Anatomical factors influencing fixation of endocardial pacing leads in the right ventricle

The anatomical factors influencing fixation of endocardial pacing leads were studied in 50 hearts. Many variations were found in the anterior, posterior and septal papillary muscles, interpapillary connections, and the moderator band. Those variations conducive to lead fixation are illustrated. Vertical bands of muscle that could influence lead fixation were seen inside the right ventricle. Variations in the conus papillary muscle and right ventricular outflow tract that facilitate lead fixation are also illustrated. In a few hearts, attention is drawn to slender support of the anterior cusp of the tricuspid valve.     

Ebstein's Anomaly with Subpulmonary Obstruction– A Rare Association

Ebstein's anomaly comprises a wide spectrum of congenital cardiac abnormalities involving the tricuspid valve (TV) apparatus and the architecture of the morphological right ventricle (RV). We report a case of Ebstein's anomaly in a 3‐year‐old boy having a unique association with severe subpulmonic obstruction caused by tethered and dysplastic anterior tricuspid leaflet (ATL), and a large ventricular septal defect. In view of poorly functioning RV, the baby was planned for a bidirectional Glenn shunt with subsequent Fontan completion.     

Mechanistic subtypes of focal right ventricular tachycardia

Idiopathic sustained focal right ventricular tachycardia (VT) is most frequently due to outflow tract (OT) tachycardia. This arrhythmia is recognized by its characteristic ECG pattern and sensitivity to adenosine. However, there are other forms of idiopathic, focal sustained VT that originate from the right ventricle (RV), which are less well appreciated and easily overlooked. This review will identify the characteristic features and electrophysiologic properties of these forms of RV VT, including those originating from the tricuspid annulus, right ventricular papillary muscles, and moderator band as well as variants of classic RVOT tachycardia and those due to microreentry in the presence of preclinical disease. Recognition of these subtypes of focal RV tachycardia should facilitate targeted therapy.     

Failure of the GORE HELEX atrial septal defect occluder to treat membranous VSDs in swine

Objective: We tested the suitability of the GORE HELEX septal occluder for closure of membranous ventricular septal defect in three Yucatan minipigs that had naturally‐occurring membranous ventricular septal defects. Methods: The animals were studied in the Gore Science Center Laboratory in Flagstaff, Arizona. In all of the device implantations, seating of the right disk along the right ventricular septum was problematic with resultant entanglement of one device in the chordae tendinae during attempted removal, implantation of one device onto the tricuspid valve papillary muscle and unlocking of one device occurring after implantation. Conclusions: A new occluder design appears to be needed to minimize the risk of disk entanglement with cardiac structures, particularly within the right ventricle. These studies did establish that the Yucatan mini swine are an acceptable and appropriate model for evaluating occluders intended for closure of membranous ventricular septal defects. © 2010 Wiley‐Liss, Inc.     

Endocardial cushion defects: an anatomical study of 54 specimens.

An anatomical study of 54 specimens with endocardial cushion defect is described. The material was divided into two groups, according to the morphology and attachments of the anterior component of the anteroseptal mitral leaflet. We suggest that there is no divided or undivided anterior common leaflet. There are always two anterior leaflets, a mitral and a tricuspid one, separated by a commissure; depending on the degree of straddling of the mitral component over the interventricular septum, this will protrude into the interventricular septum or into the anterior papillary muscle of the right ventricle. Thus, the commissure separating the mitral and the tricuspid components will lie over the interventricular septum or will be quite separate in the right ventricle. In the latter case the straddling mitral component gives the false appearance of an undivided anterior common leaflet. The septal tricuspid leaflet was found to be underdeveloped or absent but we were not able to find any clefts or divisions in it. We suggest that this leaflet derives solely from the division of the posteroinferior endocardial cushion into two halves, right and left. The left half later becomes the posterior component of the normal anteroseptal mitral leaflet. Associated anamalies are also reviewed.     

Ebstein's anomaly in adults: Doppler-echocardiographic evaluation

A systematic approach and segmental analysis are required for comprehensive assessment including both morphologic and functional abnormalities associated with Ebstein's anomaly. The essence of the disease is an apical displacement of both the septal and the posterior tricuspid leaflets, exceeding 20 mm or 8 mm/m2 in adults. As a consequence, the right heart consists of three components including the true right atrium, the functional right ventricle (RV) and an intervening zone that is anatomically ventricular but functionally right atrial (atrialized RV). The thin wall of the atrialized RV may result in an aneurysm between the anatomic tricuspid annulus and the apically displaced posterior leaflet. The annular attachment of the anterior leaflet is normal, which may be dysplastic and adherent to the RV wall. Tricuspid regurgitation is usually moderate to severe. Size, shape and function of the functional RV must be described. The paradoxical motion of the interventricular septum causes alterations in left ventricular geometry and function. An interatrial communication is frequently present. Echocardiography is the method of choice to diagnose Ebstein's anomaly on its own or in association with other heart defects.     

