Congenital atrial flutter.
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Arrhythmias are common problems following Mustard's operation for D-transposition of the great arteries. A 19-year-old male is presented who was diagnosed at birth with D-transposition of the great arteries and a right aortic arch and underwent a Mustard procedure at 12 months of age. He developed sinus node dysfunction and atrial flutter unresponsive to antiarrhythmic drugs and dual chamber pacing. Following complete heart block with radiofrequency catheter ablation of the atrioventricular junction, the patient's heart was paced in VVIR mode. Ventricular function improved after the ablation and persisted in two years' follow-up.
The wavelength theory considers two determinants of reentry, i.e., refractoriness and conduction velocity. It does not take excitability into account primarily. We evaluated frequency-dependence of excitability and refractoriness before and after flecainide or procainamide administration in relation to termination of reentrant atrial flutter. After making a Y-shaped lesion in the right atrium, we induced 62 flutters (cycle length 171 +/- 15 ms) by electrical stimulation in 15 pigs. Strength-interval curves were determined to assess excitability and refractoriness. Multiple cycle lengths were used to establish rate-dependent changes. Flutter cycle length increased after flecainide (to 290 +/- 67 ms) or procainamide (to 295 +/- 54 ms). The flutters always terminated abruptly (flecainide dose 103 +/- 104 mg, plasma concentration 370 +/- 21 ng/ml; procainamide dose 1,150 +/- 686 mg, concentration 51 +/- 24 mg/l). Flecainide caused an increase in diastolic thresholds from 0.3 +/- 0.2 to 0.8 +/- 0.5 mA (p < 0.006) and procainamide from 0.5 +/- 0.3 to 0.9 +/- 0.5 mA (p < 0.02). The increase in threshold was frequently dependent. Procainamide increased refractoriness at longer cycle lengths (> or = 250 ms), but this effect was abolished at shorter cycle lengths, indicating that only after significant slowing of the rate, prolongation of refractoriness may appear. Thus, both drugs interrupt reentrant flutter mainly by reducing excitability. Subclassification into IA and IC may be less relevant at high rates. Construction of strength-interval curves and assessment of rate-dependent "postrepolarization refractoriness" should be considered when one studies drugs that influence excitability.
BACKGROUND: Because the anatomic features of the cavotricuspid isthmus (CTI) are complex, radiofrequency (RF) energy requirements for CTI ablation may vary at each point within the CTI. Conventionally, multiple-site mapping has been required for determining CTI conduction block. OBJECTIVES: The purpose of this study was to develop a more efficacious method for ablation of isthmus-dependent atrial flutter. METHODS: Forty consecutive patients underwent CTI ablation using a CTI mapping-guided approach (20 patients) or a conventional approach (20 patients). In the CTI mapping-guided approach, an octapolar catheter was positioned on the CTI parallel to, and downstream from, the intended ablation line in order to map and ablate the breakthrough point. RESULTS: Complete CTI block was achieved in all study patients. CTI mapping of incomplete ablation lines revealed that the site with the shortest interval between double potentials did not always coincide with the conduction gap. Disappearance of a breakthrough pattern on the CTI electrograms corresponded to creation of complete CTI block. During ablation, CTI mapping exhibited pseudo-CTI block in 8% of patients in the clockwise direction and 63% of patients in the counterclockwise direction. The number and total time of RF applications were significantly lower with the CTI mapping-guided approach than with the conventional approach (7.7 +/- 3.9 applications vs 13.8 +/- 8.9 applications and 8.9 +/- 4.4 minutes vs 16.3 +/- 11.9 minutes, respectively, P <.05). In the CTI mapping-guided approach, RF applications were not required along the entire CTI in 7 patients (35%). CONCLUSION: This simplified technique was feasible for creating and determining complete CTI block, with fewer RF applications required.
Tablets of ethacizine (a phenothiazine series agent) were used for relieving paroxysms of atrial fibrillation and flutter in 30 patients during 103 attacks. The agent produced a favourable effect in 15 patients in 80 paroxysms of atrial fibrillation. The mean time of sinus rhythm recovery was 1.9 hours. It is effective when given in a single dose of 100 mg with its subsequent administration 6 hours later in the absence of the effect. This agent administered in 50 mg dose produced no results. This scheme of relieving paroxysms of atrial flutter was useful when they lasted not more than 7 days; it is not recommended in initial disturbances of intraventricular conduction. Ethacizine tablets can be used both under hospital and outpatient conditions.
Adenosine has been proposed as a useful diagnostic agent in patients with narrow complex regular tachycardia of uncertain origin. Its effects are usually transient owing to its extremely short plasma half life and, as a consequence, it is thought to be safer than other drugs used in the acute treatment of such arrhythmias. However, adenosine had a proarrhythmic effect when administered to a patient in order to confirm the diagnosis of atrial flutter. As expected, a transient increase in atrioventricular block was seen but this was followed by a doubling of the ventricular rate and haemodynamic compromise requiring immediate DC cardioversion. It is postulated that the secondary catecholamine-mediated effects of adenosine were responsible for this phenomenon.
