Left atrial mechanical function in dogs with chronic mitral valve degeneration

Author(s)

Matheus Matioli Mantovani

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2016-05-05

Examining board members

Denise Saretta Schwartz; Denise Tabacchi Fantoni; Maria Helena Matiko Akao Larsson; Guilherme Gonçalves Pereira; Ronaldo Jun Yamato

• Advisor: Denise Saretta Schwartz

Abstract

This study aimed to determine whether left atrial (LA) function indices, volume (LAV) and area (LAA) can be used to assess severity of mitral valve chronic degeneration (MVCD) in dogs, as well as to diagnose congestive heart failure (CHF) in these patients. The hypothesis stated that the increase in left atrial volumes and decrease in function are associated with the severity of MVCD and also with CHF. Eigthy dogs were included in a cross sectional prospective observational clinical study, grouped according to the severity of MVCD based on clinical signs and echocardiographic evaluation. Dogs were equitatively distribuited among groups A, B1, B2 and C + D, according to MVCD staging proposed by the American College of Veterinary Internal Medicine. The fractional area change (FAC) and left atrial ejection fraction (LAEF) were calculated based on the following equations: total FAC = 100 x (LAAmaximum LAAminimum) / LAAmaximum, passive FAC = 100 x (LAAmaximum LAApa) / LAAmaximum and active FAC ativa = 100 x (LAApa LAAminimum) / LAApa, which measurements were performed in four chamber apical view; and total LAEF = 100 x (LAVmaximum LAVminimum) / LAVmaximum, passive LAEF = 100 x (LAVmaximum LAVpa) / LAVmáximum and active LAEF = 100 x (LAVpa LAVminimum) / VLAVpa , calculated by biplanar arealength method in four and two-chambers apical view. The total and active FAC, total LAEF and active LAEF were significantly smaller in pacients from group C+D than the observed in the other groups. With increasing severity of MVCD there was increase in LAVmaximum/kg, LAVpa/kg, LAVminimum/kg, LAAmaximum/m2, LAApa/m2, LAAminimum/m2. LA volumes, as well as LA areas had a good performance as diagnostic methods, with high accuracy and increased capacity for heart failure detection in dogs with MVCD. In conclusion, left atrial total and active function are reduced in dogs with HF secondary to MVCD when compared with healthy dogs and dogs with MVCD without HF. Moreover, atrial volumes and areas can be used to diagnose HF in these patients (AU)

• FAPESP's process: 13/04444-0 - Assessment of left atrial function in dogs with mitral valve myxomatous degeneration
• Grantee: Matheus Matioli Mantovani
• Support Opportunities: Scholarships in Brazil - Doctorate