Congenital mitral valve anomalies in transposition of the great arteries

Seventy-nine specimens with transposition of the great arteries were reviewed. Among them were 45 with ventricular septal defect, including 6 with so-called "posterior aorta transposition". The morphology of the mitral valve was carefully studied. Mitral valve anomalies were found in 24 cases (30%). The anomalies involving the mitral valve were classified into 4 groups according to the different components of the valve: A) specimens with anomalies of the leaflets--2 cases with mitral cleft; B) those with anomalies of the commissures--1 case with a mitral gap; C) those with abnormalities of the chordae tendinae--2 cases of malattachment of the chordae tendinae to the ventricular septum and 2 with bridging chordae between the papillary muscles; and D) those with abnormalities of the papillary muscles--5 cases with a parachute valve, 10 with a "form fruste" of the parachute mitral valve (hypoplasia of one papillary muscle and short chordae tendinae) and 2 with abnormally placed papillary muscles, which reached the pulmonary annulus. In 14 cases, abnormalities of the tricuspid valve were also encountered, including 8 cases with a tricuspid gap and 6 with a malattachment of tricuspid chordae on the border of a ventricular septal defect. It can be concluded that mitral valve anomalies are not uncommon in transposition of the great arteries. This pathology must be carefully evaluated at the time of surgery, particularly in those patients for whom an anatomic correction is considered, for in those cases the left ventricle will be supplying the systemic circulation and therefore, a completely normal mitral valve will be required.(ABSTRACT TRUNCATED AT 250 WORDS)     

Congenital tricuspid insufficiency due to valvular dysplasia. Review of the literature in light of a case in a 40-year-old adult

Congenital tricuspid incompetence due to valvular dysplasia is a defect involving the leaflets (normally inserted on the ring) the cordae tendinae and papillary muscles of the tricuspid valve. It is a rare condition, usually diagnosed at open heart. A case of congenital tricuspid incompetence in a 40 year old adult is reported. Surgery indicated for resistant heart failure, confirmed the preoperative clinical, echocardiographic and haemodynamic diagnosis. The dysplasia comprised absence of cordae and papillary muscles on two thirds of the anterior leaflet. Valvular replacement with a bioprosthesis was carried out. 31 other reported cases were discovered on review of the literature since 1923. Two main groups of patients were individualised according to their clinical contexts and outcome: --The first group comprises the newborn and infants. Cyanosis, cardiomegaly and right ventricular failure in the neonatal period raised the differential diagnosis of Ebstein's anomaly and Uhl's disease. The outcome was fatal in several days to weeks. Autopsy confirmed the diagnosis. --The second group comprises patients who decompensate during adult life with right ventricular failure and degrees of tricuspid incompetence. The natural outcome with or without medical treatment may be prolonged, one such patient dying at the age of 53. Congenital tricuspid incompetence, diagnosed after elimination of other causes, was confirmed at operation. Complementary investigations: --Cardiac catheterisation showed tricuspid incompetence and its haemodynamic effects. --Echocardiography, in our case, showed dilatation of the right ventricle and pulsed Doppler echocardiography suggested tricuspid incompetence. The inability to record the anterior tricuspid leaflet, an unusual feature considering the right ventricular dilatation, contrasted with perfect definition of the septal leaflet. The absence of echocardiography in the other 31 reported cases does not allow any conclusions to be drawn as to the significances of this sign. --The tricuspid valve dysplasia was precisely defined on pathological examination: a) thickened valve, b) hypoplastic chordae and papillary muscles, c) incomplete separation between the leaflets and ventricular wall, d) focal agenesis of valvular tissues. --An associated pulmonary artery stenosis in the newborn may explain the severity of symptoms in this age group. This hypothesis, based only on pathological studies, cannot be confirmed. Treatment: --In the newborn, the rare surgical attempts at repair have all failed. --In the adult, surgery, indicated for heart failure resistant to all medical treatment, is as for other organic tricuspid incompetence, annuloplasty or valve replacement, by mechanical or bioprosthesis. Porcine bioprosthesis, as chosen in the case reported, has been used by some authors for 5-8 years with good results. Nevertheless, the longer-term outcome of this type of prosthesis is not yet known.     

