Impact of transesophageal electrophysiologic study to elucidate the mechanism of arrhythmia on children with supraventricular tachycardia and no preexcitation

An electrophysiologic study (EPS) of children and teenagers with paroxysmal supraventricular tachycardia (SVT) and normal electrocardiography (ECG) in sinus rhythm was evaluated. Generally, EPS is performed only before paroxysmal SVT ablation in these patients. In this study, 140 patients (mean age, 15 ± 3 years) with normal ECG in sinus rhythm were studied for SVT by a transesophageal route in baseline state and after isoproterenol. Idiopathic left or right ventricular tachycardia was diagnosed in four patients (3 %). Anterograde conduction over an atrioventricular (AV) left lateral (n = 10) or septal (n = 9) accessory pathway (AP) was noted in 19 patients (13.5 %) at atrial pacing. Orthodromic AV reentrant tachycardia (AVRT) was induced in these children. Five of the patients had a high rate conducted over AP (>240 bpm in baseline state or >290 bpm after isoproterenol). Two of the patients (a 10-year-old girl with well-tolerated SVT and a 17-year-old with syncope-related SVT) had the criteria for a malignant form with the induction of atrial fibrillation conducted over AP at a rate exceeding 290 bpm in baseline state. Of the 140 patients, 74 (53 %) had typical AV node reentrant tachycardia (AVNRT), nine had atypical AVNRT (6 %), 1 had atrial tachycardia (0.7 %), and 33 (23.5 %) had AVRT related to a concealed AP with only retrograde conduction. Electrophysiologic study is recommended for children with paroxysmal SVT and normal ECG in sinus rhythm. The data are helpful for guiding the treatment. Ventricular tachycardia or atrial tachycardia can be misdiagnosed. Masked preexcitation syndrome with anterograde conduction through AP was present in 13.5 % of the patients, and 1.4 % had a malignant preexcitation syndrome.

[Complications of prostaglandin E1 treatment of congenital heart disease in paediatric medical intensive care]

The authors undertook a retrospective study of the modes of prescription, the tolerance and efficacy of prostaglandin E1 in 62 consecutive neonates with congenital heart disease (average Age 1.6 days: 35 boys: weight: 3.1 +/- 0.6 Kg) admitted to the paediatric intensive care unit of Nancy University Hospital between 1998 and 2002. The infusion time and cumulative dosage were 134 +/- 112 (6-480) hours and 111 +/- 94 (4-396) microg/Kg respectively. The side effects that were observed were: Apnoea (19%), abdominal distension (16%), bradycardia (13%), enterocolitis (6.5%), hypotension (6.5%), vomiting (5%), fever (1.6%) and skin rash (1.6%). Gastrointestinal disturbances are associated with a low body weight (p<0.04), to prolonged treatment (p<0.02) with no influence of initial or cumulative dosages (P=NS), with respiratory assistance (p<0.03) and longer hospital stay (p<0.01). Hypotension was commoner in cases of poor neonatal adaptation. Mortality was correlated with severe initial acidosis (p<0.02), a low Apgar score, the initial prolonged use of high doses of prostaglandin (p<0.04), and the presence of severe valvular aortic stenosis or hypoplasia of the left heart (p<0.002). The authors conclude that treatment with prostaglandin is effective in the majority of cases despite the use of low maintenance doses (0.01 microg/Kg/min). Gastrointestinal disturbances favourised by the perinatal context, the cardiac disease, and prolonged treatment are significant factors for morbidity and mortality. The beneficial role of early neonatal enteral feeding was not demonstrated in this high risk population.

[Kawasaki disease in newborns and infants: refractory forms to immunoglobulin therapy]

We studied 52 consecutive patients with Kawasaki disease hospitalized (1984 -2003) during the acute phase (mean age 2.5 + 2.4 years; range 0.3 to 16 years, 34 males, 18 cases with coronary aneurysms, median follow-up 6.7 years), and identified a subgroup presenting a refractory subtype to immunoglobulin therapy.

