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Biomedical subjects

Nicolas Sadoul

Publications and source records attributed to Nicolas Sadoul.

18 recordsLinked to original sources
PubMed2005

Incidence and clinical relevance of slow ventricular tachycardia in implantable cardioverter-defibrillator recipients: an international multicenter prospective study.

BACKGROUND: This study aims to assess the incidence and clinical relevance of slow ventricular tachycardia (VT) and the effectiveness and/or deleterious effects of antitachycardia pacing in slow VT in implantable cardioverter-defibrillator recipients. METHODS AND RESULTS: This multicenter prospective randomized study included 374 patients (326 men) without prior history of slow VT (<148 bpm) implanted with a dual-chamber implantable cardioverter-defibrillator. Patients had a 3-zone detection configuration: a slow VT zone (101 to 148 bpm), a conventional VT zone (>148 bpm), and a ventricular fibrillation zone. Patients were randomized to a treatment group (n=183) with therapy activated in the slow VT zone or a monitoring group (n=191) with no therapy in the slow VT zone. During follow-up (11 months), 449 slow VTs occurred in 114 patients (30.5% slow VT incidence); 181 VTs (54 patients) occurred in the monitoring group; 3 were readmitted to the hospital; and lightheadedness and palpitations occurred in 4 and 250 (60 patients) in the treatment group treated by antitachycardia pacing (89.8% success rate) and shock delivery (n=2). There were 10 crossovers from the monitoring to treatment group and 3 crossovers from the treatment to monitoring group (P=0.09). Quality of life scores were not different between groups. CONCLUSIONS: Slow VT incidence (<150 bpm) is high (30%) in implantable cardioverter-defibrillator recipients without prior history of slow VT, has limited clinical relevance, and is efficiently and safely terminated by antitachycardia pacing.

Adult↗
PubMed2005

Potential cost savings by telemedicine-assisted long-term care of implantable cardioverter defibrillator recipients.

Home monitoring (HM) of cardioverter defibrillators (ICD) with its automated wireless remote data access, may decrease the rate of patient visits. This study examined the potential cost savings for the long-term care of ICD assisted by HM. A French database including 502 patients from 6 university hospitals was used. Costs of conventional follow-up (FU) of ICD were calculated without, and compared with the expected cost of FU with HM. Calculations included number of visits, including physician's fees, electrocardiograms, and specific ICD surveillance, and transportation costs. The mean distance between home and institutions performing follow-ups was 69 +/- 57 km. For each visit, a mean overall cost of 215 dollars was calculated, including 121 dollars for transportation and 94 dollars for medical services. HM may obviate up to 2 visits per year. Over the 5 years of expected life of the device, the decrease in costs for FU visits was estimated at 2,149 dollars. With an additional cost of 1,200 dollars for the HM system, saving began after a mean FU of 33.5 months. The time to onset of cost saving by HM ranged between 17.4 months for patients living >150 km from the medical facility to 52.2 months for those living <50 km away. It is concluded that the HM may considerably reduce the overall costs of ICD FU by saving on transportation cost, particularly when the distance between home and medical facility is >100 km.

Cost Savings↗
PubMed2005

A new dual-chamber pacing mode to minimize ventricular pacing.

Despite the low long-term incidence of high-degree atrioventricular (AV) block and the known negative effects of ventricular pacing, programming of the AAI mode in patients with sinus node dysfunction (SND) remains exceptional. A new pacing mode was, therefore, designed to combine the advantages of AAI with the safety of DDD pacing. AAIsafeR behaves like the AAI mode in absence of AV block. First- and second-degree AV blocks are tolerated up to a predetermined, programmable limit, and conversion to DDD takes place in case of high-degree AV block. From DDD, the device may switch back to AAI, provided AV conduction has returned. The safety of AAIsafeR was examined in 43 recipients (70 +/- 12-year old, 24 men) of dual chamber pacemakers implanted for SND or paroxysmal AV block. All patients underwent 24-hour ambulatory electrocardiographic recordings before hospital discharge and at 1 month of follow-up with the AAIsafeR mode activated. No AAIsafeR-related adverse event was observed. At 1 month, the device was functioning in AAIsafeR in 28 patients (65%), and the mean rate of ventricular pacing was 0.2%+/- 0.4%. Appropriate switches to DDD occurred in 15 patients (35%) for frequent, unexpected AV block. AAIsafeR mode was safe and preserved ventricular function during paroxysmal AV block, while maintaining a very low rate of ventricular pacing. The performance of this new pacing mode in the prevention of atrial fibrillation will be examined in a large, controlled study.

