Abstract

Arq Bras Cardiol

abc

Arquivos Brasileiros de Cardiologia

Arq. Bras. Cardiol.

0066-782X 1678-4170

Sociedade Brasileira de Cardiologia - SBC

vcWRrF53Gpbhxb3CDfWffwS

S0066-782X2017000200129

10.5935/abc.20170004

S0066-782X2017005003101

Original Articles

Left Atrial Deformation Analysis in Patients with Corrected Tetralogy of Fallot by 3D Speckle-Tracking Echocardiography (from the MAGYAR-Path Study)

Havasi

Kálmán

1 Domsik

Péter

1 Kalapos

Anita

1 McGhie

Jackie S.

2 Roos-Hesselink

Jolien W.

2 Forster

Tamás

1 Nemes

Attila

1 University of Szeged Medical Faculty Albert Szent-Györgyi Clinical Center

Szeged

Hungary 2nd Department of Medicine and Cardiology Center - Medical Faculty - Albert Szent-Györgyi Clinical Center - University of Szeged - Szeged - Hungary 2 Erasmus MC Department of Cardiology

Rotterdam

The Netherlands Department of Cardiology - Erasmus MC - Rotterdam - The Netherlands

Mailing Address: Attila Nemes, Semmelweis street 6, 6725, Szeged - Hungria. E-mail: nemes@in2nd.szote.u-szeged.hu, nemes.attila@med.u-szeged.hu

13 02 2017

02 2017

108 2 129 134 01 04 2016 05 09 2016 13 09 2016

This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:

Three-dimensional (3D) echocardiography coupled with speckle-tracking echocardiographic (STE) capability is a novel methodology which has been demontrated to be useful for the assessment of left atrial (LA) volumes and functional properties. There is increased scientific interest on myocardial deformation analysis in adult patients with corrected tetralogy of Fallot (cTOF).

Objectives:

To compare LA volumes, volume-based functional properties and strain parameters between cTOF patients and age- and gender-matched healthy controls.

Methods:

The study population consisted of 19 consecutive adult patients with cTOF in sinus rhythm nursing at the University of Szeged, Hungary (mean age: 37.9 ± 11.3 years, 8 men, who had repair at the age of 4.1 ± 2.5 years). They all had undergone standard transthoracic two-dimensional Doppler echocardiographic study extended with 3DSTE. Their results were compared to 23 age- and gender-matched healthy controls (mean age: 39.2 ± 10.6 years, 14 men).

Results:

Increased LA volumes and reduced LA emptying fractions respecting cardiac cycle could be demonstrated in cTOF patients compared to controls. LA stroke volumes featuring all LA functions showed no differences between the 2 groups examined. LA global and mean segmental uni- and multidirectional peak strains featuring LA reservoir function were found to be diminished in adult patients with cTOF as compared to controls. Similarly to peak strains reduced global and mean segmental LA strains at atrial contraction characterizing atrial booster pump function could be demonstrated in cTOF patients as compared to controls.

Conclusions:

Significant deterioration of all LA functions could be demonstrated in adult patients with cTOF late after repair.

Keywords: Echocardiography, Three-Dimensional / methods Heart Atria / abnormalities Tetralogy of Fallot Heart Defects, Congenital

Introduction

Nowadays the angle-independent speckle-tracking echocardiography-derived (STE) myocardial deformation analysis is one of the main focus of cardiac ultrasound technology.1 Three-dimensional (3D) echocardiography coupled with STE capability is a novel methodology which has been demonstrated to be useful for the assessment of volumes and functional properties of cardiac chambers.2 3DSTE allows complex assessment of atrial and ventricular morphology and function including volumetric and strain measurements from the same acquired 3D dataset.

There is increased scientific interest on myocardial deformation analysis in adult patients with corrected tetralogy of Fallot (cTOF).3^-5 Recently, alterations in right (RV)3^,4 and left ventricular (LV)4 and right atrial (RA)5 functional properties could be demonstrated by 3DSTE. However, quantitative left atrial (LA) deformation assessment has never been performed in cTOF patients. Therefore, the present study aimed to detect changes in LA volumes, volume-based functional properties and strain parameters in cTOF patients as compared to age- and gender-matched healthy controls.

Methods Patient population

Since 1961, more than 2,700 congenital heart disease patients have been treated and/or operated on at the Department of Pediatrics, Department of Heart Surgery, and 2nd Department of Medicine and Cardiology Center at the University of Szeged. From this patient population a registry was created (CSONGRAD Registry),6 from which 19 consecutive adult patients with cTOF in sinus rhythm were willing to participate in the present study (mean age: 37.9 ± 11.3 years, 8 men) who had repair at the age of 4.1 ± 2.5 years. In our department several hundreds of healthy control subjects without risk factors or known disorders in different age groups were examined by 3DSTE to assess the normal values of 3DSTE-derived parameters. From this pool 20 age- and gender-matched healthy subjects (mean age: 39.2 ± 10.6 years, 14 men) were selected who served as a control group in this particular study. All cTOF patients and controls were examined by two-dimensional (2D) Doppler, tissue Doppler echocardiography (TDI) and 3DSTE. The present study is a part of MAGYAR-Path Study (Motion Analysis of the heart and Great vessels bY three-dimensionAl speckle-tRacking echocardiography in Pathological cases) which has been organized at our department to examine diagnostic and prognostic significance of 3DSTE-derived variables. The institutional human research committee approved the study which complied with the 1975 Declaration of Helsinki. Informed consent was obtained from all cTOF patients and control subjects.