RESULTS

forty-nine infants benefited from a first regimen of immunoglobulins, 8.4 + 6 days following the onset of symptoms. Eleven infants (1.4 + 1.2 years, range 0.3 - 4.3 years, median 1.7 years) were non-responders, with coronary aneurysms in 8 cases (giant aneurysms (>8 mm) in 4 cases). These 11 infants were treated a second time by immunoglobulins, but 6 cases (1.8 + 1.6 years, with two cases of severe ventricular dysfunction and 2 cases of fatal myocardial infarction) required an additive therapy with (oral or IV route) corticosteroids (2) and cyclophosphamide bolus (4) with or without repetitive plasmapheresis (4). Non-responder patients had their treatment onset later (p<0.0003) using higher dosages (p<0.005), a longer delay for fever or biological signs correction (p<0.02), a worsening of coronary lesions (p<0.05) with more coronary secondary aneurysms (p<.005). The aneurysms, more frequent at the second phase of the disease (p<0.0001) are associated with: a younger age (p<0.03), a lower weight (p<0.02), a later onset of treatment (p<0.03), prolonged fever or inflammatory syndrome (p<0.05), higher level of fibrinogene (p<0.02). The overall mortality (5.7%) is correlated with giant aneurysms (p<0.001), myocardial ischemia (p<0.0001), heart failure (p<0.0001), and lack of early response to treatment (p<0.003).

CONCLUSION

immunoglobin therapy can be repeated. In case of severe forms, the use of corticosteroids, cyclophosphamide and plasmapheresis may be proposed.

[Cardiac stimulation in the infant and young child]

This study evaluates the problems and the evolution of cardiac stimulation in infants (aged < 3.5 years) by comparing the endocavity and epicardial routes in a retrospective series of 37 patients. Thirty seven patients aged 1.2 +/- 0.9 years treated with epicardial (n = 19) or endocavity (n = 18) stimulation were followed for 10.9 +/- 6.4 years (0.75-24). The 2 patient groups did not differ in age or weight. Four patients were lost to follow up, and 1 died. The functional duration of the first stimulator was not significantly different if the initial approach was epicardial or endocavity. The endocavity probes were introduced by venous denudation in 15 cases and by subclavian puncture in 3 cases. Fourteen of the 19 children fitted by the epicardial route went on to endocavity stimulation, of which 10 were at the first replacement. None of the 18 patients fitted by the endocavity route went on to epicardial stimulation. Out of 11 endocavity probe replacements and 9 atrialisations, the homolateral venous approach was always possible except in 2 cases. In conclusion, the results for the epicardial and endocavity routes are comparable. For technical reasons (calibre of the veins, size of the stimulator) it would appear reasonable if the endocavity route was used, making do initially with a mono chamber stimulation. The advances in the epicardial electrodes abolishes the major handicap (threshold elevation) of this approach which can be advocated when double chamber stimulation seems preferable.

[Isolated congenital complete atrio-ventricular block]

The objective of this work was to study the long term evolution of a retrospective series of 54 patients affected with congenital isolated complete atrio-ventricular block (CAVB) and to analyse the value of the different methods used for surveillance. Our series included 54 patients affected with isolated CAVB, without associated cardiopathy, diagnosed at an average age of 5.3 +/- 5.5 years, of which 9 were in utero. The average duration of follow up was 14.5 +/- 9.6 years. During the evolution, a cardiac stimulator was placed in 41 patients (76%) at a relatively late average age of 13.3 +/- 9 years, significantly lower for CAVB diagnosed before the age of 1 year (9.6 +/- 7.4 years) than for those diagnosed after the age of 1 year (16.2 +/- 9.2 years) (p < 0.02). The approach was endocavitary in 39 cases and epicardial in 2 cases. The only 2 deaths in our series (4%) concerned 2 patients of 18 and 26 years already fitted with a stimulator. Three patients progressed to severe dilated cardiomyopathy despite implantation of a stimulator. The decisive arguments for implantation of a PM were clinical (11 patients), Holter ECG (25 patients), stress test (17 patients), electrophysiological investigation (5 patients), echocardiography (3 patients) and surgical intervention (2 patients). In conclusion, our study confirms the good prognosis of isolated congenital complete atrio-ventricular block, but underlines the possible progression in rare cases in spite of stimulation towards dilated cardiomyopathy for which the aetiology remains uncertain. Three quarters of the patients required a stimulator at a somewhat late age.

