Search

Introduction: The efficacy and outcome of cavotricuspid isthmus ablation guided by local electrogram-based criteria of linear block were prospectively assessed., Methods and Results: In 40-consecutive patients (age 65+/-11 years) with typical right atrial (RA) flutter (cycle length = 255+/-31 msec), radiofrequency (RF) energy was delivered at electrograms in the isthmus coinciding with the center of the ECG plateau until termination of flutter, followed by local assessment of isthmus conduction during slow rate low-lateral RA pacing. 'Gaps' in the ablation line were located in the form of single or fractionated potentials centered on the isoelectric intervals of adjacent double potentials and ablated. Complete linear isthmus block was defined by the achievement of a complete corridor of parallel double potentials from the right ventricle to the inferior vena cava edge. Applications of 11+/-7 RF applications were required in all patients to achieve a complete line of double potentials separated by an isoelectric interval of 120+/-26 msec (range 60 to 190). After 6+/-3 RF applications, 6 (15%) patients had evidence of isthmus block using indirect RA activation sequence mapping without a complete line of double potentials. 5+/-5 further RF applications of eliminated local conduction and achieved complete linear block without altering descending septal RA activation. Conduction recovery occurred in 20 (50%) patients--1.85 times per patient-indicated by reversed changes in local electrograms eliminated by further ablation of the recovered gaps. After discharge, two recurrences (5%) occurred during a follow-up of 16+/-2 months., Conclusion: Double potential mapping is an effective assessment modality for local isthmus conduction. Slow conduction limited to the ablation line is observed during ablation in 15% of patients.

We performed radiofrequency catheter ablation (RFCA) in 12 consecutive patients (17-77 years) with daily, symptomatic, monomorphic ventricular ectopy (VE) (12,096 +/- 3,326 on 24-hour Holter) resistant to antiarrhythmic drugs. Nine patients had no apparent structural heart disease, 1 patient had a mild dilated cardiomyopathy, 1 patient had a treated mitral stenosis, and 1 patient had arrhythmogenic ventricular dysplasia. VE morphology was LBBB with inferior axis in 9 patients, RBBB with inferior axis in 2 patients, RBBB with superior axis in 1 patient. None of the patients had spontaneous or inducible sustained ventricular tachycardia. The VE focus was targeted with RF energy at the earliest endocardial activation site and based on a matching 12-lead ECG pace map. The VE focus was localized in the right outflow tract in 9 patients and on the left ventricle in 3 patients. RFCA was delivered with a standard 4-mm tip electrode. The ablation was initially successful in 11 patients and unsuccessful in 1 patient. All successfully ablated patients were asymptomatic and discharged without antiarrhythmic drugs. During follow-up (25 +/- 8; 17-38 months), two patients had a recurrence of symptoms, which were controlled by a previously ineffective drug. At the end of follow-up, 1,329 +/- 3198 VE were observed on Holter monitoring (P < 0.001 compared with initial values). No short- and long-term complications were observed. RFCA is a safe and effective method for treating drug-resistant symptomatic monomorphic VE in carefully selected patients. A persistent benefit without complications was obtained over a 2-year follow-up.

A patient with marked first-degree AV block and a DDDR pacemaker presented with a history of paroxysmal narrow QRS tachycardia, subsequently identified as sinus tachycardia (with a very long PR interval), causing a clinical problem similar to pacemaker syndrome because of loss of AV synchrony. The latter resulted from an excessively long postventricular atrial refractory period (PVARP) that prevented sensing of sinus P waves. The unfavorable hemodynamics caused reflex sinus tachycardia. The long PVARP was mandated by the mode switching algorithm of this particular device and was automatically set according to the selected tachycardia detection rate. The patient became asymptomatic when the mode switching function was turned off and the PVARP shortened.

The objective of this study was to test the influence of bisoprolol and verapamil on left ventricular filling in hypertensive patients in a 6 month randomized, double-blind trial in 54 hypertensive patients not previously treated with beta-blockers or calcium inhibitors. After administration of placebo for 14 days, an M echocardiogram of the left ventricle was recorded to determine left ventricular mass. Blood flow was evaluated by pulsed Doppler sonography. After randomization into two groups, one group received 10 mg of bisoprolol and the other 240 mg of verapamil LP in a single dose in the morning. After 2 months' treatment, the patients whose blood pressure was not well controlled were given a diuretic. Echo-Doppler was performed again by the same operator after 4-10 days on active treatment, after 6 months and after a subsequent 2 weeks of placebo for the patients treated with a single drug. The reduction in blood pressure was comparable in the two treated groups, but there was no significant decrease in left ventricular mass. Left ventricular filling was improved only in the patients receiving bisoprolol. The effect was observed immediately after the first administration and throughout the 6 months' treatment period declining slowly during the placebo wash-out. This effect appeared to be independent of any alteration in heart rate and was thought to be a specific action of this drug.

RF catheter ablation is highly effective in eliminating atrioventricular nodal reentrant tachycardia by targeting the slow pathway in the posteroinferior part of Koch's triangle in the right atrium. We report here a patient in whom "slow-fast" atrioventricular nodal reentrant tachycardia was eliminated only by ablation of the slow pathway in the left atrial posteroseptal region at the level of the mitral annulus after unsuccessful attempts at the traditional site on the right side.

