Maternal Left Ventricular Diastolic and Systolic Function during Normal Pregnancy in Saint Bernard Dogs.

Luís Lobo,Luís Salazar,Joana Esteves-Guimarães,Pedro Oliveira,André Pereira,Ana Patrícia Fontes-Sousa

doi:10.3390/vetsci8120306

Luís Lobo, Luís Salazar + Show 4 more

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https://doi.org/10.3390/vetsci8120306

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Abstract

This study aimed to evaluate maternal left ventricular (LV) systo-diastolic function using conventional and TDI echocardiography and included 10 healthy Saint-Bernard pregnant bitches. M-mode, peak transmitral flow velocities during early diastole (E) and atrial contraction (A), aortic and pulmonic flow, myocardial performance index (MPI), TDI studies (peak myocardial velocities during early diastole (E’), atrial contraction (A’) and peak systole (S’)), and blood pressure were measured at 21 to 28 (T1), 40 (T2) and 60 (T3) days of gestation and four to eight weeks postpartum (T4). Cardiac output and heart rate were 20% and 9% higher at T3, respectively, compared to T4 (p < 0.01). Lateral S’ was 36% higher at T3 than at T1 (p < 0.05). Changes in diastolic function were demonstrated by 10% lower E wave and 15% A wave at T1, compared to T4 (p < 0.05). E’ and A’ were 23% and 42% higher at T3 compared to T4 (p < 0.01). Both lateral E/E’ and E’/A’ were 6% and 19% lower at T3 compared to T1 (p < 0.01 and p < 0.05, respectively). At T3, MPI was 51% and 34% lower when compared to T1 or T2 (p < 0.05). The echocardiographic evaluation of maternal cardiac function is important, as structural, and functional changes occur throughout pregnancy.

Highlights

Appropriate development of the foetuses during pregnancy induces several hemodynamic alterations, with consequent cardiac changes
Pulsed wave Doppler transmitral inflow velocity may not truly reflect the left ventricle (LV) diastolic function during pregnancy since it is highly influenced by ventricular loading conditions, which are naturally altered by the pregnancy volume overload state [9]
Concerning Tissue Doppler imaging (TDI) parameters, we observed that S’ significantly increased at late pregnancy, as recently reported [8]. These results suggest that the growing foetuses’ high demands are provided by an increase in both heart rate and contractility to achieve an optimal cardiac output

Summary

Introduction

Appropriate development of the foetuses during pregnancy induces several hemodynamic alterations, with consequent cardiac changes. Echocardiographic and Doppler studies have been widely used to assess heart function during pregnancy in humans [1,2,3] and in dogs [4,5,6,7,8]. Tissue Doppler imaging (TDI) is an echocardiography technique used to estimate myocardial velocities during contraction and relaxation, which measures high-intensity, low-velocity myocardial echoes; it directly evaluates the primary events of myocardium, being relatively independent of preload [9,10]. TDI evaluation of cardiac dysfunction in veterinary medicine has been reported, highlighting the sensitivity of this technique in several cardiac diseases [11,12]

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