[Role of pediatric cardiologists in the management of neonates with congenital heart disease]

Whether diagnosed before birth or suspected in a newborn, congenital heart diseases rapidly require an evaluation by the pediatric cardiologist. The role of the pediatric cardiologist is threefold: 1) to realize a careful anatomical examination using color Doppler echocardiography; 2) in many cases to perform a palliative or curative therapeutic act based upon interventional catheterization, such as Rashkind atrioseptotomy or percutaneous balloon valvuloplasty; and 3) whenever necessary, to take a rapid decision of cardiac surgery in concert with the cardiac surgeon, and to prepare the child for surgery.

Induction of sustained ventricular tachycardia after surgical repair of tetralogy of Fallot

Between 1980 and 1996, 89 unselected consecutive patients with repaired tetralogy of Fallot (TOF) underwent examination, including a prospective right ventricular programmed stimulation with the same protocol (S1 S2, S3, S4). Age at surgery was 4.2 +/- 3.5 years and age at electrophysiologic study was 10.9 +/- 6.5 years. Follow-up since surgery was 14.4 +/- 4.8 years and patient follow-up after programmed stimulation was 7.8 +/- 4.2 years. The aim of this study was to evaluate the main predictors of the inducibility of a sustained monomorphic ventricular tachycardia (VT) and its significance to identify a group of patients at risk of sudden death: 21 (group A) had and 68 (group B) had no induced sustained VT. The induction of VT was related to older age at programmed stimulation, prolonged QRS duration, presence of complex ventricular arrhythmia, symptoms, right ventricular overload, and increased right ventricular systolic pressure. Predictors of induced VT selected by multivariate analysis were age at electrophysiologic study (p <0.0001), previous palliative shunts (p <0.001), right ventricular systolic pressure (p <0.007), and symptoms (p <0.005). Among group A patients, 4 had previous sustained VT before stimulation, and 1 had sustained VT only during follow-up after stimulation. No patients of group B had clinical sustained VT. Late mortality was low but similar between both groups. A negative electrophysiologic study may be helpful for the management of patients after surgical repair of TOF, but because the arrhythmic event rate is low, the findings of even a positive electrophysiologic study should be interpreted with caution.

[Anomalous origin of the left main coronary artery from the right coronary sinus and trajectory to the great vessels. Value of echocardiography in a child]

During a routine medical check-up, a pathological electrocardiogram was recorded in an asymptomatic 6 year old girl. The demonstration of coronary insufficiency by exercise stress testing and sestamib myocardio-scintigraphy led to the diagnosis of an anomalous origin of the left coronary artery. This vessel arose from the right coronary sinus and continued anteriorly to the main coronary artery. The data of the literature suggest that the risk of sudden death and of coronary insufficiency is associated with the passage of the left coronary artery between the aorta and pulmonary artery. The authors describe the anomalous origin of the left coronary artery and its trajectory with respect to the great vessels by echocardiography, using a high frequency transducer. The anterior direction of the left coronary artery in front of the main pulmonary artery may lead to ischaemia on effort even without stenosis at coronary angiography. Echocardiography may therefore be useful in children with positive exercise stress tests for diagnosing anomalous coronary vessels and their relationship with respect to the great vessels.

Three-dimensional echocardiography improves noninvasive assessment of left ventricular volume and performance

To calculate left ventricular (LV) volume by two-dimensional echocardiography (2DE), assumptions must be made about ventricular symmetry and geometry. Three-dimensional echocardiography (3DE) can quantitate LV volume without these limitations, yet its incremental value over 2DE is unknown. The purpose of this study was to compare the accuracy of LV volume determination by 3DE to standard 2DE methods. To compare the accuracy of 3DE with standard 2DE algorithms for quantitating LV volume, 28 excised canine ventricles of known volume and varying shapes (15 symmetric and 13 aneurysmal) and 10 instrumented dogs prepared so that instantaneous ventricular volume could be measured were examined by 2DE (bullet and biplane Simpson's formulas) and again by 3DE. In both excised and beating hearts, 3DE was more accurate in quantitating volume than either 2DE method (excised: error = 0.6 +/- 3.2, 2.5 +/- 10.7, and 4.0 +/- 8.5 ml by 3D, bullet, and Simpson's, respectively; beating: error = -0.5 +/- 3.5, -0.3 +/- 9.6, and -7.6 +/- 8.0 ml by 3DE, bullet, and Simpson's, respectively). This difference in accuracy between 3DE and 2DE methods was especially apparent in asymmetric ventricles distorted by ischemia or right ventricular volume overload. Stroke volume and ejection fraction calculated by 3DE also demonstrated better agreement with actual values than the bullet or Simpson methods with less variability (ejection fraction: error = -2.0% +/- 5.1%, 7.7% +/- 8.5%, and 6.8% +/- 12.3% by 3DE, bullet, and Simpson's, respectively). In both in vitro and in vivo settings, 3DE provides improved accuracy for LV volume and performance than current 2DE algorithms.