Two-dimensional Doppler and tissue Doppler echocardiography

All M-mode (MME), 2D Doppler and TDI studies were performed in the left lateral decubitus position with a commercially available Toshiba Artida^™ echocardiography equipment (Toshiba Medical Systems, Tokyo, Japan) using a PST-30SBP phased-array transducer in all patients. LV dimensions were assessed by MME using the Teichholz method.7 Valvular regurgitations were confirmed by colour Doppler echocardiography-derived visual grading. Following Doppler assessment of E/A, the ratio of transmitral E velocity to early diastolic mitral annular velocity (E/E') was measured by TDI.

Three-dimensional speckle-tracking echocardiography

All 3D echocardiographic data acquisitions were performed using a 1-4 MHz PST-25SX matrix phased-array transducer (Toshiba Medical Systems, Tokyo, Japan).2 During a single breathhold full volume 3D datasets were created from the apical view from 6 wedge-shaped subvolumes using 6-beat electrocardiographically gated acquisitions. LA was quantified by the 3D Wall Motion Tracking software version 2.7 (Toshiba Medical Systems, Tokyo, Japan).8 Each 3D dataset was displayed in a five plane-view, namely apical two- (AP2CH) and four-chamber (AP4CH) views and three short-axis views at different levels of the LA. After positioning the main axis line through the center of the LA cavity the reader traced LA endocardial border in both orthogonal long-axis views. Firstly, the edge of the septal side of the mitral valve ring was traced, then markers were set in a counterclockwise rotation around the LA to the edge of the lateral side of the mitral valve ring. Subsequently, 3D wall motion tracking was then automatically performed through the entire cardiac cycle.

3DSTE for left atrial volumetric measurements

To characterize systolic reservoir and diastolic conduit and active contraction phases of the LA function, calculation of volume-based functional properties respecting cardiac cycle is an available option (Figure 1).8^-12 End-systolic LA volume [largest LA volume before mitral valve opening (V_max)], end-diastolic LA volume [smallest LA volume before mitral valve closure (V_min)] and diastolic LA volume before atrial contraction [at time of P wave on ECG (V_preA)] could be measured using the LA 3D cast, from which the following functional properties were calculated:

Figure 1 - Images from three-dimensional (3D) full-volume dataset showing left atrium (LA) in a patient with corrected tetralogy of Fallot is presented: (A) apical four-chamber view, (B) apical two-chamber view, (C3) short-axis view at basal, (C5) mid- and (C7) superior left atrial level. A 3D cast (D), volumetric data (E), time - global volume and time - segmental strain curves (F) of the LA are also presented. Dashed curve (F) represents LA volume changes during cardiac cycle with maximum (Vmax), minimum (Vmin) LA volumes and LA volume at atrial contraction (VpreA). White arrow represents peak strain, while dashed arrow represents strain at atrial contraction (F). LA: left atrium; LV: left ventricle.

Reservoir function:

- Total Atrial Stroke Volume (TASV): V_max−V_min.

- Total Atrial Emptying Fraction (TAEF): TASV/V_max×100.

Conduit function:

- Passive Atrial Stroke Volume (PASV): V_max-V_preA

- Passive Atrial Emptying Fraction (PAEF): PASV/V_max×100

Active contraction:

- Active Atrial Stroke Volume (AASV): V_preA−V_min.

- Active Atrial Emptying Fraction (AAEF): AASV/V_preA×100.

3DSTE for left atrial strain measurements

Several unidirectional [radial (RS), longitudinal (LS) and circumferential (CS) strains] and complex [area (AS) and 3D (3DS) strains] LA strain parameters could be calculated from the same 3D model, as demonstrated before.10^-14 Not only global and mean segmental peak strains featuring LA reservoir function were measured for each patient, but strains at atrial contraction, characteristics of LA active contraction, were also evaluated (Figure 1).

Stastical analysis

Continuous data are presented as mean values ± standard deviation, while categorical data are summarized as a count and percentage. For comparing variables, the Student's t-test, chi-square analysis, and Fisher's exact test were used. All statistical tests were two-tailed and statistical significance was defined with a probability value less than 0.05. Recently, intra- and interobserver agreements for LA volumes and functional properties were performed in papers originating from MAGYAR-Healthy and MAGYAR-Path Studies.8^,11 Data were analysed using Medcalc software (MedCalc, Mariakerke, Belgium).

