Tricuspid Anulus Research Articles

Superior vena cava flow and tricuspid anular motion after cardioversion of atrial fibrillation, and role of right atrial relaxation on systolic venous return

To determine whether atrial relaxation or systolic descent of the tricuspid anulus is the predominant factor determining systolic venous return, 22 patients with atrial fibrillation were studied. Venous return (i.e., superior vena cava (SVC) flow) was measured using pulsed Doppler echocardiography. Systolic descent of the tricuspid anulus (i.e., total excursion of tricuspid anulus during systole) was also measured using echocardiography. Serial examinations were performed before and after cardioversion of atrial fibrillation in 15 patients. In 11 patients, both the total excursion of the tricuspid anulus and SVC flow were examined in relation to the ratio of the preceding to the pre-preceding RR interval ( R2 R1 ). Systolic forward flow of SVC increased as the ratio of late diastolic to total excursion of the trieuspid anulus (i.e., right atrial systolic function) increased. It correlated significantly with the ratio of late diastolic to total excursion of the tricuspid anulus but not with total excursion. Total excursion of the tricuspid anulus correlated significantly with R2 R1 , but systolic forward flow of SVC did not. These results indicate that atrial relaxation rather than systolic descent of the tricuspid anulus was the predominant factor determining systolic forward flow in the SVC.

Intermediate septal accessory pathways: Electrocardiographic characteristics, electrophysiologic observations and their surgical implications

Intermediate septal accessory pathways are located in close proximity to the atrioventricular (AV) node and His bundle, have unique features that distinguish them from typical anterior and posterior accessory pathways and have been associated with a high risk for unsuccessful pathway division and the production of complete AV block after surgery. Between July 1986 and May 1990, 4 of 70 patients (3 men and 1 woman; mean age 33 ± 13 years) undergoing surgery for accessory pathway division were found to have an intermediate septal accessory pathway. The presenting arrhythmia was atrial fibrillation with rapid anterograde conduction over the accessory pathway in two patients and recurrent orthodromic reciprocating tachycardia in two patients.In all patients, the delta wave on the electrocardiogram (ECG) was inversed in lead V1, but two patterns of delta wave configuration were observed. In three patients (type 1 intermediate septal accessory pathway), the delta wave was upright in lead II, inverted in lead III and isoelectric in lead aVF; the transition from a negative to an upright delta wave occurred in lead V2. The fourth patient exhibited a different delta wave pattern (type 2 intermediate septal accessory pathway). The delta wave was upright in each of leads II, III and aVF; the transition from a negative to an upright delta wave occurred at lead V3.Intraoperative electrophysiologic study localized the atrial insertion of type 1 pathways to the midpoint of Koch's triangle close to the AV node. In the one patient with a type 1 pathway in which both anterograde and retrograde accessory pathway conduction was present, preoperative catheter mapping demonstrated that earliest retrograde atrial activation occurred near the foramen ovale. Intraoperative mapping during anterograde conduction over the type 1 pathway demonstrated earliest epicardial ventricular activation to occur simultaneously at the crux and the base of the aorta. The atrial insertion of the type 2 intermediate septal accessory pathway was localized to the apex of Koch's triangle in close proximity to the bundle of His. Preoperative catheter mapping revealed that earliest retrograde atrial activation occurred on the His bundle electrogram. Intraoperative mapping during anterograde conduction over the type 2 pathway demonstrated that earliest epicardial ventricular activation occurred anteriorly at the base of the aorta.Intraoperative ablation of the intermediate septal accessory pathway was accomplished by cooling the endocardium at the site of pathway insertion on the atrial side of the tricuspid anulus with a 5 mm cryoprobe. Patients with a type 1 intermediate septal accessory pathway had preservation of AV conduction, but the patient with the type 2 pathway did not and required permanent pacing. At late follow-up study, no patient has had return of intermediate septal accessory pathway conduction. Distinguishing an intermediate septal accessory pathway close to the AV node (type 1) from one close to the His bundle (type 2) is useful to predict both surgical success and success without the production of permanent complete AV block.