[Long-term efficacy and tolerability of amiodarone in children]

The authors reviewed the files of 37 patients under 15 years of age (22 boys and 15 girls) in order to study the long-term efficacy and tolerance of amiodarone therapy. The mean age of the patients at the time of initiation of amiodarone was 6.2 +/- 4.7 years. Amiodarone was prescribed at a loading dose of 500 mg/m2 and at a maintenance dose of 250 mg/m2. This drug was prescribed in second intention in 29/37 patients and as monotherapy in 15/37 patients. The treated arrhythmias were supraventricular in 25 patients (atrial: 10; junctional: 15) and ventricular in 12 patients. Underlying cardiac disease was present in 21/37 patients (57%) and the arrhythmias were postoperative in 14/37 cases (38%). Efficacy and tolerance of amiodarone were estimated on clinical and biological data, the results of Holter monitoring, ophthalmological slit-lamp examination and thyroid function tests. The average duration of therapy was 4 +/- 3 years. The efficacy of amiodarone was judged to be good in 59% and satisfactory in 38% of cases. Secondary effects and complications included: corneal deposits: 14 cases (38%); skin pigmentation: 1 case; photosensitivity: 10 cases (27%). There was a high incidence of thyroid disorders: 7 cases (19%) with 4 cases of biological or clinical hyperthyroidism and 3 cases of clinical or biological hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous wave Doppler echocardiography for noninvasive assessment of left ventricular dP/dt and relaxation time constant from mitral regurgitant spectra in patients

OBJECTIVES

We previously demonstrated experimentally that the mitral regurgitant velocity spectrum can be used to estimate left ventricular pressure throughout systole and may provide a new noninvasive method for estimating maximal dP/dt and the relaxation time constant. This study was designed to test this method in patients.

BACKGROUND

The maximal first derivative of left ventricular pressure (dP/dt) and the time constant of left ventricular isovolumetric relaxation (tau) are important variables of left ventricular function, but the need for invasive measurement with high fidelity catheters has limited their use in clinical cardiology.

METHODS

Twelve patients with mitral regurgitation were studied. The Doppler mitral regurgitant velocity spectrum was recorded simultaneously with micromanometer left ventricular pressure tracings in all patients. The regurgitant velocity profiles were digitized and converted to ventriculoatrial (VA) pressure gradient curves using the simplified Bernoulli equation and differentiated into instantaneous dP/dt. The relaxation time constant (tau) was calculated assuming a zero pressure asymptote from catheter left ventricular pressure decay (tau c) and from the Doppler-derived VA gradient curve with corrections. Two methods were used to correct the Doppler gradient curve to better approximate the left ventricular pressure decay before calculating the relaxation time constant: 1) adding an arbitrary 10 mm Hg (tau 10), and 2) adding the actual mean pulmonary capillary pressure (tau LA).

RESULTS

The Doppler-derived maximal positive dP/dt (1,394 +/- 302 mm Hg/s [mean +/- SD]) correlated well (r = 0.91) with the catheter-derived maximal dP/dt (1,449 +/- 307 mm Hg/s). Although the Doppler-derived negative maximal dP/dt differed slightly from catheter measurement (1,014 +/- 289 vs. 1,195 +/- 354 mm Hg/s, p < 0.01), the correlation between Doppler and catheter measurements was similarly good (r = 0.89, p < 0.0001). The correlation between tau 10 and tau c was excellent (r = 0.93, p < 0.01), but the Doppler-derived tau 10 (50.0 +/- 11.0 ms) slightly underestimated the catheter-derived tau c (55.5 +/- 12.8 ms, p < 0.01). This slight underestimation could be corrected by adding the actual pulmonary capillary wedge pressure to the Doppler gradient curve.