Results Clinical data

Risk factors, medications applied and 2D echocardiographic data are presented in Table 1. Significant (>grade 2) mitral and tricuspid regurgitations could be detected in 2 (11%) and 8 (42%) cTOF patients. None of the healthy controls had significant regurgitations. The TAPSE and RV-FAC values of cTOF patients proved to be 18.2 ± 4.6 mm and 34.2 ± 3.9%, respectively.

Table 1 Demographic and clinical data of patients with tetralogy of Fallot and that of controls

	cTOF patients (n=19)	Controls (n=23)	p value
Risk factors
Age (years)	37.9 ± 11.3	39.2 ± 10.6	0.70
Male gender (%)	8 (42)	14 (61)	0.35
Hypertension (%)	3 (16)	0 (0)	0.08
Hypercholesterolemia (%)	1 (5)	0 (0)	0.45
Diabetes mellitus (%)	0 (0)	0 (0)	1.00
Medications
β-blockers (%)	5 (26)	0 (0)	0.01
ACE-inhibitors (%)	3 (16)	0 (0)	0.08
Diuretics (%)	3 (16)	0 (0)	0.08
Two-dimensional echocardiography
LA diameter (mm)	42.4 ± 6.8	33.2 ± 3.8	<0.0001
LV end-diastolic diameter (mm)	54.6 ± 19.6	48.3 ± 6.9	0.16
LV end-diastolic volume (ml)	113.7 ± 31.7	102.2 ± 21.1	0.17
LV end-systolic diameter (mm)	32.7 ± 7.1	30.4 ± 4.1	0.20
LV end-systolic volume (ml)	43.8 ± 23.2	35.6 ± 10.6	0.14
Interventricular septum (mm)	9.9 ± 1.5	9.5 ± 2.0	0.46
LV posterior wall (mm)	9.8 ± 1.5	9.4 ± 2.3	0.55
LV ejection fraction (%)	62.7 ± 11.5	65.4 ± 6.5	0.34

ACE: angiotensin-converting enzyme; LA: left atrial; LV: left ventricular; cTOF: corrected tetralogy of Fallot.

3DSTE-derived LA volumes and volume-based functional properties

Table 2 Comparison of 3DSTE-derived volumes and volume-based functional properties between patients with corrected tetralogy of Fallot and controls

	Calculated volumes (ml)			Stroke volumes (ml)			Emptying fractions (%)
	V_max	V_min	V_preA	TASV	PASV	AASV	TAEF	PAEF	AAEF
cTOF patients	53.3 ± 28.1	35.1 ± 24.4	42.7 ± 26.0	18.2 ± 7.4	10.6 ± 6.4	7.6 ± 4.4	37.1 ± 11.7	21.4 ± 11.6	20.1 ± 10.8
Controls	36.8 ± 6.6	18.2 ± 6.3	26.3 ± 8.1	18.6 ± 4.1	10.5 ± 4.6	8.1 ± 3.2	51.4 ± 11.4	29.5 ± 13.3	31.1 ± 9.1
p value	0.009	0.003	0.006	0.84	0.96	0.71	0.0003	0.04	0.0009

V_max: maximum left atrial volume; Vmin: minimum left atrial volume; V_preA: left atrial volume before atrial contraction; TASV: total atrial stroke volume; TAEF: total atrial emptying fraction; AASV: active atrial stroke volume; AAEF: active atrial emptying fraction; PASV: passive atrial stroke volume; PAEF: passive atrial emptying fraction. cTOF: corrected tetralogy of Fallot.

3DSTE-derived LA peak strain parameters

LA global and mean segmental uni- and multidirectional peak strains featuring LA reservoir function were found to be diminished in adult patients with cTOF as compared to controls (Table 3).

Table 3 Comparison of 3DSTE-derived peak strains and strains at atrial contraction between patients with tetralogy of Fallot and controls (global and mean segmental parameters)

	Radial strain (%)		Circumferential strain (%)		Longitudinal strain (%)		Three-dimensional strain (%)		Area strain (%)
	Global	Mean segmental	Global	Mean segmental	Global	Mean segmental	Global	Mean segmental	Global	Mean segmental
Peak strains
cTOF patients	-12.8 ± 9.5	-17.0 ± 8.5	13.2 ± 9.2	18.3 ± 8.8	17.4 ± 8.3	19.7 ± 8.1	-7.0 ± 6.3	-11.5 ± 6.2	33.1 ± 14.2	38.9 ± 13.7
Controls	-18.0 ± 9.9	-21.7 ± 8.9	29.0 ± 13.4	34.2 ± 13.1	26.3 ± 7.7	29.6 ± 7.4	-11.0 ± 8.2	-15.1 ± 6.9	59.7 ± 22.0	67.9 ± 21.7
p value	0.10	0.09	0.0001	0.0001	0.0008	0.0002	0.09	0.09	0.0001	<0.0001
Strains at atrial contraction
cTOF patients	-2.8 ± 4.6	-6.5 ± 5.6	4.5 ± 5.0	7.3 ± 5.0	2.9 ± 4.6	4.7 ± 3.9	-1.7 ± 6.4	-4.7 ± 4.8	8.1 ± 9.7	12.4 ± 8.9
Controls	-7.2 ± 7.9	-8.2 ± 5.5	11.2 ± 10.4	13.9 ± 9.2	8.1 ± 8.8	9.0 ± 5.8	-5.5 ± 5.1	-6.4 ± 4.8	16.7 ± 16.1	20.3 ± 14.2
p value	0.03	0.33	0.01	0.008	0.03	0.10	0.04	0.24	0.04	0.04

cTOF: corrected tetralogy of Fallot.