Aged↗
PubMed2004

Differences in mechanisms and outcomes of syncope in patients with coronary disease or idiopathic left ventricular dysfunction as assessed by electrophysiologic testing.

OBJECTIVES: This study evaluated the causes of syncope and the significance and differences in left ventricular (LV) dysfunction, coronary disease, and idiopathic dilated cardiomyopathy (DCM). BACKGROUND: Risk stratification of and indications for an automated defibrillator could differ according to the cause of LV dysfunction. METHODS: Electrophysiologic study, including atrial and ventricular programmed stimulation, was performed in 119 patients with coronary disease (group I) and 61 patients with DCM (group II) with an left ventricular ejection fraction (LVEF) <40% and syncope. Patients were followed from one to six years (mean 4 +/- 2 years). RESULTS: Sustained monomorphic ventricular tachycardia (VT) was induced in 44 group I patients (37%) and 13 group II patients (21%); ventricular flutter (>270 beats/min) or ventricular fibrillation (VF) was induced in 24 group I patients (19%) and 9 group II patients (15%); and various other arrhythmias were identified. Syncope remained unexplained in 34 group I patients (30%) and 16 group II patients (27%). Prognosis depended on the heart disease: VT or VF induction was a predictive factor of mortality in coronary disease and identified a group with high cardiac mortality (46%), compared with patients with a negative study, who had a lower mortality (6%; p < 0.001) than in other studies. Cardiac mortality was only correlated with LVEF in DCM. CONCLUSIONS: Various causes could explain syncope in 70% of patients with coronary disease and DCM, but differences were noted: VT was frequent in coronary disease with a bad prognosis, and ischemia could explain syncope; in DCM, different causes such as atrial tachycardia could be responsible for syncope, but the prognosis only depended on LVEF.

Aged↗
PubMed2004

Enhanced specificity of a dual chamber ICD arrhythmia detection algorithm by rate stability criteria.

Inappropriate therapy remains an important limitation of implantable cardioverter defibrillators (ICD). PARAD+ was developed to increase the specificity conferred by the original PARAD detection algorithm in the detection of atrial fibrillation (AF). To compare the performances of the two different algorithms, we retrospectively analyzed all spontaneous and sustained episodes of AF and ventricular tachycardia (VT) documented by state-of-the-art ICDs programmed with PARAD or PARAD+ at the physicians' discretion. The results were stratified according to tachycardia rates <150 versus > or =150 beats/min. The study included 329 men and 48 women (64 +/- 10 years of age). PARAD was programmed in 263, and PARAD+ in 84 devices. During a mean follow-up of 11 +/- 3 months, 1,019 VT and 315 AF episodes were documented among 338 devices. For tachycardias with ventricular rates <150 beats/min, the sensitivity of PARAD versus PARAD+ was 96% versus 99% (NS), specificity 80% versus 93% (P < 0.002), positive predictive value (PPV) 94% versus 91% (NS), and negative predictive value (NPV) 86% versus 99% (P < 0.0001). In contrast, in the fast VT zone, the specificity and PPV of PARAD (95% versus 84% and 100% versus 96%) were higher than those of PARAD+ (NS, P < 0.001). Among 23 AF episodes treated in 16 patients, 3 episodes triggered an inappropriate shock in 3 patients, all in the PARAD population. PARAD+ significantly increased the ICD algorithm diagnostic specificity and NPV for AF in the slow VT zone without compromising patient safety.

Algorithms↗
PubMed2003

Sudden death in noncoronary heart disease is associated with delayed paced ventricular activation.