CONCLUSIONS

Doppler echocardiography provides an accurate and reliable method for estimating left ventricular maximal positive dP/dt, maximal negative dP/dt and the relaxation time constant (tau) in patients with mitral regurgitation.

Three-dimensional reconstruction of ventricular septal defects: validation studies and in vivo feasibility

OBJECTIVES

The purpose of this study was to demonstrate the feasibility of in vivo three-dimensional reconstruction of ventricular septal defects and to validate its quantitative accuracy for defect localization in excised hearts (used to permit comparison of three-dimensional and direct measurements without cardiac contraction).

BACKGROUND

Appreciating the three-dimensional spatial relations of ventricular septal defects could be useful in planning surgical and catheter approaches. Currently, however, echocardiography provides only two-dimensional views, requiring mental integration. A recently developed system automatically combines two-dimensional echocardiographic images with their spatial locations to produce a three-dimensional construct.

METHODS

Surgically created ventricular septal defects of varying size and location were imaged and reconstructed, along with the left and right ventricles, in the beating heart of six dogs to demonstrate the in vivo feasibility of producing a coherent image of the defect that portrays its relation to surrounding structures. Two additional gel-filled excised hearts with defects were completely reconstructed. Quantitative localization of the defects relative to other structures (ventricular apexes and valve insertions) was then validated for seven defects in excised hearts. The right septal margins of the exposed defects were also traced and compared with their reconstructed areas and circumferences.

RESULTS

The three-dimensional images provided coherent images and correct spatial appreciation of the defects (two inlet, two trabecular, one outlet and one membranous Gerbode in vivo; one inlet and one apical in excised hearts). The distances between defects and other structures in the excised hearts agreed well with direct measures (y = 1.05x-0.18, r = 0.98, SEE = 0.30 cm), as did reconstructed areas (y = 1.0x-0.23, r = 0.98, SEE = 0.21 cm2) and circumferences (y = 0.97x + 0.13, r = 0.97, SEE = 0.3 cm).

CONCLUSIONS

Three-dimensional reconstruction of ventricular septal defects can be achieved in the beating heart and provides an accurate appreciation of defect size and location that could be of value in planning interventions.

Three-dimensional echocardiography. In vivo validation for left ventricular volume and function

BACKGROUND

Current two-dimensional quantitative echocardiographic methods of volume assessment require image acquisition from standardized scanning planes. Left ventricular volume and ejection fraction are then calculated by assuming ventricular symmetry and geometry. These assumptions may not be valid in distorted ventricles. Three-dimensional echocardiography can quantify left ventricular volume without the limitations imposed by the assumptions of two-dimensional methods. We have developed a three-dimensional system that automatically integrates two-dimensional echocardiographic images and their positions in real time and calculates left ventricular volume directly from traced endocardial contours without geometric assumptions.

METHODS AND RESULTS

To study the accuracy of this method in quantifying left ventricular volume and performance in vivo, a canine model was developed in which instantaneous left ventricular volume can be measured directly with an intracavitary balloon connected to an external column. Ten dogs were studied at 84 different cavity volumes (4 to 85 cm3) and in conditions of altered left ventricular shape produced by either coronary occlusion or right ventricular volume overload. To demonstrate clinical feasibility, 19 adult human subjects were then studied by this method for quantification of stroke volume. Left ventricular volume, stroke volume, and ejection fraction calculated by three-dimensional echocardiography correlated well with directly measured values (r = .98, .96, .96 for volume, stroke volume, and ejection fraction, respectively) and agreed closely with them (mean difference, -0.78 cm3, -0.60 cm3, -0.32%). In humans, there was a good correlation (r = .94, SEE = 4.29 cm3) and agreement (mean difference, -0.98 +/- 4.2 cm3) between three-dimensional echocardiography and Doppler-derived stroke volumes.

