Intracardiac echocardiography during simulated aortic and mitral balloon valvuloplasty: in vivo experimental studies.

The feasibility of intracardiac echocardiography with a low-frequency transducer to assess catheter position and detect complications during experimental aortic and mitral balloon valvuloplasty was studied in 10 dogs. Intracardiac echocardiography was performed with a transesophageal echocardiographic probe placed in the right atrium. In all instances high-quality images of cardiac structures were obtained. The guide wire and balloon catheter were clearly seen as they crossed the valves. With inflation the balloon was seen as a hyperechoic structure. Doppler echocardiography documented aortic regurgitation after inflations. Acute pericardial effusion was instantly detected. It is concluded that intracardiac echocardiography is a potentially useful technique for cardiac imaging, assessing wire and balloon catheter position, evaluating valvular regurgitation, and instantly detecting acute pericardial effusion. Further research in humans with low-frequency, catheter-based transducers needs to be performed.     

Caveats of balloon dilation of conduits and conduit valves

The results and complications of percutaneous balloon dilation involving 10 patients with a stenotic right ventricle to pulmonary artery prosthetic conduit and 1 patient with an obstructed right atrium to left pulmonary artery Dacron graft (modified Fontan) are reported. For the 10 patients (14.5 +/- 5 years) with a right ventricle to pulmonary artery conduit, the mean (+/- SD) predilation conduit valve gradient was 57 +/- 22 mm Hg, right ventricular pressure 104 +/- 21 mm Hg and right ventricle to pulmonary artery gradient 75 +/- 23 mm Hg; 2 of the patients had additional pulmonary artery stenosis requiring dilation. In one patient, the balloon could not be advanced across the conduit valve. In 9 of 10 patients in whom dilation was successfully performed, the conduit valve gradient decreased by 59 +/- 13%, right ventricle to pulmonary artery gradient by 43 +/- 22% and right ventricular pressure by 31 +/- 11%. After dilation, right ventricular pressure was less than 65% of systemic pressure in seven patients, although no pressure was less than 40%. In 8 of the 11 patients, surgery was avoided or postponed. Complications included loss of a balloon fragment after rupture during the unsuccessful dilation of the right atrium to left pulmonary artery graft and circumferential balloon rupture requiring catheter retrieval of the distal portion of the balloon from the femoral vein after successful dilation of the right ventricle to pulmonary artery conduit. Conduit valve dilation by balloon can reduce but rarely eliminate conduit obstruction, and balloon rupture may occur and can result in fragment loss or embolization.     

Fiberoptic angioscopy of cardiac chambers, valves, and great vessels using a guiding balloon catheter in dogs

The applicability of fiberoptic angioscopy with a guiding balloon catheter to observe the cardiac chambers, valves and the great vessels was examined in anesthetized dogs. A No. 11 French guiding balloon catheter (balloon diameter 50 French) was introduced through either the right jugular vein or the right femoral vein into the right heart, and then a fiberscope (4.3 French in diameter) was introduced through the catheter into the right heart in 10 dogs. The balloon was inflated with air and gently pushed against the luminal surface, warm saline was infused through the catheter to displace the blood, and the luminal surfaces were photographed on 16 mm color cinefilms. Pulmonary angioscopy was also performed in these dogs. Similarly, the guiding catheter and fiberscope were introduced through the right common carotid artery into the left ventricle for observation of the luminal changes in the other 10 dogs. The luminal surfaces of the superior vena cava, right atrium, right ventricle, and pulmonary artery could be observed in all dogs. The trabeculae of the left ventricle, contracting and relaxing synchronously with the cardiac beat, could also be observed in all dogs. However, observations of the tricuspid valve, aortic valve, papillary muscle, and chordae were successful in only some dogs. Postmortem examinations revealed no obvious endocardial or intimal damage. The results indicate the applicability and safety of angioscopy guided by a balloon catheter for observations of the luminal changes in the cardiac chambers and great vessels.     

