Добавил:

Sekretar kiopkiopkiop18@yandex.ru t.me/Prokururor I Вовсе не секретарь, но почту проверяю Опубликованный материал нарушает ваши авторские права? Сообщите нам.

Вуз:

Ростовский Государственный Медицинский Университет

Предмет:

Медицина общая

Файл:

Книга_3752_Библиотеки_им_академика_М_И_Перельмана

.pdf

Скачиваний:

Добавлен:

31.08.2026

Размер:

24 Мб

Скачать

☆

<<< < Предыдущая 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 4748 / 5048 49 50 > Следующая >>>

467

Atrial Appendage Thrombus Assessment

The recognition of atrial thrombi is extremely important prior to consideration of atrial ﬁ brillation ablation. The left atrial appendage is a complicated potentially multi-lobed tube-like structure with an intricate array of pectinate mus-

cles (Fig. 24.21 ). Contractile function of the appendage in the setting of atrial myopathy and atrial ﬁ brillation is depressed with concomitant decreased ﬂ ow velocity. These factors make it difﬁ cult to analyze for thrombi, as ﬁ lling defects can be due to inadequate contrast ﬁ lling of the appendage [ 92 – 94 ].

Fig. 24.19 Components of electroanatomic mapping with CCTA and intracardiac echo image integration, with a catheter-based anatomic map ( upper left image ), CCTA ( lower left image ), and intracardiac echo ( right image )

Fig. 24.20 Electroanatomic mapping with CCTA and intracardiac echo image integration demonstrating an endocardial view after radiofrequency catheter pulmonary vein isolation with encircling radiofrequency energy applications ( red spheres )

24 CCTA Cardiac Electrophysiology Applications: Substrate Identiﬁ cation, Virtual Procedural Planning, and Procedural Facilitation

https://t.me/medicina_free

468

Transesophageal echo is the gold standard for the assessment of left atrial appendage thrombi. In patients with preprocedure non-gated CCTA prior to atrial ﬁ brillation ablation, the sensitivity is high for ruling out thrombus, especially in lower risk patients (age <52 and CHADS2 score <1), but speciﬁ city, positive predictive value, and inter-observer consensus remains more limited (Fig. 24.22 ) [ 95 – 101 ]. The degree of pseudoﬁ lling defects correlate with the degree of left atrial emptying abnormality in patients with chronic atrial ﬁ brillation as assessed by CCTA volumetric analysis [ 102 ]. Delayed CCTA images allow more time for left atrial appendage ﬁ lling, improving detection of pseudoﬁ lling defects (Fig. 24.23 ) [ 103 – 105 ]. These images can be performed with a more restricted ﬁ eld of view to limit radiation exposure with delayed imaging. Imaging in the prone position may decrease false positive results [ 106 ]. The left atrial appendage/ascending aorta Hounsﬁ eld Unit ratio is inversely related to the degree of spontaneous echo contrast and presence of thrombi [ 107 ]. This ratio may be useful as there are limitations to the visual assessment of the left atrial appendage for thrombus [ 99 ]. Deﬁ nition of the optimal left atrial appendage/ascending aorta Hounsﬁ eld Unit ratio is dependent on whether the ratio is

Fig. 24.21 Double oblique 2-D view ( left panel ) showing the complex anatomy of the left atrial appendage ( arrow ) with a multi-lobed tube- like structure with an intricate array of pectinate muscles. Endocardial

views ( right panels ) show the shape of the left atrial appendage ostium and ridge separating it from the left upper pulmonary vein

Fig. 24.22 Double oblique 2-D view demonstrating a ﬁ lling defect ( arrow ) in the tip of the left atrial appendage with a differential diagno- sis of incomplete ﬁ lling of the appendage versus thrombus

J.S. Shinbane et al.

https://t.me/medicina_free

469

assessed during standard left atrial opaciﬁ cation or delayed images and whether the focus is on sensitivity and negative predictive values or speciﬁ city and positive predictive value. With these techniques the sensitivity and negative predictive value are excellent with some limitations to positive predictive value and speciﬁ city [ 99 , 108 – 110 ].