Catheter modification of the atrioventricular junction with radiofrequency energy for control of atrioventricular nodal reentry tachycardia.

The utility of transcatheter application of radiofrequency energy to eliminate atrioventricular nodal reentrant tachycardia (AVNRT) was investigated. Thirty-nine patients (mean age, 53 +/- 20 years; range 14-86 years) with medically refractory AVNRT underwent perinodal ablation with radiofrequency energy. A custom-designed 6F catheter with a large (3-mm-long) distal electrode and interelectrode pacing of 2 mm was used in the majority of cases. The catheter used for ablation was initially positioned across the tricuspid anulus to obtain the largest His bundle electrogram, then withdrawn to obtain the largest atrial:ventricular electrogram ratio, with a small His bundle electrogram (less than or equal to 100 microV). Each application of radiofrequency energy (350-550 kHz, 16.2 +/- 5.2 W) was stopped after 60 seconds or if PR prolongation or an impedance rise was noted. The endpoints of the procedure were persistent modification of atrioventricular nodal conduction (either first-degree atrioventricular block or impairment of ventriculoatrial conduction) and noninducibility of AVNRT before and during isoproterenol administration. Radiofrequency energy was applied a mean of 6.8 +/- 3.5 times per session. After a mean follow-up of 8 +/- 3.0 months, 32 of the 39 patients (82%) have been free of AVNRT, and did not have high grade AV block. Three patients (8%) developed complete atrioventricular block and had pacemakers implanted. Two patients had unsuccessful initial procedures, and two patients had initially successful ablations but had recurrences of tachycardia 4-6 weeks later. Elimination of AVNRT appeared to be due to effects on the retrograde fast pathway in most patients. Radiofrequency ablation of the perinodal right atrium appears to be safe and effective for treatment of typical AVNRT:

Radiofrequency catheter ablation of Mahaim fibers at the lateral tricuspid anulus

Radiofrequency catheter ablation of Mahaim fibers at the lateral tricuspid anulus

Localization and radiofrequency catheter ablation of accessory AV pathways in Wolff-Parkinson-White syndrome.

Direct catheter recordings of accessory pathway activation were utilized to localize accessory atrioventricular (AV) pathways for radiofrequency catheter ablation in 187 patients with Wolff-ParkinsonWhite syndrome. Closely spaced bipolar catheter electrodes (1.5-2.5 mm center-to-center) were positioned perpendicular to the mitral anulus (orthogonal electrodes placed circumferentially around the catheter) and the tricuspid anulus (conventional ring electrodes), and recordings were obtained at low gain « 1 cm/mV). The small recording range of the close bipolar electrodes minimized the recording of distant atrial or ventricular potentials occurring simultaneously with accessory pathway activation and enabled differentiation of accessory pathway activation potentials from local atrial and ventricular potentials. For ablation, a special large tip electrode (7F, 4 mm long, 27 mrrr' surface area) was positioned against the mitral or tricuspid anulus at a site guided by direct recordings of accessory pathway activation. The large tip electrode was positioned either beneath or above the leaflet, and radiofrequency current (power approximately 30 watts) was delivered for approximately 45 seconds to the large tip electrode using a large skin lead for the return electrode .

Doppler assessment of right ventricular filling in a normal population. Comparison with left ventricular filling dynamics.