Absence of right and left atrioventricular connexion

Fifty seven hearts with absence of atrioventricular (A-V) connection were studied morphologically to specify their types of ventriculoarterial connection and their associated anomalies; the anatomic features of the hearts were correlated with their echocardiographic and cardioangiographic images in order to establish their mutual correspondence. Fifty six hearts had situs solitus; fifty specimens had right absent A-V connection and six had left absent A-V connection. One had situs inversus. All the specimens had: A deep A-V sulcus at the site of the absent A-V connection, a dimple in the muscular floor of the involved atrium connected with the dilated and hypertrophic left ventricle, incomplete right ventricle without inlet portion, ventricular septal defect of variable dimensions (it was obliterated in two), atrial septal defect, the ventricular septum deviated from the crux cordis. The left absent A-V connection had ventricular inversion and discordant ventriculoarterial connection. In the right absent A-V connection the ventriculoarterial connections were concordant in thirty eight hearts, from which thirty four had pulmonary stenosis both infundibular and valvular (five had the tetrad of Fallot), two had pulmonary valve atresia and two had a dilated pulmonary artery; discordant in nine hearts, one with aortic atresia; double outlet, from the right ventricle in two, (one with the tetrad of Fallot) and from the left ventricle in one. The heart in situs inversus had ventricular inversion, right absent A-V connection (left-sided), single (right) ventricle and atresia of the left ventricle. The correlations between cardiac morphology and imaging were precise. Developmentally, this cardiopathy is the result of an ectopic unequally lateralized septation of the common atrioventricular canal, which separates two canals, one stenotic leading to atresia and the other which develops too wide.     

Hemodynamic measurements by Doppler echocardiography

This paper discusses the measurement of cardiac output and pulmonary artery pressures by Doppler echocardiography. Blood flow may be measured through the aortic valve, the left ventricle and the mitral and pulmonary valves. In each case certain conditions for the validity of calculations must be respected. These measurements contribute to the evaluation of valvular stenosis and regurgitation, intracardiac shunts and cardiac function. Pulmonary artery pressures may be estimated from Doppler signals of tricuspid and pulmonary regurgitation, from the morphology of systolic pulmonary blood flow and from the duration of the right ventricular isovolumic relaxation period. They provide important information for the evaluation of many cardiac and pulmonary diseases.     

Intracardiac echocardiography. Experimental observations on intracavitary imaging of cardiac structures with 20-MHz ultrasound catheters

Recently catheter-based ultrasound devices have become available for obtaining high-resolution images of blood vessels. In this study we evaluated the feasibility of imaging cardiac structures using 20-MHz ultrasound catheters. In 25 dogs, the ultrasound catheter was advanced into the right and left heart chambers percutaneously. The intravascular devices yielded images of the right atrial wall, right and left ventricular myocardia, tricuspid, pulmonic, and aortic valves, and the great vessels. Although the small depth of field inherent to the frequency range of 20 MHz limited the visualization to only portions of the cardiac chambers, the images obtained were of high resolution and allowed easy identification of the various cardiac structures. Intracardiac echocardiography was easy to perform and did not result in damage to the cardiac structures. We conclude that intracardiac echocardiography using ultrasound catheters provides a new approach to cardiac imaging and that the development of lower frequency catheters could aid in extending the potential utility of intracardiac echocardiography.     

Double outlet right ventricle {S,D,L} with subaortic ventricular septal defect and pulmonary stenosis: Report of six cases

The clinical, hemodynamic, angiocardiographic and pathologic findings are presented in an infrequent but surgically correctable type of double outlet right ventricle. This study is based on six cases, one with autopsy confirmation. In all, the viscera and atria were in situs solitus (S). A ventricular d-loop was present (D). There was l-malposition of the great arteries, the aorta being to the left of, and anterior to, the pulmonary artery (L). Hence, this anomaly may conveniently be represented as double outlet right ventricle {S,D,L}. The ventricular septal defect was subaortic because the aorta was anterior and leftward, adjacent to the ventricular septum. A bilateral conus was present beneath both the aortic and pulmonary valves, preventing any semilunar-atrioventricular fibrous continuity. The subpulmonary conus was poorly expanded, resulting in pulmonary infundibular and valvular (annular) stenosis.The clinical features were those of cyanosis, clubbing and accentuation of the second heart sound in the pulmonary area (related to aortic valve closure). There was a systolic ejection murmur along the upper left sternal border, related to pulmonary outflow tract stenosis. Selective right and left ventricular angiocardiography was diagnostic.Relatively early surgical correction is suggested to minimize the progression of pulmonary infundibular stenosis and to avoid acquired atresia. In this malformation, pulmonary outflow tract reconstruction is more difficult than in tetralogy of Fallot because of the rather posterior location of the pulmonary outflow tract, and because the right coronary artery crosses the stenotic pulmonary outflow tract in front of the pulmonary valve.     