Hypertrophic cardiomyopathy with midventricular and subvalvular obstruction in both heart ventricles

Typical (subaortic) and atypical (midventricular or apical) obstructions of both ventricles in HOCM are rare events. This combination could be demonstrated in a 21-year-old female patient by heart catheterization and angiocardiography. Simultaneous registration via 2 catheters in each ventricle showed pressure gradients with two steps in both ventricles: RV apical/RV midventricular 70-100 mm Hg, RV midventricular/subvalvular 25 mm Hg; LV apical/LV midventricular 70 mm Hg, LV midventricular/LV subvalvular 30 mm Hg; no valvular pressure gradients. Morphology of the obstructions is demonstrated by angiography: severe bilateral septal hypertrophy with midventricular systolic obstruction, systolic obstruction of right ventricular infundibulum by hypertrophy of the crista supraventricularis, systolic apical separation in the right ventricle; stenosis of the left ventricular outflow tract by SAM, systolic apical separation in the left ventricle by hypertrophy of papillary muscles.     

Traumatic wound of the heart: value of intraoperative colour Doppler flow imaging

A patient who sustained a traumatic ventricular septal defect from a stab wound is presented. Intraoperative echo-Doppler imaging provided an additional diagnosis of avulsion of anterior papillary muscle of the tricuspid valve prior to cardiotomy. It was concluded that intraoperative echo-Doppler imaging proves a useful guide for cardiac surgery following penetrating trauma.     

Tricuspid valve replacement using a cryopreserved mitral homograft. Surgical technique and initial results

BACKGROUND AND AIM OF THE STUDY: The surgical management of tricuspid valve endocarditis, especially in patients with positive serology for HIV and hepatitis C, is complicated by the inappropriateness of reconstruction and the late complications of mechanical prostheses and bioprostheses. Late results of mitral homograft replacement of the tricuspid valve have been satisfactory, but evidence of moderate and severe regurgitation appears in some patients. This report presents a novel approach to implantation of a mitral homograft in the tricuspid position. METHODS: Five patients with complications of native tricuspid valve endocarditis underwent mitral homograft replacement of the tricuspid valve, the homograft being implanted with the anterior leaflet orientated to the septum, the papillary muscles exteriorized and sutured to the right ventricular wall, the posteromedial muscle anteriorly, and the anterolateral muscle inferiorly. The annular attachment was reinforced with a rigid mitral annuloplasty ring in the anti-anatomical relationship. RESULTS: There was no early mortality. Among three patients available for echocardiographic assessment during the first year, regurgitation was absent in two cases, and trivial in one case. The latter patient died of a drug overdose after nine months. Two patients required insertion of atrioventricular pacemakers for complete heart block. CONCLUSION: This novel extension to the technique of mitral homograft replacement of the tricuspid valve for uncontrollable native endocarditis in drug abusers makes the procedure more technically feasible, and should be considered a procedure of choice.     

Injury to the tricuspid valve and membranous atrioventricular septum caused by huge calcified right ventricular myxoma: report of a case.

A 64-year-old female, admitted because of severe dyspnea on exertion and facial edema, showed echocardiographic findings of a large tumor in the right ventricle (RV). Echocardiography revealed a cardiac mass extending from the RV across the tricuspid valve into the right atrium, synchronized with the cardiac cycle, and severe tricuspid regurgitation was apparent. The mass was removed under cardiopulmonary bypass. It measured 7 x 5 x 5 cm with diffuse superficial calcification and arose from the posterior wall of the RV, just under the tricuspid valve ring, with a short pedicle. During the same procedure, after the successful excision of the tumor, small atrial and ventricular septal defects were found that had been caused by the tumor and these were closed directly. The tricuspid valve was repaired with valvuloplasty, chordoplasty and annuloplasty. The microscopic findings were of typical myxoma; however, a right ventricular myxoma protruding into the right atrium is exceedingly rare.     

