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G Ndrepepa

Publications and source records attributed to G Ndrepepa.

At least 19 recordsLinked to original sources
PubMed2006

Left and right ventricular diastolic functions in patients with rheumatoid arthritis without clinically evident cardiovascular disease.

The aim of this study was to assess the prevalence of diastolic dysfunction of the left ventricle (LV) and of the right ventricle in patients with rheumatoid arthritis (RA) without clinically evident cardiovascular manifestations and to estimate whether there is a correlation between the duration of RA and the degree of LV diastolic dysfunction. The study included 81 patients (61 females and 20 males) with RA without clinically evident heart disease (group 1) and 40 healthy subjects (29 females and 11 males) who served as a control group (group 2). Both groups were matched for age and sex. Echocardiographic and Doppler studies were conducted in all patients with RA and control subjects. There were significant differences between patients with RA vs. control group with regard to early diastolic flow velocity (E), atrial flow velocity (A) and the E/A ratio (0.68 +/- 0.19 m/s vs. 0.84 +/- 0.14 m/s, p < 0.001; 0.73 +/- 0.15 m/s vs. 0.66 +/- 0.13 cm/s, p = 0.01; and 0.97 +/- 0.3 vs. 1.32 +/- 0.37, p < 0.001, respectively). There was significant difference between groups regarding the right ventricular early diastolic (Er)/atrial (Ar) flow velocities (Er/Ar ratio) (1.07 +/- 0.3 vs. 1.26 +/- 0.3, p = 0.002). There was a weak correlation between transmitral E/A ratio and the duration of RA (r = - 0.22, p = 0.001). Myocardial performance index (MPI) appeared to differ little in patients with RA as compared with control group (0.51 +/- 0.1 vs. 0.52 +/- 0.2, p = NS). In patients with RA without clinically evident cardiovascular disease, the left ventricular diastolic function and the right ventricular diastolic function are reduced. Left ventricular wall thickness, dimensions, systolic function and MPI were found to be normal. LV diastolic function had a weak correlation with the duration of RA.

Arthritis, Rheumatoid↗
PubMed2002

Dissimilar atrial rhythms: coexistence of reentrant atrial tachycardia, atrioventricular nodal reentrant tachycardia and interatrial conduction block.

We report a patient in whom mapping of the right atrium with multipolar catheters and electroanatomic mapping revealed the presence of three dissimilar rhythms: a reentrant atrial tachycardia in the antero-lateral wall of the right atrium and an atrioventricular nodal reentrant tachycardia (AVNRT) isolated from each other and a conduction disturbance at the interatrial septum resulting in a rate-related interatrial block and a slow left atrial rhythm. The AVNRT was stopped with intravenous adenosine (6 mg) and induced repeatedly by atrial extrastimuli associated with a critical atrioventricular delay and dual atrioventricular nodal pathways. Electroanatomic mapping disclosed extensive fibrosis isolating viable myocardium of the antero-lateral wall from the rest of the right atrium. The viable myocardium in the antero-lateral wall was activated by a reentrant rhythm circulating around an islet of fibrosis located in the middle of the viable tissue. The AVNRT was ablated by a standard approach and the reentrant atrial tachycardia by producing a linear lesion bridging the central islet of fibrosis with the anterior tricuspid annulus. This case highlights the complicated nature of some dissimilar atrial rhythms and the power of electroanatomic mapping tools to reveal the exact mechanism and guide radiofrequency ablation.

Adrenergic beta-Antagonists↗
PubMed2001

Modes of initiation of paroxysmal atrial fibrillation from analysis of spontaneously occurring episodes using a 12-lead Holter monitoring system.