Background: Activation mechanisms through gaps in ablation lines and resulting electrograms are poorly understood., Methods and Results: Eight patients (all men; age, 59+/-9 years) were studied during a recurrence of typical atrial flutter (cycle length, 233+/-19 ms) after a previous catheter ablation in the cavotricuspid isthmus. High-density 3-dimensional mapping of the isthmus was performed with the Cordis-Biosense EP Navigation system, and local conduction velocity (CV) was estimated. Maps created with 96+/-19 points revealed 0.8+/-0.3-cm gaps of recovered conduction in the ablation line. A broad wave front entered the lateral isthmus with a CV of 1.8+/-0.7 m/s, halted on the lesion line, and penetrated slowly through the gap with a CV of 0.3+/-0.1 m/s. Activation then curved and returned antidromically to activate the downstream flank of the line with a CV of 1.1+/-0.7 m/s. This front fused downstream of the line with slow transverse activation (CV, 0.4+/-0.3 m/s) parallel to it. The ablation line was demarcated by an incomplete line of convergent double potentials with isoelectric intervals (from 123+/-34 to 62+/-16 ms); each potential corresponded to local activation upstream and downstream of the lesions, while the intervening delay was produced by slow conduction through the gap combined with the progressively longer curved pathway of downstream antidromic activation as a function of distance from the gap., Conclusions: High-density isthmus mapping during recurrent flutter indicates slow conduction through gaps of recovered conduction of varying dimensions in the ablation line followed by a curved front of activation antidromically activating its downstream flank, this detour producing wide double potentials on the line.

Transcatheter radiofrequency (RF) ablation of atrial fibrillation or flutter requires the creation of linear lesions. However, conventional catheters are not predictably effective because of poor endocardial contact, and limited lesion size and penetration. The purpose of the study was to assess in the right atrium, the efficacy and safety of a new catheter designed to create long myocardial tissue lesions using RF energy. The main characteristics of this 8 Fr deflectable RF ablation catheter were: (1) a perpendicularly contacting articulated bilimb electrodes ensuring stable and firm endocardial firm contact; and (2) an irrigated planar interface. Three different electrode prototypes were tested. Fourteen anesthetized sheep weighing 61 +/- 7 kg underwent RF ablation in the right atrium using three incremental power levels (25 to 45, 50, 55 to 75 W) with the aim of creating fully transmural (FT) lesions, defined as continuous and complete epicardial and endocardial lesion imprints. The animals were euthanized 1 hour later for macroscopic and histologic examinations. Forty-three of the 80 right atrial lesions created, in smooth as well as in trabeculated areas, were FT. The percentage of FT lesions increased with the applied power from 37% with 25-45 W, to 49% with 50 W, and up to 86% for 55-75 W. In all but two cases, histologic examination showed no discontinuity between FT lesions produced by both limbs resulting in 19 coalescent linear lesions with an average size of 25 x 6 x 4 mm (length x width x depth). In situ bipolar electrograms after ablation in the FT group showed split potentials and/or a marked decrease in amplitude from 2.85 +/- 1.79 to 0.33 +/- 0.14 mV (P = 0.001) accompanied by near complete disappearance of unipolar electrograms. There was no perforation due to RF ablation. In conclusion, continuous and FT lesions can be achieved in various areas of sheep atria, including the trabecular right atrium, with a perpendicularly contacting bilimb electrode catheter. It represents a promising tool for catheter ablation of atrial fibrillation and flutter.

Unlabelled: Catheter ablation of paroxysmal atrial fibrillation using long linear lesions in the right atrium is still under investigation, and its long-term follow-up is unknown., Methods: Thirty-six men and nine women (aged 51 +/- 12 years) with symptomatic daily episodes of AF for 6 +/- 5 years despite the use of 4.7 +/- 1.5 antiarrhythmic drugs were studied between July 1994 and January 1996. Progressively longer ablation lines were performed in 3 groups of 15 consecutive patients each, using a 14-electrode catheter or a single-electrode dragging technique. Success was defined as atrial fibrillation elimination or recurrence for no longer than 6 hours over 3 months of observation. Patients who had fewer than 6 hours of atrial fibrillation per month were considered "improved." Medium- (11 +/- 4 months) and long-term (26 +/- 5 months) results were assessed clinically from a patient's diary and from Holter recordings., Results: After a follow-up of 11 months, 24 patients had a favorable result of the ablation procedure with or without additional antiarrhythmic drug therapy, representing 53% of the original cohort. After 26 +/- 5 months of follow-up, these successful results were reduced to 17 patients (37%)., Conclusions: After linear atrial ablation, a significant long-term attrition of arrhythmia-free patients was observed. This may be due to a combination of disease progression, incomplete linear block, and ineffective ablation of arrhythmogenic triggers.

Simultaneous right and left ventricular pacing was performed in a 73-year-old man with coronary artery disease end-stage congestive heart failure and a DDD pacemaker implanted for sick sinus syndrome. An endocardial LV lead was introduced transseptally after unsuccessful attempts to enter the coronary sinus. This new approach for multisite pacing offers an alternative to epicardial LV from the coronary sinus or by thoracotomy.

Background: Atrial fibrillation, the most common sustained cardiac arrhythmia and a major cause of stroke, results from simultaneous reentrant wavelets. Its spontaneous initiation has not been studied., Methods: We studied 45 patients with frequent episodes of atrial fibrillation (mean [+/-SD] duration, 344+/-326 minutes per 24 hours) refractory to drug therapy. The spontaneous initiation of atrial fibrillation was mapped with the use of multielectrode catheters designed to record the earliest electrical activity preceding the onset of atrial fibrillation and associated atrial ectopic beats. The accuracy of the mapping was confirmed by the abrupt disappearance of triggering atrial ectopic beats after ablation with local radio-frequency energy., Results: A single point of origin of atrial ectopic beats was identified in 29 patients, two points of origin were identified in 9 patients, and three or four points of origin were identified in 7 patients, for a total of 69 ectopic foci. Three foci were in the right atrium, 1 in the posterior left atrium, and 65 (94 percent) in the pulmonary veins (31 in the left superior, 17 in the right superior, 11 in the left inferior, and 6 in the right inferior pulmonary vein). The earliest activation was found to have occurred 2 to 4 cm inside the veins, marked by a local depolarization preceding the atrial ectopic beats on the surface electrocardiogram by 106+/-24 msec. Atrial fibrillation was initiated by a sudden burst of rapid depolarizations (340 per minute). A local depolarization could also be recognized during sinus rhythm and abolished by radiofrequency ablation. During a follow-up period of 8+/-6 months after ablation, 28 patients (62 percent) had no recurrence of atrial fibrillation., Conclusions: The pulmonary veins are an important source of ectopic beats, initiating frequent paroxysms of atrial fibrillation. These foci respond to treatment with radio-frequency ablation.