Subxyphoid 2-dimensional echocardiographic identification of left ventricular papillary muscle anomalies in complete common atrioventricular canal

Mitral valve dysfunction is probably the major cause of operative mortality from total repair of complete common atrioventricular (AV) canal in infancy. The presence of a solitary left ventricular (LV) papillary muscle appears to be 1 anatomic factor influencing the success of mitral reconstruction because suturing of the cleft between the superior and inferior components of the anterior mitral leaflet creates a parachute mitral valve deformity, which may result in stenosis or in unduly high tension on the components of the repair. This study reports on (1) the 2-dimensional (2-D) echocardiographic appearance of the LV papillary muscle architecture in patients with complete common AV canal compared with that in normal subjects, and (2) the incidence of solitary LV papillary muscle in patients with complete common AV canal.

Two-dimensional echocardiography was performed in 31 infants with complete common AV canal, 14 normal infants, and 9 infants with a large ventricular septal defect not involving the AV canal region. Of 31 infants with complete common AV canal, 26 (80%) had 2 LV papillary muscles on 2-D echocardiography, 3 (10%) had 3 LV papillary muscles, and 3 (10%) had 1 LV papillary muscle. In patients with 2 LV papillary muscles, the anterolateral papillary muscle was displaced posteriorly compared with that in normal subjects and in patients with ventricular septal defect, whereas the posteromedial papillary muscle was in its normal location.

Among the 25 patients with complete common AV canal with 2 LV papillary muscles, there was 1 operative death. Among the 6 infants with complete common AV canal with LV papillary muscle anomalies, 5 underwent surgical repair with 4 early deaths.

Subxyphoid 2-D echocardiography is a useful technique for evaluating LV papillary muscle architecture in complete common AV canal and permits identification of patients who may be at higher risk for unsuccessful mitral reconstruction.     

Anatomic obstruction of the right ventricular outflow tract in transposition of the great arteries

In 126 hearts with transposition of the great arteries (TGA), morphologic features of the right ventricular (RV) outflow tract were analyzed. Distinct anatomic outflow tract obstruction was found in 15 of the 55 hearts with a ventricular septal defect (VSD) (27%): 12 had a perimembranous defect (predominantly extending into the infundibulum), 2 had an inlet, and 1 had an infundibular defect. In 12 hearts, outflow tract obstruction was caused by anterior displacement of infundibular septum and ventriculoinfundibular fold; in 3 hearts, it was caused by bulging of the trabecula septomarginalis or ventriculoinfundibular fold, or both. Of 71 hearts with an intact ventricular septum, only 2 (3%) had RV outflow tract obstruction: 1 had a trabecula in front of the aortic ostium and in the other an aberrant hypertrophic muscle bundle crossed the RV cavity, obstructing the entrance to the infundibulum. Associated malformations included aortic arch malformations (6 cases) and tricuspid valve anomalies (6 cases). Thus, anatomic RV outflow tract obstruction may constitute a complicating factor in TGA, notably in cases with VSD. A systemic RV blood pressure may trigger hypertrophy, resulting in progression of the obstruction; establishing normal RV pressure by a “switch” procedure might prevent this progression.     

Straddling mitral and tricuspid valves: Morphologic differences and developmental backgrounds

The anatomy of 25 hearts with a straddling mitral or tricuspid valve, or both, is described. Malalignment of atrial and ventricular septa is an essential feature of a straddling tricuspid valve, creating an inlet septal defect. Across this defect, the tricuspid valve straddles into the opposite (left ventricular) chamber, where it is separated from the mitral valve by a posterior muscular ridge, the posteromedial muscle. A straddling mitral valve requires an infundibular septal defect, predominantly of the malalignment type, in which the anterior part of the ventricular septum deviates to the left of the infundibular septum. The mitral valve straddles into the opposite (right ventricular) chamber, anterior to the trabecula septomarginalis.

From normal developmental stages, it is concluded that valve formation takes place only after completion of ventricular septation. Any malformation of the valves is therefore considered to be superimposed on a primary malformation of the septum. The ventricular septum itself develops from three different components. Malseptation in the inlet portion of the embryonic heart may lead to the characteristic septal malformation seen in straddling tricuspid valve. Malseptation in the outlet portion may lead to the septal malformation that characterizes straddling mitral valve.     

Rupture of a papillary muscle of the tricuspid valve in primary pulmonary hypertension

Rupture of a papillary muscle of the tricuspid valve is a rare occurrence, and nontraumatic rupture is still rarer. We describe a 26-year-old male with primary pulmonary hypertension presenting with severe dyspnea and paroxysmal nocturnal dyspnea following spontaneous rupture of the septal papillary muscle of the tricuspid valve. The clinical diagnosis was confirmed at autopsy.     