3DSTE-derived LA strain parameters at atrial contraction

Similarly to peak strains reduced global and mean segmental LA strains at atrial contraction characterizing atrial booster pump function could be demonstrated in cTOF patients as compared to controls (Table 3).

Discussion

Three-dimensional speckle-tracking echocardiography, which is an echocardiographic technique based on block-matching algorithm of the myocardial speckles,2 has been increasingly used as a tool for volumetric and functional assessment of atria5^,8^-14 and ventricles.3^,15^-21 In recent studies 3DSTE-derived complex evaluation of LA function including assessment of volume-based functional properties and strains has been demonstrated.8^-14 The study reported here is the first to analyse 3DSTE-derived LA deformation in adult patients with cTOF. Increased LA volumes and diminished LA emptying fractions and strains could be demonstrated in this detailed analysis. Results suggest significant deterioration of all LA functions (reservoir, conduit and booster pump) in adult patients with cTOF late after repair.

STE was found to be a valuable tool for volumetric and functional assessment of cardiac chambers in adult patients with cTOF.3^-5 In a recent study RV free wall strain and strain rate were found to be decreased in adults late after TOF repair, especially at the apical segment suggesting that apical function is most affected in these RVs.4 Regarding the LV, septal strain was decreased indicating that RV dysfunction adversely affects LV function, probably by mechanical coupling of the ventricles. In another study, the majority of adults with cTOF showed a reduced LV twist.22 Strikingly, one-quarter of these patients had an abnormal apical rotation which has been found to be associated with decreased systolic LV and RV function. These findings suggested that abnormal apical rotation could be a new objective diagnostic criterion for detection of ventricular dysfunction in cTOF.

The complexity of RA dysfunction could also be demonstrated by 3DSTE in cTOF patients.5 Comparing this with the present study, both RA and LA volumes seemed to be increased in adult patients with cTOF. Moreover, large similarity of RA and LA deformation could also be demonstrated: while RA/LA emptying fractions were found to be decreased, RA/LA stroke volumes remained unchanged. All the peak LA strains and LA strains at atrial contraction were found to be reduced and this reduction was more pronounced in cTOF as compared to the values related to RA. Therefore it seems that the LA is very important. From other studies also the LA proved to be important.23

Several factors may play a role in the altered atrial function in cTOF, such as the interaction between both atria, the presence of mitral/tricuspid regurgitation, arrhythmias and changes in both ventricular features as demonstrated before. Further studies are warranted to understand the real pathophysiologic background of these findings.

Limitation

The present study covered only a relatively small number of patients from a single center by a single observer (DP). Therefore, future multicenter studies with larger patient populations are necessary. Another limitation of image acquisition for 3DSTE is the relatively slow volume rate. During creating 3D model of the LA, septum was considered as a part of the LA similarly to other studies evaluating RA.5 Finally, LA appendage and pulmonary veins were excluded which could theoretically affect results. During the present study, LV, RV and RA functional characterization was not aimed to be performed.

Conclusions

Significant deterioration of all LA functions could be demonstrated in adult patients with cTOF late after repair.

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Artigos Originais

Análise por Speckle-Tracking com Ecocardiografia 3D da Deformação de Átrio Esquerdo em Pacientes com Tetralogia de Fallot Corrigida (do MAGYAR-Path Study)

Havasi

Kálmán

1 Domsik

Péter

1 Kalapos

Anita

1 McGhie

Jackie S.

2 Roos-Hesselink

Jolien W.

2 Forster

Tamás

1 Nemes

Attila

1 2nd Department of Medicine and Cardiology Center - Medical Faculty - Albert Szent-Györgyi Clinical Center - University of Szeged - Szeged - Hungary 2 Department of Cardiology - Erasmus MC - Rotterdam - The Netherlands

Correspondência: Attila Nemes, Semmelweis street 6, 6725, Szeged - Hungria. E-mail: nemes@in2nd.szote.u-szeged.hu, nemes.attila@med.u-szeged.hu

Resumo Fundamento:

Ecocardiografia tridimensional (3D) acoplada à técnica de speckle-tracking (3DSTE) é uma nova metodologia útil para a avaliação de volumes e propriedades funcionais do átrio esquerdo (AE). Há crescente interesse científico na análise da deformação miocárdica em adultos com tetralogia de Fallot corrigida (cTOF).

Objetivos:

Comparar os volumes de AE, propriedades funcionais baseadas no volume e parâmetros de strain entre pacientes com cTOF e controles saudáveis pareados por idade e sexo.

