PubMed Health⌕ Search

Biomedical subjects

Jean-Jacques Blanc

Publications and source records attributed to Jean-Jacques Blanc.

33 records · Page 2Linked to original sources
PubMed2004

Midterm benefits of left univentricular pacing in patients with congestive heart failure.

BACKGROUND: Resynchronization therapy by simultaneous pacing of the right and left ventricles has gained wide acceptance as a useful treatment for patients with severe congestive heart failure. Several short-term hemodynamic studies in humans and animals failed to demonstrate any benefit of biventricular pacing over left univentricular pacing, but long-term studies on this pacing mode are lacking. The objective of this study was to assess the outcome over a 1-year period of patients paced exclusively in the left ventricle. METHODS AND RESULTS: Clinical, angiographic, echocardiographic, and ergometric data were collected at baseline and after 12 months in 22 patients (age, 69.3+/-6.5 years) with NYHA class III or IV (10 patients), sinus rhythm, left bundle-branch block, and no bradycardia indication for pacing. After 12 months, compared with baseline values, NYHA class improved significantly by 40% (P<0.0001), 6-minute walk distance by 30% (P=0.01), peak VO2 by 26% (P=0.01), left ventricular end-diastolic diameter by 5% (P=0.02), ejection fraction by 22% (P=0.07), mitral regurgitation area by 40% (P=0.01), and norepinephrine level by 37% (P=0.04). CONCLUSIONS: In patients with severe congestive heart failure, sinus rhythm, and left bundle-branch block despite optimal pharmacological treatment, left univentricular pacing is feasible and results in significant midterm benefit in exercise tolerance and left ventricular function.

Aged↗
PubMed2004

Assessment of upgrading to biventricular pacing in patients with right ventricular pacing and congestive heart failure after atrioventricular junctional ablation for chronic atrial fibrillation.

AIMS: Effects of cardiac resynchronization therapy (CRT) in patients with right ventricular pacing and congestive heart failure (CHF) have only been reported in limited series. CRT in patients with atrial fibrillation remains controversial. Patients with AV junctional ablation offer a unique opportunity to study the effects of CRT in patients with right ventricular pacing combined with atrial fibrillation. The aims of the present study were to evaluate the effects of upgrading to biventricular pacing patients with CHF, permanent atrial fibrillation, and prior ablation of the atrioventricular (AV) junction followed by conventional right ventricular pacing. METHODS AND RESULTS: We studied 16 consecutive patients with permanent atrial fibrillation treated by AV junctional ablation. After a mean follow-up of 20+/-19 months (6 weeks to 5 years) they were successfully upgraded to biventricular pacing for severe CHF. Parameters were prospectively evaluated at baseline and at 6 months. The 14 surviving patients at 6 months demonstrated significant improvement (P<0.02) in New York Heart Association class but the exercise test parameters remained unchanged. Cardiothoracic ratio decreased by 5% (P=0.04), end-systolic diameter by 8% (P=0.001), end-diastolic diameter by 4% (P=0.08), systolic pulmonary artery pressure by 17% (P<0.0001) and mitral regurgitation area by 40% (P<0.05). Ejection fraction increased by 17% (P=0.11) and fractional shortening by 24% (P=0.01). CONCLUSION: CRT improves left ventricular performance and functional status in patients with permanent atrial fibrillation and prior remote right ventricular pacing.

Aged↗
PubMed2004

Atrial pacing for prevention of atrial fibrillation: assessment of simultaneously implemented algorithms.

AIMS: Several preliminary studies indicated that right atrial pacing could prevent atrial tachyarrhythmias (ATA). We sought to compare the safety and the efficacy of atrial-based pacing supplemented by dedicated combined algorithms with conventional atrial pacing in the prevention of ATA. METHODS: Fifty-five patients with a history of recurrent paroxysmal ATA implanted with a dual-chamber pacemaker were studied during two randomized cross-over pacing periods (conventional DDD and DDD with ATA prevention algorithms) of 6 months duration. The primary endpoint was the burden of ATA episodes recorded by the device mode switch algorithm. RESULTS: The cross-over analysis did not demonstrate any significant difference between the two pacing modes: 254+/-533 h of ATA during the control period versus 238+/-518 h during the ATA prevention period. Analysis of a subgroup of patients found that those with the lower percentage of ventricular pacing benefited from ATA prevention algorithms (120+/-182 h versus 225+/-350 h during the control period; P < 0.04). CONCLUSION: When compared with DDD pacing at 70 bpm, ATA prevention algorithms have not demonstrated significant efficacy. However, a subgroup of patients with preserved native AV conduction (low percentage of ventricular pacing) responded to ATA prevention algorithms.

Aged↗
PubMed2004

Value of entrainment mapping in determining the isthmus-dependent nature of atrial flutter in the presence of amiodarone.

