Felipe Atienza

Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Madrid, Spain

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Publications (73)285.32 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The role of tissue remodeling in the reentrant activity during atrial fibrillation (AF) is not well understood. The aim of this study is to evaluate in an in-vitro model of AF the role of tissue remodeling in the mechanisms of perpetuation of this arrhythmia.
    Cardiovascular research. 07/2014; 103(suppl 1):S20.
  • Revista espanola de cardiologia. 06/2014;
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    ABSTRACT: Ablation is an effective therapy in atrial fibrillation (AF) patients in which an electrical driver can be identified.
    Heart rhythm: the official journal of the Heart Rhythm Society 05/2014; · 4.56 Impact Factor
  • Revista Espa de Cardiologia 03/2014; · 3.20 Impact Factor
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    ABSTRACT: Background Ablation is an effective therapy in atrial fibrillation (AF) patients in which an electrical driver can be identified. Objective The aim of this study is to present and discuss a novel and strictly non-invasive approach to map and identify atrial regions responsible for AF perpetuation. Methods Surface potential recordings of 14 patients with AF were recorded using a 67-lead recording system. Singularity points (SPs) were identified in surface phase maps after band-pass filtering at the highest dominant frequency (HDF). Mathematical models of combined atria and torso were constructed and used to investigate the ability of surface phase maps to estimate rotor activity in the atrial wall. Results The simulations show that surface SPs originate at atrial SPs, but not all atrial SPs are reflected at the surface. Stable SPs were found in AF signals during 8.3±5.7% vs. 73.1±16.8% of the time in unfiltered vs. HDF-filtered patient data respectively (p<0.01). The average duration of each rotational pattern was also lower in unfiltered than in HDF-filtered AF signals (160±43 vs. 342±138 ms, p<0.01) resulting in 2.8±0.7 rotations per rotor. Band-pass filtering reduced the apparent meandering of surface HDF rotors by reducing the effect of the atrial electrical activity taking place at different frequencies. Torso surface SPs representing HDF rotors during AF were reflected at specific areas corresponding to the fastest atrial location. Conclusion Phase analysis of surface potential signals after HDF-filtering during AF shows reentrant drivers localized to either the LA or RA, helping in localizing ablation targets.
    Heart Rhythm. 01/2014;
  • Revista Española de Cardiología. 01/2014;
  • Revista Española de Cardiología. 01/2014;
  • Revista Española de Cardiología (English Edition). 01/2014;
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    ABSTRACT: The aim of this study is to evaluate the safety and feasibility of using the Amigo Remote Catheter System (RCS) in arrhythmia ablation procedures. Because Amigo allows the physician to operate all catheter function outside of the radiation field, operator exposure time was also evaluated. This is a nonrandomized, prospective clinical trial conducted at 1 site (identifier: NCT01834872). The study prospectively enrolled 50 consecutive patients (mean age 59 ± 15 years, 72% men) with any type of arrhythmia (23 atrial fibrillation ablation, 12 common atrial flutters, 10 patients with other supraventricular tachycardia, 4 ventricular tachycardia, and 1 patient with palpitations with no arrhythmia induced) referred for catheter ablation, in which we used RCS. Fifty matched ablation procedures (mean age 57 ± 14 years, 70% men) performed during the same time period, without RCS, were enrolled into the control group. Acute ablation success was 96% with RCS and 98% in the manual group. In only 2 cases, the physician switched to manual ablation (1 ventricular tachycardia and 1 accessory pathway) to complete the procedure. There were no complications related to the use of RCS. No differences were observed in total procedure time, total fluoroscopy time, or total radiofrequency delivery compared with the manual group. In procedures performed with RCS, the operator's fluoroscopy exposure time was reduced by 68 ± 16%. In conclusion, arrhythmia ablation with RCS is safe and feasible. Furthermore, it significantly reduces operator's exposure to radiation.