Background: Catheter ablation of typical right atrial flutter is now widely performed. The best end point has been demonstrated to be bidirectional isthmus block. We investigated the use of irrigated-tip catheters in a small subset of patients who failed isthmus ablation with conventional radiofrequency (RF) ablation., Methods and Results: Of 170 patients referred for ablation of common atrial flutter, conventional ablation of the cavotricuspid isthmus with >21 applications failed to create a bidirectional block in 13 (7.6%). An irrigated-tip catheter ablation was performed on identified gaps in the ablation line according to a protocol found to be safe in animals: a moderate flow rate of 17 mL/min and temperature-controlled (target, 50 degrees C) RF delivery with a power limit of 50 W. Bidirectional isthmus block was achieved in 12 patients by use of a mean delivered power of 40+/-6 W with a single application in 6 patients and 2 to 6 applications in the other 6. No side effects occurred during or after the procedure., Conclusions: Irrigated-tip catheter ablation is safe and effective for achieving cavotricuspid isthmus block when conventional RF energy has failed.

Left ventricular hypertrophy is associated with a high risk of cardiovascular complications in all the populations in which it has been studied, especially in hypertensive patients. The echocardiographic measurements of left ventricular mass provides a quantitative approach to this risk, independent of the classical cardiovascular risk factors. It is very tempting to wish to replace the measurement of risk factors which, due to their great variability, are not easy to assess (blood pressure) by a marker which integrates several of them (blood pressure, age, weight, salt intake, blood viscosity, serum cholesterol ...) and their variation with respect to time. However, it is too early to recommend this practice for routine use. M mode echocardiographic measurement of left ventricular mass is relatively difficult technique feasible only in about 80% of the population. Even in the hands of experts, its reproducibility is far from perfect. Technical developments may lead to improvement. It remains to be demonstrated that the use of these values improves the management of hypertensive patients and this will not be an easy task. However the follow-up of left ventricular mass during treatment may be an alternative to trials of morbi-mortality in hypertensive patients with the advantage of requiring a shorter follow-up period and fewer patients. It also remains to be demonstrated that regression of left ventricular hypertrophy is accompanied by a corresponding reduction in cardiovascular complications.

We evaluated the effect of atrial overdrive on the incidence of atrial arrhythmias (AA) in 22 patients (67 +/- 9 years, 7 women, 15 men) with Chorus 6234 DDD pacemakers. Atrial overdrive was defined as a programmed paced rate 10 ppm faster than the mean ventricular rate stored for the last 24-hour period in the pacemaker memory. The protocol consisted of three phases of 1 month each. Phase I: observation after discontinuation of antiarrhythmic therapy. Phase II: arrhythmia analysis using the pacemaker memory after programming the lower rate to 55 ppm. The fallback function and histogram data were used to document the number and maximal duration of AA episodes as well as the total AA time in a month. Phase III: atrial overdrive. The mean ventricular heart rate was 65 +/- 4 beats/min before atrial overdrive versus 75 +/- 5 with atrial overdrive (P = 0.02). At the end of phase II, all patients presented with AA episodes (mean number per patient: 42 +/- 78 in one month). In phase III (with atrial overdrive), 14 (64.6%) patients had no recorded AA (group A). In the other eight patients with persistent AA episodes in phase III (group B), there was a significant reduction in the number of AA episodes (90 +/- 106 in phase II vs 38 +/- 87 in phase III; P = 0.01), their total duration (166 +/- 115 in phase II vs 92 +/- 134 hours in phase III; P = 0.03) and their maximal duration (121 +/- 103 in phase II vs 85 +/- 89 min; P = 0.04). Our short-term data suggest that atrial overdrive prevents or reduces AA episodes and demonstrate the feasibility and need of long-term studies to determine whether this benefit is sustained.

Special software allowing the memorization of 24-hour minute ventilation can be loaded into the memory of the Chorus RM, a DDDR pacemaker driven by minute ventilation. This feature was tested in the postimplant period in 13 patients. Measurements of minute ventilation, respiratory rate, and respiratory amplitude were analyzed according to prospectively defined diurnal and nocturnal time periods. Minute ventilation decreased by 39% (P < 0.001) from the diurnal to the nocturnal phase, while respiratory rate and amplitude decreased by 18% and 28%, respectively (P < 0.001 each). Thus, minute ventilation allowed discrimination between sleep and waking hours. This information could be utilized to modulate the backup rate of the pacemaker.

To optimize programming of rate adaptive pacemakers (RAPs), we explored a new mathematical method to assess the performance of RAPs during daily-life tests, using customized Windows-based software. By stepwise discriminant analysis and linear regression, this method allows calculation of the acceleration and deceleration capacity of pacemakers and their general behavior during effort and recovery phases. Twenty-three patients (10 females and 13 males; 68 +/- 8 years) with chronic atrial fibrillation and a slow ventricular response were evaluated. They randomly received an accelerometer-controlled VVIR Dash Intermedics pacemaker (10 patients) or a vibration piezoelectric-controlled VVIR Sensolog III Siemens pacemaker (13 patients). All patients underwent the same test protocol: 6 minutes walking, 1.5 minutes climbing stairs, 1.5 minutes descending stairs, and 0.5 minutes sit-ups. By definition, the pacemaker responsiveness slope was programmed so that the heart rate response of paced patients during the walking test corresponded best to that of healthy controls. The slope was left unchanged for the other tests. We considered four scores: an acceleration score (EA score), an effort rate score (ER score), a deceleration score (RD score), and a recovery rate score (RR score). Scores ranged from -10 (hypochronotropic behavior of the pacemaker) to +10 (hyperchronotropic behavior), based on daily-life tests of 15 healthy controls (7 females and 8 males, 65 +/- 9 years). A score of 0 represented exact concordance with healthy controls. During stair descent, the Sensolog III produced excessive acceleration (EA score = +2.9 +/- 1.1) compared to: (1) stair climbing (EA score = -4.0 +/- 1.9; P = 0.01, with the same pacemakers); and (2) the Dash (+1.8 +/- 1.9; P = 0.04) and healthy controls (P = 0.02). The sit-up tests revealed a hypochronotropic response of both pacemakers compared to healthy controls, with a larger difference for the Sensolog III (EA score = -2.0 +/- 5.8; P = 0.04; RD score = -6.8 +/- 3.8' P = 0.02). We conclude that activity-driven pacemakers can accommodate brief activities, except for isovolumetric exercise such as sit-ups. During daily activities, accelerometer-driven pacemakers seem to provide a heart rate resoibse closer to that of healthy controls. Our new mathematical analysis is a simple and reproducible method for evaluating and quantifying the efficacy of any sensor-driven pacemaker.