INTRODUCTION: The cavotricuspid isthmus can be ablated using an anatomic approach or an electrogram mapping approach in which sites at which there is a gap in the line of block are targeted. The aim of this study was to compare the anatomic and electrogram mapping approaches for creating a line of block in the cavotricuspid isthmus after an initial, unsuccessful anatomically directed ablation line. METHODS AND RESULTS: The subjects of this study were 63 patients with isthmus-dependent atrial flutter in whom a single series of contiguous applications of radiofrequency energy guided by fluoroscopy in the cavotricuspid isthmus did not result in complete block. The patients were randomly assigned to additional ablation on an anatomic basis (n = 31) or guided by single potentials or narrowly split double potentials during coronary sinus pacing (n = 32). After every 15 applications of radiofrequency energy, the alternate approach was used until complete block was achieved. Before cross-over, complete block was achieved in 6 patients (19%) with the anatomic approach compared with 19 patients (59%) with the electrogram mapping approach (P < 0.005). The electrogram mapping approach also was more effective than the anatomic approach in achieving complete isthmus block after the first cross-over (72% vs 23%, P < 0.005) and after the second cross-over (80% vs 42%, P < 0.05). CONCLUSION: When there is incomplete block after an initial series of applications of radiofrequency energy in the cavotricuspid isthmus, complete block is achieved more efficiently with an electrogram mapping approach than with an anatomic approach.
Cardiac arrhythmias have troubled patients and fascinated physicians for centuries. The twentieth century was an era of progress, when the mechanism of cardiac disorders became more commonly recognised. Arrhythmias may be due to abnormalities of automaticity, to abnormalities of conduction, or to a combination of both. In order for re-entry to occur, an area of slowing conduction combined with unidirectional block must be present. Much investigation has centred on the underlying re-entry mechanisms of atrial flutter. In the light of these facts, it would seem that a close acquaintance with the detailed topography of the vena cava orifice (cavo), coronary sinus orifice (sinus) and the attachment of the septal leaflet of the tricuspid valve (tricupid) area could be of great interest, especially for invasive cardiologists. The research was conducted carried out on material consisting of 41 hearts of humans of both sexes from the age of 12 to 80 (6 female, 35 male). Classical macroscopic methods of anatomical evaluation were used. The following measurements were made: the shortest distance between the Eustachian valve and the attachment of the tricuspid valve on the left margin of the coronary sinus orifice (diameter 1), the distance between the attachment of the tricuspid valve and the inferior margin of the sinus orifice (diameter 2), the distance between the Eustachian valve and the attachment of the tricuspid valve on the right margin of the coronary sinus orifice (diameter 3), the distance between the inferior margin of the vena cava inferior and the attachment of the tricuspid valve (diameter 4) and, finally, the diameter between the attachment of the septal cusp of the tricuspid valve and the extemal border of the vena cava inferior (diameter 5). No correlation was found between the age and sex of the three groups of the material. The dimensions of the structure examined were similar in the three groups of hearts. In young adult hearts all the diameters measured ranged from 4 to 47 mm. The average diameters were, respectively: 15.02 mm (diameter 1), 8.97 mm (diameter 2), 17.27 mm (diameter 3), 26.87 mm (diameter 4), 36.42 mm (diameter 5). In the mature adult hearts all the diameters measured ranged from 8 to 45 mm; 18.19 mm (diameter 1), 10.54 mm (diameter 2), 19.95 mm (diameter 3), 28.90 mm (diameter 4), 39.63 mm (diameter 5). In the older adults hearts all the diameters measured ranged from 4 to 47 mm. The average diameters were, respectively: 15.65 mm (diameter 1), 8.70 mm (diameter 2), 7.25 mm (diameter 3), 26.80 mm (diameter 4), 35.85 mm (diameter 5). On the basis of our study we were able to conclude that the diameters of the cavo-sinus-tricuspid area were constant and did not differ significantly within the three (young, mature, old) adult groups examined.
A patient with episodes of palpitation in whom the electrocardiogram showed a right bundle branch (RBBB) configuration and right axis deviation underwent electrophysiologic study and radiofrequency ablation. Left ventricular endocardial mapping during ventricular tachycardia (VT) identified the earliest ventricular activation in the anterolateral wall of the left ventricle. The fused Purkinje potential was recorded at that site, and preceded the QRS complex by 47 mseg, with pace mapping showing an optimal match between the paced rhythm and the clinical VT. The stimulus to QRS time was equal to the Purkinje potential-QRS time. Several radiofrequency lesions were applied in this region, one of them resulted with termination of the tachycardia. Following delivery of this lesion the ventricular tachycardia couldn't be induced either at baseline or during isoproterenol infusion. During VT, atrial fibrillation and atrial flutter were observed, cardioversion was performed reverting to sinus rhythm.
PURPOSE: Radio frequency treatment in cardiology generates short acute pain during the heating process. The present study evaluates two techniques used for sedation/analgesia for this procedure. METHODS: Two groups of 20 patients each were studied prospectively. Patients were randomized to receive sedation for the procedure using either a patient-controlled analgesia device with remifentanil (Group R), or a target controlled infusion of propofol (Group P). Patients in Group R had a basal infusion of remifentanil 0.02-0.04 microg x kg(-1) x min(-1) with self administered bolus doses of 0.3 microg x kg(-1) i.v. every minute as required, with a delivery time greater than 30 sec. Patients in Group P had an initial plasma target concentration set at 3-4 microg x mL(-1). RESULTS: Sedation scores were significantly higher in Group P, and two patients required supplementation with remifentanil and insertion of an laryngeal mask airway. Pain scores were higher in Group R, and two patients experienced muscular rigidity, one with transient apnea. Systolic blood pressure decreased significantly in Group P, and at the end of the procedure, PaCO(2) values were higher in that group (P < 0.01). Recovery time was significantly longer in Group P. Patient and physician satisfaction scores were similar in the two groups. CONCLUSIONS: A basal infusion of remifentanil plus remifentanil patient controlled analgesia and target controlled infusion of propofol were adequate but not optimal techniques for sedation/analgesia for radio frequency treatment of atrial flutter.