BACKGROUND: Slowed or delayed myocardial activation and dispersed refractoriness predispose to reentrant excitation that may lead to ventricular fibrillation (VF). Increased ventricular electrogram duration (DeltaED) in response to extrastimuli and increased S1S2 coupling intervals at which electrogram duration starts to increase (S1S2delay) are seen both in hypertrophic cardiomyopathy (HCM) in those at risk of VF and in patients with idiopathic VF (IVF). METHODS AND RESULTS: DeltaED and S1S2delay have been measured using paced electrogram fractionation analysis in 266 patients with noncoronary heart disease. Of these, one group of 61 patients had a history of VF and included 21 HCM, 17 IVF, 13 long-QT syndrome (LQTS), 5 dilated cardiomyopathy (DCM), and 5 others. These were compared with 205 patients with similar diseases with no VF history (non-VF group) and a control group (n=12) without heart disease. Results from HCM VF patients (DeltaED, 19+/-3.3 ms; S1S2delay, 350+/-9.7 ms) differed sharply from observations in HCM non-VF patients (DeltaED, 7.3+/-1.35 ms; S1S2delay, 312+/-6.7 ms; P<0.001). DCM VF patients had longer delays (DeltaED, 14.3+/-5.9; S1S2delay, 344+/-11.2) than DCM non-VF patients (DeltaED, 5.8+/-1.87 ms; S1S2delay, 311+/-5.7 ms; P<0.001), with major differences also seen comparing LQTS VF (DeltaED, 12.4+/-5.3 ms; S1S2delay, 343+/-13.8 ms) and LQTS non-VF patients (DeltaED, 11.0+/-2.7 ms; S1S2delay, 320+/-5.4 ms; P<0.001). IVF patients had both severely abnormal and normal areas of myocardium. CONCLUSIONS: Slowed or delayed myocardial activation is a common feature in patients with noncoronary heart disease with a history of VF, and its assessment may allow the prospective prediction of VF risk in these patients.

Cardiac Pacing, Artificial↗
PubMed2003

Causes and prognosis of cardiac arrest in a population admitted to a general hospital; a diagnostic and therapeutic problem.

BACKGROUND: The purpose of this study was to determine the causes and the prognosis of consecutive patients resuscitated from cardiac arrest occurring in a general hospital. We assessed 28 females and 94 males (aged 13-82 years) who were resuscitated from cardiac arrest not attributable to acute myocardial infarction. Ventricular fibrillation (VF) was documented in 97. Non-cardiac causes were excluded. Non-invasive studies (24 h Holter monitoring, 2D echocardiogram, signal-averaged ECG, exercise testing, magnetic resonance imaging) and invasive studies (right and left ventricular angiography, coronary angiography and complete electrophysiologic study (EPS) were performed. RESULTS: An underlying cardiac disease was found in 107 patients (88%). Patients were followed for a period ranging from 6 months to 10 years (mean 4+/-5 years). Several causes for cardiac arrest were identified and treated specifically. The prognosis was variable. Among surviving patients the following causes of cardiac arrest were found: Wolff-Parkinson-White syndrome (n=2), rapid supraventricular tachycardia (n=6), acquired or congenital long QT syndrome (n=7), complete atrioventricular block (n=3), proarrhythmic effect of an antiarrhythmic drug (n=5), vasospastic angina (normal coronary arteries) (n=5). Among ten patients with VF related to cardiac ischaemia two died suddenly. Ventricular tachycardia (VT) or VF was the main cause leading to resuscitation after cardiac arrest (n=64). The risk of recurrence of arrest is confirmed in the present study particularly in patients in whom VT/VF could not be suppressed by antiarrhythmic drug therapy (n=45) and in those where an ICD was not implanted (18 cardiac deaths (nine sudden cardiac deaths (SCD's)). The cause of cardiac arrest was not elucidated in 20 patients (16%). The prognosis of these patients differed according to the documentation of VF at the time of cardiac arrest: of those with documented VF (n=12), six patients died suddenly (one with an ICD); of those without documented VF (n=8), all are alive. CONCLUSION: To determine the precise cause of cardiac arrest was the first problem; the diagnosis of cardiac arrest clearly was erroneous in 8 of 122 patients (6.5%). In other patients, a ventricular tachyarrhythmia was identified as the cause for cardiac arrest in half of the population; the indication for an ICD is evident in this group. In 31% of patients with proven cardiac arrest, another arrhythmia requiring specific treatment was identified and ICD implantation was avoided; these patients had a survival of 92% at 3 years. In patients without an identified cause of cardiac arrest and negative EPS, the prognosis was unfavorable only in those with documented VF.

Adolescent↗
PubMed2003

Noninvasive quantitation of blood flow turbulence in patients with aortic valve disease using online digital computer analysis of Doppler velocity data.