Background: The full circuit of common atrial flutter using conventional methods of sequential or multielectrode activation mapping is not completely understood., Methods and Results: We performed three-dimensional right atrial endocardial activation mapping during common counterclockwise atrial flutter in 17 patients (16 men, 1 woman; mean age, 53+/-11 years) by using the Cordis-Biosense EP Navigation system and assessed the distribution of estimated conduction velocities and double and fractionated potentials. ECG flutter wave morphologies were compared with activation patterns. Points (91+/-29) were sequentially acquired covering 88+/-11% of the flutter cycle length of 239+/-22 ms. A wide and variable posterior zone of double and fractionated potentials coincided with blocking and colliding wave fronts and formed the posterior limit of the circuit. A progressively widening septal (sep) wave front ascending from just beyond the coronary sinus ostium, passed cranially as a broad front anterior to the superior vena cava (SVC) in 14 patients, whereas fusion around the SVC formed the superior (sup) limb of the circuit in 3. Bounded anteriorly by the tricuspid valve, the wave front descended down the lateral (lat) aspect of the right atrium before completing the circuit in all cases through the inferior vena cava-tricuspid annulus isthmus. The estimated conduction velocity in the medial isthmus (0.6+/-0.3 m/s) was lower than in the other limbs of the circuit (sup=1+/-0.5 m/s, lat=1+/-0.5 m/s, sep=0.9+/-0.4 m/s, P=.05). Double and fractionated potentials were constant and more prevalent in the posterior right atrium. ECG flutter wave morphology did not correlate with three-dimensional activation maps., Conclusions: Interindividual variations occur in the right atrial circuit of common atrial flutter, with constant activation through the cavotricuspid isthmus. A variable zone of block forms the posterior limit. Fusion around the SVC can occur, and ascending medial septal activation does not follow a consistent pattern.

Atrioventricular junctional reentrant tachycardia (AVJRT) is the most common form of paroxysmal regular supraventricular tachycardia. In patients with disabling, drug refractory AVJRT, catheter ablation has evolved rapidly from a last-resort treatment in the form of interruption of atrioventricular (AV) conduction to selective modification of AV nodal function as an ideal treatment. This article will focus on the frequently unappreciated electrophysiological activities recordable in man in Koch's triangle during ablation of the so-called slow pathway.

Although a negative retrograde P wave in lead I during orthodromic reciprocating tachycardia is thought to indicate a left free wall accessory pathway, we describe similar negative P waves in lead I during orthodromic reciprocating tachycardia through anteroseptally situated accessory pathways.

Calculation of left ventricular mass by M mode echo is based on the assumption that the geometry of the left ventricle is an ellipsoid, the long axis of which is twice that of its short axis. The hypothesis in not always true and often leads to overestimation of the ventricular mass. The authors propose a method combining M mode data (end diastolic dimension, septal and posterior wall thickness) and 2D measurement of the left ventricular long axis: the left ventricular mass was measured by Devereux's and the authors' methods in 185 hypertensives. The 2D measurement of the long axis (mean: 84.7 mm) was much smaller than twice the short axis (mean: 52.3 mm) and the two measurements were poorly correlated. Measurement of the long axis was reproducible. The two methods of calculation were closely correlated (r = 0.95) but, on average, 23% lower with the authors' method. These results seem to be more closely related to ambulatory blood pressure than those of the classical method. The authors' combined method takes into account the true geometry of the left ventricle better than M mode method alone and avoids overestimation of left ventricular mass and the prevalence of excentric left ventricular hypertrophy in hypertensive patients.

Background: Atrial fibrillation is usually thought to be due to multiple circulating reentrant wavelets. From previous studies, a focal mechanism is considered to be very unlikely. In this report, focal atrial fibrillation is defined on an ECG pattern of atrial fibrillation and later demonstrated to be due to a focal source., Methods and Results: Nine patients (five men and four women, age, 38 +/- 7 years) with paroxysmal focal atrial fibrillation are reported here. All were free of structural heart disease and had frequent episodes of atrial fibrillation despite the use of a mean of 4 +/- 2 antiarrhythmic drugs. Atrial fibrillation was associated with runs of irregular atrial tachycardia or monomorphic extrasystoles. The electrophysiological study demonstrated that all the atrial arrhythmias were due to the same focus firing irregularly and exhibiting a consistent and centrifugal pattern of activation. Three foci were found to be located in the right atrium, two near the sinus node and one in the ostium of the coronary sinus. Six others were located in the left atrium at the ostium of the right pulmonary veins (n = 5) and at the ostium of the left superior pulmonary vein (n = 1). All atrial arrhythmias were successfully treated by use of a mean of 4 +/- 4 radiofrequency pulses., Conclusions: In some patients, the surface ECG pattern of atrial fibrillation is due to a focal rapidly firing source of activity that can be eliminated by discrete radiofrequency energy applications.