Use of an ultrasonic contrast method in the diagnosis of valvular regurgitation and intracardiac shunts

Injection of normal saline solution or indocyanine green dye through intracardiac catheters results in ultrasonic reflections from the site of injection. To evaluate the diagnostic usefulness of this observation, ultrasonic transducers were first placed directly on the pulmonary artery or ascending aorta of six open chest dogs. The rapid injection of 5 ml of normal saline solution into the femoral vein or left atrium produced a “cloud” of contrast echoes filling the pulmonary artery or ascending aorta. Thus, the echo-reflecting phenomenon persists during the passage of blood across two cardiac valves. Sixty-two patients aged 2 months to 70 years were then studied during cardiac catheterization; recordings were made during injection of indocyanine green dye or normal saline solution. Contrast echoes appeared in the left atrium after left ventricular injection in 14 of 16 patients with mitral regurgitation. Aortic root injection produced contrast echoes in the left ventricle in 13 of 16 patients with aortic regurgitation. Valvular regurgitation as small as 10 percent by angiographic determination was detected. Shunting was detected In patients with atrial and ventricular septal defects, patent ductus arteriosus and tetralogy of Fallot. Catheter-induced mitral regurgitation was demonstrated in one patient. This method is a sensitive and accurate qualitative technique for detecting intracardiac shunts and valvular regurgitation.     

Utility of in vivo, intracardiac two-dimensional echocardiography in the assessment of myocardial risk area and myocardial dyssynergy during coronary occlusion and reperfusion

We have previously reported the potential use of intracardiac echocardiography (ICE) in a variety of clinical settings, including detection of pericardial effusion, intracardiac masses, congenital cardiac defects, and during simulated balloon valvuloplasty. The utility of intracardiac ultrasound imaging of the left ventricle (LV) in patients with coronary disease needs to be further explored. We performed this study with the purpose of evaluating risk area and regional wall-motion abnormalities produced by ischemia using ICE. Ten episodes of ischemia were produced by transiently occluding the left anterior descending coronary artery in five dogs. ICE was performed with a modified 5-MHz transesophageal echocardiographic probe placed in the right atrium. Continuous short-axis images of the LV were obtained before, during, and after coronary occlusion. Risk area was defined using myocardial contrast echocardiography. In all cases, ICE provided high resolution images of the LV. Risk area and regional wall-motion abnormalities were readily detected. There was good correlation between the risk area (x) and extent of dyssynergy (y), defined by the equation y = 0.76x + 6.38 (r = 0.80, P less than 0.01). We conclude that ICE provides potentially useful information concerning regional LV dysfunction, and, when combined with myocardial contrast echocardiography, area at risk. This technique may be useful during interventional procedures once a catheter-based ultrasound transducer with adequate depth of field to provide images of the entire LV can be developed.     

Assessment of trans‐aortic pressure gradient using a coronary pressure wire in patients with mechanical aortic and mitral valve prostheses

Accurate evaluation of trans‐aortic valvular pressure gradients is challenging in cases where dual mechanical aortic and mitral valve prostheses are present. Non‐invasive Doppler echocardiographic imaging has its limitations due to multiple geometric assumptions. Invasive measurement of trans‐valvular gradients with cardiac catheterization can provide further information in patients with two mechanical valves, where simultaneous pressure measurements in the left ventricle and ascending aorta must be obtained. Obtaining access to the left ventricle via the mitral valve after a trans‐septal puncture is not feasible in the case of a concomitant mechanical mitral valve, whereas left ventricular apical puncture technique is associated with high procedural risks. Retrograde crossing of a bileaflet mechanical aortic prosthesis with standard catheters is associated with the risk of catheter entrapment and acute valvular regurgitation. In these cases, the assessment of trans‐valvular gradients using a 0.014? diameter coronary pressure wire technique has been described in a few case reports. We present the case of a 76‐year‐old female with rheumatic valvular heart disease who underwent mechanical aortic and mitral valve replacement in the past. She presented with decompensated heart failure and echocardiographic findings suggestive of elevated pressure gradient across the mechanical aortic valve prosthesis. The use of a high‐fidelity 0.014? diameter coronary pressure guidewire resulted in the detection of a normal trans‐valvular pressure gradient across the mechanical aortic valve. This avoided a high‐risk third redo valve surgery in our patient. © 2017 Wiley Periodicals, Inc.     