Previous experimental studies have demonstrated that aortic valve disease is associated with significant downstream turbulence (T). In this study, we developed a noninvasive method on the basis of Doppler velocity recording for quantitating aortic blood flow T in patients with aortic valve disease. The instantaneous blood velocity at a point in the aorta is equal to the sum of a mean periodic velocity component with a random or turbulent velocity component. According to the ensemble average method, time mean absolute T intensity is the root-mean-square value of turbulent velocity averaged over time and T is better quantitated by the relative T intensity (TIr), which is the ratio of absolute T intensity to the ensemble average velocity averaged over time. We computed TIr in 18 patients with mild to severe aortic stenosis and in 13 healthy volunteers from instantaneous modal velocities of 70 cycle length-matched heart beats recorded in the proximal part of the descending aorta by pulsed Doppler using an ultrasound system with an output port for online digital data transfer into a microcomputer. TIr was greater in patients with aortic valve disease (18.4 +/- 5.1%, range 11.2%-28.9%) than in control patients (7.9 +/- 1.9%, range 4.8%-9.8%; P =.0001). In patients with aortic valve disease, TIr was better linearly related to the ratio of postvalvular aorta to valvular orifice cross-sectional areas (r = 0.89, P =.0001) than to other parameters of valve restriction: transvalvular pressure gradient (r = 0.78, P =.0001); valve area (r = -0.56, P =.01); and valve resistance (r = 0.72, P =.0002). Thus, T that can be computed noninvasively from direct digital transfer of Doppler velocity data appears to be linearly related to indices of aortic valve restriction. Our data support the concept of the postvalvular aorta to valvular orifice cross-sectional areas ratio as a new important hemodynamic parameter in patients with aortic valve disease.

Adult↗
PubMed2003

Significance of external cardioversion induced atrial tachyarrhythmias.

External cardioversion is used to stop VT or VF in emergency. Supraventricular tachyarrhythmias are sometimes noted after cardioversion in patients known to be previously in sinus rhythm. The purpose of the study was to evaluate the significance of supraventricular tachyarrhythmias induced by external cardioversion. The study population consisted of 22 patients who developed supraventricular tachyarrhythmias after transthoracic cardioversion (300 J) delivered to stop a VT or VF induced by electrophysiological study. Defibrillation used monophasic waveform. Supraventricular tachyarrhythmias complicated 6% of cardioversions for VT; before cardioversion, all patients were in sinus rhythm. After cardioversion, three patients developed a paroxysmal reentrant supraventricular tachycardia (PSVT), which was stopped by atrial pacing. The remaining patients developed AF that lasted from 3 minutes to 24 hours (n = 4). One patient remained in AF. AF developed after a sinus pause or bradycardia, which was due to the interruption of VT or VF in nine patients or was noted just when VT or VF stopped (n = 10). The analysis of clinical data indicated that all three patients who presented a PSVT had a history of PSVT. Among patients who developed a sinus pause dependent AF, two had a history of AF. Among ten patients who developed AF at the time of cardioversion, three had a history of AF. During follow-up (1-9 years), no patient without a history of AF developed spontaneous AF, but patients with history of tachycardias had arrhythmia recurrences. The mechanism of cardioversion related tachycardias can be a pause related dispersion of atrial refractoriness or an adrenergic reaction induced by VT or VF, factors that precipitate arrhythmias in patients with history of atrial arrhythmias (one third of patients). In conclusion, supraventricular tachyarrhythmia is relatively frequent after external cardioversion for ventricular tachyarrhythmia, has no prognostic significance in patients without previous history of atrial arrhythmias, but in those with history of tachycardias is associated with a high risk of recurrence.

Adult↗
PubMed2003

Study of precursors of ventricular tachycardia from data stored in the memory of a dual chamber implantable cardioverter defibrillator.