Introduction: The purpose of this study was to evaluate the efficacy and safety of radiofrequency (RF) catheter ablation of common atrial flutter and to determine the optimum target sites in a large series of patients. Three different approaches were used to target the ablation site. The first used a combined anatomic and electrophysiologic approach, whereas the second and the third approaches relied primarily on anatomic guidelines to target the critical area in the atrial flutter reentrant circuit located in the low right atrium., Background: Recent studies report the efficacy of RF current application in the low right atrial region to interrupt and prevent recurrences of common atrial flutter using either anatomic or electrophysiologic targets. However, larger groups of patients are required to confirm the efficacy of this technique and to specify the target sites., Methods and Results: Two hundred consecutive patients with drug-resistant common atrial flutter were studied. In the first 50 patients, target sites were localized using both anatomic landmarks and electrophysiologic parameters. The anatomic landmarks were area 1 between the tricuspid valve and inferior vena cava orifice; area 2 between the tricuspid valve and coronary sinus ostium; and area 3 between the inferior vena and coronary sinus. The electrophysiologic criterion was to ablate when there was an atrial electrogram occurring during the plateau phase (preceding F wave). The first targeted area was that giving the more stable catheter position. In the following 30 patients, we assessed the effect of RF energy application in a single line to area 1 in the first 10 patients, area 2 in the next 10, and area 3 in the last 10 patients. In the last 120 patients, RF energy was applied only in area 1 using repeated applications. RF energy of 12 to 30 W, or that achieving a temperature of 70 degrees C, was applied for 60 to 90 seconds at each site. The endpoint of the ablation procedure was interruption and noninducibility of common atrial flutter in the first 110 patients and additional isthmal block in 48 of the last 90 patients. Overall, atrial flutter was interrupted and rendered noninducible after a single session in 191 (95%) patients and could not be interrupted in 9 (4.5%) patients. The mean number of RF applications was 12 +/- 8. After a mean follow-up of 24 +/- 9 months, recurrences occurred in 31 (15.5%) patients, 26 of whom underwent a successful second or third session without further recurrences of atrial flutter. Atrial fibrillation not documented before the ablation was detected in 11 patients. On a retrospective analysis of the final successful site in the first group of 50 patients, the location was in area 1 in 39% of patients; area 2 in 36% of patients, and area 3 in 25% of patients. Atrial electrograms recorded at these sites showed a single spike pattern in 46% of patients, and double spike pattern (28%) or fractioned electrogram in 26% patients. When lines of RF lesions were placed at several sites, they produced a success rate of 70%, 40%, and 10% at areas 1, 2, and 3 respectively. In the last series of 120 patients, the procedure was successful in 119 patients: 92% of whom were successfully treated only by a linear lesion between the tricuspid annulus isthmus and the inferior vena cava, and the other 8% by additional applications near the coronary sinus ostium. No complications were observed., Conclusions: RF catheter ablation of atrial flutter can be done with a high success rate and is safe. The highest success rate is achieved with RF energy applied in the isthmus between the inferior vena cava orifice and the tricuspid valve. However, 15.5% of patients need multiple sessions to achieve success because of recurrence of flutter. Further follow-up is needed to evaluate the long-term effects of this procedure.

Unlabelled: Previous experimental data suggest that atrial activity is homogeneously distributed during paroxysmal atrial fibrillation (AFib). Little is known about this in human paroxysmal AFib., Methods: Twenty-five men and two women (mean age 49 +/- 11 years; five with structural heart disease) with paroxysmal AFib for a mean 5 +/- 6.2 years despite the use of a mean of 3.6 +/- 1.7 antiarrhythmic drugs underwent atrial mapping. The right atrium was divided into four regions: posterior (intercaval), lateral, anterior, and septal. A 14-pole catheter was positioned to assess complex electrical activity defined as the duration of continuous electrical activity or electrograms with FF intervals < 100 ms for 60 seconds (expressed as percentage of time). In addition, the left atrium (divided into three regions: posterior, anterior, and septal) was explored in 12 patients with a multipolar catheter., Results: The complex electrical activity time between all the regions explored was significantly different. In the right atrium, the septal (74% +/- 32%; P = 0.02) and the posterior (63% +/- 32%; P = 0.04) areas were significantly more disorganized than the lateral (22% +/-23%) and anterior (21% +/- 26%) regions. In the left atrium, complex electrical activity was predominant and widely distributed (posterior: 87% +/- 11%; septal: 65% +/- 27%) except in the appendage area (anterior region: 18% +/- 14%)., Conclusions: Quantitative assessment of complex electrical activity in both atria in humans shows heterogeneous temporal and spatial distribution. This may have implications for guiding catheter ablation of AFib.

Flecainide acetate is a powerful antiarrhythmic initially used to treat ventricular arrhythmias. Despite an excess mortality in this indication and in the presence of heart disease, flecainide remains a good antiarrhythmic for supraventricular tachycardias in a healthy heart.

Radiofrequency (RF) catheter ablation is the curative treatment of choice for atrioventricular (AV) nodal reentrant tachycardia (AVNRT). Analogous to the development of surgical techniques, catheter ablation has evolved from AV nodal ablation to selective "fast" and "slow" pathway ablation. "Slow" ablation is now the method of choice because of the lower incidence of associated AV block. Though slow pathway ablation can be achieved with equal success using either the anatomic or the electrogram-guided approach, fewer applications of RF energy are required for the potential-guided technique.

Atrioventricular nodal reentrant tachycardias which, for a long time, could only be treated medically, may now benefit from catheter ablation. The rapid retrograde pathway was an effective initial target but carried a risk of complete atrioventricular block of about 10%. Nowadays, most operators deliver the radiofrequency energy (endocavitary cautery) to the slow nodal pathway. Different techniques of guidance (anatomical, electrophysiological, rapid potential, slow potential) are associated with high success rates: 90 to 100%. However, experimental studies suggest that the slow potentials arise from transitional cells within the tachycardia circuit (the anatomical substrate of the slow pathway). There is still a risk of complete atrioventricular block (1 to 5%) which should be clearly explained to patients referred for ablation of this constantly benign arrhythmia.