Left Atrial Appendage Occlusion Devices for Stroke Prevention with Atrial Fibrillation/ Atrial Flutter

Devices have been developed for left atrial appendage occlusion to decrease thromboembolic risk associated with atrial ﬁ brillation and atrial ﬂ utter [ 111 , 112 ]. Classiﬁ cation sys- tems deﬁ ning left atrial appendage morphology are evolving as multiple shapes and geometries exist [ 113 ]. These mor- phologies can be deﬁ ned by the left atrial appendage ostial size, morphology and location, the length of the main body, the number, length, angulation and degree of trabeculation of lobes, and the relationship of the appendage to other structures (Figs. 24.24 , 24.25 , 24.26 , 24.27 , and 24.28 , Videos 7, 8, 9, 10, 11, 12). CCTA deﬁ ned left atrial appendage morphology has become important to decisions to whether to proceed with closure, the choice of closure approach, and the speciﬁ c type of closure device [ 114 , 115 ]. The methods for left atrial appendage occlusion include endovascular occlusion via a

transseptal route, minimally invasive catheter-based epicardial occlusion, and minimally invasive or open surgical appendectomy. CCTA can provide virtual procedural images deﬁ ning the path and possible obstacles to transseptal, subxiphoid transcatheter, minimally invasive surgical or open surgical approaches (Figs. 24.29 and 24.30 ). Stroke risk based on left atrial appendage morphology requires further study due to variability in results [ 116 – 122 ].

CCTA in Other Supraventricular Tachycardias

CCTA deﬁ nition of atrial structures is important to the spectrum of supraventricular tachycardia ablation. CCTA has been used to deﬁ ne anatomic characteristics important to ablation of cavotricuspid isthmus dependent atrial ﬂ utter. Visualization of characteristics including steep angulation of a thick-walled cavotricuspid isthmus and prominence of the Eustachian ridge distinguished challenging cases and determined successful approach to this anatomy [ 123 ]. CCTA with image integration and electroanatomic mapping is useful for ablation of complex atrial tachycardia circuits [ 124 ].

For ablation of accessory pathways in Wolff-ParkinsonWhite syndrome, issues related to the coronary sinus/great cardiac vein have ramiﬁ cations for mapping. The coronary sinus/great cardiac vein has a variable location in relation to the mitral annulus often coursing above the annulus rather

Fig. 24.23 2-D double oblique views of the left atrial appendage showing a ﬁ lling defect ( arrow ) on ﬁ rst pass imaging ( a ) and complete opaciﬁ ca- tion ( arrow ) of the appendage on a delayed image ( b )

24 CCTA Cardiac Electrophysiology Applications: Substrate Identiﬁ cation, Virtual Procedural Planning, and Procedural Facilitation

https://t.me/medicina_free

470

than at the annular level. In these anatomic scenarios, coronary sinus catheters record the atrial insertion of an accessory pathway rather than providing a true annular signal [ 125 ]. CCTA can deﬁ ne the individual relationship between the coronary sinus/great cardiac vein and the annulus important to interpretation of coronary sinus lead electrograms. In regard to ablation in the coronary sinus, knowledge of the relationship of the

coronary sinus to the circumﬂ ex coronary artery is important in order to avoid complications. CCTA can deﬁ ne areas of crossing and overlap between these structures (Fig. 24.31 ) [ 60 , 126 ]. CCTA can also deﬁ ne anatomic ﬁ ndings important to catheter placement and mapping of certain accessory pathway substrates. The presence of a coronary sinus diverticulum or isolated unroofed coronary sinus can be visualized [ 127 , 128 ].

Fig. 24.25 Left lateral 3-D views demonstrating the relationship of a “chicken wing” morphology left atrial appendage to an aneurysmal pulmonary artery. LAA left atrial appendage, PA main pulmonary artery

Fig. 24.24 Multimodal views demonstrating a “chicken-wing” morphology left atrial appendage ( arrows ) with a long main lobe which subsequently has an acute angulation. Views include: 3-D ( a ), 2-D

double oblique ( b ), endovascular ( c ), and 2-D double oblique aligned along long axis ( d ) and short axis ( e ) of the appendage ostium

J.S. Shinbane et al.

https://t.me/medicina_free

471

Assessment of Anatomic Substrates Associated with Ventricular Arrhythmias and Sudden Cardiac Death

Ventricular arrhythmias are associated with a spectrum of cardiovascular structural or primary electrophysiologic

abnormalities, often with the ﬁ rst manifestation of disease being sudden death. Vascular and valvular anatomies associated with sudden cardiac death due to hemodynamic compromise or ventricular arrhythmias can be identiﬁ ed by CCTA, and include anomalous coronary arteries, severe coronary artery disease, critical aortic stenosis, and aortic

Fig. 24.26 3-D ( a ) and 2-D double oblique ( b ) views demonstrating the morphology of the left atrial appendage to be “cauliﬂ ower” shaped ( arrow ) with a single short lobe

Fig. 24.27 3-D ( a ) and 2-D double oblique ( b ) views demonstrating the morphology of the left atrial appendage to be “cactus” shaped ( arrow ) with a long main lobe followed by several branching lobes

24 CCTA Cardiac Electrophysiology Applications: Substrate Identiﬁ cation, Virtual Procedural Planning, and Procedural Facilitation

https://t.me/medicina_free

472

aneurysm and dissection. High risk anomalous coronary artery anatomies include coronary artery off of the contralateral sinus with an interarterial course and slit-like ostium, coronary artery origin from the pulmonary artery, and left main coronary atresia, all of which can be visualized by CCTA [ 129 – 132 ].