Although new, possibly curative radiofrequency ablation techniques for atrial fibrillation (AF) have been developed in recent years, little is known about the mechanisms of spontaneous onset of AF episodes. Using a 12-lead 24-hour Holter monitoring system, we aimed to characterize such episodes. A total of 297 spontaneous episodes of AF in 33 patients with intermittent AF (mean age of 59 +/- 11 years) were analyzed. Two hundred seventy-six episodes (93%) were initiated by atrial premature complexes (APCs), whereas 19 episodes (6.4%) were preceded by typical atrial flutter and 2 (0.7%) by atrial tachycardia. Based on 12-lead electrocardiographic criteria, the origin of ectopic beats initiating AF was classified in 230 episodes (77.5%) as being of left atrial origin, in 6 episodes (2.0%) as being of right atrial origin and in 40 episodes (13.5%) the exact location could not be determined. In 16 of 23 patients (70%) with multiple episodes of AF, ectopic beats that initiated AF were consistently monomorphic. In the 120 seconds (6.2 APCs/min for a 30-second period) before onset of AF, frequency of ectopic beats increased from 0.8 APCs/min in AF-free intervals to 4.1/min (6.2 APCs/min for a 30-second period), (p = 0.003 and p = 0.016, respectively). In 209 of 254 episodes (82%), AF onset occurred during normal sinus rate (60 to 100 beats/min). Thus, paroxysmal AF is triggered most frequently by monomorphic left APCs. In most AF episodes, the increase in the number of ectopic beats that initiated episodes of AF occurred at a normal sinus rate.

Adult↗
PubMed2001

Value of programmed ventricular stimulation for prophylactic internal cardioverter-defibrillator implantation in postinfarction patients preselected by noninvasive risk stratifiers.

OBJECTIVES: The aim of this prospective study was to evaluate the role of programmed ventricular stimulation (PVS) after noninvasive risk stratification to identify a subgroup of acute myocardial infarction (AMI) survivors considered at risk for ventricular arrhythmias and whether these patients could benefit from internal cardioverter-defibrillators (ICDs). BACKGROUND: The predictive value of noninvasive and invasive risk stratifiers after AMI has been questioned. The question of whether the group of patients with inducible monomorphic ventricular tachycardia (VT) after AMI could profit from ICD implantation is unanswered. METHODS: A consecutive series of 1,436 AMI survivors was screened noninvasively by Holter monitoring, heart rate variability, ventricular late potentials, and ejection fraction. A subgroup of 248 patients (17.3%) were identified as high-risk patients and scheduled for PVS. Due to the study design, 54 patients >75 years were excluded; thus, 194 patients were eligible for PVS. Triple extrastimuli at two paced cycle lengths (600 ms and 400 ms) were applied. RESULTS: In a subgroup of 98 (51%) high-risk patients, PVS was performed; 21 patients had an abnormal response, and in 20 patients an ICD was implanted. During a mean follow-up of 607 days the arrhythmic event rate (sudden cardiac death, symptomatic VT, cardiac arrest) was 33% with a positive electrophysiological test versus 2.6% (p < 0.0001) with a negative electrophysiological test. A subgroup of 96 high-risk patients declined electrophysiological study. In this nonconsent group, cardiac mortality (combined sudden and nonsudden) was significantly higher (log-rank chi-square 9.38, p = 0.0022, relative risk 4.7, 1.6 to 13.9) compared to the group guided by electrophysiological testing and consecutive ICD implantation. CONCLUSIONS: After a two-step risk stratification, PVS is helpful in selecting a subgroup of AMI survivors without spontaneous ventricular arrhythmias who benefit from prophylactic ICD implantation.

Defibrillators, Implantable↗
PubMed2001

Reentry circuit location and left atrial three-dimensional activation patterns in left atrial flutter.

We report the case of a patient with left atrial flutter (LAF) in whom the reentry circuit location was mapped with a 64-electrode basket catheter deployed in the left atrium. Left atrial three-dimensional activation patterns were constructed with a software program and presented as color-coded isochrones. The reentrant activation traveled preferentially around the mitral annulus in a clockwise direction. It consisted of a single reentry confined anteriorly by the mitral annulus and posteriorly by an anatomic-functional barrier composed of a functional conduction block extending between pulmonary veins and surrounding a part of the posterior wall of the left atrium. The lower portion of the posterior wall and the anterior wall in close proximity to mitral annulus were preferentially used by the reentrant impulse.

Atrial Flutter↗
PubMed2001

Electrophysiologic characteristics of paroxysmal and chronic atrial fibrillation in human right atrium.

