitral Regurgitation.

OBJECTIVES: The aim of this study was to evaluate the feasibility, procedural results, and 6-month outcomes of a novel transfemoral transcatheter mitral valve implantation (TMVI) system (Cephea) in patients with complex primary mitral regurgitation (MR). BACKGROUND: TMVI is emerging as an alternative to surgery in patients with severe MR. To date, the great majority of TMVI systems use the transapical surgical approach. METHODS: This study included consecutive patients undergoing transfemoral TMVI with the Cephea valve system. All patients were suboptimal candidates for catheter-based repair for anatomic reasons. Patients underwent clinical, echocardiographic, and computed tomographic angiographic follow-up at 6 months. Main outcomes were procedural success, peri-procedural complications, and valve hemodynamic status early and at 6-month follow-up. RESULTS: Three patients with severe primary MR (2 women, mean age 79 ± 3 years) at prohibitive surgical risk (mean European System for Cardiac Operative Risk Evaluation II score 13.8 ± 2.4%) were included. The valves were successfully implanted in all patients, with no procedural complications. Post-procedural echocardiography showed normal valve function in all patients (mean transvalvular gradient 3 mm Hg; range: 2 to 4 mm Hg), no moderate to severe valvular or paravalvular leak, and no clinically significant left ventricular outflow tract obstruction. At 6 months, all patients had improved quality of life (mean improvement vs. baseline 16.4 ± 12 points). All valve hemodynamic parameters were maintained. Computed tomographic angiography confirmed annular stability, proper valve geometry and no structural failure. CONCLUSIONS: The transfemoral delivery of a purposely designed mitral prosthesis (Cephea valve) was safe and feasible in prohibitive risk patients. Valve performance was sustained, and clinical outcomes improved at 6 months. Larger clinical studies are required.

Effect of Music Therapy on the Chronic Pain and Midterm Quality of Life of Patients after Mechanical Valve Replacement.

OBJECTIVE: To evaluate the effect of music therapy on the chronic pain and midterm quality of life of patients after mechanical valve replacement. METHODS: Patients were divided into two groups according to whether or not they received music therapy. The patients in the music group received 30 minutes of music therapy every day for 6 months after the operation. The patients in the control group received standard treatment and had 30 minutes of quiet rest time every day in the same period. The short-form of McGill Pain Questionnaire (SF-MPQ) was used to evaluate the degree of postoperative chronic pain, and the SF-36 was used to evaluate the midterm quality of life of patients. RESULTS: In terms of the degree of postoperative chronic pain, the score of the pain rating index (PRI) emotional item in the music group was significantly lower than that in the control group. In the evaluation of the postoperative midterm quality of life using the SF-36, the emotional function score in the music group was significantly higher than that in the control group. CONCLUSION: This study preliminarily showed that music therapy can effectively reduce chronic pain and improve midterm quality of life after surgery.

Rheumatic mitral valve repair: a personal perspective and results.

Rheumatic mitral valve disease remains a challenge for cardiac surgeons. Valve repair has several advantages over valve replacement but is technically demanding for good results. To improve rheumatic mitral valve repair, surgeons need to have a deep understand of the mitral valve complex and its dynamics. The goal of repair is to restore normal diastolic and systolic function. The current approach is to perform a holistic repair of the entire mitral complex. Each part of the complex is thoroughly explored to define the problem. Several innovative techniques have been introduced to correct valve dysfunction and provide gratifying results. The details of these techniques will be described, based on an understanding of the relationship of the mitral valve complex and dynamics. With this approach, rheumatic mitral valve repair is becoming more successful, reproducible, and safe. Long-term follow-up is mandatory.

Impact of the Commercial Introduction of Transcatheter Mitral Valve Repair on Mitral Surgical Practice.

Background There has been uncertainty regarding the effect of transcatheter mitral valve repair (TMVr) with MitraClip on cardiac surgical practice. Our aim was to examine the impact of the commercial introduction of TMVr to a comprehensive mitral program. Methods and Results We evaluated 875 patients (aged 69±14 years; 58% men) who underwent transcatheter or mitral surgical procedures over a 6-year period at our institution. Main outcomes were changes in surgical procedural volume after TMVr introduction and short-term mortality for surgical and TMVr procedures. The numbers of patients treated with MitraClip, isolated mitral repair, and any mitral surgery were 249, 292, and 626 patients, respectively. Compared with surgery, patients with MitraClip were older (aged 82±8 versus 64±12 years; P<0.001) and had more severe morbidity. Following the introduction of MitraClip, surgical volumes steadily increased to a rate of 10 (95% CI, 3-7) procedures per year for isolated mitral procedures and 17 (95% CI, 13-20) procedures per year for all mitral surgeries. Both MitraClip and surgical volumes increased at the same rate (P=0.42). In-hospital mortality was 3.2% for MitraClip and 2.1% for all mitral surgeries (P=0.33). At 30 days, survival free of all mortality (P=0.17) and freedom from heart failure rehospitalization (P=0.75) were similar for transcatheter and surgical procedures. Conclusions The commercial introduction of TMVr may be associated with growth in cardiac surgery, without detracting from other therapies, and favorable clinical outcomes for all treated mitral regurgitation patients. These findings demonstrate the potential benefits of complementary therapies in the treatment of patients with mitral regurgitation.