限制型心肌病的临床表现

本文报告限制型心肌病１０例，其中５例诊断为心内膜心肌纤维化（右室型４例，左室型１例）。其临床特点为慢性右心压塞征象；心室流入道收缩变形，心尖部闭塞，流出道增宽，巨大右房或左房扩大，房室瓣反流，左室收缩功能大致正常，舒张功能受限。其他５例诊断为特发性限制型心肌病，其特点为肺和体循环淤血，不同程度房室瓣反流，房性心律失常，心房明显扩大，左室不扩大，双室舒张末压升高，无明显心肌缺血或心包疾患。３例患者心脏病症状出现后半年至７年，死于顽固性心力衰竭。１例右室型，１例左室型心内膜心肌纤维化患者行心室内膜剥脱和房室瓣替换手术。     

Intracardiac phonocardiography in experimental left ventricular cavity obliteration: potential clinical applicability for the distinction of obliterating left ventricle from hypertrophic obstructive cardiomyopathy

Intracardiac sound was measured in six dogs, four with left ventricular cavity obliteration induced by isoproterenol, and two with catheter entrapment. In left ventricular cavity obliteration, no murmur occurred within the left ventricle. Whenever a systolic murmur occurred, it was distal to the aortic valve. In entrapment, no murmur occurred within the left ventricle or distal to the aortic valve. Previous studies in patients with hypertrophic obstructive cardiomyopathy showed that the systolic murmur was of greatest intensity within the left ventricular outflow tract. Therefore, intracardiac phonocardiography may assist in differentiating these conditions which produce an intraventricular pressure gradient.     

Utility of intracardiac echocardiography in left heart ablation for tachyarrhythmias

Catheter-based radiofrequency ablation in the left heart can provide effective therapy for tachyarrhythmias. The recent development of the real time intracardiac echocardiography (ICE) with 2D and Doppler color flow imaging can facilitate left heart ablation procedures. This report reviews the use of ICE during radiofrequency catheter ablation procedures for atrial fibrillation (AF) and ventricular tachycardia and is based on our own experience in 955 patients. ICE has a critical role for guiding transseptal catheterization, assisting placement of mapping/ablation catheters and monitoring lesion morphologic changes, especially in the pulmonary vein ostia, Marshall ligament region, thickened interatrial septum, left atrial posterior wall contiguous to esophagus, aortic valve cusps, and the epicardial regions. One of the more powerful utilities of ICE lies in its ability to identify and potentially reduce procedural complications including damage to intracardiac structures, residual atrial septal defect, left atrial thrombus formation, pulmonary vein stenosis, esophageal injury, myocardial air-embolization and pericardial effusion during left heart ablation.     

Intracardiac phased-array imaging: methods and initial clinical experience with high resolution, under blood visualization: initial experience with intracardiac phased-array ultrasound

OBJECTIVES: This study was designed to test the feasibility of high-resolution phased-array intracardiac imaging. BACKGROUND: Intracardiac echocardiographic imaging of the heart during interventional electrophysiologic (EP) procedures has been limited by inadequate ultrasound penetration and absence of Doppler hemodynamic and flow information produced by rotating mechanical ultrasound elements. METHODS: A 10F (3.2 mm) phased-array, variable 5.5 to 10 MHz frequency imaging catheter with a four-way deflectable tip was applied in 24 patients undergoing EP studies. Sixteen prespecified cardiac targets were imaged from a right heart venue. RESULTS: Fifteen patients had no underlying organic heart disease; nine had ischemic, cardiomyopathic, valvular or congenital heart disorders. Longitudinal and short-axis imaging readily disclosed each cardiac valve, support structures and chamber, as well as the pericardium, right and left atrial appendages, the junction of the right atrium and superior vena cava, crista terminalis, tricuspid valve isthmus, coronary sinus orifice, membranous fossa ovalis and pulmonary veins. The average target depth was 8.8+/-1.5 cm (range 0.5 to 15 cm), with adequate penetration at a 7.5 MHz imaging frequency. Color flow and Doppler utilities clearly characterized transaortic and pulmonic valve and pulmonary vein blood flow, including during low output states. CONCLUSIONS: These first human studies with this technology demonstrate the methods, feasibility and utility of intracardiac phased-array vector and Doppler imaging for long-axis, apex-to-base global cardiac imaging. High resolution of endocardial structures and catheters suggests additional utility for visualizing interventional procedures from the right heart.     