OBJECTIVES: The aim of the study was to analyze the electrophysiologic characteristics of paroxysmal (PAF) and chronic (CAF) atrial fibrillation (AF) in the human right atrium (RA). BACKGROUND: Differences that exist between PAF and CAF and the mechanisms of self-sustenance of these arrhythmias are incompletely understood. METHODS: A total of 53 patients with PAF (25 patients, mean age 59 +/- 6.1 years, 3 women) and CAF (28 patients, mean age 59 +/- 13 years, 7 women) underwent multisite mapping of the RA during ongoing AF using a 64-electrode basket catheter. Quantitative evaluation and three-dimensional activation patterns were performed using a computerized system. RESULTS: Patients with PAF, as compared with patients with CAF, had significantly longer AF cycle length, shorter time intervals with type III AF throughout the RA and a smaller number of endocardial breakthroughs (mean 51 +/- 19 vs. 104 +/- 40, p < 0.001). The majority of endocardial breakthrough points (88% in PAF patients and 98% in CAF patients) were located in the septal region and coincided anatomically with major interatrial connection routes. Coexistence of re-entrant and apparently focal activation determined maintenance of AF in the RA in PAF, whereas random re-entry was documented more frequently in patients with CAF. In patients with CAF, the duration of arrhythmia (in years) correlated strongly with the percentage of time during which type III AF was observed in the lateral wall of the RA (r = 0.71). CONCLUSIONS: Clinical PAF and CAF, as recorded in the RA, have, at least quantitatively, distinct electrophysiologic features and different mechanisms of maintenance.

Aged↗
PubMed2001

Inappropriate shock delivery due to ventricular double detection with a biventricular pacing implantable cardioverter defibrillator.

This report describes a patient with advanced heart failure, pronounced intraventricular conduction delay, and ventricular tachycardias who underwent implantation of a multisite pacing ICD. Pacing leads were placed in the right atrium, right ventricular apex, and to the left ventricular posterior wall via a coronary sinus vein. The system proved to have correct sensing and pacing function in an atrial synchronized biventricular pacing mode and an appropriate detection of ventricular fibrillation. However, 1 month after implantation the patient received an inappropriate shock delivery due to double detection of ventricular premature beats. The inherent detection problem of dual ventricular sensing is discussed.

Defibrillators, Implantable↗
PubMed2001

Internal atrial defibrillation during electrophysiological studies and focal atrial fibrillation ablation procedures.

Induction of sustained AF during electrophysiological studies requires electrical cardioversion to restore sinus rhythm for continuation of the electrophysiological study and mapping procedure. The study included 104 consecutive patients (age 59 +/- 12 years, 74 men), who were in stable sinus rhythm at the beginning of the electrophysiological study, underwent internal atrial defibrillation (IAD) of AF (> 15 minutes) that was induced during electrophysiological study. In 21 patients, AF was regarded to be the clinical problem (group I), and in the remaining 83 patients other arrhythmias represented the primary target of the electrophysiological study (group II). A 7.5 Fr cardioversion catheter (EP Medical) equipped with a distal array was used and placed in the left pulmonary artery and a proximal array of the same size was located along the lateral right atrial wall. All patients were successfully cardioverted with a mean energy of 6.2 +/- 4.0 1. In 18 (78%) of 21 group I patients and in 12 (14%) of 81 group II patients, AF recurred 3.7 +/- 3.4 and 2.4 +/- 1.4 times during electrophysiological study, respectively. The IAD shock did not suppress focal activity, thus the mapping of atrial foci responsible for AF could be continued even after several IADs. No IAD related complications occurred during the study. In conclusion, (1) IAD can be safely and successfully performed during electrophysiological study without using narcotic drugs or high electric energies; (2) IAD does not suppress focal activity; and (3) even if AF recurs frequently during the electrophysiological study, IAD can be performed several times without significant time delay.

Atrial Fibrillation↗
PubMed2001

Noncontact mapping-guided ablation of atrial flutter and enhanced-density mapping of the inferior vena caval-tricuspid annulus isthmus.