To examine whether alterations in right ventricular filling dynamics occur with increasing age and to compare right and left ventricular filling in normal subjects, pulsed Doppler echocardiographic studies were performed at the tricuspid and mitral anuli in 50 normal volunteers (23 males and 27 females) with an age range of 5-66 years. An age-related decrease in peak early filling velocity, increase in peak late velocity, and augmentation in the late/early ratio of peak velocities at the tricuspid anulus were observed (r = -0.68, 0.63, and 0.84, respectively). Significant correlations were also found between age and first third, first half, and atrial filling fractions (r = -0.60, -0.72, and 0.69, respectively). Weaker relations were observed between heart rate and Doppler-derived diastolic parameters (r = 0.18-0.54). Right ventricular filling indexes related significantly to those of the left ventricle (r = 0.58-0.88), the best being for the late/early ratio of peak velocities. With inspiration, an increase in early and late right ventricular filling occurred, whereas a reduction in filling occurred in the left ventricle. Thus, careful consideration for age, heart rate, and respiration is necessary in examining the effect of disease states or therapeutics on the filling dynamics of either the right or left ventricle.

Catheter ablation of Mahaim fibers with preservation of atrioventricular nodal conduction.

Three patients with refractory preexcited tachycardia implicating Mahaim fibers underwent attempted catheter ablation of the accessory pathway. In the absence of demonstrable retrograde conduction in Mahaim fibers, we located the accessory pathway ventricular insertion site using the criteria of concordance between paced and spontaneous QRS morphologies during pace-mapping and earliest onset of local electrogram relative to surface preexcited QRS. At this site, a QS-like pattern of unfiltered unipolar electrograms with steep downstroke was recorded. The optimal site appeared radiologically at the right ventricular anterior wall or the adjacent septum, 2-4 cm from the tricuspid anulus. Three to six 160-J shocks were delivered at this site using an anterior chest wall plate as anode. After fulguration, conduction through the Mahaim tract was absent. A right bundle branch block persisted in two patients. All patients remained free of preexcited tachycardia during 12-16 months of follow-up. Postablation electrophysiological assessment showed no preexcitation in any patient. No reciprocating tachycardia was inducible, even during isoproterenol infusion. Atrioventricular nodal conduction parameters were unchanged from baseline study. Catheter ablation of Mahaim fibers is an effective alternative method for the treatment of tachycardias that include the accessory pathway in the circuit.

Effects of sample volume location, imaging view, heart rate and age on tricuspid velocimetry in normal subjects

The effects of imaging view and sample volume location on tricuspid velocimetry and of heart rate and aging on mitral and tricuspid inflow were evaluated in 41 normal subjects aged 20 to 76 years. Pulsed Doppler recordings were obtained in the parasternal short-axis, right ventricular inflow and apical 4-chamber views at the level of the tricuspid and mitral anuli and 1 cm caudad and 1 cm cephalad to the tricuspid anulus in the 4-chamber apical view. The right ventricular filling pattern was not affected by imaging view. However, placement of the sample volume 1 cm cephalad resulted in a 16% reduction (p < 0.01) in early velocity with a 9% increase in atrial filling fraction. Conversely, late velocity was 11% higher (p < 0.05) at the anular level versus the other locations. Right and left ventricular filling velocities were modestly related (r = 0.50 to 0.63). Relations between age and tricuspid late velocity, velocity ratio and atrial filing fraction were weaker (r = 0.34 to 0.47; all p < 0.05) than those between age and mitral variables (r = 0.59 to 0.74. Also, aging had a greater effect on mitral than tricuspid late velocity (i.e., a steeper slope; p < 0.01). Tricuspid late velocity and atrial filling fraction were each modestly inversely related to RR interval (r = −0.48, r = −0.54; p < 0.01). Thus, tricuspid velocity is affected by sample volume location, aging and heart rate, but not imaging view. Sample volume location, heart rate and age should be considered when evaluating right ventricular inflow parameters.

