{"id":959,"date":"2026-03-04T10:31:41","date_gmt":"2026-03-04T10:31:41","guid":{"rendered":"https:\/\/cansaran.com\/?p=959"},"modified":"2026-10-13T20:08:19","modified_gmt":"2026-10-13T20:08:19","slug":"cardiac-changes-in-twin-to-twin-transfusion-syndrome","status":"publish","type":"post","link":"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/","title":{"rendered":"Twin-to-Twin Transfusion Syndrome (TTTS): Effects on the Fetal Heart"},"content":{"rendered":"<p>Cardiac changes in Twin-to-Twin Transfusion Syndrome occur as a result of unbalanced blood flow associated with placental vascular anastomoses. In the recipient fetus, cardiomegaly and ventricular hypertrophy due to volume overload may be observed, while decreased cardiac output related to hypovolemia may occur in the donor fetus.<\/p>\n<p>Signs of cardiovascular overload in the recipient fetus are characterized by myocardial wall thickening, tricuspid regurgitation, and pulmonary hypertension due to increased blood volume. In advanced cases, hydrops fetalis may develop, significantly increasing the risk of perinatal mortality.<\/p>\n<p>Cardiac dysfunction in the donor fetus is associated with low cardiac output and growth restriction due to decreased circulating volume. Hypotension and oligohydramnios frequently accompany this condition. Prolonged hypoperfusion may negatively affect organ development and myocardial functions.<\/p>\n<p>Cardiac evaluation with fetal echocardiography is critically important in determining the prognosis in Twin-to-Twin Transfusion Syndrome. Ventricular functions, valvular insufficiencies, and flow patterns are examined in detail to perform staging and ensure appropriate treatment planning.<\/p>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_89 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #ffffff;color:#ffffff\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #ffffff;color:#ffffff\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Hemodynamic_Basis_of_Twin-to-Twin_Transfusion_Syndrome\" >Hemodynamic Basis of Twin-to-Twin Transfusion Syndrome<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Mechanism_of_Cardiac_Overload_in_the_Recipient_Fetus\" >Mechanism of Cardiac Overload in the Recipient Fetus<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Structural_Cardiac_Changes\" >Structural Cardiac Changes<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Functional_Cardiac_Disorders\" >Functional Cardiac Disorders<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Cardiac_Changes_in_the_Donor_Fetus\" >Cardiac Changes in the Donor Fetus<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Cardiac_Evaluation_in_the_Diagnostic_Process\" >Cardiac Evaluation in the Diagnostic Process<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Course_of_Cardiac_Changes_After_Treatment\" >Course of Cardiac Changes After Treatment<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/cansaran.com\/en\/cardiac-changes-in-twin-to-twin-transfusion-syndrome\/#Importance_of_Cardiac_Findings_for_Families\" >Importance of Cardiac Findings for Families<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Hemodynamic_Basis_of_Twin-to-Twin_Transfusion_Syndrome\"><\/span>Hemodynamic Basis of Twin-to-Twin Transfusion Syndrome<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The pathophysiology of TTTS is based on arterio-venous (AV), arterio-arterial (AA), and veno-venous (VV) anastomoses present in the placenta. Especially when there is net blood flow from one fetus to the other through deep arteriovenous connections, a chronic volume imbalance develops between the donor and recipient fetuses.<\/p>\n<p>While the donor fetus develops hypovolemia (decreased blood volume) and consequently oligohydramnios (reduced amniotic fluid), the recipient fetus experiences hypervolemia (increased blood volume) and polyhydramnios (increased amniotic fluid). This chronic volume load leads to structural and functional changes particularly in the cardiac system of the recipient fetus.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Mechanism_of_Cardiac_Overload_in_the_Recipient_Fetus\"><\/span>Mechanism of Cardiac Overload in the Recipient Fetus<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The recipient fetus is continuously exposed to increased preload (the amount of blood returning to the heart) and increased afterload (the resistance encountered while the heart pumps blood). This condition may cause adaptive but eventually pathological changes in the cardiovascular system.<\/p>\n<p>Increased intravascular volume may lead to dilation of the cardiac chambers. The right ventricle is affected more prominently by the volume load because it is dominant in fetal circulation. Prolonged volume overload may predispose to the development of myocardial dysfunction.<\/p>\n<p>During this process, the fetal heart initially attempts to adapt through compensatory mechanisms; however, signs of heart failure may appear in later stages.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Structural_Cardiac_Changes\"><\/span>Structural Cardiac Changes<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The most commonly observed cardiac changes in the recipient fetus with TTTS include:<\/p>\n<ul>\n<li aria-level=\"1\">Cardiomegaly (heart enlargement)<\/li>\n<li aria-level=\"1\">Ventricular hypertrophy (thickening of the heart muscle)<\/li>\n<li aria-level=\"1\">Atrioventricular valve insufficiency (especially tricuspid regurgitation)<\/li>\n<li aria-level=\"1\">Pulmonary valve stenosis or right ventricular outflow tract obstruction<\/li>\n<\/ul>\n<p>Increased pressure and volume load may lead to hypertrophy in the ventricular walls. Increased right ventricular wall thickness is particularly notable. Tricuspid valve insufficiency may develop due to increased right ventricular pressure and can be detected by Doppler during fetal echocardiography.