Métodos:

A população do estudo consistiu em 19 adultos com cTOF consecutivos, em ritmo sinusal, acompanhados na Universidade Szeged, Hungria (idade média: 37,9 ± 11,3 anos; 8 homens; com correção cirúrgica aos 4,1 ± 2,5 anos de idade). Todos foram submetidos a ecocardiografia transtorácica bidimensional com Doppler padrão e 3DSTE. Os resultados foram comparados aos de 23 controles saudáveis pareados por idade e sexo (idade média: 39,2 ± 10,6 anos; 14 homens).

Resultados:

Aumento dos volumes de AE e redução das frações de esvaziamento de AE em relação ao ciclo cardíaco foram demonstrados em pacientes com cTOF em comparação aos dos controles. Os volumes de ejeção de AE caracterizando todas as funções do AE não diferiram entre os dois grupos. Strains de AE global e segmentar médio uni- e multidimensional, caracterizando função de reservatório de AE, estavam diminuídos em adultos com cTOF em comparação aos de controles. À semelhança dos strains de pico, reduzidos strains de AE global e segmentar médio na contração atrial, caracterizando função de bomba atrial, foram demonstrados em pacientes com cTOF em comparação aos de controles.

Conclusões:

Demonstrou-se significativa deterioração das funções de AE em adultos com cTOF em fase tardia após correção.

Palavras-chave: Ecocardiografia Tridimensional / métodos Átrios do Coração / anormalidades Tetralogia de Fallot Cardiopatias Congênitas

Introdução

Atualmente, a análise da deformação miocárdica pela técnica de rastreamento de pontos (speckle tracking) pela ecocardiografia (STE) de maneira ângulo-independente é um dos principais focos da ultrassonografia cardíaca.1 A ecocardiografia tridimensional (3D) acoplada à STE (3DSTE) é uma nova metodologia que se mostrou útil para a avaliação dos volumes e propriedades funcionais das câmaras cardíacas.2 A 3DSTE permite uma complexa avaliação da morfologia e da função dos átrios e ventrículos, como as medidas volumétricas e de strain do mesmo conjunto de dados 3D adquiridos.

Há grande interesse científico na análise da deformação miocárdica em adultos com tetralogia de Fallot corrigida (cTOF).3^-5 Recentemente, alterações nas propriedades funcionais de ventrículo direito (VD),3^,4 ventrículo esquerdo (VE)4 e átrio direito (AD)5 foram demonstradas por 3DSTE. Entretanto, avaliação quantitativa da deformação do átrio esquerdo (AE) não foi realizada em pacientes com cTOF. Assim, o presente estudo visou a detectar alterações de volume de AE, propriedades funcionais com base em volume e parâmetros de strain em pacientes com cTOF em comparação a controles saudáveis pareados por idade e sexo.

Métodos População de pacientes

Desde 1961, mais de 2.700 pacientes com cardiopatia congênita foram tratados e/ou operados no Departamento de Pediatria, Departamento de Cirurgia Cardíaca, e no Segundo Departamento de Medicina e Centro de Cardiologia da Universidade Szeged. A partir dessa população de pacientes, criou-se um registro (CSONGRAD Registry),6 do qual 19 pacientes adultos consecutivos com cTOF e em ritmo sinusal quiseram participar do presente estudo (idade média: 37,9 ± 11,3 anos; 8 homens), tendo sido submetidos à correção na idade de 4,1 ± 2,5 anos. No nosso departamento, várias centenas de controles saudáveis sem fatores de risco ou distúrbios conhecidos, de diferentes grupos etários, foram examinadas por 3DSTE para avaliar os valores normais dos parâmetros obtidos com 3DSTE. Desse conjunto, 20 indivíduos saudáveis pareados para idade e sexo (idade média: 39,2 ± 10,6 anos; 14 homens) foram selecionados e serviram como grupo controle deste estudo. Todos os pacientes com cTOF e os controles foram examinados por ecocardiografia bidimensional (2D) com Doppler, ecocardiografia com Doppler tecidual (TDI) e 3DSTE. O presente estudo é parte do MAGYAR-Path Study (Motion Analysis of the heart and Great vessels bY three-dimensionAl speckle-tRacking echocardiography in Pathological cases), organizado pelo nosso departamento para examinar o significado diagnóstico e prognóstico das variáveis obtidas através de 3DSTE. O comitê de pesquisa em seres humanos da instituição aprovou o estudo, que atendeu às exigências da Declaração de Helsinque de 1975. O termo de consentimento livre e esclarecido foi assinado por todos os pacientes com cTOF e os controles.

Ecocardiografia bidimensional com Doppler e com Doppler tecidual

Todos os estudos ecocardiográficos em M-modo (MME), 2D com Doppler e com TDI foram realizados em decúbito lateral esquerdo com equipamento de ecocardiografia comercialmente disponível Toshiba Artida^™ (Toshiba Medical Systems, Tokyo, Japão), usando um transdutor "phased-array" PST-30SBP em todos os pacientes. As dimensões do VE foram avaliadas por MME usando o método de Teichholz.7 Regurgitações valvulares foram confirmadas por gradação visual na ecocardiografia com Doppler colorido. Em seguida à avaliação com Doppler de E/A, mediu-se a razão da velocidade transmitral E para a velocidade diastólica inicial do anel mitral (E/E') por TDI.

