From the first endocardial electrogram to the ablative techniques. Half a century of cardiac electrophysiology.
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Cardiac Pacing, Artificial↗
Biomedical subjects
G Fontaine
Publications and source records attributed to G Fontaine.
[Right precordial leads and sudden death. Relation with arrhythmogenic right ventricular dysplasia].
Non-coronary ST-segment elevation during right sided chest pain has been described in subjects with episodes of ventricular fibrillation at rest. This syndrome has been attributed to functional phenomena or to structural myocardial changes. A personal case has features belonging to two categories: ST-segment elevation observed before, during and after episodes of arrhythmia was compared to 11 previously recorded ECG recordings. Right ventricular dysplasia was shown by electrocardiography, electrophysiology and echocardiography. In addition, ST-segment elevation is classified in 3 categories: triangular and dome-shaped are the most commonly observed forms during the arrhythmias: the third form with "saddle"-shaped appearances has not been previously described and would seem to be a minor equivalent observed during intercritical periods. This form is found in 30% of clinically documented cases of arrhythmogenic right ventricular dysplasia.
Arrhythmias, Cardiac↗
[Sudden death of a young athlete, is it explained?].
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Adolescent↗
Sudden death during sports activities.
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Athletic Injuries↗
Time- and frequency-domain analyses of the signal-averaged ECG in patients with arrhythmogenic right ventricular dysplasia.
BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by recurrent ventricular tachycardia of right ventricular origin and a cardiomyopathy with hypokinetic areas involving the free wall of the right ventricle. Subjects have a risk of sudden cardiac death, particularly during sports and strenuous exercise. Routine clinical examinations may be normal, but fragmented or delayed electrograms are usually recorded in the right ventricle of these patients. However, the frequency with which late potentials are detected by conventional time-domain analysis of the signal-averaged ECG (SAECG) is not high. This study evaluated the usefulness of the frequency-domain analysis of the SAECG in addition to the conventional time-domain analysis for a screening test to detect patients with ARVD. METHODS AND RESULTS: SAECG was recorded by using a bipolar X, Y, and Z lead system in 28 patients with ARVD (mean age, 38 +/- 13 years) and 35 age-matched normal subjects (mean age, 35 +/- 11 years). The conventional time-domain analysis of the SAECG was performed at two different high-pass filter settings, 25 and 40 Hz, and the low-pass cutoff frequency was fixed at 250 Hz. The fast-Fourier transform analysis of SAECG was performed using a Blackman-Harris window. Area ratio 1 (area of 20 to 50 Hz)/(area of 0 to 20 Hz) and area ratio 2 (area of 40 to 100 Hz)/(area of 0 to 40 Hz) were calculated. In the conventional time-domain analysis, 20 (71%) and 18 (64%) patients had positive criteria at filter settings of 25 and 40 Hz, respectively. In the frequency-domain analysis, 18 (64%) and 20 (71%) patients had abnormal values in area ratios 1 and 2, respectively. Combining the time- and frequency-domain analyses, all patients were judged positive, with a sensitivity of 100% and a specificity of 94%. CONCLUSIONS: Each result of the time- and frequency-domain analyses revealed that both methods had equivalent value. Combining the two domain analyses improved the sensitivity without reducing the specificity. These findings suggest that combining the time- and frequency-domain analyses of the SAECG may be useful as a screening test to detect patients with ARVD.
Adult↗
The arrhythmogenic right ventricle. Dysplasia versus cardiomyopathy.
Twenty-four patients presenting with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ventricular tachycardia of right ventricular origin associated with structural abnormalities of the right ventricle) were divided into two groups with left ventricular ejection fraction (LVEF) above or below 45%. The distribution of LVEF in the group with LVEF below 45% was comparable with the distribution in 6 patients with idiopathic dilated cardiomyopathy who had ventricular tachycardia originating in the left ventricle (P = 0.2). They also had the same unfavorable long-term prognosis. Therefore, it is suggested that the term, arrhythmogenic right ventricular cardiomyopathy (ARVC), be restricted to patients with a LVEF below 45%. Histological data obtained in the ARVC group showed signs of acute or chronic myocarditis (in the right and left ventricles). It can be hypothesized that patients with arrhythmogenic right ventricular dysplasia (ARVD) may be prone to develop infectious myocarditis. In patients in whom an abnormal host immune response had been seen, progressive deterioration of right and left ventricular function could be observed. This pattern may be superimposed on the genetically determined background of ARVD. This could explain the wide spectrum of clinical presentation observed in patients with tachycardia originating in an abnormal right ventricle.
Adolescent↗
Arrhythmogenic right ventricular dysplasia.