    The American journal of cardiology 12/2013; · 3.58 Impact Factor
  • Circulation Arrhythmia and Electrophysiology 12/2013; 6(6):e80-e84. · 5.95 Impact Factor
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    ABSTRACT: Radiofrequency ablation (RFCA) of septal accessory pathway (SAPs) locations is associated with a significant rate of first procedure failures and complications. Several single-center studies suggest that cryothermal ablation might be a safer alternative. The purpose of our study was to systematically review the available literature, including the nonpublished experience of our center, and to compare the safety and efficacy of RFCA vs cryoablation of SAPs. We conducted an electronic search in MEDLINE guided by key terms. In addition, manual review of editorials, review articles, textbooks, and guidelines was undertaken. The search was restricted to studies in humans and publication dates between January 1991 and December 2012. We recorded patient numbers, demographics, procedural data, outcome data, and procedural complications. A random effects meta-analysis model was performed using Stata (version 10.1, StataCorp, College Station, TX). Of the 927 articles screened, 128 were selected for detailed review and 55 were finally retained for analysis: 35 reported RFCA between 1991 and 2012, 20 articles reported cryoablation between 2002 and 2012. Of them, 24 studies referred totally or partially to pediatric patients. Additionally, we included our single-center experience of 118 consecutive SAPs undergoing cryoablation. Overall, 3775 patients constitute our study population: 3328 in the RFCA cohort and 447 in the cryoablation cohort. Efficacy outcomes consistently favored RFCA compared to cryoablation. Acute procedural success rate of cryoablation was 84% (95% confidence interval [CI] 78%-88%) vs RFCA 90% (95% CI 87%-92%). Recurrence rate of cryoablation was 21% (95% CI 18%-26%) vs RFCA 11% (95% CI 10%-12%). Long-term success rate after multiple ablation procedures of cryoablation was 73% (95% CI 63%-81%) vs RFCA 90% (95% CI 86%-93%). There were no reported cases of persistent AV block with cryoablation compared to 2.8% (95% CI 2.2%-3.5%) with RFCA. Studies of RFCA for treatment of SAPs report higher efficacy rates than do studies using cryoablation. However, the excellent safety profile of cryoablation makes it the energy of choice in high-risk SAP ablation, particularly in young individuals.
    Heart rhythm: the official journal of the Heart Rhythm Society 11/2013; 10(11):1753-4. · 4.56 Impact Factor
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    ABSTRACT: AIMS: Pulmonary vein ganglia (PVG) are targets for atrial fibrillation ablation. However, the functional relevance of PVG to the normal heart rhythm remains unclear. Our aim was to investigate whether PVG can modulate sinoatrial node (SAN) function.Methods and Results49 C57BL and 7 Connexin40(+/EGFP) mice were studied. We used tyrosine-hydroxylase (TH) and choline-acetyltransferase (ChAT) immunofluorescence labeling to characterize adrenergic and cholinergic neural elements. PVG projected postganglionic nerves to the SAN which entered the SAN as an extensive, mesh-like neural network. PVG neurons were adrenergic, cholinergic and biphenotypic. Histochemical characterization of 2 human embryonic hearts showed similarities between mouse and human neuroanatomy: direct neural communications between PVG and SAN. In Langendorff-perfused mouse hearts PVG were stimulated using 200-2000&emsp14;ms trains of pulses (300&emsp14;µs, 400&emsp14;µA, 200&emsp14;Hz). PVG stimulation caused an initial heart rate (HR) slowing (36±9%) followed by acceleration. PVG stimulation in the presence of propranolol caused HR slowing (43±13%) that was sustained over 20 beats. PVG stimulation with atropine progressively increased HR. Time-course effects were enhanced with 1000 and 2000&emsp14;ms trains (P<0.05 vs 200&emsp14;ms). In optical mapping PVG stimulation shifted the origin of SAN discharges. In 5 paroxysmal AF patients undergoing PV ablation, application of radiofrequency energy to the PVG area during sinus rhythm produced a decrease in heart rate similar to that observed in isolated mouse hearts. CONCLUSIONS: PVG have functional and anatomical biphenotypic characteristics. They can have significant effects on the electrophysiological control of the SAN.