Ecocardiografia tridimensional com <italic>speckle-tracking</italic>

As aquisições de todos os dados de ecocardiografia 3D foram realizadas usando-se um transdutor phased-array 1-4 MHz PST-25SX matrix (Toshiba Medical Systems, Tóquio, Japão).2 Durante uma única apneia, criaram-se conjuntos de dados 3D de volume total a partir do corte apical de 6 subvolumes "wedge-shaped", usando aquisições com sincronização com ECG de 6 batimentos. O AE foi quantificado pelo programa 3D Wall Motion Tracking, versão 2.7 (Toshiba Medical Systems, Tóquio, Japão).8 Cada conjunto de dados 3D foi exibido em corte de cinco planos, principalmente cortes apicais de duas (AP2CH) e quatro câmaras (AP4CH), e três cortes de eixo curto em diferentes níveis do AE. Após posicionar a linha do eixo principal passando pelo centro da cavidade do AE, o observador traçou a margem endocardial do AE nos dois cortes ortogonais de eixo longo. Primeiro, traçou-se a borda do lado septal do anel valvar mitral, estabelecendo-se os marcadores no sentido anti-horário em torno do AE até a borda da face lateral do anel valvar mitral. Em seguida, realizou-se automaticamente o rastreamento 3D da motilidade da parede por todo o ciclo cardíaco.

3DSTE para medidas volumétricas do AE

Para caracterizar as fases de reservatório sistólico, conduto diastólico e contração ativa da função do AE, o cálculo das propriedades funcionais baseadas no volume em relação ao ciclo cardíaco é uma opção (Figura 1).8^-12 O volume sistólico final do AE [maior volume do AE antes da abertura da valva mitral (V_max)], o volume diastólico final do AE [menor volume do AE antes do fechamento da valva mitral (V_min)] e o volume diastólico do AE antes da contração atrial [na ocasião da onda P no ECG (V_preA)] foram medidos usando um modelo 3D do AE, a partir do qual as seguintes propriedades funcionais foram calculadas:

Figura 1 Imagens do conjunto de dados tridimensionais (3D) de volume total mostrando o átrio esquerdo (AE) em paciente com tetralogia de Fallot corrigida: (A) corte apical de quatro câmaras; (B) corte apical de duas câmaras; corte transversal do AE nos níveis basal (C3), médio (C5) e superior (C7). Apresentam-se ainda um modelo 3D do AE (D), dados volumétricos do AE (E) e curvas de tempo-volume global e tempo-strain segmentar (F) do AE. A linha pontilhada (F) representa as mudanças de volume do AE durante o ciclo cardíaco com volumes máximo (Vmax), mínimo (Vmin) e durante contração atrial (VpreA). A seta branca representa strain de pico, enquanto a linha tracejada representa tensão na contração atrial (F). AE: átrio esquerdo; VE: ventrículo esquerdo.

Função reservatório:

- Volume de ejeção atrial total (TASV): V_max−V_min.

- Fração de esvaziamento atrial total (TAEF): TASV/V_max×100.

Função conduto:

- Volume de ejeção atrial passivo (PASV): V_max-V_preA

- Fração de esvaziamento atrial passivo (PAEF): PASV/V_max×100.

Contração ativa:

- Volume de ejeção atrial ativo (AASV): V_preA−V_min.

- Fração de esvaziamento atrial ativo (AAEF): AASV/V_preA×100.

3DSTE para medidas de <italic>strain</italic> do AE

Vários parâmetros unidirecionais [strain radial (RS), longitudinal (LS) e circunferencial (CS)] e complexos [strain de área (AS) e 3D (3DS)] de strain do AE foram calculados a partir do mesmo modelo 3D, como já demonstrado.10^-14 Não apenas strains de pico global e segmentar médio referentes à função de reservatório do AE foram medidos para cada paciente, mas também strains da contração atrial, característicos da contração ativa do AE (Figura 1).

Análise estastísca

As variáveis contínuas são apresentadas como médias ± desvio padrão, e as categóricas, como contagem e porcentagem. Para a comparação das variáveis, usaram-se os testes t de Student, qui-quadrado e exato de Fisher. Todos os testes estatísticos foram bicaudais, sendo o significado estatístico definido como p < 0,05. Recentemente, as concordâncias intra- e interobservador para volumes e propriedades funcionais do AE foram realizadas em trabalhos derivados dos estudos MAGYAR-Healthy e MAGYAR-Path.8^,11 Os dados foram analizados com o programa Medcalc (MedCalc, Mariakerke, Bélgica).

Resultados Dados clínicos

Os fatores de risco, medicações usadas e dados de ecocardiografia 2D são apresentados na Tabela 1. Regurgitações mitral e tricúspide significativas (> grau 2) foram detectadas em 2 (11%) e 8 (42%) pacientes com cTOF. Nenhum controle saudável apresentou regurgitação significativa. Os valores de TAPSE e RV-FAC dos pacientes com cTOF foram 18,2 ± 4,6 mm e 34,2 ± 3,9%, respectivamente.