This study was performed to examine precursors of ventricular tachyarrhythmias in patients who experienced a sustained ventricular tachyarrhythmia and received appropriate therapy by ICD. From an overall consecutive population of 77 patients, 18 patients (1 woman, mean age 61.7 +/- 10.8 years) were selected for having experienced a sustained ventricular tachyarrhythmia and received at least one appropriate ICD therapy preceded by 20 minutes of internal information. The number of premature ventricular complexes (PVCs)/min for each of the 20 minutes preceding the onset of ventricular tachyarrhythmia, the shortest coupling intervals between PVC and normal sinus beat, and the presence of short-long-short (SLS) interval sequences were examined. Data were stratified according to underlying disease, left ventricular ejection fraction, rate of ventricular tachyarrhythmia, and antiarrhythmic therapy. One hundred twenty-eight episodes of spontaneous ventricular tachyarrhythmia were retrieved. Rapid ventricular tachyarrhythmia (>160 beats/min) were preceded by a significantly greater mean number (3.71 +/- 6.36)of PVCs than slower ventricular tachyarrhythmia (<or=160 beats/min) (0.63 +/- 0.88, P = 0.0004). The mean shortest PVC coupling interval was significantly shorter in patients with (588 +/- 99 ms) versus without (643 +/- 111 ms, P = 0.03)ischemic heart disease, before episodes of rapid(527 +/- 55 ms)versus slower (636 +/- 105 ms, P = 0.0001)ventricular tachyarrhythmia, and in the absence (538 +/- 80 ms)versus the presence(620 +/- 105 ms, P = 0.006)of amiodarone. SLS sequences preceded 29% of rapid ventricular tachyarrhythmic episodes, versus 8% of the slower ventricular tachyarrhythmia (P < 0.01). Significant differences were found in the characteristics of PVCs preceding ventricular tachyarrhythmic episodes in accordance to their rate and the underlying cardiomyopathy. Though insufficient in isolation, these findings may be helpful when combined with other observations to develop preventive algorithms, or to refine the programming of implantable devices.

Amiodarone↗
PubMed2003

Heart rate variability before ventricular arrhythmias in patients with coronary artery disease and an implantable cardioverter defibrillator.

BACKGROUND: Changes in autonomic regulation of the heart may be responsible for the occurrence of arrhythmias. Although a decrease in 24-hour heart rate variability is a strong predictor of subsequent arrhythmias in patients with heart disease, many questions remain unanswered concerning changes in heart rate and heart rate variability in the minutes or hours preceding an arrhythmia. The aim of our study was to analyze changes in heart rate and heart rate variability occurring during the 90 minutes preceding an arrhythmia, in patients with coronary heart disease and an implantable defibrillator. MATERIALS AND METHODS: Thirty-eight patients, with a total of 93 episodes of ventricular arrhythmia, were included in the study. Heart rate and heart rate variability were measured in three 30-minute and five 2-minute periods preceding the arrhythmia. Heart rate variability was assessed using measurements of Poincaré plots. RESULTS: The results show a gradual increase in heart rate before the arrhythmia, from 73+/-13/min, to 75+/-14/min, and finally 78+/-15/min in the 90 minutes preceding the arrhythmia (P<0.05). CONCLUSION: Measurements of Poincaré plots showed a significant increase in their length and no significant change in their width. These results suggest that sympathetic activation is the predominant change in autonomic nervous system before a ventricular arrhythmia in patients with coronary heart disease. This change may occur as early as one hour and a half before the arrhythmia.

Aged↗
PubMed2003

Safety and efficacy of a dual chamber implantable cardioverter defibrillator capable of slow ventricular tachycardia discrimination: a randomized study.

New developments in dual chamber implantable cardioverter defibrillators (ICD) have increased the specificity of therapy delivery. This study was performed to examine the performance of an algorithm, focusing on its ability to distinguish slow ventricular tachycardia (VT) from sinus rhythm or supraventricular tachyarrhythmias. The patient population included 77 men and 13 women, 63 +/- 11 years old, treated with ICDs after episodes of spontaneous or inducible ventricular tachyarrhythmias. They were randomized to programming of the ICD to a lower limit of VT detection at 128 beats/min (group I, n = 44), versus 153 beats/min II (group II, n = 46). The primary endpoint of the study consisted of comparing the specificity and sensitivity of the algorithm between the two groups of patients. Over a 10.1 +/- 3.5 months follow-up, 325 episodes were detected in the Tachy zone in group I, versus 106 in group II. The sensitivity and specificity of the algorithm in group I were 98.8% and 94.4%, respectively, versus 100% and 89% in group II (NS). A single episode of VT at a rate of 132 beats/min was diagnosed as SVT in group I. The sensitivity and specificity of the algorithm for tachycardias <153 beats/min were 97.4% and 94.5%, respectively. Overall VT therapy efficacy was 100% in both groups. The performance of this algorithm in the slow VT zone supports the programming of a long Tachy detection interval to document slow events, and allows to treat slow VT, if necessary, without significant risk of inappropriate interventions for sinus tachycardia.