    Cardiovascular Research 04/2013; · 5.94 Impact Factor
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    ABSTRACT: BACKGROUND: -Ablation of high frequency sources in patients with atrial fibrillation (AF) is an effective therapy to restore sinus rhythm. However, this strategy may be ineffective in patients without a significant dominant frequency (DF) gradient. The aim of this paper was to investigate whether sites with high frequency activity in human atrial fibrillation (AF) can be identified noninvasively, which should help intervention planning and therapy. METHODS AND RESULTS: -In 14 patients with a history of AF, 67-lead body surface recordings were simultaneously registered with 15 endocardial electrograms from both atria including the highest DF site, which was pre-determined by atrial-wide real-time frequency electroanatomical mapping. Power spectra of surface leads and the body-surface location of the highest DF site were compared with intracardiac information. Highest DFs found on specific sites of the torso showed a significant correlation with DFs found in the nearest atrium (ρ=0.96 for right atrium and ρ=0.92 for left atrium) and the DF gradient between them (ρ=0.93). The spatial distribution of power on the surface showed an inverse relationship between the frequencies vs. the power spread area, consistent with localized fast sources as the AF mechanism with fibrillatory conduction elsewhere. CONCLUSIONS: -Spectral analysis of body surface recordings during AF allows a noninvasive characterization of the global distribution of the atrial DFs and the identification of the atrium with the highest frequency, opening the possibility for improved noninvasive personalized diagnosis and treatment.
    Circulation Arrhythmia and Electrophysiology 02/2013; · 5.95 Impact Factor
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    ABSTRACT: Functional rotors have been defined as a mechanism responsible for the maintenance of atrial fibrillation (AF). These re-entrant patterns can be identified in the atrial wall by detecting phase singularities (PS) in the epicardial phase maps. In this study, we evaluate the potential role of body surface phase maps to non-invasively locate atrial sites that may harbor rotors. This technology could be of great interest for diagnosis and treatment of AF.
    Computing in Cardiology Conference (CinC), 2013; 01/2013
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    ABSTRACT: BACKGROUND: In patients with organic intraventricular conduction defects (IVCDs), (1) QRS morphology during sinus rhythm frequently meets ventricular tachycardia (VT) morphological criteria and (2) there are further rate-related changes in QRS morphology. OBJECTIVE: To search for the best morphological criteria in this context. METHODS: We prospectively studied 69 patients, in sinus rhythm, with QRS duration >/=120 ms. Continuous rapid atrial pacing (RAP) trains were introduced at increasing rates in order to mimic supraventricular tachycardia. We analyzed the specificity of VT criteria during RAP. Finally, we used the criteria with a specificity of >/=0.9 in a "test sample" of 53 patients with preexisting IVCD and wide complex tachycardia to confirm their validity. RESULTS: Only 10 of the 20 analyzed criteria had a specificity of >/=0.9 during RAP at the highest rate. The specificity of these 10 criteria was confirmed in the test sample. The best accuracy to diagnose VT was obtained: for an isolated criterion: "R-wave peak time (RWPT) >/=50 ms at lead II" (specificity = 0.97; sensitivity = 0.67); for an algorithm: the combination of 2 criteria "RWPT >/=50 ms at lead II" and "absence of RS patterns in precordial leads" (specificity = 0.97; sensitivity = 0.88). CONCLUSIONS: In patients with IVCD, (1) specificity of most VT criteria is low during RAP, suggesting a limited applicability of many of these criteria in case they develop supraventricular tachycardia, and (2) the superior accuracy to diagnose VT was observed with "RWPT >/=50 ms at lead II" and for an algorithm with the combination of "RWPT >/=50 ms at lead II" and "absence of RS patterns in precordial leads."
