Biomedical subjects

David Tamborero

Publications and source records attributed to David Tamborero.

3 recordsLinked to original sources

PubMed2006

Relation of response to cardiac resynchronization therapy to left ventricular reverse remodeling.

Cardiac resynchronization therapy (CRT) reverses left ventricular (LV) remodeling in patients with congestive heart failure. However, the mechanisms leading to the clinical response to CRT remain unclear. The aim of this study was to analyze whether patients who improve clinically have greater LV reverse remodeling than nonresponders after a 12-month follow-up period. The sample comprised 64 consecutive patients with heart failure, complete left bundle branch block, and LV ejection fractions (EFs) < or =35% who were treated with CRT. Doppler echocardiographic scans were taken just before and immediately after the implantation of the pacemakers and at 6- and 12-month follow-up examinations. LV diameters, volumes, and EFs were compared. Responders were defined as those patients who were alive without cardiac transplantation and with > or =10% improvement in the 6-minute walking test after 1 year of follow-up. There were no clinical differences at baseline between responders and nonresponders. At 6- and 12-month follow-up, LV dimensions decreased significantly in responders but did not change in nonresponders. Furthermore, LVEFs improved only in responders. In conclusion, patients who clinically respond to CRT have greater LV reverse remodeling than nonresponders after 6 and 12 months of follow-up. The effect of CRT on LV remodeling may explain, at least in part, the clinical benefit of this therapy.

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PubMed2006

Anodal capture in cardiac resynchronization therapy implications for device programming.

INTRODUCTION: Right ventricular (RV) anodal capture (AC) has been reported in cardiac resynchronization therapy (CRT), when left ventricular (LV) pacing uses pseudobipolar (LV tip to RV proximal electrode) configuration. The aim of the study was to analyze the prevalence of AC and its implications for device programming. METHODS AND RESULTS: When AC occurred, the resulting QRS morphology was evaluated with the following pacing modes: (1) LV tip pacing plus RV AC, (2) Biventricular (BiV) pacing (i.e., both LV and RV tip pacing), and (3) BiV pacing plus RV AC. Several interventricular pacing (VV) intervals from 50 ms of LV preactivation to 30 ms of RV preactivation were tested in modes 2 and 3. From 38 consecutive patients, AC was achieved in 14 (in 74% of the pacemakers and in none of the defibrillators). LV tip pacing plus RV AC obtained narrower QRS than BiV pacing at all VV intervals in seven of the patients with AC (50%). When BiV pacing is combined with RV AC, it produced a ventricular depolarization through two wave fronts (one from the LV tip and the second from either the ring or the tip of the RV lead depending on the VV interval programmed). CONCLUSIONS: AC obtained the narrowest QRS of all tested pacing modes in a significant proportion of patients undergoing CRT. Though the stimulus was delivered from three sites (BiV pacing plus RV AC mode), only two wave fronts of ventricular activation were seen by ECG.

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PubMed2005

Incidence of pulmonary vein stenosis in patients submitted to atrial fibrillation ablation: a comparison of the Selective Segmental Ostial Ablation vs the Circumferential Pulmonary Veins Ablation.

INTRODUCTION: Pulmonary vein (PV) stenosis is an important complication of the AF ablation and could be underestimated if their assessment is not systematically done. Selective Segmental Ostial Ablation (SSOA) and Circunferential Pulmonary Veins Ablation (CPVA) have demonstrated efficacy in atrial fibrillation (AF) treatment. In this study the real incidence of PV stenosis in patients (pts) submitted to both SSOA and CPVA was compared. METHODS: Those pts with focal activity and normal left atrial size were submitted to SSOA, remaining pts were submitted to CPVA to treat refractory, symptomatic AF. Contrast enhanced magnetic resonance angiography (MRA) was routinely performed in all patients 4 months after the procedure. RESULTS: A series of 73 consecutive patients (mean age of 51 +/- 11 years; 75% male) were included. SSOA was performed in 32 patients, and the remaining 41 patients underwent to CPVA, obtaining similar efficacy rates (72% vs 76% arrythmia free probability at 12 months; log rank test p = NS). Six patients had a significant PV stenosis, all in SSOA group none in CPVA group (18.8% vs 0%; p = 0.005). All patients were asymptomatic and the stenosis was detected in routine MRA. No predictors of stenosis has been identified analysing patient procedure characteristics. CONCLUSION: PV stenosis is a potential complication of SSOA not seen in CPVA. The study confirms than MRA is useful for identifying patients with asymptomatic PV stenosis.

Atrial Fibrillation↗