Algorithms↗
PubMed2002

Isthmus characteristics of reentrant ventricular tachycardia after myocardial infarction.

BACKGROUND: The reentrant mechanism of postinfarct ventricular tachycardia (VT) has been documented by surgical mapping analysis, but little is known about postinfarct VT circuits and the characteristics of their related protected isthmus with the use of 3D catheter mapping systems. METHODS AND RESULTS: A 3D electroanatomic mapping was performed in 21 patients with well-tolerated, postinfarct, sustained VT. In total, 33 episodes of tachycardia (mean cycle length 432+/-74 ms) were induced and mapped. Complete maps demonstrated macroreentrant circuits with 1 loop (n=8) or 2 loops (n=25) rotating around a protected isthmus bounded by 2 approximately parallel conduction barriers that consisted of a line of double potentials, a scar area, or the mitral annulus. A total of 26 critical isthmi were identified for the 33 VTs mapped, with the same isthmus being shared by 2 to 4 different tachycardic morphologies in 5 patients. On average, isthmi were 31+/-7 mm long (ranging from 18 to 41 mm) and 16+/-8 mm wide (ranging from 6 to 36 mm) and harbored diastolic electrograms. The isthmus axis was oriented parallel to the mitral annulus plane in perimitral circuits and perpendicular to the mitral annulus plane in all other circuits. Linear radiofrequency ablation performed across the most accessible part of the isthmus prevented the recurrence of tachycardia in 19 patients (90%) with a follow-up at 16+/-8 months. CONCLUSIONS: Detailed 3D electroanatomic mapping is helpful in reconstructing postinfarct VT circuits and in defining the characteristics of their related protected isthmi. The wide range of isthmus width values supports the need of linear radiofrequency lesions to eliminate the reentrant substrate of postinfarct VTs.

Aged↗
PubMed2002

Identification of extremely slow conduction in the cavotricuspid isthmus during common atrial flutter ablation.

INTRODUCTION: Complete isthmus block has been used as an endpoint for radiofrequency ablation for common atrial flutter (AF). We sought to systematically evaluate extremely slow conduction (ESC), which is easily misinterpreted as complete block. METHODS AND RESULTS: We studied 107 consecutive patients (92 men, 15 women, 58 +/- 11 years) who had undergone a successful AF ablation procedure. A 24-pole catheter was positioned along the tricuspid annulus spanning the isthmus. Complete isthmus block was defined as the presence of a complete corridor of double potentials along the ablation line. Activation delay time (AT), activation difference (deltaA) between two adjacent dipoles, maximum activation difference (deltaA(max)), change in polarity (CP) and change in amplitude (CA) of the bipolar atrial electrogram were recorded and P-wave morphology in the surface electrocardiogram was analyzed. ESC was observed in 16 patients. Between ESC and complete block, differences were found on the two lateral dipoles adjacent to the ablation line (AT: 148 +/- 17 vs. 183 +/- 27 ms and 155 +/- 18 vs. 170 +/- 28 ms, P < 0.01; deltaA: -91 +/- 22 vs. -126 +/- 28 ms and -7 +/- 13 vs. 13 +/- 6 ms, P < 0.01). Statistically significant differences in CP were detected on the relevant dipoles (7/16 vs. 14/16 and 6/16 vs.13/16, P < 0.05). No significant difference was found either in CA or in terminal P wave positivity. Mean deltaA(max) were 13.8 +/- 5.0 and 27.8 +/- 9.5 ms (P < 0.001) respectively in ESC and complete block. Two types of ESC, regular and irregular, were demonstrated during the ablation procedure. CONCLUSIONS: (1) ESC was observed in 15% of the patients during the AF ablation procedure. (2) The parameters of AT, deltaA, and CP may help to differentiate ESC from complete block. DeltaA(max) might be the most powerful indicator. (3) To verify complete block, it is essential to position the mapping catheter across the CTI in order to demonstrate the activation sequence up to the ablation line.

Aged↗
PubMed2002

Catheter ablation or modulation of the AV node.