Arrhythmogenic right ventricular dysplasia is a relatively newly described clinical entity that is more and more frequently recognized. It may explain an increasing number of unexpected, sudden deaths in young adults that are or are not preceded by cardiac symptoms. A genetic transmission of the disease has been suggested by the study of familial cases. A location on chromosome 14 appears to be responsible for this disease. In some patients, a superimposed inflammatory process mixed with the pattern of arrhythmogenic right ventricular dysplasia may explain the progressive deterioration of left ventricular function. The systematic study of electrocardiograms demonstrates prolongation of the QRS complex and repolarization abnormalities in the right precordial leads due to a parietal block. Multiple therapeutic approaches are now available. The first line of therapy remains antiarrhythmic drugs, which are effective in most cases. Ablative techniques, implantable defibrillators, and heart transplantation have been used in the most severe examples of the disease.
Adult↗
Arrhythmogenic right ventricular dysplasia/cardiomyopathy: a review.
Right ventricular dysplasia is being recognized with increasing frequency. It should be considered as a cause of ventricular tachycardia of left bundle branch block configuration and/or sudden unexpected death particularly during exercise in young men. The electrocardiogram (ECG) may show anterior precordial T wave inversion, particularly in lead V2 and/or a QRS complex duration > or = 110 ms in the right precordial leads. Echocardiographic studies focusing on the size and wall-motion abnormalities of the right ventricle are useful in confirming the diagnosis. Radionuclide angiography usually shows a moderately or markedly depressed right ventricular ejection fraction with normal or relatively well preserved left ventricular function. Cinemagnetic resonance imaging demonstrates abnormal fatty infiltration of the right ventricular myocardium and can show increased right ventricular dimensions as well as wall-motion abnormalities. Contrast ventricular angiography remains the gold standard to establish the diagnosis but must be performed with appropriate views and with care to avoid ventricular premature beats. Quantitative analysis of right ventricular dimensions can be performed in selected centers. Three-dimensional echocardiography is a promising approach to evaluate right ventricular wall-motion abnormalities as well as to demonstrate enlargement. The etiology and pathogenesis of this condition is not clear. A familial incidence has been well-documented in certain areas and an abnormal gene has been identified. Sporadic cases are the most common. In contrast to Uhl's anomaly, characterized pathologically by areas of paper thin myocardium, the right ventricular free wall is minimally decreased in thickness. Histologically there appears to be a replacement of musculature by fatty tissue. Medical therapy with sotalol or amiodarone, or combination therapy (Class Ic drugs plus beta-blocking drugs, or amiodarone plus beta-blocking drugs) is frequently effective in preventing recurrent ventricular tachycardia. Ablation using radiofrequency (RF) or direct current (DC) energy is reserved for patients who are unresponsive or intolerant of antiarrhythmic drugs. Ventricular arrhythmia recurrence of different morphology is not uncommon after apparent successful ablation. There appears to be a lower rate of successful ablation using RF energy. However, patients with this condition who have been resuscitated from sudden cardiac death or those refractory to medical treatment are candidates for ablation, implantation of an automatic cardioverter defibrillator, or cardiac transplantation. Surgery consisting of total disconnection of the right ventricle is a promising therapeutic modality.
Adult↗
[History of the first radiofrequency ablation].
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Cardiac Pacing, Artificial↗
[Significance of lymphoplasmocytic infiltration in arrhythmogenic right ventricular dysplasia. Apropos of 3 own cases and review of the literature].
Three patients with typical histological signs of arrhythmogenic right ventricular dysplasia progressed to fulminating heart failure in 1 case and unexplained sudden death in the other two. There were signs of superacute myocarditis in the first case, previous healed pericarditis in the second and chronic myocarditis in the third case. These cases suggested the presence of an inflammatory process complicating the substrate of the dysplasia. Arrhythmogenic right ventricular dysplasia seems to be a developmental defect which is complicated in 50 to 70% of patients, according to a review of 74 cases reported in the literature, by a varying degree of myocarditis suggesting particular susceptibility of these patients to infection and explaining the presence of unusual amounts of fibrous tissue in some and the so called "progressive" nature of the disease in other patients.
Adult↗
[Outcome of arrhythmogenic right ventricular dysplasia. Apropos of 4 cases].