Three-dimensional visualization of cardiac activation has become important in providing further insights into pathophysiological mechanisms of arrhythmias and to increase the efficacy of catheter ablation. The noncontact mapping enables a single beat analysis in a reconstructed geometry of the cardiac chamber. The aim of the study was to describe three-dimensional activation patterns and inferior vena caval-tricuspid annulus (IVC-TA) isthmus conduction characteristics in patients with atrial flutter and the noncontact guidance of the radiofrequency ablation of this arrhythmia. In 34 patients with atrial flutter, the noncontact probe was deployed in the RA. The global three-dimensional activation and the isthmus conduction (enhanced density mapping) were delineated during ongoing a trial flutter and paced rhythms. Ablation was performed nonfluoroscopically based on reconstructed anatomy and conduction patterns. Noncontact mapping was compared and validated with conventional multielectrode technique. IVC-TA isthmus ablation was completed successfully in 33 (97%) of 34 patients. In one patient a lower loop reentry around the inferior vena cava was depicted as a mechanism of atrial flutter. In another patient with positive flutter waves in inferior leads, an activation pattern typical of counterclockwise flutter was demonstrated in propagation maps. During a follow-up of 15.9 +/- 5.9 months, two atrial flutter recurrences occurred (5.8%). A gap of the resumed conduction through the IVC-TA isthmus was delineated as a mechanism of recurrence and ablated with one and three radiofrequency applications. Noncontact mapping allows construction of the global activation patterns in typical and atypical atrial flutter. It enables the nonfluoroscopic guidance of atrial flutter ablation and a comprehensive evaluation of the ablation results.

Atrial Flutter↗
PubMed2001

Pseudotermination of intermittent atrial fibrillation by a pacemaker algorithm: antitachycardia pacing without capture miscounted as successful termination of fibrillation episodes.

A patient is described with intermittent AF and an implanted pacemaker which provides preventive pacing and overdrive stimulation designated to terminate atrial arrhythmias. The case highlights the possibility of false estimation of therapeutic efficacy and possible proarrhythmic effect of this therapeutic modality.

Algorithms↗
PubMed2001

Do current dual chamber cardioverter defibrillators have advantages over conventional single chamber cardioverter defibrillators in reducing inappropriate therapies? A randomized, prospective study.

INTRODUCTION: Supraventricular tachyarrhythmias are the main cause of inappropriate therapies in patients with conventional single chamber implantable cardioverter defibrillators (VVI-ICD). It was anticipated that dual chamber cardioverter defibrillators (DDD-ICD), with their capacity to analyze atrial and ventricular rhythm, could substantially reduce inappropriate therapies. METHODS AND RESULTS: Our prospective study included 92 patients (87 men; mean age 61 +/- 12.7 years) who were randomly assigned to a VVI-ICD (45 patients) or a DDD-ICD (47 patients). Both groups were followed for 7.5 +/- 3.5 and 7.6 +/- 4.1 months, respectively. During the follow-up period, overall 725 ventricular tachycardia (VT)/ventricular fibrillation (VF) episodes were recorded in 45 (49%) of 92 patients. Of these episodes, 404 (56%) occurred in the VVI-ICD group and 321 (44%) episodes occurred in the DDD-ICD group. Twenty-three (51%) patients in the VVI-ICD group and 22 (47%) patients in the DDD-ICD group (P = 0.8) developed VT/VF. Overall, 73 (10%) of 725 treated episodes were inappropriate in 6 (13%) patients in the VVI group and in 10 (21%) patients in the DDD-ICD group (P = 0.2). There were 22 (31%) inappropriately treated episodes in the VVI-ICD group and 51 (69%) in the DDD-ICD group. Thirty-two of the 51 inappropriate episodes in the DDD-ICD patients resulted from intermittent atrial sensing problems that led to failure of the respective dual chamber algorithms. Nonfatal complications occurred in 6 (13%) patients in the VVI-ICD group and in 3 (6%) patients in the DDD-ICD group (P = 0.7). CONCLUSION: We conclude that the implanted DDD-ICD and conventional VVI-ICD are equally safe and effective for therapy of life-threatening ventricular tachyarrhythmias. Although DDD-ICDs allow better rhythm classification, the applied detection algorithms do not offer benefits in avoiding inappropriate therapies during supraventricular tachyarrhythmias.

Aged↗
PubMed2001

Dissociation between coronary sinus and left atrial conduction in patients with atrial fibrillation and flutter.