Significance of laminar systolic regurgitant flow in patients with tricuspid regurgitation: A combined pulsed-wave, continuous-wave Doppler and two-dimensional echocardiographic study

To define the significance of laminar systolic tricuspid regurgitant (TR) flow, pulsed-wave and continuous-wave Doppler (PWD, CWD), and two-dimensional and M-mode echocardiography (2-DE, M-mode) were performed in 68 patients with TR, which included five patients with tricuspid valvectomy. The pattern of TR flow (laminar versus turbulent), TR severity (the distance that the regurgitant flow extended into the right atrium [1+ to 4+ as measured by PWD]), the peak flow velocity of TR by CWD, the presence or absence and the amount of systolic tricuspid cusp separation by 2-DE, and the dimension of the right ventricle and the inferior vena cava by M-mode, were assessed. A laminar pattern of TR flow in systole was obtained in 21 patients, five of whom had undergone tricuspid valvectomy. Fourteen of 21 had visible tricuspid cusp separation in systole on 2-DE; of the seven who had no visible tricuspid cusp separation during systole, five had undergone tricuspid valvectomy. All 47 patients with a turbulent pattern of TR flow had no visible systolic tricuspid cusp separation. Severe 4+ TR was present in 14 of 21 (67%) patients with laminar TR flow and in 4 of 47 (9%) patients with turbulent TR flow (p less than 0.001). The peak flow velocity of TR in patients with laminar TR flow (2.0 +/- 0.7 m/sec) was lower (p less than 0.001) than in those with turbulent TR flow (3.1 +/- 0.7 m/sec).(ABSTRACT TRUNCATED AT 250 WORDS)

Improved guides to tricuspid valve repair: Two-dimensional echocardiographic analysis of tricuspid anulus function and color flow imaging of severity of tricuspid regurgitation

Improved guides to tricuspid valve repair: Two-dimensional echocardiographic analysis of tricuspid anulus function and color flow imaging of severity of tricuspid regurgitation

Can two-dimensional echocardiography and Doppler color flow mapping identify the need for tricuspid valve repair?

Tricuspid regurgitation severity was assessed preoperatively with Doppler color flow mapping and these assessments were compared with surgical findings in 90 patients undergoing mitral or aortic valve replacement, or both. Group I (n = 52) required tricuspid valve annuloplasty because tricuspid regurgitation was judged intraoperatively to be severe; in Group II (n = 38), tricuspid valve annuloplasty was not performed because tricuspid regurgitation was judged intraoperatively not to be severe. With use of the apical four chamber and parasternal short-axis imaging planes, the severity of tricuspid regurgitation by Doppler color flow mapping was assessed by comparing the maximal area of tricuspid regurgitant signals with the right atrial area taken in the same frame in which the maximal tricuspid regurgitant signals were noted. This ratio was found to be ≥34% (mean 50.2 ± 11.8%) in 50 (96%) of 52 patients in Group I and <34% (mean 27.5 ± 6.9%) in 36 (95%) of 38 patients in Group II (p < 0.001).The maximal diastolic tricuspid anulus diameter measured with the same two-dimensional imaging planes was ≥21 mm/m2body surface area (mean 26.7 ± 5.2 mm/m2) in 46 patients (88%) in Group I and <21 mm/m2(mean 17.8 ± 2.5 mm/m2) in 36 patients (95%) in Group II (p < 0.001). The percent shortening of the tricuspid anulus diameter was <25% (mean 17.2 ± 6.5%) in 47 patients (90%) in Group I and was ≥25% (mean 31.2 ± 5.9%) in 37 patients (97%) (p < 0.001) in Group II. The two patients groups could not be distinguished with use of two-dimensional right ventricular ejection fraction.Both Doppler color flow mapping and two-dimensional echocardiography are useful in identifying patients who would require tricuspid valve repair for severe tricuspid regurgitation during mitral or aortic valve replacement, or both.

Contrast-enhanced magnetic resonance imaging of cardiac tumors in children

Although the median survival of unoperated patients with ASD is 36 years,3 survival beyond age 70 is not uncommon.4 Associated tricuspid insufficiency is probably the result of right ventricular enlargement and dilation of the tricuspid anulus. The direction of the shunt in an ASD is ultimately a function of ventricular compliance, and the degree of left-to-right shunt in this patient was probably not significant until aortic stenosis worsened to the extent that left ventricular compliance declined. Acquired aortic stenosis in association with ASD has not previously been reported. Operative mortality for ASD repair in patients over 60 is about 6% ,4, 5 and subsequent survival is equal with that of age-matched controls.6 Advanced age alone does not correlate with a poor surgical outcome, and this patient exemplifies the remarkable improvement that can be observed.