Endocavitary catheter ablation by radiofrequency energy applied on the slow pathway is an effective method of treatment of nodal reentrant tachycardias. The aim of this report was to determine the criteria predictive of success during radiofrequency ablation of the slow pathway guided by the presence of slow potentials. Thirty-five patients (21 women, 14 men, mean age 44 +/- 14 years) with frequent attacks of junctional tachycardia were studied. After confirmation of the diagnosis by electrophysiological investigation, radiofrequency energy was delivered at a site characterised by the presence of slow potentials between the atrial (A) and ventricular (V) potentials. The criteria investigated at each site were: before application: A/V ratio; amplitude of A and V: maximum A/minimum A ratio; amplitude and duration of the A potential; during ablation: radiological stability of the catheter position and occurrence of a junctional rhythm. All 35 patients had successful procedures with no inducible tachycardia at the end of the procedure. The slow pathway was destroyed in 20 cases (57%) with no complication of atrioventricular block. The duration of the A potential was longer in the successful cases (56 +/- 16 vs 48 +/- 14 ms; p = 0.04). The appearance of junctional rhythm and catheter stability during the procedure were predictive of success (79% vs 48%; p = 0.02; 74% vs 43%; p = 0.01). The authors concluded that an ablation site with a long duration A potential and a slow potential is a good target. In addition, ablation should be started when the catheter is radiologically stable and should not be interrupted in the absence of a junctional rhythm.

Survival after His bundle ablation for supraventricular arrhythmias was analysed over 10 years (May 1982 to December 1992) in 312 consecutive patients (5 were lost to follow-up): 54 died (17.3%), 13 of sudden death (24%). The survival rates were 94.5% at 1 year (n = 256), 80.1% at 5 years (n = 88), 72.8% at 8 years (n = 20) and 51% at 10 years (n = 4); patients without apparent heart disease had a better prognosis. This series serves as a reference for other techniques of His bundle ablation.

Background: Accessory pathways (APs) with anterograde decremental conduction properties referred to as Mahaim fibers have recently been recognized as originating from the right lateral atrium. Little information is available about their distal insertion. The purpose of this study was to determine the different kinds of APs involved and the characteristics of their distal insertion site., Methods and Results: Twenty-one patients (mean age, 28 +/- 13 years) with reciprocating tachycardia or atrial fibrillation were studied. Right-sided atrial and/or ventricular endocardial mapping during tachycardia identified different types of APs. (1) Seventeen patients had long APs originating from the right lateral atrium and coursing several centimeters to the right ventricle. In 10 patients, the AP terminated in or close to the right bundle-branch system (atriofascicular AP) and in 7, the AP terminated in the anterior right ventricle (atrioventricular AP). Patients with atriofascicular APs had narrower QRS complexes (133 +/- 10 versus 165 +/- 26 milliseconds, P = .02) and narrower initial r wave in leads V2 through V4 during maximal preexcitation than patients with atrioventricular APs. In addition, they had earlier His-bundle and right bundle-branch retrograde activation, ie, shorter V-His (16 +/- 5 versus 37 +/- 9 milliseconds, P < .01) and V-right bundle intervals (3 +/- 5 versus 25 +/- 6 milliseconds, P < .01). In 6 patients, minimal preexcitation not readily apparent was present in sinus rhythm despite the appearance of a narrow QRS complex. A wide distal insertion site of 0.5 to 2 cm in diameter consistent with arborization of the AP was found in 10 patients. The distal application of radiofrequency current produced a change in the preexcitation pattern in 4 patients and ablated the AP in 2 patients. In the other patients, radiofrequency current was applied more proximally and successfully ablated the AP bundle (n = 9) or AP proximal insertion (n = 6). No recurrence was observed during a follow-up period of 12 +/- 10 months. (2) Four patients had short paratricuspid atrioventricular APs; in one, the decremental conduction property was acquired as demonstrated by two electrophysiological studies performed 7 years apart. Radiofrequency ablation was successfully accomplished in all 4 patients at the tricuspid annulus., Conclusions: Different types of APs account for tachycardias previously called Mahaim fibers. Long and short atrioventricular APs are observed in 81% and 19%, respectively. Long APs often have a distal arborization and may have either a fascicular or ventricular insertion. Radiofrequency current is more efficient when applied to the AP bundle or AP proximal insertion rather than to the distal insertion in patients with long APs.

The object of this study was to assess the efficacy and risks of radiofrequency ablation of common atrial flutter and to determine the optimal site of ablation in a large population of patients. Three different methods were used to determine the site of ablation: the first was anatomical and electrophysiological whilst the two others were based essentially on anatomical landmarks for localising the critical zone of the reentry circuit. Recent studies report that radiofrequency ablation is effective in interrupting and preventing recurrences of common atrial flutter both by using anatomical and electrophysiological methods. Nevertheless, a larger series of patients was necessary to establish the efficacy and to determine the optimal site of ablation. A series of 110 consecutive patients with common atrial flutter resistant to antiarrhythmic drugs was studied. The site of ablation of the first 50 patients was determined using both anatomical landmarks and electrophysiological parameters. The anatomical zones were: zone 1, between the septal leaflet of the tricuspid valve and the orifice of the inferior vena cava; zone 2, between the septal leaflet of the tricuspid valve and the ostium of the coronary sinus, and zone 3: between the orifice of the inferior vena cava and the ostium of the coronary sinus. The electrophysiological criterion was an endocavitary auriculogramme occurring during the plateau phase preceding the F wave of the flutter.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular hypertrophy is an important risk factor in hypertension and the results of the HYCAR study confirm that it is possible to treat this risk factor independently of an action on the blood pressure. Should systematic echocardiography be performed in every hypertensive patient to diagnose left ventricular hypertrophy and follow up its outcome with treatment? This attitude seems to be premature for two reasons. Firstly, echocardiography, though much more sensitive than electrocardiography for diagnosing left ventricular hypertrophy, has a number of limitations. Good recordings cannot be obtained in all patients; even under the best conditions of reproducibility, the measurement of left ventricular mass is not excellent and does not allow reliable individual follow-up of treatment; even the criteria of left ventricular hypertrophy used at present are open to criticism. Secondly, it remains to be shown whether the reversibility of left ventricular hypertrophy, independently of lowering the blood pressure, improves the prognosis of the hypertensive patient. The intensive research into this problem, further stimulated by the encouraging results of the HYCAR study, should help define the role and value of echocardiography in the future management of hypertension.