INTRODUCTION: Coronary sinus (CS) recordings are routinely used during electrophysiologic studies for various supraventricular and ventricular arrhythmias with the understanding that they represent left atrial (LA) activity. However, the behavior of CS electrical activity during atrial arrhythmias has not drawn any special attention beyond standard considerations. METHODS AND RESULTS: The study population consisted of 9 patients (3 women; mean age 59 +/- 11 years) with atrial fibrillation (AF) and atrial flutter (AFL) who developed dissociation of conduction between the CS and posterior LA during spontaneous AF and AFL. In all patients, the LA and the CS were mapped using a 64-electrode basket catheter and a multipolar electrode catheter, respectively. The right atrium (RA) was mapped simultaneously using a 24-polar electrode catheter (7 patients) or a 64-electrode basket catheter (2 patients). Eight patients showed stable double potentials in CS recordings during AF (9 episodes) and AFL (3 episodes). During ongoing arrhythmias, the first row of potentials maintained a constant relationship with the RA activity, whereas the second row of potentials was discordant with the posterior wall of the LA in 7 patients and concordant in 2 patients. In 1 patient with counterclockwise AFL, CS activation was isolated from the posterior wall of the RA until it reached the distal portion of the CS, after which it entered the lateral region of the LA. In 1 patient, a macroreentrant LA tachycardia involving CS muscle was observed. Rapid atrial pacing from the proximal CS and extrastimuli produced longitudinal dissociation of CS activation in all patients. CONCLUSION: Conduction between the CS and posterior LA can be dissociated during spontaneous atrial arrhythmias and provocative proximal CS pacing.

Arrhythmias, Cardiac↗
PubMed2001

Activation patterns in the left atrium during counterclockwise and clockwise atrial flutter.

INTRODUCTION: Activation of the left atrium (LA) in patients with isthmus-dependent right atrial flutter (AFL) has not yet been studied. The aim of this study was to analyze the activation patterns in the LA in patients with counterclockwise and clockwise AFL. METHODS AND RESULTS: The study population consisted of 12 patients (10 men and 2 women; mean age 61+/-13 years) with documented AFL and atrial fibrillation referred for ablation. The LA was mapped with a 64-electrode basket catheter inserted through a transseptal approach (10 patients) or an open foramen ovale (2 patients). In patients with counterclockwise AFL (10 episodes), the LA was activated for a mean of 133+/-28 msec. Two endocardial breakthroughs of earliest activity on the left side of the interatrial septum, separated in time by an interval of 38+/-15 msec, were observed in 9 episodes (90%). Two wavefronts originated from these breakthroughs, which activated the posterior and the anterior LA walls, respectively. In one patient, the entire LA was activated from the inferior breakthrough. In patients with clockwise AFL (five episodes), the LA activation time was 130+/-13 msec. During ongoing episodes, two early electrical breakthroughs, separated in time by an interval of 41+/-15 msec, appeared in the high anteroseptal and low posteroseptal LA regions. The superior wavefront that emerged from the high anterolateral LA region was the dominant activation pathway in 4 (80%) of 5 episodes. CONCLUSION: In patients with AFL, the LA is activated by two wavefronts originating from the high anterior and the low posterior regions of the interatrial septum. The sequence of activation of these interatrial connections in counterclockwise or clockwise AFL and the conductive properties of the LA conduction pathways determine the activation patterns in the LA.

Activation Analysis↗
PubMed2001

Maintenance of sinus rhythm after electrical cardioversion of persistent atrial fibrillation; sotalol vs bisoprolol.

AIMS: The purpose of the study was to compare the efficacy and safety of sotalol and bisoprolol in the maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation. METHODS: Patients (n=128) were randomized to sotalol (80 mg b.i.d.) or bisoprolol (5 mg x day(-1)). Patients with contraindications to beta-blockers, class III antiarrhythmic drugs or prior treatment with use of study medication for prevention of atrial fibrillation were excluded. Follow-up clinical evaluation was performed 1 day and 1 month after cardioversion and thereafter at 3-month intervals. RESULTS: There were no group differences in baseline clinical characteristics. After a follow-up of 12 months, 59% of all patients were still in sinus rhythm. The fraction remaining in sinus rhythm was calculated for the two groups by Kaplan--Meier analysis. During follow-up, 41% of patients on sotalol and 42% on bisoprolol developed atrial fibrillation (ns). In two patients (3.1%) on sotalol, life-threatening proarrhythmias (torsade de pointes tachycardias) occurred, whereas none were found in the bisoprolol group. Symptomatic bradycardias occurred in two patients on sotalol and three on bisoprolol. CONCLUSION: This study demonstrates that sotalol (160 mg x day(-1)) and bisoprolol (5 mg x day(-1)) are equally effective in maintaining sinus rhythm. Because of the side effects of sotalol, bisoprolol seems to be advantageous for maintenance of sinus rhythm after cardioversion of atrial fibrillation.