The ablate and pace strategy may be considered a viable therapy in the palliative management of patients with medically refractory highly symptomatic atrial fibrillation (AF). The overall success rate is approaching 100%, the inhospital course is usually event free, and the procedure is a relatively safe therapeutic option. There is no doubt that one of the major findings after atrioventricular (AV) node ablation is the significant reduction of cardiac symptoms and health care use, while exercise tolerance and quality of life significantly improved after the procedure. It is also well accepted that catheter ablation and pacemaker (PM) implantation are usually associated with significant improvement in left ventricular ejection fraction, particularly in patient with AF and reduced systolic function at baseline. On the other hand, AV node ablation seems unlikely to have a negative effect on long term survival. The mortality rate in some reports have raised concerns about excess deaths (mainly sudden deaths) attributable to AV node ablation and pacing therapy. These findings are not confirmed by recent data. Modulation of the AV node has been more recently introduced in the clinical practice in order to avoid permanent complete AV block and lifetime PM dependency. AV node modulation procedure is effective in approximately 70% of cases. The short duration of following periods does not allow to draw definitive conclusions concerning the potential evolution of AV node conduction disorders. Both AV node ablation and AV node modulation, when successful, are effective means to improve quality of life and cardiac performance in patients with medically refractory AF. The exact place of these procedures is, today, a matter of debate which is more controversial in patients with paroxysmal AF than with uncontrolled permanent AF.

Anticoagulants↗
PubMed2002

Diagnostic performance of a dual-chamber cardioverter defibrillator programmed with nominal settings: a European prospective study.

INTRODUCTION: Despite technologic developments, accurate discrimination of ventricular tachyarrhythmia from rapid rhythms of nonventricular origin remains a challenge. We sought to examine the sensitivity and specificity of a dual-chamber arrhythmia detection algorithm, the PARAD algorithm, incorporated in a dual-chamber implantable cardioverter defibrillator, the Defender (ELA Medical). METHODS AND RESULTS: All detailed tachycardia episodes (i.e., with stored atrial and ventricular channel markers and electrograms) retrieved from the Holter memory of the device were analyzed from 95 patients (86 men and 9 women; age 62 +/- 12 years) implanted with the Defender with the algorithm programmed at nominal settings. Over a follow-up of 15 +/- 8 months, 559 detailed sustained tachycardia episodes detected in the tachycardia zone were gathered in 62 patients. Of the 300 ventricular tachycardia (VT) episodes, 298 were appropriately classified as VT by the algorithm. Of the 259 supraventricular tachycardia (SVT) episodes, 231 were appropriately classified as SVT. In 8 patients, 28 episodes of SVT were misclassified as VT: 25 atrial fibrillation episodes (6 patients), 2 sinus tachycardia (1 patient), and 1 atrial tachycardia. Calculated sensitivity and specificity were 99.3% and 89.2% on a per episode basis and 99.8% (95% confidence interval: 97.8 to 100) and 91.6% (95% confidence interval: 86.0 to 97.3) on a per patient basis, respectively. CONCLUSION: In this selected population of patients, the PARAD algorithm was safe and reliable for detection of a wide spectrum of tachyarrhythmias. Its specificity was high, particularly with respect to sinus tachycardia detection, but it must be improved with respect to detection of atrial fibrillation.

Adult↗
PubMed2002

Impact of local agricultural and industrial practices on organic contamination of little egret (Egretta garzetta) eggs in the Rhone Delta, southern France.

The purpose of this study was to determine the importance of the effects of local agricultural and industrial activities on the contamination of little egret eggs laid in the Camargue area, a protected wetland area in the Mediterranean region. Despite the fact that human activity is widespread in the Camargue, concentrations of lindane (0.01-0.7 microg/g wet wt) and of polycyclic aromatic hydrocarbons (<0.5 microg/g wet wt) do not seem to be deleterious-at least for herons. Residues of dichlorodiethyltrichlorethylene (DDE) were usually below 1 microg/g wet weight. The principal threat comes from high concentrations of polychlorinated biphenyls (PCBs; 0.1-12 microg/g wet wt), which are known to have teratogenic effects in other bird species at similar concentrations and are thought to originate locally (sediments of the delta and industrial complex of Fos/Mer). For this reason, particular interest should be focused on the water/sediment quality of the Rhĵne River (France), on industrial sewage, and on wildlife contamination. A significant but weak link between colony site and lindane concentration was detected in eggs and may be attributed to the fact that our egg collection from each sampled colony was not synchronized with pesticide spread. A stronger site effect was observed for PCBs. Eggs collected near the industrial complex of Fos/Mer (petroleum, power plants) displayed the highest median concentration and the most contaminated eggs. Such results warrant thorough monitoring of this colony.

Agriculture↗