Doppler-echocardiographic assessment of the degree of pulmonary hypertension and right-ventricular pressure in patients with ventricular septal defects

The study was performed in 53 children aged 3 months to 4 years who had ventricular septal defect. Systolic pressure in the right ventricle, pulmonary artery and the severity of pulmonary hypertension were determined by two way: 1) from arteriovenous shunt via ventricular septal defect before its surgical closure; 2) from systolic regurgitation via the tricuspid valve after its seal. Right ventricular diastolic pressure was measured by Doppler echocardiography using diastolic blood flow through the tricuspid valve. Before ventricular septal defect closure, the correlation ratio of Doppler echocardiographic to cardiac catheterization values was 0.76 and that of Doppler echocardiographic to intrasurgical manometry was 0.79. In the postoperative period, a catheter was left in the right ventricle in 14 children and its pressure was simultaneously measured by the blind method. The correlation was 0.97 for right ventricular systolic pressure and 0.89 for diastolic one.     

超声心动图评价成人房间隔缺损封堵术后心脏结构和功能的变化

目的探讨超声心动图评价成人房间隔缺损(atrial septal defects,ASD)介入封堵术后心脏形态和功能变化。方法经超声心动图和心电图检查确诊为ASD并成功施行ASD封堵术的患者74例,年龄(35.63±12.74)岁,ASD直径为(16.29±5.11)mm。于封堵器堵闭术后24h、1个月、3个月、6个月和12个月进行经胸超声心动图追踪测量主动脉内径、左心室舒张末内径、左心室收缩末内径和右心室前后径,肺动脉内径和肺动脉瓣血流速度,右心房和右心室的上下径、主动脉瓣口血流速度、二尖瓣口血流速度、三尖瓣口血流速度和左心室射血分数,同时测量封堵器的直径和长度,并进行统计学分析。结果术后24h与术前相比,右心房内径、右心室内径、肺动脉内径、三尖瓣口血流速度和肺动脉瓣口血流速度均显著减少(P0.01);左心房内径、左心室内径、主动脉内径、二尖瓣口血流速度和主动脉瓣口血流速度均显著增加(P0.05);左心室射血分数无明显变化。房室大小和血流速度在术后24h内变化明显,在术后1个月后的随访中逐渐趋于稳定。结论封堵器介入封堵ASD,既纠正了解剖畸形,又改善了左心和右心系统的几何结构。     

Nonuniformity of pericardial surface pressure in dogs

Previously, we have shown that pericardial constraint cannot be measured by true (hydrostatic) pressure except when an excess of pericardial fluid is present and that a device such as a balloon (which reflects radial contact stress as well as hydrostatic pressure) must be used. Since radial contact stress is the major component of the constraint exerted by the pericardium when little pericardial liquid is present, it follows that the pressure measured by the balloon might be different over different parts of the heart. In an attempt to test this hypothesis, in 11 anesthetized dogs we placed pericardial balloons over the right and left ventricular free walls, instrumented the animals to measure ventricular dimensions (sonomicrometry) and pressure, mounted pneumatic constrictors on the aortic and pulmonary artery, reapproximated the pericardium, and closed the chest under suction. We studied the transient effects of constrictions of the ascending aorta and pulmonary artery and of angiotensin infusion before and after intravenous saline infusion. Aortic constriction and, to a lesser degree, angiotensin increased pericardial pressure over the left ventricle more than over the right ventricle. Pulmonary artery occlusion increased pericardial pressure over the right ventricle but significantly decreased pericardial pressure over the left ventricle. We conclude that there are significant local differences in pericardial pressure (recorded by balloon) over the lateral ventricular surfaces during acute changes in afterload. These observations may be explained in part by decreased venous return to the contralateral ventricle, the tendency of the heart to resist lateral displacement, and the limited mobility of the pericardium.     