Adrenergic beta-Antagonists↗
PubMed2000

Relationship between surface electrocardiogram characteristics and endocardial activation sequence in patients with typical atrial flutter.

OBJECTIVES: The relationships that exist between endocardial and surface electrocardiogram (ECG) activity in patients with AFl have not been satisfactorily delineated. The aim of the study was to determine the relationships that exist between the atrial endocardial activity and the surface ECG in patients with atrial flutter (AFl). METHODS: In 40 patients with AFl, a 64-electrode basket catheter (BC) was deployed in the right atrium (RA). A decapolar catheter was inserted into the coronary sinus (CS) to record from the left atrium. The temporal relationship between endocardial and surface ECG activity was determined by means of electronic calipers. RESULTS: In counterclockwise AFl, the activation of the lateral wall of RA coincided with the positive deflections in lead I, V1 and V6 and the upstroke component in inferior leads. Plateau duration in lead III (121 +/- 27 ms) correlated strongly with isthmus conduction time (117 +/- 23 ms) (r = 0.91). Septal and left atrial conduction coincided with negative components in lead I, inferior leads and V6 and positive deflections in leads aVL and V1. In clockwise AFl, the F wave was notched in all ECG leads. The first component resulted from the activation of the septum and posterior wall of the RA. The second component was coincident with activity recorded in CS electrograms. The interval between the two deflections (60 +/- 18 ms) correlated strongly with interatrial conduction time (57 +/- 19 ms) (r = 0.84). Interatrial conduction interval was prolonged during AFl as compared to sinus rhythm (60 +/- 18 ms vs 43 +/- 13 ms, p = 0.04). Activation of the lateral wall of RA coincided with the negative components in lead I, inferior leads and V6. CONCLUSIONS: The electrical activity in surface ECG closely correlates with conduction in specific parts of the atria. Polarity of the F wave in an ECG lead is determined by a resultant of opposing activities from the lateral wall of the RA and the left atrium.

Aged↗
PubMed2000

Acute electrophysiologic effects and antifibrillatory actions of the long linear lesions in the right atrium in a sheep model.

UNLABELLED: Linear lesions (LL) represent an option for curing of atrial fibrillation (AF) with ablation techniques. METHODS AND RESULTS: In 11 sheep (w. 72+/-16 kg), LL were created with radiofrequency ablation in the lateral, posterior and septal walls of the right atrium (RA). AF was induced before and after LL with burst pacing. Mapping of the AF was performed with a 64-electrode basket catheter deployed in the RA. Quantitative analysis was performed with a custom-made software program. LL were confirmed histologically 7 to 10 days after the procedure. LL were transmural in 78% of their length. Stimulation thresholds and right atrial activation times were increased after LL compared to preablation values. Effective refractory periods of the RA were prolonged significantly in 7 out of 12 regions after generation of LL. Conduction velocities in the RA segments between LL were reduced in lateral, posterior and septal walls. During paced rhythms double potentials were recorded in all animals. AF could be induced in all animals of this model despite the presence of LL in the RA. AF episodes were significantly more regular after LL throughout the RA due to a significant reduction of the number of the wave fronts in the RA. During AF episodes, in the presence of LL, the RA was driven by wave fronts of left atrial origin entering the right side of the septum through interatrial connections. CONCLUSIONS: 1) LL profoundly affect electrophysiologic parameters of RA. 2) In the presence of LL, AF manifest a higher degree of regularity as compared to preablation episodes. 3) Dissociation between wave fronts of left atrial origin entering the RA through the interatrial connections is an important mechanism of the antifibrillatory action of the septal LL.

Animals↗