Right ventricular function in patients with first inferior myocardial infarction: assessment by tricuspid annular motion and tricuspid annular velocity

BACKGROUND: Unlike left ventricular function, right ventricular (RV) function has not been widely studied after a myocardial infarction (MI). The current study describes RV function determined by tricuspid annular motion and tricuspid annular velocity after MI. METHODS AND RESULTS: Thirty-eight patients with a first acute inferior MI were prospectively compared with 33 patients with a first anterior MI and 24 age-matched healthy individuals. Association of RV infarction in inferior MI was defined as the presence of >/=1-mm ST-segment elevation at the right precordial lead, V(4)R, of the electrocardiograms. From the echocardiographic apical 4-chamber views, the systolic motion of the tricuspid annulus was recorded at the RV free wall with the use of 2-dimensional guided M-mode recordings. Peak systolic and peak early and late diastolic velocities of the tricuspid annulus at the RV free wall also were recorded with the use of pulsed-wave Doppler tissue imaging. The tricuspid annular motion was reduced in inferior MI compared with that in healthy individuals (20.5 and 25 mm, P <.001). The peak systolic velocity of the tricuspid annulus was significantly reduced in inferior MI compared with that in healthy individuals (12 vs 14.5 cm/s, P <.001) and patients with anterior MI (12 and 14.5 cm/s, P <.001). Patients with inferior MI were divided into 2 subgroups: those with and those without electrocardiographic signs of RV infarction. The tricuspid annular motion was significantly lower in patients with RV infarction than in patients without RV infarction (17 and 22.7 mm, P <.001). In addition, compared with patients without electrocardiographic signs of RV infarction, patients with RV infarction also had a significantly decreased peak systolic tricuspid annular velocity (13.3 and 10.3 cm/s, P <.001) and peak early diastolic velocity (13 and 8.2 cm/s, P <.001). CONCLUSIONS: These results suggest that tricuspid annular motion and tricuspid annular velocity can be used to assess RV function in association with inferior MI.     

Visualization of Ebstein's anomaly of the tricuspid valve by two-dimensional and standard echocardiography.

Seven patients with Ebstein's anomaly were studied by two-dimensional echocardiography, with and without stop-action technique, and by standard echocardiography. Sagittal two-dimensional echocardiograms visualized a small functional right ventricle and a large atrialized right ventricle. These two parts of the chamber were separated by the anterior tricuspid leaflet and its chordae tendineae. The echocardiograms corresponded to the findings of the right ventriculogram. In horizontal two-dimensional echocardiograms a huge anterior tricuspid leaflet, atrialized right ventricle, and a displaced septal tricuspid leaflet, intervening between the functional right ventricle and the sinus portion of the functional right ventricle, were visualized. The origin of the septal tricuspid leaflet was clearly shown to be abnormal in five cases. The left ventricle was small with distinct clockwise rotation of the interventricular septum. Two-dimensional echocardiography provided information useful in evaluation of the functions of the right ventricle and the tricuspid valve and determination of what surgical procedure to follow.     

Morphology and classification of complete atrioventricular defects

Anatomical studies were made on 70 necropsied hearts with atrioventricular defects from patients with situs solitus and atrioventricular concordance, all having a common atrioventricular orifice. The arterial connections were concordant in 68 and were double outlet right ventricle in two; cases with arterial discordance (transposition) or single outlet of the heart were excluded. It proved possible to subdivide the hearts, depending on the morphology of the valve leaflets. Five leaflets were distinguished by the commissural pattern and their insertion to major papillary muscles. They were a posterior bridging leaflet, right and left lateral leaflets, and right and left anterior leaflets. Subdivision was made on the basis of the disposition of the anterior leaflets. In six hearts the left anterior leaflet was committed to the left ventricle and the right anterior leaflet to the right ventricle, the commissure between them being on the crest of the ventricular septum. In 39 hearts there was minimal bridging of the left anterior leaflet so that it extended between the anterior papillary muscle of the left ventricle and the medial papillary complex of the right ventricle. In eight hearts the right margin of the left anterior leaflet was attached to an apical papillary muscle, while in 17 hearts it was attached to the anterolateral papillary muscle of the right ventricle. As the bridging of the left anterior leaflet increased, so the size of the right anterior leaflet decreased, but in all hearts both leaflets were identified. These findings were compared with previous classifications of complete atrioventricular defects.