Intractable mechanical hemolytic anemia complicating mitral valve surgery: a case series study.

BACKGROUND: Intractable, mechanical hemolytic anemia (IMHA) is a rare catastrophic complication following mitral valve surgery. We analyzed patient characteristics and IMHA management by reoperations after mitral valve surgery. METHODS: We collected medical records from mitral valve patients requiring reoperation due to IMHA. INCLUSION CRITERIA: hemoglobin < 100 g/L; positive hemolysis tests and echocardiography results; and exclusion of other hemolysis causes. RESULTS: Data from 25 IMHA cases included 10 (40%) early onset (1.3 (0.3,3.0) months) and 15 (60%) late onset (120 (24,204) months) cases. Early IMHA etiologies included surgical defects (6, 60%), uncontrolled infection (3, 30%) and Bechet's disease (1, 10%). Late IMHA etiologies included degeneration (13, 87%), new infection (1, 7%) and trauma (1, 7%). There were more mechanical valves (15, 88%) than bio-valves (2, 12%); the main valvular dysfunction was paravalvular leak (16, 64%). IMHA manifestations included jaundice (18, 72%), dark urine (21, 84%), heart failure (16, 64%), acute kidney injury (11, 44%), hepatomegaly (15, 60%), splenomegaly (15, 60%) and pancreatitis (1, 4%). Laboratory results showed decreased hemoglobin (70 ± 14 g/L) and increased bilirubin (72 ± 57 µmol/L), lactate dehydrogenase (2607 ± 2142 IU/L) and creatinine (136 ± 101 µmol/L) levels. Creatinine level negatively correlated with hemoglobin level (B = -3.33, S.E. B = 1.31, Exp(B) = 368.15, P = 0.018). Preoperative medications included iron supplements (20, 80%), erythropoietin (16, 64%) and beta-blocker (22, 88%). Two patients died of cardiac causes before reoperation. The other 23 underwent reoperation with long surgical times (aortic cross clamp 124 ± 50 min, cardiopulmonary bypass 182 ± 69 min) and blood transfusions (red blood cells 6 (6, 8) units, plasma 600 (400,800) ml, platelet 1(0,2) units). Postoperative complications included cardiac dysfunction (5, 22%), arrhythmia (10, 43%), sepsis (6, 26%), pulmonary infection (5, 22%), gastrointestinal bleeding (3, 13%), cerebral hemorrhage (2, 9%), chronic renal dysfunction (1, 4%) and surgical hemorrhage (1, 4%). Five (33%) patients died after reoperation from cardiac dysfunction (3, 60%), septic shock (1, 20%) and self-discharge (1, 20%). CONCLUSIONS: IMHA induces severe multi-organ dysfunction, contributing to high mortality. Perioperative management should focus on etiological treatment, organ protection, and blood management.

Evaluation of left atrial function in asymptomatic dogs with chronic myxomatous mitral valve disease: two-dimensional feature-tracking echocardiography and Simpsons monoplanar methods / Avaliação da função atrial esquerda em cães assintomáticos com degeneração mixomatosa crônica de valva mitral: métodos ecocardiográficos bidimensional feature tracking e monoplanar de Simpson