Cardiomyopathic substrates associated with sudden cardiac death due to hemodynamic compromise or ventricular arrhythmias can be identiﬁ ed by CCTA. CineCCTA can characterize cardiomyopathic substrates through reproducible volumetric measurement of ventricular volumes and ejection fraction, ventricular wall thickness, and ventricular regional wall motion. Direct

visualization of the coronary arteries with CCTA may facilitate differentiation between ischemic and non-ischemic cardiomyopathy [ 133 – 135 ].

The visualization of myocardial ﬁ brosis is important to the differential diagnosis and prognosis of cardiomyopathic states. CMR delayed gadolinium enhancement has played a primary role in ﬁ brosis imaging. CMR delayed contrast enhancement has the ability to visualize myocardial infarct scar and its anatomic relationship to viable myocardium [ 136 – 139 ]. In ischemic cardiomyopathy, delayed contrast enhancement can be used to localize myocardial segments with scar, determine the morphology, transmurality and complexity of scar, and deﬁ ne the total percentage of myo-

ab c

Fig. 24.29 Serial cranial to caudal 3-D axial views ( a – c ) demonstrating the anatomic relationship between a “chicken-wing” morphology left atrial appendage and the main pulmonary artery. Ao aorta, LAA left atrial appendage, PA main pulmonary artery

Fig. 24.28 Left lateral 3-D views demonstrating the anterior angulation of the left atrial appendage. LAA left atrial appendage, PA main pulmo- nary artery

J.S. Shinbane et al.

https://t.me/medicina_free

473

ef gh

bcd

Fig. 24.30 Serial caudal to cranial ( a – h ) 3-D axial views demonstrat- ing a virtual subxiphoid approach to a “chicken-wing” morphology left atrial appendage. Cx circumﬂ ex coronary artery, LAD left anterior

descending coronary artery, LA left atrium, LAA left atrial appendage, LV left ventricle, and RV right ventricle

Fig. 24.31 The left-lateral view ( left panel ) and diaphragmatic view ( right panel ) of the heart. The left circumﬂ ex coronary artery and coro- nary veins are clearly displayed. The great cardiac vein is seen overlying the left circumﬂ ex coronary artery for a short (<30 mm) segment. The marginal vein is dominant, and the posterior vein is small in size.

AIV anterior interventricular vein, CS coronary sinus, GV great cardiac vein, LA left atrium, LAV left atrial vein, LCX left circumﬂ ex coronary artery, LV left ventricle, MV middle cardiac vein, MRV marginal vein, PV posterior vein (Reprinted from Mao et al. [ 60 ] with permission from Elsevier)

cardium infarcted. The presence and degree of delayed contrast enhancement is associated with increased ventricular arrhythmias and worse prognosis in ischemic cardiomyopathy [ 140 – 142 ], nonischemic dilated cardiomyopathy [ 142 – 147 ], hypertrophic cardiomyopathy [ 148 – 154 ], and

arrhythmogenic right ventricular cardiomyopathy [ 155 , 156 ]. CMR derived 3-D location, transmurality, heterogene- ity and complexity of the scar, presence of an anatomic isthmus, and relation of the ﬁ brosis to the atrioventricular annuli can assist in the planning and performance of ventricular

24 CCTA Cardiac Electrophysiology Applications: Substrate Identiﬁ cation, Virtual Procedural Planning, and Procedural Facilitation

https://t.me/medicina_free

474

tachycardia ablation. These imaging factors can help to delineate whether an epicardial approach is required to reach a ventricular tachycardia circuit, whether ablation lines should be extended to an atrioventricular annulus, and where the location of a potential critical isthmus areas for ablation [ 157 – 162 ]. Integration of 3-D ﬁ brosis reconstruction from late gadolinium enhancement CMR with electroanatomic catheter mapping in the EP laboratory can further facilitate ventricular tachycardia ablation [ 157 ].