Prolapsed left atrium behind the left ventricular posterior wall: Two dimensional echocardiographic and angiographlc features

Left atrial enlargement can usually be detected accurately using M mode echocardiography. However, in the presence of heart disease, asymmetric enlargement may lead to inaccurate assessment of left atrial size and shape. Pericardial effusion can usually be diagnosed on the basis of characteristic M mode echocardiographic findings. However, false positive patterns sometimes occur with the use of this single dimensional technique. Three patients with a greatly enlarged left atrium are described whose M mode echocardiogram suggested significant posterior pericardial fluid accumulation. In each patient, two dimensional echocardiography detected portions of a huge left atrium that prolapsed behind the left ventricular posterior wall and mimicked an isolated posterior pericardial effusion. In one case a right anterior oblique left ventricular cineangiogram suggested the presence of a ventricular septal defect or a false aneurysm of the left ventricle due to the prolapsed left atrium. Because two dimensional echocardiography can provide accurate spatial orientation with visualization of intracardiac structures in relation to one another in real time, it can identify the presence of left atrial prolapse and play an important role in the differential diagnosis of isolated echo-free spaces behind the left ventricle detected with M mode echocardiography.     

Changes in intracardiac blood flow velocities and right and left ventricular stroke volumes with gestational age in the normal human fetus: a prospective Doppler echocardiographic study

We used Doppler echocardiography to quantitate the changes in intracardiac blood flow velocities and right and left ventricular stroke volumes in 80 normal human fetuses from 19 to 40 weeks gestation. Blood flow velocity spectra across the aortic, pulmonary, tricuspid, and mitral valves were digitized to obtain peak velocities (m/sec) and flow velocity integrals. Aortic and pulmonary diameters were measured at valve level from two-dimensional echocardiographic images and cross-sectional area was calculated assuming a circular orifice. Ventricular stroke volume was calculated as the product of the cross-sectional area of a great vessel and the flow velocity integral through that vessel. The pulmonary arterial and aortic diameters increased linearly with gestational age (r = .82, r = .84), and pulmonary arterial diameter consistently exceeded aortic diameter. There was a positive relationship between stroke volume and gestational age: stroke volume increased exponentially from 0.7 ml at 20 weeks to 7.6 ml at 40 weeks for the right ventricle (r = .87) and from 0.7 ml at 20 weeks to 5.2 ml at 40 weeks for the left ventricle (r = .91). Similar results were obtained for right and left ventricular and combined cardiac outputs. In 44% of the fetuses it was possible to quantitate both right and left ventricular stroke volumes. There was a close correlation between right and left ventricular stroke volumes in these fetuses (r = .96) and right ventricular stroke volume exceeded left ventricular stroke volume by 28%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Symptoms of advanced heart failure—A case for radiofrequency catheter ablation?

A sixty-year-old man with previous history of coronary artery disease was admitted due to progressive worsening of dyspnoea at exertion (NYHA III functional class) and no angina. Coronary angiography confirmed occlusion of the right coronary artery which was naturally bypassed by homocollaterals with TIMI 3 flow to the peripheral branches. The lesion was not technically suitable for percutaneous angioplasty. The left coronary artery was without stenosis. On echocardiography, both the left ventricle and the left atrium were dilated and hemodynamically significant mitral regurgitation was present. Surface ECG showed a left bundle branch block with repeated runs of monomorphic ventricular ectopic beats (PVC). Radiofrequency catheter ablation of the focus in the posteroseptal region of the left ventricle underneath the mitral valve was performed using electroanatomical mapping system. After the procedure, mitral regurgitation decreased and reverse remodeling of the left ventricle and the left atrium occurred with concomitant significant clinical improvement of the patient. The authors discuss several treatment strategies: mitral valve repair surgery combined with revascularization, implantation of a biventricular ICD system or elimination of the focus of monomorphic VT runs by radiofrequency catheter ablation as a possible causal approach in the treatment of PVC-induced cardiomyopathy.