The authors propose a classification of the outcome of arrhythmogenic right ventricular dysplasia with reference to 4 selected cases with a follow-up period of over 9 years. In type I, the left ventricular ejection fraction is normal (EF > 50%) and the risk, exclusively arrhythmic, can be controlled by appropriate antiarrhythmic therapy. This is the commonest form of arrhythmogenic right ventricular dysplasia with different varieties according to the degree of dilatation of the right ventricle. In type II, there is a variable degree of left ventricular involvement (30 < EF < 50%) either by extension of a comparable disease process as observed in the right ventricle or by an isolated or superimposed phenomenon of myocarditis. This form is stable and may remain stable for many years providing the arrhythmias are correctly treated. In type III, progressive degradation of the myocardium is observed over a period of about 10 years with a clinical presentation comparable to that of certain arrhythmogenic dilated cardiomyopathies which are often hereditary. In this case, the patients have an arrhythmic risk associated with that of cardiac failure which becomes progressively irreversible. The histology shows interstitial fibrosis with biventricular lymphocytic infiltration suggesting an autoimmune phenomenon. Therefore, the classification of cases of arrhythmogenic right ventricular dysplasia depends on the potential evolutivity of the lesions. When the patient is seen in the early stages of the disease, the prognosis should be garded, especially in a hereditary form.
Adult↗
Idiopathic ventricular tachycardia: feasibility and efficacy of catheter ablation.
Idiopathic ventricular tachycardia is a well described syndrome of both left and right ventricular origin. This study reports the feasibility and efficacy of catheter ablation in this entity. Fourteen patients (mean age 30 +/- 10 years of age) and six patients (mean age 51 +/- 9 years of age) underwent endocardial catheter ablation with either direct-current shocks and radiofrequency energy, respectively. Earliest right and left ventricular activation and endocardial mapping during tachycardia were made to localize the site of ventricular tachycardia origin. The overall clinical efficacy was 93% for direct-current method with a mean number of shocks of 3.3 +/- 0.9/patient after a mean follow-up of 38 +/- 25 months. Radiofrequency ablation achieved an overall clinical efficacy of 83.6% with a mean of 3.2 pulses/patient during a follow-up of 10.5 +/- 4 months. The isoenzyme MB fraction of peak creatine kinase after ablation was less than 5%. There were no complications in any patient who underwent radiofrequency energy. Endocardial catheter ablation is feasible in patients with idiopathic ventricular tachycardia. Both methods are highly effective but radiofrequency energy is most desirable because of its lack of barotrauma, and may be considered as early therapy.
Adult↗
Pyridoxine-responsive gyrate atrophy of the choroid and retina: clinical and biochemical correlates of the mutation A226V.
We discovered the missense mutation, A226V, in the ornithine-delta-aminotransferase (OAT) genes of two unrelated patients with gyrate atrophy of the choroid and retina (GA). One patient, who was a compound for A226V and for the premature termination allele R398ter, showed a significant (P < .01) decrease in mean plasma ornithine levels, following pyridoxine supplementation with a constant protein intake: 826 +/- 128 microM (n = 5; no pyridoxine supplementation) versus 504 +/- 112 microM (n = 6; 500 mg pyridoxine/d) and 546 +/- 19 microM (n = 6; 1,000 mg pyridoxine/d). In extracts of fibroblasts from a second GA patient homozygous for A226V and from Chinese hamster ovary cells expressing an OAT-cDNA-containing A226V, we found that OAT activity increased from undetectable levels to approximately 10% of normal when the concentration of pyridoxal phosphate was increased from 50 to 600 microM. A226V is the fourth disease-causing pyridoxine-responsive human mutation to be reported.
Amino Acid Sequence↗
[Arrhythmogenic right ventricle: dysplasia or cardiomyopathy? Value of left ventricle ejection fraction].
The left ventricular ejection fraction (LVEF) of 76 patients suffering from arrhythmogenic dysplasia or cardiomyopathy of the right ventricle (ventricular tachycardia associated with structural abnormalities of the right ventricle) demonstrated two subgroups situated above and below 45%. Values of LVEF less than 45% were similar to those of a control population of 6 cases of idiopathic dilated cardiomyopathy with ventricular tachycardia of left ventricular origin (p = 0.2). These patients also have the same unfavourable long-term prognosis. Histological data obtained from four cases belonging to the group of patients with dysplasia or cardiomyopathy of the right ventricle with a low ejection fraction demonstrated the presence of signs of myocarditis involving both ventricles. This suggests that these patients may suffer from an infectious phenomenon superimposed on a specific histological substrate, which may lead to deterioration of their myocardial function. These results are in line with those of the literature. The term arrhythmogenic cardiomyopathy of the right ventricle should therefore be reserved to the subgroup of patients with an LVEF less than 45%. Finally, arrhythmogenic cardiomyopathy of the right ventricle appears to be a complication of dysplasia following the development of a myocarditic phenomenon. This may explain the wide range of clinical forms observed in patients with ventricular tachycardia of right ventricular origin associated with structural abnormalities of the right ventricle.