The presence of a non-MR conditional implantable device continues to limit the application of CMR imaging. Additional limitation is related to quality of image acquisition in patients with devices. In settings where delayed gadolinium enhancement CMR has been utilized in patients with ICDs, artifact can potentially limit image quality, but techniques to minimize these artifacts are being investigated [ 14 ]. CCTA delayed contrast enhancement imaging is particularly useful in the assessment of patients with preexisting non-MR conditional cardiac devices. Delayed enhancement imaging with CCTA can image ﬁ brosis associated with myocardial infarction [ 163 – 165 ]. Lipomatous metaplasia of areas of chronic myocardial infarction can be identiﬁ ed with CT [ 166 ]. CCTA delayed contrast enhance- ment can characterize dense areas of ﬁ brosis in hypertrophic cardiomyopathy [ 167 ].

The diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia involves criteria including clinical and family history, electrophysiologic ﬁ ndings, and right ventricular structural, functional and tissue pathology abnormalities [ 168 , 169 ]. Although CMR imaging has been the diagnostic imaging modality of choice, CCTA can also visualize the anatomic features associated with arrhythmogenic right ventricular cardiomyopathy/dysplasia, such as epicardial and myocardial fat, low-attenuation trabeculations, right ventricular free wall scalloping, right ventricular enlargement, and global and regional right ventricular wall motion abnormalities (Fig. 24.32 ) [ 170 , 171 ]. Biventricular involvement in arrhythmogenic right ventricular cardiomyopathy/dysplasia by CCTA has also been seen [ 172 ].

Ventricular Tachycardia Ablation

CCTA can be useful in the planning and performance of ablation for ventricular tachycardia. CT can deﬁ ne areas of wall thinning which correlate with areas of low voltage and abnormal ventricular activity important to ventricular tachycardia circuits [ 173 ]. CT deﬁ ned areas of lipomatous metaplasia in regions of chronic myocardial infarction can be deﬁ ned and may have relevance to critical sites of ventricular tachycardia circuits [ 174 ]. The combined integration of CMR assessment of ﬁ brosis and CCTA derived wall thinning and location of the coronary arteries with electroanatomic mapping is feasible and provides important features for ventricular tachycar-

dia ablation [ 175 ]. Multiple techniques have been used to integrate CCTA images into modalities for mapping and ablation of ventricular tachycardia circuits. CCTA delayed contrast enhancement imaging of infarct scar has been used to facilitate epicardial ablation of a ventricular tachycardia circuit in the setting of an ICD [ 176 ]. Myocardial infarct scar related ventricular tachycardia circuits have been ablated in sinus rhythm, facilitated by integration of single-photon emission CT, CCTA, and electroanatomic mapping [ 177 ]. Facilitation of ventricular tachycardia ablation through fusion imaging of delayed enhancement CMR, CCTA and electroanatomic mapping for ablation of ventricular tachycardia has been performed [ 178 ]. CCTA has also demonstrated evidence of microvascular obstruction after radiofrequency ablation of ventricular tachycardia as evidenced by wall motion abnormalities, ﬁ rst pass hypoenhancement and delayed contrast hyperenhancement correlating with CMR [ 179 ].

For patients with congenital heart disease undergoing supraventricular and ventricular tachycardia ablation, CMR also characterizes important anatomy for procedural planning. Important ﬁ ndings on CMR include ventricular septal defects, ventricular thrombus, bafﬂ e pathways to the ventricles, and myocardial ﬁ brosis. Pressure and volume overload from unrepaired and repaired congenital lesions as well as atrial and ventricular surgical incisions lead to ﬁ brosis and therefore arrhythmia substrate [ 180 – 185 ]. Challenges of ven- tricular tachycardia ablation include mapping during ventricular arrhythmias with attendant risk of hemodynamic instability. Characterization of critical isthmuses based on advanced cardiac imaging are useful to ablation of ventricular

Fig. 24.32 CCTA axial view demonstrating ﬁ brofatty replacement of right ventricular myocardium, low-attenuation trabeculations, and right ventricular free wall scalloping in arrhythmogenic right ventricular cardiomyopathy. A right ventricular deﬁ brillation lead is present with beam hardening artifact.

J.S. Shinbane et al.

https://t.me/medicina_free

475

tachycardia circuits while the patient is in sinus rhythm. Ventricular tachycardia incisional reentry isthmuses in operated congenital heart disease can be deﬁ ned and ablated in sinus rhythm by spanning isthmuses between annuli and scar/ patch [ 186 ]. The combination of remote magnetic navigation, 3-D image integration, and electroanatomic mapping has facilitated safe and feasible ablation in patients with complex congenital anomalies [ 187 ].