Tabela 1 Dados demográficos e clínicos dos pacientes com tetralogia de Fallot e dos controles

	Pacientes com cTOF (n=19)	Controles (n=23)	Valor de p
Fatores de risco
Idade (anos)	37,9 ± 11,3	39,2 ± 10,6	0,70
Sexo masculino (%)	8 (42)	14 (61)	0,35
Hipertensão (%)	3 (16)	0 (0)	0,08
Hipercolesterolemia (%)	1 (5)	0 (0)	0,45
Diabetes mellitus (%)	0 (0)	0 (0)	1,00
Medicações
β-bloqueadores (%)	5 (26)	0 (0)	0,01
Inibidores da ECA (%)	3 (16)	0 (0)	0,08
Diuréticos (%)	3 (16)	0 (0)	0,08
Ecocardiografia bidimensional
Diâmetro do AE (mm)	42,4 ± 6,8	33,2 ± 3,8	<0,0001
Diâmetro diastólico final do VE (mm)	54,6 ± 19,6	48,3 ± 6,9	0,16
Volume diastólico final do VE (ml)	113,7 ± 31,7	102,2 ± 21,1	0,17
Diâmetro sistólico final do VE (mm)	32,7 ± 7,1	30,4 ± 4,1	0,20
Volume sistólico final do VE (ml)	43,8 ± 23,2	35,6 ± 10,6	0,14
Septo interventricular (mm)	9,9 ± 1,5	9,5 ± 2,0	0,46
Parede posterior do VE (mm)	9,8 ± 1,5	9,4 ± 2,3	0,55
Fração de ejeção do VE (%)	62,7 ± 11,5	65,4 ± 6,5	0,34

ECA: enzima de conversão da angiotensina; AE: átrio esquerdo; VE: ventrículo esquerdo; cTOF: Tetralogia de Fallot corrigida.

Volumes do AE e propriedades funcionais baseadas no volume obtidas na 3DSTE

Aumento dos volumes do AE e redução das frações de esvaziamento do AE com relação a um ciclo cardíaco foram demonstrados em pacientes com cTOF em comparação aos de controles. Os volumes de ejeção do AE caracterizando todas as funções do AE não mostraram diferenças entre os grupos examinados (Tabela 2).

Tabela 2 Comparação dos volumes obtidos através de 3DSTE e propriedades funcionais com base no volume entre pacientes com tetralogia de Fallot corrigida e controles

	Volumes calculados (ml)			Volumes de ejeção (ml)			Frações de esvaziamento (%)
	V_max	V_min	V_preA	TASV	PASV	AASV	TAEF	PAEF	AAEF
Pacientes cTOF	53,3 ± 28,1	35,1 ± 24,4	42,7 ± 26,0	18,2 ± 7,4	10,6 ± 6,4	7,6 ± 4,4	37,1 ± 11,7	21,4 ± 11,6	20,1 ± 10,8
Controles	36,8 ± 6,6	18,2 ± 6,3	26,3 ± 8,1	18,6 ± 4,1	10,5 ± 4,6	8,1 ± 3,2	51,4 ± 11,4	29,5 ± 13,3	31,1 ± 9,1
p valor	0,009	0,003	0,006	0,84	0,96	0,71	0,0003	0,04	0,0009

V_max: volume atrial esquerdo máximo; V_min: volume atrial esquerdo mínimo; V_preA: volume atrial esquerdo antes da contração atrial; TASV: volume de ejeção atrial total; TAEF: fração de esvaziamento atrial total; AASV: volume de ejeção atrial ativo; AAEF: fração de esvaziamento atrial ativo; PASV: volume de ejeção atrial passivo; PAEF: fração de esvaziamento atrial passivo; cTOF: Tetralogia de Fallot corrigida.

Parâmetros de <italic>strain</italic> de pico do AE obtidos na 3DSTE

Strains de pico de AE global e segmentar médio uni- e multidirecionais caracterizando função de reservatório de AE estavam diminuídos em adultos com cTOF em comparação aos de controles (Tabela 3).

Tabela 3 Comparação dos strains de pico obtidos na 3DSTE e strains durante contração atrial entre pacientes com tetralogia de Fallot e controles (parâmetros global e segmentar médio)