INTRODUCTION: Entrainment mapping is a useful procedure for localizing macroreentrant tachycardia circuits. In patients with isthmus-dependent atrial flutter, entrainment mapping from the isthmus during tachycardia results in postpacing intervals (PPI) close to the tachycardia cycle length (TCL). However, the influence of antiarrhythmic drugs on the method's value is not clearly established. The aim of our study was to assess the value of entrainment mapping in the presence of amiodarone in patients undergoing radiofrequency ablation (RFA) of isthmus-dependent atrial flutter. METHODS AND RESULTS: The study consisted of 83 patients with isthmus-dependent atrial flutter: 52 were taking amiodarone at the time of RFA (group 1) and 31 were in a drug-free state (group 2). Entrainment mapping was performed from the cavotricuspid isthmus, and PPI minus TCL was determined. The two groups had similar baseline clinical characteristics. In all patients, RFA of the isthmus resulted in termination of tachycardia, confirming the isthmus-dependent nature of the flutter. TCL was significantly longer in group 1 than in group 2 (263 +/- 31 msec vs 238 +/- 27 msec, P < 0.0002). PPI minus TCL at the isthmus was significantly longer in group 1 than in group 2 (17 +/- 17 msec vs 8 +/- 4 msec, P < 0.01). More patients in group 1 had PPI-TCL>20 msec compared to group 2 (37% vs 10%, P = 0.01). CONCLUSION: Amiodarone significantly alters the entrainment mapping response from the isthmus. In this setting, long return cycles exceeding the TCL by >20 msec do not exclude isthmus-dependent atrial flutter.

Aged↗
PubMed2003

Effect of left ventricular function on long-term left ventricular pacing and sensing threshold.

BACKGROUND: The effect of left ventricular (LV) systolic function on the long-term left ventricular pacing and sensing threshold is unclear. METHODS AND RESULTS: We studied the effect of LV ejection fraction (LVEF) on the LV pacing and sensing threshold in 56 patients (mean age: 70.2 +/- 10.5 years) underwent permanent LV pacing using a self-retaining coronary sinus lead (Model 1055 K, St Jude Medical, USA). In 49 patients, the LV lead was implanted for conventional pacemaker indication (sick sinus syndrome = 14, heart block = 26 or slow atrial fibrillation = 9). The remaining 7 patients were implanted for congestive heart failure. The LV pacing and sensing threshold, and lead impedance were compared between patients with LVEF <40% (Group 1, n = 28) and LVEF >40% (Group 2, n = 28) during implant and at 3-month follow up. The LV pacing lead was successfully implanted in all patients without any lead dislodgement on follow-up. At implant, Group 1 patients had a significant lower R wave amplitude, but similar LV pacing threshold and lead impedance as compared to Group 2. However, at 3-month follow-up, Group 1 patients had a significantly higher LV pacing threshold compared to Group 2 patients. There were no significant differences in the sensing threshold and lead impedance between the two groups. Furthermore, there was also a significant interval increase in LV pacing threshold in Group 1 patients (0.94 +/- 0.12 V) after 3 months, but not in Group 2 patients (0.16 +/- 0.08 V, p < 0.01). CONCLUSIONS: The results of this study suggest that the LV systolic function has a significant impact on the long-term LV pacing threshold. The long-term left ventricular pacing threshold in patients with left ventricular systolic dysfunction increased after implant and was higher than patients with normal left ventricular systolic function.

Aged↗
PubMed2002

Heart rate variability, a target for the effects of angiotensin II in the brain of the trout Oncorhynchus mykiss.

This study was conducted on unanesthetized rainbow trout equipped with two ECG electrodes and with an intracerebroventricular (i.c.v.) micro-guide. The ECG signal was recorded during three experimental sessions of 30 min and the heart rate variability (HRV) spectral analysis was performed during stabilized periods of recording. The first recording session was conducted during the control period and the mean heart rate (HR) of the trout was 44+/-2 bpm. The total power spectral density (PSD) of the R-R interval signal of the ECG was 21233+/-4400 ms(2)/Hz. A major high frequency (HF) spectral band centered at 0.16 Hz and a minor low frequency (LF) spectral band centered at 0.04 Hz were the two main components of the PSD. An i.c.v. injection of 0.5 microl of vehicle during the second session had no significant statistical effect, either on the mean HR (43+/-2 bpm), the total PSD (24693+/-6394 ms(2)/Hz) or on the center frequency and power of the two main spectral bands. Conversely, an i.c.v. injection of ANGII (1.5, 6.25 and 50 pmol) during the third recording session induced a significant increase in the mean HR (+3%, +15%, +30%, respectively) but the effect of the peptide was more obvious on the total PSD which was profoundly decreased (-27%, -65%, -76%, respectively). The two main spectral bands of the PSD were totally blunted after the injection of 50 pmol of ANGII. In another group of control trout, intraperitoneal (i.p.) injection of atropine abolished the PSD of the R-R interval signal of the ECG demonstrating that the parasympathetic system is the main contributor of HRV in trout. Our results have thus demonstrated for the first time, at least in a non-mammalian species, that i.c.v. injection of native ANGII profoundly reduces HRV. We hypothesize that ANGII in the brain of the trout alters the pattern of the electrical activity along preganglionic cardiac vagal motoneurons.

Angiotensin II↗