<\/p>\n<p>In some cases, functional stenosis may develop at the level of the pulmonary valve. This condition is associated with increased pressure load in the right ventricular outflow tract and may rarely progress to permanent structural cardiac pathology.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Functional_Cardiac_Disorders\"><\/span>Functional Cardiac Disorders<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>In addition to structural changes, myocardial function may also be affected. The following findings may be observed on fetal echocardiography:<\/p>\n<ul>\n<li aria-level=\"1\">Systolic and diastolic dysfunction<\/li>\n<li aria-level=\"1\">Increased myocardial performance index (MPI)<\/li>\n<li aria-level=\"1\">Abnormalities in ductus venosus flow<\/li>\n<\/ul>\n<p>Diastolic dysfunction means impairment in the filling of the heart during the relaxation phase. This condition is associated with increased ventricular stiffness and pressure load. In advanced stages, fetal hydrops (widespread fluid accumulation in fetal tissues) may develop; this picture suggests severe heart failure.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cardiac_Changes_in_the_Donor_Fetus\"><\/span>Cardiac Changes in the Donor Fetus<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>In the donor fetus, a different type of cardiac adaptation related to hypovolemia is generally observed. Due to decreased preload, the cardiac chambers may appear smaller. However, marked cardiomegaly or severe structural heart changes are rarer in the donor fetus compared to the recipient fetus.<\/p>\n<p>Nevertheless, chronic hypoperfusion (decreased blood flow to tissues) is associated with fetal growth restriction and reduced organ perfusion. This condition may indirectly affect cardiac function.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Cardiac_Evaluation_in_the_Diagnostic_Process\"><\/span>Cardiac Evaluation in the Diagnostic Process<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>TTTS is generally diagnosed by obstetric ultrasound. However, fetal echocardiography is the primary examination method for evaluating cardiac effects.<\/p>\n<p>In fetal cardiac evaluation:<\/p>\n<ul>\n<li aria-level=\"1\">Sizes of the cardiac chambers<\/li>\n<li aria-level=\"1\">Ventricular wall thicknesses<\/li>\n<li aria-level=\"1\">Valve functions (especially tricuspid and mitral valves)<\/li>\n<li aria-level=\"1\">Doppler flow patterns<\/li>\n<li aria-level=\"1\">Myocardial performance index<\/li>\n<\/ul>\n<p>are examined in detail.<\/p>\n<p>This evaluation plays an important role in determining the stage of the syndrome and predicting prognosis. For example, while Quintero staging is based on amniotic fluid and bladder findings, the presence of cardiac dysfunction may suggest increased clinical risk.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Course_of_Cardiac_Changes_After_Treatment\"><\/span>Course of Cardiac Changes After Treatment<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Today, the most commonly applied treatment method for TTTS is fetoscopic laser ablation of placental anastomoses. This procedure aims to stop the pathological blood transfer between the fetuses.<\/p>\n<p>After successful laser treatment, many cardiac changes observed in the recipient fetus may regress over time. In particular, some functional disorders may be reversible. However, valvular anomalies or permanent cardiac sequelae may be observed in some cases.<\/p>\n<p>Therefore, prenatal and postnatal pediatric cardiology evaluation is important. The degree of cardiac recovery may differ in each case and requires individualized follow-up.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Importance_of_Cardiac_Findings_for_Families\"><\/span>Importance of Cardiac Findings for Families<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>For families diagnosed with TTTS, one of the most concerning issues is the risk of permanent heart damage. The presence of cardiac changes does not always mean permanent structural disease. In many cases, cardiac functions may improve once the hemodynamic load is eliminated.<\/p>\n<p>However, the risk may increase when advanced dysfunction, hydrops, or severe valvular pathology is detected. Therefore, the multidisciplinary approach of perinatology, fetal cardiology, and neonatology specialists is of great importance.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Cardiac changes in Twin-to-Twin Transfusion Syndrome occur as a result of unbalanced blood flow associated with placental vascular anastomoses. In the recipient fetus, cardiomegaly and ventricular hypertrophy due to volume overload may be observed, while decreased cardiac output related to hypovolemia may occur in the donor fetus. Signs of cardiovascular overload in the recipient fetus [&#8230;]\n","protected":false},"author":1,"featured_media":958,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[],"class_list":["post-959","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-general"],"_links":{"self":[{"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/posts\/959","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/comments?post=959"}],"version-history":[{"count":3,"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/posts\/959\/revisions"}],"predecessor-version":[{"id":3075,"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/posts\/959\/revisions\/3075"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/media\/958"}],"wp:attachment":[{"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/media?parent=959"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/categories?post=959"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cansaran.com\/en\/wp-json\/wp\/v2\/tags?post=959"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}