	Strain radial (%)		Strain circunferencial (%)		Strain longitudinal (%)		Strain tridimensional (%)		Strain de área (%)
	Global	Segmentar médio	Global	Segmentar médio	Global	Segmentar médio	Global	Segmentar médio	Global	Segmentar médio
Strains de pico
Pacientes com cTOF	-12,8 ± 9,5	-17,0 ± 8,5	13,2 ± 9,2	18,3 ± 8,8	17,4 ± 8,3	19,7 ± 8,1	-7,0 ± 6,3	-11,5 ± 6,2	33,1 ± 14,2	38,9 ± 13,7
Controles	-18,0 ± 9,9	-21,7 ± 8,9	29,0 ± 13,4	34,2 ± 13,1	26,3 ± 7,7	29,6 ± 7,4	-11,0 ± 8,2	-15,1 ± 6,9	59,7 ± 22,0	67,9 ± 21,7
Valor de p	0,10	0,09	0,0001	0,0001	0,0008	0,0002	0,09	0,09	0,0001	<0,0001
Strains durante contração atrial
Pacientes com cTOF	-2,8 ± 4,6	-6,5 ± 5,6	4,5 ± 5,0	7,3 ± 5,0	2,9 ± 4,6	4,7 ± 3,9	-1,7 ± 6,4	-4,7 ± 4,8	8,1 ± 9,7	12,4 ± 8,9
Controles	-7,2 ± 7,9	-8,2 ± 5,5	11,2 ± 10,4	13,9 ± 9,2	8,1 ± 8,8	9,0 ± 5,8	-5,5 ± 5,1	-6,4 ± 4,8	16,7 ± 16,1	20,3 ± 14,2
Valor de p	0,03	0,33	0,01	0,008	0,03	0,10	0,04	0,24	0,04	0,04

cTOF: Tetralogia de Fallot corrigida.

Parâmetros de <italic>strain</italic> do AE durante contração atrial obtidos na 3DSTE

À semelhança dos strains de pico, reduzidos strains de AE global e segmentar médio na contração atrial, caracterizando função de bomba atrial, foram demonstrados em pacientes com cTOF em comparação aos de controles (Tabela 3).

Discussão

A 3DSTE, uma técnica ecocardiográfica baseada no algoritmo block-matching de speckles miocárdicos,2 vem sendo cada vez mais usada como ferramenta para avaliação volumétrica e funcional dos átrios5^,8^-14 e ventrículos.3^,15^-21 Estudos recentes realizaram avaliação complexa da função de AE com 3DSTE, incluindo avaliação de propriedades funcionais baseadas em volume e strains.8^-14 O presente estudo é o primeiro a analizar a deformação de AE através de 3DSTE em adultos com cTOF. Aumento de volume de AE e diminuição de fração de esvaziamento de AE e de strains foram demonstrados em análise detalhada. Os resultados sugerem significativa deterioração das funções de AE (reservatório, conduto e bomba) em adultos com cTOF numa fase tardia após reparo.

A técnica de STE mostrou-se uma ferramenta valiosa para avaliação volumétrica e funcional das câmarass cardíacas em adultos com cTOF.3^-5 Estudo recente mostrou diminuição do strain da parede livre do VD e da taxa de strain em adultos numa fase tardia após correção de TOF, especialmente no segmento apical, sugerindo que a função apical seja mais afetada nesse VD.4 Com relação ao VE, houve diminuição do strain septal, indicando que a disfunção do VD tem efeito adverso na função do VE, provavelmente devido ao acoplamento mecânico dos ventrículos. Em outro estudo, a maioria dos adultos com cTOF apresentou redução da torção do VE.22 Vale ressaltar que um quarto desses pacientes tinha uma rotação apical anormal, que se mostrou associada à diminuição da função sistólica de VE e VD. Tais achados sugerem que a rotação apical anormal pudesse ser um novo critério diagnóstico objetivo para a detecção de disfunção ventricular em cTOF.

A complexidade da disfunção de AD também foi demonstrada através de 3DSTE em pacientes com cTOF.5 Quando comparado ao presente estudo, os volumes de AD e AE pareceram aumentados em adultos com cTOF. Além disso, grande semelhança na deformação de AD e de AE pode ser demonstrada: enquanto as frações de esvaziamneto AD/AE mostraram-se diminuídas, os volumes de ejeção AD/AE permaneceram inalterados. Todos os strains de AE de pico e strains de AE na contração atrial mostraram-se reduzidos, sendo tal redução mais pronunciada na cTOF se comparada aos valores relados para o AD. Parece, portanto, ser o AE muito importante. Outros estudos também provaram a importância do AE.23

Vários fatores podem desempenhar um papel na alteração da função atrial na cTOF, como a interação entre os dois átrios, a presença de regurgitação mitral/tricúspide, arritmias e mudanças nas características dos dois ventrículos, como anteriormente demonstrado. Estudos adicionais são necesários para esclarecer o real fundamento fisiopatológico desses achados.

Limitação do estudo

O presente estudo consistiu na análisse de um número relativamente pequeno de pacientes de um único centro e por um único observador (DP). Portanto, estudos multicêntricos com maior número de pacientes são necessários. Outra limitação foi a taxa de volume relativamente lenta da aquisição de imagem por 3DSTE. Durante a criação do modelo 3D do AE, o septo foi considerado parte do AE, à semelhança de outros estudos avaliando o AD.5 Por fim, o apêndice do AE e as veias pulmonares foram excluídos, o que teoricamente pode ter afetado os resultados. O presente estudo não teve por objetivo realizar a caracterização funcional de VE, VD e AD.

Conclusões

Significativa deterioração das funções de AE foi demonstrada em adultos com cTOF em fase tardia após correção.