Survival after closed-chest ablation of His bundle with DC shock for supraventricular arrhythmias was analyzed for a 10-year period (May 1982-December 1992) with 317 consecutive patients (167 males, 150 females; mean age 66 years; range 33-93 years). Of these, 54 patients died (17.3%) and 5 were lost to follow-up. The mean age at ablation was 70.3 +/- 8.3 years with a range of 49-93 years. Of those who died, the mean survival was 30.5 +/- 28.6 months with a range of 36 hours to 120 months; the diagnosis of heart disease was: hypertension (n = 14), cardiomyopathy (n = 8), ischemic (n = 7), valvular (n = 6), cor pulmonale (n = 3), valvular and ischemic (n = 2), hypertension and ischemic (n = 1), miscellaneous (n = 3), and none (n = 10). Of the patients who died after ablation, the arrhythmias at the time of the ablation were atrial fibrillation (AF; n = 33), sick sinus syndrome (n = 5), atrial flutter (AFL; n = 4), paroxysmal AV junctional tachycardia (PAVJT; n = 4), AF + AFL (n = 4), atrial tachycardia (n = 2), PAVJT + AFL (n = 1), and AF +AFL + atrial tachycardia (n = 1). Death was sudden in 13 patients (25%), due to heart failure in 10 (19.2%), myocardial infarction in 4 (7.7%), stroke in 4 (7.7%), aortic vascular accident in 3 (5.8%), miscellaneous in 18 (34.6%), and undetermined in 2.(ABSTRACT TRUNCATED AT 250 WORDS)

The introduction of ablative methods has revolutionised therapeutic strategy in cardiac arrhythmias. Accessory pathways are the most commonly targeted arrhythmogenic substrate. Several parameter may be used to determine the optimal site of ablation: accessory pathway potential, atrioventricular interval, atrial or ventricular pole of the pathway, morphology of the unipolar wave. The localisation of the accessory pathway sometimes requires specific techniques. The success rate reported in the literature is generally over 90%. However, the number of applications of radiofrequency current varies according to the authors from an average of three to eight. A combination of "timing related" criteria and direction of activation and the use of infraliminal stimuli minimise the number of radiofrequency applications. The incidence of complications in multicenter registers is 5% and the relapse rate is 8%. The long-term effects of catheter ablation are unknown, especially when used in childhood. A certain reserve should be maintained in the indications of ablation. Only high-risk, life-threatening arrhythmias, or those resistant to pharmacological intervention, are formal indications. Other (so-called "convenience") indications depend on the express wish of patients clearly informed of the advantages and risks of this method.

A retrospective study of 192 patients centered on the outcome of supraventricular arrhythmias after catheter ablation of the atrioventricular junction provided some useful information concerning the choice of pacing mode in these patients. With the exception of atrioventricular bloc after ablation of the rapid nodal pathway where simple DDD pacing is adequate, rate adaptive pacing would seem to be essential. The VVIR mode should be the mode of choice in atrial flutter, permanent atrial fibrillation, poorly controlled atrial fibrillation and paroxysmal atrial fibrillation of elderly subjects (over 70 years) and/or of male sex, and/or complicating advanced cardiac disease (valvular, ischaemic or primary). The DDDR mode (with an algorithm to prevent endless loop tachycardia) is the mode of choice in sinus node dysfunction and/or in young patients (under 60), and/or females and/or in idiopathic arrhythmias and/or when retrograde VA conduction persists. When the pacemaker is replaced, the indication should be reviewed with respect to the outcome of the arrhythmia, which underlines the value of accurate implanted Holter systems.

Ambulatory monitoring of Korotkoff sounds appearance time (QKD interval) was performed during 24 hours in 131 normal subjects (85 males, 46 females, aged 14-78 years, mean 36 +/- 15 years) with a new device (Diasys 200RK, Novacor-France). This device allows simultaneous measurements of blood pressure, heart rate and QKD interval at programmed intervals, every 15 minutes in this study. For each patient we calculated the average 24th QKD interval, the QKD interval for a systolic BP of 100 mmHg and a heart rate of 60 bt/min (QKD: 100-60), and the slope (S) of the variations of the QKD interval against systolic BP and pulse pressure (PP). Results are presented for each 10 years age group (mean +/- SD).

The incidence of sudden death in the Wolff-Parkinson-White (WPW) syndrome is not well documented and probably underestimated. This retrospective study concerned 28 consecutive patients presenting with ventricular fibrillation either spontaneously (20) or during electrophysiological investigation (8) but whose characteristics allowed them to be assimilated into a single group. Their clinical and electrophysiological characteristics were compared with those of 60 consecutive patients with the WPW syndrome who had documented atrial fibrillation (and even reciprocating tachycardia) but never ventricular fibrillation. There were no significant differences between the two groups with respect to the following clinical parameters: sex, duration of symptoms, the type of tachycardia previously recorded, history of syncope and presence of underlying cardiac disease. With respect to the electrophysiological data, there were no differences in the point of anterograde block, the effective anterograde refractory period of the accessory pathway, the effective and functional refractory periods of the right atrium and atrial vulnerability. On the other hand, a significant difference was observed in the age of patients with ventricular fibrillation (29 +/- 13 years vs 36 +/- 12 years; p < 0.02), the prevalence of multiple accessory pathways (25% vs 7%; p < 0.04) with a dominant localisation in the postero-septal region (75% vs 47%, p < 0.026), preexcitation during exercise stress testing and under antiarrhythmic therapy (95% vs 68%, p < 0.037). The most discriminating parameter was the shorter RR interval during atrial fibrillation (172 +/- 23 ms vs 230 +/- 50 ms, p < 0.008). Multivariate analysis only showed one independent predictive factor: the minimum preexcited RR interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheter ablation techniques are now advocated as the first line of therapy for arrhythmias caused by accessory pathways (APs). The most common energy source is radiofrequency current, but technical characteristics vary. Several parameters can be used to determine the optimal target site: AP potential, AV time, atrial or ventricular insertion site, or unipolar morphology. Specific considerations are needed depending on AP location. Despite the different approaches described, there is no significant difference in the reported success rate, which is over 90%. However, the number of radiofrequency applications needed to achieve ablation appears to differ significantly, with median values from 3 to 8 reported. A combination of criteria related to both timing and direction of the activation wavefront or use of subthreshold stimulation could improve the accuracy of mapping. In patients with "resistant" APs, different changes in ablation technique must be considered during the procedure to achieve elimination of AP conduction. The incidence of complications in multicenter reports is close to 4%, with a recurrence rate of 8%. The long-term safety of catheter ablation requires further study.