Prevalence of multivalvular regurgitation in athletes

To assess the effects of exercise training on the prevalence of valvular regurgitation, 2-dimensional echocardiography and Doppler flow mapping were performed in 45 athletes and 26 sedentary control subjects of similar age and sex. Mitral, tricuspid, aortic and pulmonic regurgitations were sought in all possible views and mitral and tricuspid flow velocities were recorded. Mitral and tricuspid anulus diameters and the maximal areas of regurgitant flow were planimetered. Regurgitation of at least one of the cardiac valves was found in 91% of athletes but in only 38% of control subjects (p < 0.001). Mitral and tricuspid regurgitation occurred more commonly in athletes than in control subjects (mitral 69 vs 27%; tricuspid 76 vs 15%). The prevalence of aortic and pulmonic regurgitation was similar. Although athletes and sedentary normal subjects differed with respect to heart rate, right and left ventricular filling patterns and tricuspid and mitral anulus diameters, none of these variables was related to the presence or severity of regurgitation. Thus, exercise training is associated with an increased prevalence of mitral and tricuspid regurgitation and altered ventricular inflow patterns. The mechanism of these findings is unclear. Multivalvular regurgitation is common in athletes and does not imply structural valvular abnormalities.

Real-time and simultaneous measurement of tricuspid orifice and tricuspid anulus areas in anesthetized dogs.

Tricuspid valve orifice and tricuspid valve anulus areas were measured simultaneously in the anesthetized dog with a newly developed area-measuring system based on electromagnetic induction. This system permitted real-time monitoring of the area enclosed by the edges of valve leaflets and by the juncture of the valve leaflet and the cardiac wall in situ, without artificial constraint to the valve motion. Right atrial and right ventricular pressures were measured with two catheter-tipped micromanometers. During control state, tricuspid valve orifice area (TOA) increased up to its peak [1.38 +/- 0.26 cm2 (mean +/- SD)] coincidently with either atrial systole or rapid ventricular filling. Atrial contraction evoked distinct presystolic tricuspid anulus narrowing with concomitant slow TOA reduction. This slow TOA reduction began 30.0 +/- 16.1 msec before systolic atrioventricular pressure crossover, and the following rapid TOA decrease was completed 38.7 +/- 12.2 msec after systolic atrioventricular pressure crossover. TOA began to increase 48.4 +/- 30.4 msec before diastolic atrioventricular pressure crossover at the end portion of the isovolumic relaxation phase, opposing residual transvalvular pressure gradient (3.33 +/- 1.79 mm Hg). The slow presystolic TOA decrease was considered to be a reflection of the presystolic anulus narrowing caused by atrial systole. An isolated atrial contraction induced by administering 1 mg acetylcholine chloride into the atrioventricular node artery or by vagus nerve stimulation could produce complete valve closure. Even in an isolated atrial contraction, the inflection point that marks the boundary between slow "atriogenic" closure presumably due to anulus narrowing and rapid closure presumably due to hemodynamic force was easily identified.

Oxygen uptake and heart rate during cross-country skiing and track walking after myocardial infarction