The present study evaluated the volume and function of the left atrium by two-dimensional echocardiographic feature-tracking imaging (2D-FTI) and Simpson's monoplanar modeling in dogs with asymptomatic degenerative mitral valve disease (DMVD). The study consisted of 80 dogs that were divided into the following three groups: Group 1, 21 dogs (A); Group 2, 30 dogs (B1) and Group 3, 29 dogs (B2). The variable strain (contraction phase) was significantly lower in Group 3 than in Group 1 (12.92±4.54 x 16.69±5.74, p=0.014), and significant differences in the contraction strain index (CSI) were observed between all of the groups that were evaluated (1 = 46.82±8.10, 2 = 39.88±8.03, 3 = 35.25±5.64, p<0.0001). The atrial diastolic volume index (AdVi) that was measured by 2D-FTI was significantly higher in Group 3 than in Group 1 (1.31±0.95 x 0.96±0.31, p=0.038), and the atrial cardiac index (ACI) was also higher in Group 3 than in Group 1 (102.38±80.18 x 78.19±33.38, p=0.030). Atrial function was assessed by Simpson's monoplanar method, which demonstrated an increase in the left atrial systolic volume, while the contractile function decreased with an increasing disease severity (Group 1 0.21±0.06; Group 2 0.25±0.06; Group 3 0.32±0.08, p<0.0001). The intraobserver and interobserver assessments showed low to moderate variability; most of the values for the coefficient of variation for the variables that were analysed with each method were below 25%. Thus, DMVD was determined to cause an alteration in atrial function, especially in the contraction phase, and even in asymptomatic animals, and the methods of 2D-FTI echocardiography and Simpson's monoplanar evaluation are sensitive and early methods for the detection of left atrial dysfunction.(AU)

O presente estudo avaliou o volume e a função atrial esquerda obtidos por meio da ecocardiografia bidimensional feature tracking (2D-FTI) e pelo método monoplanar de Simpson em cães saudáveis e cães com DMVD assintomáticos. Foram avaliados 80 cães distribuídos em três grupos: Grupo 1, 21 cães (classe A); Grupo 2, 30 cães (classe B1) e Grupo 3, 29 cães (classe B2). A variável strain (fase de contração) foi significativamente menor no Grupo 3 que no Grupo 1 (12,92±4,54 x 16,69±5,74, p=0,014) e para a variável índice de strain de contração (CSI), houve diferença estatística entre todos os grupos avaliados (1 = 46,82±8,10; 2 = 39,88±8,03; 3 = 35,25±5,64, p<0,0001). O índice de volume diastólico atrial (iVdA) mensurado por meio do 2D-FTI foi significativamente maior no Grupo 3 que no Grupo 1 (1,31±0,95 x 0,96±0,31, p=0,038), assim como para o índice cardíaco atrial (iCA) também foi maior no Grupo 3 (102,38±80,18 x 78,19±33,38, p=0,030). A função atrial avaliada pelo método monoplanar de Simpson demonstrou um aumento do volume atrial esquerdo e do volume sistólico do átrio esquerdo, enquanto que a função contrátil diminuiu com o aumento da gravidade da doença (Grupo 1 0,21±0,06; Grupo 2 0,25±0,06; Grupo 3 0,32±0,08; p<0,0001). A avaliação intraobservador e interobservador, demonstrou variabilidade baixa a moderada, uma vez que a maioria dos valores de coeficiente de variação se concentraram abaixo de 25% para as variáveis analisadas em ambos os métodos. Dessa forma, conclui-se que a DMVD causa alteração na função atrial, principalmente na fase de contração, mesmo em animais assintomáticos e que a ecocardiografia 2D-FTI e o método monoplanar de Simpson são métodos sensíveis e precoces na detecção da disfunção atrial esquerda.(AU)

Dietary intervention reduces left atrial enlargement in dogs with early preclinical myxomatous mitral valve disease: a blinded randomized controlled study in 36 dogs.

BACKGROUND: Myxomatous mitral valve disease (MMVD), the most common naturally-occurring heart disease in dogs, is associated with alterations in energy metabolism, oxidative stress and inflammation. Energy deprivation plays a causal role in the development of heart failure. This study was designed to determine if a cardiac protection blend (CPB) of nutrients containing medium-chain triglycerides as an alternative energy source, fish oil to reduce inflammation, antioxidants, and other key nutrients important to cardiac health and function could slow or prevent MMVD progression. Nineteen dogs with early stage MMVD and 17 breed-, age-, and sex-matched healthy dogs were enrolled for a 6-month blinded, placebo-controlled study. Dogs in each cardiac health group were randomly assigned to either control diet (CON) or CPB-supplemented diet. Echocardiography was performed at baseline, 3 months and 6 months. RESULTS: No changes were found in healthy dogs. While MMVD-CON dogs had an average 10% increase over baseline in left atrial diameter (LAD) and left atrial to aortic root ratio (LA/Ao) at 6 months, MMVD-CPB dogs showed 3% decreases, resulting significant diet by time interactions (P = 0.037, P = 0.005, respectively). More MMVD-CON dogs progressed from stage B1 to B2 during the study. A positive correlation was found between 6-month changes in LAD and blood pressures in MMVD-CPB dogs (systolic: P = 0.050, diastolic: P = 0.035) but not MMVD-CON dogs. CONCLUSIONS: Our results demonstrated efficacy of CPB-based dietary intervention in reducing LA size and mitral regurgitation, and in slowing or preventing the progression of early MMVD in dogs.