Junctional tachycardias may be related to intranodal reentry or to the existence of an accessory pathway. All are suitable for radical treatment by radiofrequency current applied either in the perinodal region or at the tricuspid or mitral atrioventricular rings respectively. 176 patients with intranodal reentry were treated by preferential modification of the rapid (8) or slow (167) anterograde pathway of the reentry circuit, with a 99% success rate (1 failure) and without significant complications, in particular atrioventricular block in the case of ablation of the slow pathway. 362 patients with one or more accessory pathways, patent or latent, were treated using the same type of energy. The ablation site was determined on the basis of indirect criteria and/or recording of the specific activity of the accessory pathway. The success rate here was 98%, once again without significant complications with the exception of those inherent to catheterisation procedures. Treatment duration time was 41 +/- 38 min in the treatment of intranodal reentry and 58 +/- 49 when one or more accessory pathways were responsible. X-ray exposure times were 14 +/- 14 min and 23 +/- 21 min respectively. Such results would justify the expectation of widened indications of the method.

There are three fundamental mechanisms of ventricular tachycardia (VT) reentry, abnormal automaticity and triggered activity (TA) related to early or late after potentials. Reentry is certainly the mechanism of branch to branch and post-infarction VT. Early TA is responsible for Torsades de Pointes. Late TA is possibly the cause of certain verapamil-responsive VT but calcium-dependent reentry cannot be excluded. Abnormal automaticity or late TA may also play a role in catecholamine-induced VT. The development of drugs specific for the mechanism confronted with the results of programmed stimulation and mapping should improve the understanding of the mechanism of VT in each individual patient and allow more effective and better tolerated antiarrhythmic therapy.

The aim is the analysis of the P wave on the signal averaged ECG in 31 pts: 12 control pts (6 M, 6 W, 40 +/- 10 y) 12 HTA (9 M, 3 W, 60 +/- 7 y), 7 pts (5 M, 2W, 48 +/- 7 y) with sustained paroxystic atrial fibrillation (AF) without organic heart disease, without antiarrhythmic drugs. We measured the filtered P wave duration (Ad), the integral of Ad, the root mean square voltage of Ad for the last 10, 20, 30, 40, 60 msec and the duration of P wave on the ECG in lead II (P II) and the echocardiographic dimensions of the atria (LAd). HTA Ad (132 +/- 12 msec)* et > control Ad (116 +/- 10 msec) HTA LAd (38 +/- 3 mm) et > control LAd (31 +/- 0.7 mm) HTA PII (120 +/- 1.5 mm)* et > control PII (88 +/- 10 mm). The difference between HTA Ad (132 +/- 12 msec) and AF Ad (129 +/- 7 msec) is not significant. The linear regression tests don't show correlation between P II and Ad and between LAd and Ad in HTA group. There is a correlation between Ad and LAF in AF group (r = 0.83, p 0.02). HTA RMS 2o (2.2 + 0.6 microV), control RMS 2o (3.9 + 1.8 V) but HTA RMS 2o and AF RMS 2o (2.4 +/- 0.6 microV) are not significantly different and are not correlated with LAd and PII. A long duration of P filtered P wave and a low RMS 2o observed in HTA group and AF group would be a criteria of atrial vulnerability. p < 0.05.

Left ventricular hypertrophy (LVH) which is a mechanism of adaptation of the heart to hypertension (HT) may become a cardiovascular risk factor independent of the HT which has caused it. Causing the regression of LVH is thus one of the mid-term aims of antihypertensive therapy. Certain antihypertensive drugs are capable of producing an early and durable regression of LVH: methyldopa, beta-blockers, ACEI, calcium blockers. The effect of mass reduction is moderate or doubtful with diuretics, while it is nil or inconstant with vasodilators. The regression of LVH in HT raises various problems: 1) reliability of the measurement technique, 2) inter-individual and inter-drug variations, 3) favourable nature of regression, 4) preventive effect of regression against cardiovascular complications. Finally, in the light of recent studies it appears that early treatment of HT may prevent the onset of LVH.

Epidemiological data has established a relationship between left ventricular hypertrophy (LVH) and sudden cardiac death. This relationship is independent. The search for ventricular and atrial arrhythmias in hypertensives confirms a greater prevalence of these arrhythmias in patients with LVH. The mechanism of these arrhythmias is multifactorial: ischemia, subendocardial fibrosis, increased sympathetic tone, electrolyte disturbances, age, and hemodynamic changes may be arrhythmogenic substrates both at the ventricular and auricular levels. The relationship between LVH (marker or cause) and the detected arrhythmias remain obscure. The most sensitive markers of severity seem to be the ECG parameters (LVH with overload), echocardiographic mass (greater than + 20%) and septal thickness (greater than 12 mm). The evolution of arrhythmias with regression of LVH is unknown. Respect of electrolyte equilibrium would seem to be the only unquestioned therapeutic intervention.