stenosis, but also because of the tricuspid regurgitation. Although mitral valvuloplasty would have been a reasonable alternative therapy, the patient was referred for mitral and tricuspid surgery and subsequently did well. The pathologic findings that resulted from examination of the tricuspid valve confirmed that the tricuspid valvuloplasty procedure reduced the severity of the tricuspid stenosis. The fractures occurred within the commissures and not in the valve leaflets themselves. These findings, and those of the in vitro balloon valvuloplasty, indicate that the mechanism of catheter balloon valvuloplasty of stenotic tricuspid valves is similar to that reported for stenotic mitral valves, i.e., commissural splitting.5 Although the balloon size for this procedure was chosen because of the measurement of the tricuspid anulus at echocardiography, about 40 mm, and from the in vitro results from a similar tricuspid valve, it is possible that use of slightly smaller balloons may have produced less regurgitation. The development of right bundle branch block was presumably due to the stretching of the tricuspid valve anulus and again lends support to the possibility that the balloons were oversized for this particular patient. In conclusion, although percutaneous tricuspid balloon valvuloplasty can be performed for organic tricuspid stenosis, there is a chance that tricuspid regurgitation will result as it did in this patient, particularly if there is any preexisting tricuspid regurgitation. Pathologic findings indicate that fracture of the fused commissures of stenotic tricuspid valves can be achieved by balloon dilatation.

Serial Echocardiographic Findings Early After Heart Transplantation: Evidence for Reversible Right Ventricular Dysfunction and Myocardial Edema

Serial M-mode and two-dimensional echocardiograms were performed on 10 patients at 1 week, 1 month, and 3 months after heart transplantation to determine early structural and functional changes in the allograft. Standard M-mode echocardiographic measurements of at least five cardiac cycles were averaged. Right ventricular size and function were assessed by mid-ventricular diameter and the right ventricular apex to lateral tricuspid anulus shortening fraction, respectively, on the two-dimensional apical four-chamber view. There were no consistent differences in left ventricular end-diastolic dimension or fractional shortening between study periods. Left ventricular posterior wall thickness decreased from 15 +/- 2 to 11 +/- 1 mm (p = 0.001), and septal thickness decreased from 15 +/- 2 to 12 +/- 2 mm (p = 0.0006) between the 1-week and 3-month studies. Right ventricular cross-sectional dimension increased from 34 +/- 6 to 39 +/- 6 mm (p = 0.047), and right ventricular fractional shortening increased from 13% +/- 3% to 21% +/- 5% (p = 0.0051) between the 1-week and 3-month studies. There were no correlations between any of the above changes and rejection episodes. There was a weak correlation (r = 0.53) between ischemic time and change in posterior wall thickness. Right ventricular dysfunction and increased left ventricular wall thickness presumably caused by interstitial edema appear to be normal findings early after heart transplantation.

Echocardiographic Assessment of Neonates With Pulmonary Atresia and Intact Ventricular Septum

In this prospective study, 27 consecutive neonates suspected to be suffering from pulmonary atresia and intact ventricular septum underwent detailed two-dimensional echocardiographic examination before cardiac catheterization. Of the 27 neonates 25 had pulmonary atresia and intact ventricular septum and the remaining 2 had "functional pulmonary atresia" secondary to severe Ebstein's anomaly of the tricuspid valve.In all 25 neonates with pulmonary atresia and intact ventricular septum, the diagnosis and right ventricular morphology based on the tripartite approach were correctly established by echocardiography. The associated Ebstein's anomaly in two babies with pulmonary atresia and intact ventricular septum was also correctly identified by echocardiography. Among the five babies who had a sinUSOidal-coronary artery communication, echocardiography demonstrated the fistula in one and provided clues for its diagnosis in two others. In the 25 neonates with pulmonary atresia and intact ventricular septum, the echocardiographic dimensions of their tricuspid anulus, right ventricular infundibulum and main pulmonary artery correlated well with the angiocardiographic measurements (r>0.8).The results of this study suggest that, in the management of neonates with pulmonary atresia and intact ventricular septum, preoperative evaluation by echocardiography is usually sufficient and cardiac catheterization should be reserved for selected cases.

The transponder system: A new method of precise catheter placement in the right atrium under echocardiographic guidance

The ability to localize catheters within the heart has gained importance with the use of percutaneous catheter ablation and the transseptal approach for valvuloplasty. A prototype interactive transponder catheter system, specifically designed to mark the catheter tip for echocardiographic visualization, was used to place catheters at the trieuspid anulus and the fossa ovalis in anesthetized dogs. Catheter tip location was marked by lesions produced by radiofrequency energy delivered at the dinal catheter electrode. At autopsy, the center of the radofrequency-induced lesion was located 2.8 ± 0.7 mm from the edge of the lateral tricuspid anulus and 3.5 ± 3.1 mm from the center of the fossa ovalis. The transponder catheter system offers the ability to precisely position catheters in the right atrium under echocardiographic guidance.