CCTA for Device Therapies

CCTA can visualize the coronary venous system and may potentially play an important role in cardiac resynchronization therapy (CRT) [ 60 , 188 ]. CRT is used to optimize cardiac function through resynchronization of ventricular contraction in patients with dilated ischemic and non- ischemic cardiomyopathy, ventricular conduction abnormalities, and moderate to severe heart failure. With CRT, a pacing lead is placed in a branch vessel of the coronary venous system to achieve left ventricular pacing. As opposed to the right atrial and right ventricular leads, which can be actively ﬁ xated in many positions in their respective chambers with relative ease, placement of the coronary venous lead can be challenging, as lead position is limited by the individual conﬁ nes and variation of the existing coronary venous anatomy.

CCTA coronary venous imaging can provide roadmaps for lead placement, with potential avoidance of a percutaneous approach in the setting of inadequate anatomy. Detailed assessment of the coronary venous anatomy includes coronary sinus diameter, 3-D location of branch vessels relative to the left ventricle myocardial segments , branch vessel diameter and angulation off of the coronary sinus/great cardiac vein (Figs. 24.33 and 24.34 , Videos 13 and 14 ) [ 60 ]. CCTA can also visualize structures which could complicate access to the coronary venous system, such as a prominent Thebesian valve covering the coronary sinus ostium (Fig. 24.35 ) [ 189 ]. Other abnormalities, such as coronary sinus diverticulae, left superior vena cava to coronary sinus connections, and unroofed coronary sinuses can also be identiﬁ ed (Figs. 24.36 and 24.37 ). Visualization of the phrenic nerve and its relation to the coronary venous anatomy may be important to lead placement in order to avoid diaphragmatic pacing (Fig. 24.38 ) [ 190 ]. CCTA is deemed appropriate for the assessment of coronary venous imaging for CRT [ 191 – 193 ].

Fig. 24.33 3-D volume rendered image demonstrating visualization of the coronary venous system including the coronary sinus ( double white arrow ), a middle cardiac vein ( black arrow ), and a posterolateral vein ( single white arrow )

Fig. 24.34 CCTA 3-D views demonstrating localization of the myocardial segment associated with the distal portion of the posterolateral vein ( arrows )

24 CCTA Cardiac Electrophysiology Applications: Substrate Identiﬁ cation, Virtual Procedural Planning, and Procedural Facilitation

https://t.me/medicina_free

476

Preliminary data suggest that pre-procedure knowledge of the 3-D coronary venous anatomy can facilitate procedures through decreased procedure time and utilization of guide

catheters [ 194 ]. CCTA fusion with ﬂ uoroscopy has been per- formed preliminarily with accurate fusion of structures [ 195 ]. CCTA can be used to plan CRT approach when obsta- cles to standard approaches are identiﬁ ed. CCTA delineation of ostial abnormalities limiting access to the coronary sinus ostium have permitted procedural planning and facilitation of alternate approaches to endovascular access rather than proceeding to epicardial lead placement (Fig. 24.39 ) [ 196 ]. CCTA deﬁ ned assessment of the location of the coronary

Fig. 24.36 CCTA demonstrating a coronary sinus diverticulum ( arrow ). CS coronary sinus, DV diverticulum, GV great cardiac vein, IV inferior vena cava, LA left atrium, MV marginal vein, and RA right atrium

Fig. 24.35 Axial images at the coronary sinus os level demonstrating a prominent Thebesian valve. CS coronary sinus, RA right atrium, RV right ventricle, and LV left ventricle (Reprinted from Shinbane et al. [ 189 ] with permission from John Wiley and Sons)

Fig. 24.37 3-D volume rendered view demonstrating a left superior vena cava with connection to an aneurysmal coronary sinus. A rightsided superior vena cava was not present

Fig. 24.38 3-D volume rendered image showing visualization of the course ( a – e ) of the left phrenic nerve (Reprinted from Matsumoto et al. [ 190 ] with permission from Elsevier)

J.S. Shinbane et al.

https://t.me/medicina_free

<<< < Предыдущая 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 4748 / 5048 49 50 > Следующая >>>

Соседние файлы в папке Библиотека им академика М.И. Перельмана

#
31.08.202625 Мб0Книга_3745_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3748_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3749_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3750_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3751_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3752_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3753_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3754_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3755_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202624 Мб0Книга_3756_Библиотеки_им_академика_М_И_Перельмана.pdf
#
31.08.202623 Мб0Книга_3757_Библиотеки_им_академика_М_И_Перельмана.pdf