Publicação
Pitfalls of M-mode Echocardiography Enddiastolic and End-systolic Measurements: a study of 154 dogs with Myxomatous Mitral Valve Disease
| Resumo: | Myxomatous mitral valve disease (MMVD) is considered the most common cardiac condition in dogs and is primarily characterized by mitral valve regurgitation and cardiac remodelling, which progressively leads to congestive heart failure. Echocardiography is considered the gold standard for the diagnosis of this disease. M-mode is essential for accurately staging the disease, according to the American College of Veterinary Internal Medicine (ACVIM) guidelines, as it provides information regarding the maximum internal dimension of the left ventricle at the end of the diastole (LVIDd). Typically, the onset of the QRS wave is the reference point used for the end of the diastole; however, in some cases, this point does not correspond to the largest internal dimension of the heart chamber. In addition, the systolic function can also be evaluated using M-mode, by calculating the minimum internal dimension of the left ventricle at the end of the systole (LVIDs). The standard recommendation is to perform this quantification at the point of maximum septal wall contraction. Although this method is suitable for the average patient, it may not be adequate for animals presenting signs of ventricular asynchrony. Therefore, the main objective of this study was to compare the commonly used reference points for LVIDd and LVIDs to other measurement methods that represent the maximum and minimum internal dimensions of the left chamber, respectively. The echocardiographic exams of 154 dogs diagnosed with MMVD in the Hospital Veterinário do Porto were retrospectively reviewed for the measurements of LVIDd. Out of the 154 dogs, 25 had a significant difference in septal and free wall contraction times and were considered as having signs of ventricular asynchrony. These 25 dogs were further used for the measurements of LVIDs. Each of the measurements were calculated using two different methods. The LVIDd was obtained by using the onset of the QRS wave (Method D1) and by measuring the largest distance between the septal and free wall (Method D2). Furthermore, the results of each of the measurement methods utilized for the LVIDd were used to classify each dog according to the staging criteria suggested by ACVIM guidelines. On the other hand, the LVIDs was calculated using the maximum contraction point of the septal wall as the starting point (Method S1) and the minimum distance between the septal and free wall maximum contraction point (Method S2). Most of the population consisted of male, neutered dogs, with no defined breed, aged between 8 and 14 years old, and with an average (M) weight of 14.58 kg. Analysis of the LVIDd results revealed a significant difference of 3.17 mm (p < 0.001) depending on the method used. The D2 method produced higher values in 152 animals (98.7%) (M = 35.47 mm). Meanwhile, higher values obtained using the D1 method were verified in only 2 of the dogs (M = 32.30 mm). The normalized values maintained higher results in the D2 method in 128 of the dogs, while 26 had equal values in both methods. Applying the ACVIM staging criteria to both measurement methods resulted in 111 of the dogs being classified as B1 and 29 as B2 when using the D1 method. Simultaneously, the measurements obtained using the D2 method resulted in 99 dogs categorized as B1 and 41 as B2, which means that the staging differed in 12 dogs, depending on the method used. Regarding the 25 dogs with signs of ventricular asynchrony, results showed that the S1 method (M = 28.95 mm) obtained significantly higher LVIDs measurements (p < 0.001) in all the dogs and an average difference of 4.41 mm, when compared to the S2 method results (M = 24.54 mm). For the normalized measurements, the S1 method showed higher values in 23 of the dogs, while the remaining 2 had equal values using both methods. This study demonstrates that the different methods used result in different LVIDd measurements, and possibly a different ACVIM staging classification for the patient in some cases. Moreover, the commonly used reference point for LVIDs is not adequate for dogs with signs of ventricular asynchrony. Further research is required to better define this condition and properly include it in future echocardiographic guidelines. |
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| Autores principais: | Pereira, Guilherme Gonçalves da Cunha e Moura |
| Assunto: | Myxomatous mitral valve disease Echocardiography M-mode Enddiastolic measurement End-systolic measurement |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Trás-os-Montes e Alto Douro |
| Idioma: | inglês |
| Origem: | Repositório da UTAD |
| Resumo: | Myxomatous mitral valve disease (MMVD) is considered the most common cardiac condition in dogs and is primarily characterized by mitral valve regurgitation and cardiac remodelling, which progressively leads to congestive heart failure. Echocardiography is considered the gold standard for the diagnosis of this disease. M-mode is essential for accurately staging the disease, according to the American College of Veterinary Internal Medicine (ACVIM) guidelines, as it provides information regarding the maximum internal dimension of the left ventricle at the end of the diastole (LVIDd). Typically, the onset of the QRS wave is the reference point used for the end of the diastole; however, in some cases, this point does not correspond to the largest internal dimension of the heart chamber. In addition, the systolic function can also be evaluated using M-mode, by calculating the minimum internal dimension of the left ventricle at the end of the systole (LVIDs). The standard recommendation is to perform this quantification at the point of maximum septal wall contraction. Although this method is suitable for the average patient, it may not be adequate for animals presenting signs of ventricular asynchrony. Therefore, the main objective of this study was to compare the commonly used reference points for LVIDd and LVIDs to other measurement methods that represent the maximum and minimum internal dimensions of the left chamber, respectively. The echocardiographic exams of 154 dogs diagnosed with MMVD in the Hospital Veterinário do Porto were retrospectively reviewed for the measurements of LVIDd. Out of the 154 dogs, 25 had a significant difference in septal and free wall contraction times and were considered as having signs of ventricular asynchrony. These 25 dogs were further used for the measurements of LVIDs. Each of the measurements were calculated using two different methods. The LVIDd was obtained by using the onset of the QRS wave (Method D1) and by measuring the largest distance between the septal and free wall (Method D2). Furthermore, the results of each of the measurement methods utilized for the LVIDd were used to classify each dog according to the staging criteria suggested by ACVIM guidelines. On the other hand, the LVIDs was calculated using the maximum contraction point of the septal wall as the starting point (Method S1) and the minimum distance between the septal and free wall maximum contraction point (Method S2). Most of the population consisted of male, neutered dogs, with no defined breed, aged between 8 and 14 years old, and with an average (M) weight of 14.58 kg. Analysis of the LVIDd results revealed a significant difference of 3.17 mm (p < 0.001) depending on the method used. The D2 method produced higher values in 152 animals (98.7%) (M = 35.47 mm). Meanwhile, higher values obtained using the D1 method were verified in only 2 of the dogs (M = 32.30 mm). The normalized values maintained higher results in the D2 method in 128 of the dogs, while 26 had equal values in both methods. Applying the ACVIM staging criteria to both measurement methods resulted in 111 of the dogs being classified as B1 and 29 as B2 when using the D1 method. Simultaneously, the measurements obtained using the D2 method resulted in 99 dogs categorized as B1 and 41 as B2, which means that the staging differed in 12 dogs, depending on the method used. Regarding the 25 dogs with signs of ventricular asynchrony, results showed that the S1 method (M = 28.95 mm) obtained significantly higher LVIDs measurements (p < 0.001) in all the dogs and an average difference of 4.41 mm, when compared to the S2 method results (M = 24.54 mm). For the normalized measurements, the S1 method showed higher values in 23 of the dogs, while the remaining 2 had equal values using both methods. This study demonstrates that the different methods used result in different LVIDd measurements, and possibly a different ACVIM staging classification for the patient in some cases. Moreover, the commonly used reference point for LVIDs is not adequate for dogs with signs of ventricular asynchrony. Further research is required to better define this condition and properly include it in future echocardiographic guidelines. |
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