The necessity for tricuspid valve repair can be determined intraoperatively by two-dimensional echocardiography

Residual significant tricuspid regurgitation after mitral valve operations may significantly increase postoperative morbidity and mortality. However, routine techniques to detect tricuspid regurgitation preoperatively and intraoperatively are inaccurate. Two-dimensional echocardiography was performed intraoperatively to assess its ability to evaluate and quantify the severity of tricuspid regurgitation. In 50 patients who underwent cardiac operations, 5 ml of dextrose or saline was injected into the right ventricle to generate echogenic "contrast." In patients with tricuspid regurgitation, there was systolic reflux of contrast into the right atrium, which could be semiquantified on a scale of 0 to 4+. Besides correlating well with preoperative Doppler studies for the presence or absence of tricuspid regurgitation in 18 patients (sensitivity = 0.90, specificity = 1.00), the intraoperative contrast method could quantify the severity of reflux. The 50 patients were divided into two groups on the basis of severity of tricuspid regurgitation as assessed by intraoperative two-dimensional contrast echocardiography. Group I (36 patients) had no or mild (0-2+) regurgitation, and Group II (14 patients) had moderate to severe (3-4+) tricuspid regurgitation. Patients with significant tricuspid regurgitation (Group II) had greater intraoperative preprocedure and postprocedure systolic and diastolic pulmonary pressures. Additionally, the systolic tricuspid anulus length, as measured in the intraoperative right ventricular inflow view, correlated better with severity of tricuspid regurgitation (r = 0.76, p = 0.005) than mean pulmonary pressure (r = 0.52, p less than 0.01). Therefore, intraoperative contrast two-dimensional echocardiography can accurately assess the relative severity of tricuspid regurgitation. Importantly, intraoperative measurement of tricuspid anulus diameter could predict the presence of significant echocardiographic tricuspid regurgitation before as well as immediately after the operation. Two-dimensional echocardiography may be an important intraoperative method both for evaluating the presence and severity of residual tricuspid regurgitation immediately after left heart operations as well as for determining which patients should undergo tricuspid valve repair.

Effects of catheter-delivered electrical discharges near the tricuspid anulus in dogs

The possibility of using electrical discharges to ablate right free wall accessory pathways by delivering a series of catheter shocks near the tricuspid anulus was assessed in a canine model. Before the shock, the amplitudes of the atrial and ventricular electrograms recorded from the distal electrodes were compared (A/V ratio), and the atrial pacing threshold was determined. To assess effects on function and arrhythmogenicity, right heart pressures were measured and programmed ventricular stimulation was performed before the shock and prior to sacrifice 7 to 10 days after the shock. Nine dogs received a total of 24 discharges at varying energies (50 to 400 J). Nonsustained ventricular tachycardia occurred with 13 shocks (62%) and transient atrioventricular block with 9 shocks (43%). There was no worsening in cardiac or valvular function as determined by right heart pressure measurements or right ventriculography. Programmed ventricular stimulation performed before the shocks and repeated before sacrifice failed to induce ventricular arrhythmias. The endocardial lesion produced by the shock was roughly circular and its area correlated with both the magnitude of the shock as well as the atrial pacing threshold. Transmural necrosis always occurred at the anulus when the A/V ratio was between 1.00 and 1.50 and preshock atrial pacing threshold suggested adequate wall contact (less than 1.5 mA). There was mild inflammation of the adventitia of the right coronary artery near two discharge sites (both 200 J) and inflammation of the media near one discharge site (400 J); no intimal involvement was seen.(ABSTRACT TRUNCATED AT 250 WORDS)