CONCLUSIONS

Three-dimensional echocardiography allows accurate assessment of left ventricular volume and systolic function.

A new integrated system for three-dimensional echocardiographic reconstruction: development and validation for ventricular volume with application in human subjects

OBJECTIVES

The purpose of this study was to improve three-dimensional echocardiographic reconstruction by developing an automated mechanism for integrating spark gap locating data with corresponding images in real time and to validate use of this mechanism for the measurement of left ventricular volume.

BACKGROUND

Initial approaches to three-dimensional echocardiographic reconstruction were often limited by inefficient reconstructive processes requiring manual coordination of two-dimensional images and corresponding spatial locating data.

METHODS

In this system, a single computer overlays the binary-encoded positional data on the two-dimensional echocardiographic image, which is then recorded on videotape. The same system allows images to be digitized, traced, analyzed and displayed in three dimensions. This system was validated by using it to reconstruct 11 ventricular phantoms (19 to 271 ml) and 11 gel-filled excised ventricles (21 to 236 ml) imaged in intersecting long- and short-axis views and by apical rotation. To measure cavity volume, a surface was generated by an algorithm that takes advantage of the full three-dimensional data set.

RESULTS

Reconstructed cavity volumes agreed well with actual values: y = 0.96x + 2.2 for the ventricular phantoms in long- and short-axis views (r = 0.99, SEE = 2.7 ml); y = 0.95x + 2.9 for the phantoms, reconstructed by apical rotation (r = 0.99, SEE = 2.7 ml); and y = 0.99x + 0.11 ml for the excised ventricles (reconstructed in long- and short-axis views; r = 0.99, SEE = 5.9 ml). The mean difference between three-dimensional and actual volumes was 3% of the mean (3.0 ml) for the phantoms and 6% (4.6 ml) for the excised ventricles. Observer variability was 2.3% for the phantoms and 5.6% for the excised ventricles. Application to 14 normal subjects demonstrated feasibility of left ventricular reconstruction, which provided values for stroke volume that agreed well with an independent Doppler measure (y = 0.97x + 0.94; r = 0.95, SEE = 3.2 ml), with an observer variability of 4.9% (2.4 ml).

CONCLUSIONS

A system has therefore been developed that automatically integrates locating and imaging data in no more time than the component two-dimensional echocardiographic scans. This system can accurately reconstruct ventricular volumes in vitro over a wide range and is feasible in vivo, thus laying the foundation for further applications. It has increased the efficiency of three-dimensional reconstruction and enhanced our ability to address clinical and research questions with this technique.

Methylergometrine-induced coronary artery spasm causing total occlusion of all three coronary arteries

In a 58-year-old man with rheumatic mitral valve disease and nocturnal chest pain of recent onset, intravenous injection of 0.4 mg methylergometrine during coronary angiography resulted in the total occlusion of all three angiographically normal coronary arteries, with electromechanical dissociation. Intravenous isosorbide dinitrate failed to relieve coronary spasm which had to be treated by intracoronary administration of nitrates and nifedipine.

Role of previous angina pectoris and collateral flow to preserve left ventricular function in the presence or absence of myocardial infarction in isolated total occlusion of the left anterior descending coronary artery

The aim of this study was to determine whether previous angina pectoris and collateral circulation influenced myocardial function after isolated coronary occlusion. In 58 consecutive patients, coronary angiography showed a complete isolated occlusion of the left anterior descending coronary artery; 43 patients (74%) had previous myocardial infarction. Duration of previous angina pectoris was defined as the time from the first ischemic symptom to the date of myocardial infarction or of coronary angiography in the absence of myocardial infarction. Left ventricular ejection fraction was measured on the 30 degrees right anterior oblique projection of the left ventricular angiogram. Collateral circulation was graded as follows: none or filling limited to side branches (group 1) and partial or complete filling of the epicardial arterial segment (group 2). Group 2 (40 patients) had higher ejection fraction (57 vs 38%; p less than 0.0001) and longer duration of previous angina pectoris (11 vs 0.1 months; p less than 0.002) than group 1 (18 patients). A longer duration of previous angina pectoris probably allows collateral development before coronary occlusion in 1-vessel coronary artery disease, thereby limiting myocardial damage.