Adolescent↗
[Supraventricular tachycardia with wide QRS complexes during Vaughan-Williams class I anti-arrhythmic treatment. Diagnostic and therapeutic implications].
The authors report 8 cases of regular tachycardia with wide QRS complexes during treatment with Vaughan-Williams class 1 antiarrhythmic drugs. These antiarrhythmics, prescribed to prevent atrial fibrillation (3 patients) and atrial flutter (5 patients), were flecainide in 4 cases, propafenone in 2 cases and cibenzoline and hydroquinidine respectively associated with digitoxine and propranolol. These wide complex tachycardias were regular atrial tachycardias with 1/1 conduction to the ventricle. The action of the drug, more pronounced on intra-atrial conduction velocities than on atrioventricular node refractoriness resulted in transformation of flutter at 300 cycles/min with 2/1 conduction and a ventricular rate of 150 cycles/min to atrial flutter at 210 cycles/min with 1/1 ventricular conduction. This acceleration of the ventricular rate was accompanied by widening of the QRS complex. Using the new ventricular tachycardia criteria recently published by Brugada resulted in a diagnostic error in 7 out of the 8 cases. The recording of a wide QRS complex tachycardia in a patient on class 1 antiarrhythmic therapy for an atrial arrhythmia should alert the physician to 1/1 atrial tachycardia despite morphological electrocardiographic criteria of ventricular tachycardia. The 1/1 atrial tachycardia may be poorly tolerated and require emergency treatment. The preventive association of a drug which slows conduction through the atrioventricular node is not always effective.
Adult↗
[Ablation of arrhythmia disorders: endocavitary catheter surgery. 2 decades of cardia electrophysiology].
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Adolescent↗
The ablative techniques from surgery to catheter ablation in the treatment of cardiac arrhythmias : a 20 year experience.
The first European surgical intervention of a Wolff-Parkinson-White syndrome guided by epicardial mapping was performed by C. Cabrol and G. Guiraudon in May 1971 in Paris, in a patient with a type AB syndrome. Experiments had been performed in animal models for six months before its application to the humans, in order to develop the equipment (amplifiers, electrodes and protocols). In December 1971, the same methodology was used to manage one case of post-myocardial infarction ventricular tachycardia. An incision in the diaphragmatic wall of the left ventricle (where the "site of origin" was determined) proved successful. In one patient with VT studied in December 1972, the first detailed sinus rhythm epicardial mapping was performed in 85 test points to describe completely the epicardial activation. This case presented with a left bundle branch block and superimposed trouble of parietal conduction because of an important anteroseptal aneurysm. In May 1973, in a patient with idiopathic dilated cardiomyopathy two transmural incisions at the "site of origin" of ventricular tachycardias proved effective in preventing recurrence of ventricular arrhythmias of two different morphologies. Epicardial delayed potentials were clearly documented. In October 1973 in the 1st case of Arrhythmogenic Right Ventricular Dysplasia, a simple incision made at the site of origin of ventricular tachycardia proved successful to prevent recurrence of the arrhythmia and contributed to the identification of this disease. The endocavitary catheter ablation (fulguration) was discovered in our laboratory in 1979. It was used intentionally for the first time in 1986 in a patient with Wolff-Parkinson-White syndrome with multiple mechanisms of reciprocating tachycardia. His bundle ablation proved clinically effective confirming that it was the elective critical pathway for tachycardia perpetuation. Localization of the site of slow conduction in ventricular tachycardia was important to delineate precisely the VT critical pathway in order to guide radiofrequency and fulguration techniques.
Animals↗
[Non-pharmacological methods of treatment of tachycardia].
Anti-tachycardia drugs have the advantage of preventing recurrent arrhythmia in most cases but have the disadvantage of requiring long-term prescriptions and producing extra-cardiac and cardiac side effects. In addition, paradoxical arrhythmogenic effects sometimes occur. With the advent of radiofrequency catheter ablation and implantable defibrillators, a whole new range of indications for non-drug treatments suddenly became possible. Radiofrequency ablation is now a real alternative in cases of Wolff-Parkinson-White junctional tachycardia with intranodal re-entry and accessory pathways since the success rate is 95%. For atrial flutter and ventricular tachycardia, myocardial localizations of the causal lesions are more diffuse and the clinical success rate is lower. Consequently, since other arrhythmias may occur, ablative treatment is usually reserved for drug-resistant cases. An implantable defibrillator is the only treatment, with the exception of cases with an identifiable acute origin, for ventricular fibrillation. In many countries, defibrillators are also implanted for drug-resistant ventricular tachycardia.
Catheter Ablation↗