    Heart Rhythm. 01/2013; 10(9):1393-401.
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    ABSTRACT: Conduction channels and electrograms with isolated component/late potentials are sensitive markers of the substrate of post-myocardial infarction sustained monomorphic ventricular tachycardia (VT). Ablation of all conduction channels and isolated component/late potentials (complete endocardial VT substrate ablation [CEVTSA]) during sinus rhythm could simplify and facilitate the ablation procedure, mainly in patients without references for clinical VT substrate identification. The aim of this study was to assess the safety, efficacy, and predictors of VT recurrence after CEVTSA. Electroanatomic mapping and CEVTSA were performed in 59 post-myocardial infarction patients (mean age 67 ± 9 years, mean left ventricular ejection fraction 30 ± 11%), 24 of whom did not have clinical VT substrate references. The mean areas of scar (≤1.5 mV) and dense scar (≤0.5 mV) were 76 ± 42 and 34 ± 24 cm(2), respectively; isolated component/late potentials and conduction channels were identified and ablated in 97% and 83% of patients (mean ablation area 14 ± 10 cm(2)). No life-threatening complications occurred during the procedure. After 1 year and at the end of follow-up (mean 39 ± 21 months), 81% and 58% of patients were free of VT. No differences were observed between patients with and without specific clinical VT substrate identification. Univariate analysis identified the left ventricular ejection fraction, VT cycle length (VTCL), infarct location (inferior vs anterior), and dense scar area as predictors of VT recurrence, and Cox analysis identified VTCL (hazard ratio 0.42, p <0.001) and dense scar area (hazard ratio 2.65, p <0.0006) as independent predictors. No patients with dense scar area ≤25 cm(2) and VTCL >350 ms had recurrences. In conclusion, CEVTSA is safe and effective, even in patients without clinical VT substrate identification. Scar area and VTCL are valuable predictors of VT recurrence.
    The American journal of cardiology 12/2012; · 3.58 Impact Factor
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    ABSTRACT: Background Ventricular fibrillation (VF) has been proposed to be maintained by localized high-frequency sources. We tested the hypothesis that combined spectral and nonlinear analyses of the standard ECG enables accurate localization of VF sources. Methods Six precordial ECG leads were used to record from 10 ischemic cardiomyopathy (IC) and 15 Brugada syndrome (BrS; type 1 ECG) patients during VF. Fourier and Hilbert transforms of ECG waveforms were used for frequency and phase analyses, respectively. Results Despite temporal variability, induced VF episodes recorded for 19.9 ± 8.6 seconds displayed long-lasting periods (7.8 ± 2.1 seconds [range 4.9–12.8 seconds]) of spectral power at a common frequency (shared frequency [SF]) in all leads (5.9 ± 0.8 Hz). In BrS patients, phase analysis of the SF showed a V1–V6 activation sequence as would be expected from waves originating at the base of the ventricles in patients displaying a type 1 ECG pattern (Friedman P <.001). Hilbert-based phase comparison confirmed that the V1–V6 sequence was the most stable over the whole VF duration. However, phase analysis of the SF in IC patients with anteroseptal (n = 4), apex (2), and lateral (4) myocardial infarction displayed activation at V1–V2, V3–V4, and V5–V6 as the earliest, respectively, consistent with an activation originating from the scar location (P <.01). The observed patterns correlated with the more stable sequence observed during Hilbert-based phase analysis (P <.05). Paired comparison showed that phase sequences were similar during monomorphic ventricular tachycardia and VF (Pearson coefficient 0.58, P <.001). Also, a dominant frequency gradient was observed between precordial leads corresponding to the scar region and the contralateral leads (5.86 ± 0.9 Hz vs 5.44 ± 1.1 Hz; paired t-test P = .011). Conclusions Early VF in BrS and IC patients is characterized by a steady sequence in the phase-frequency domain consistent with anatomic location of the arrhythmogenic substrate. These results are consistent with the prediction that VF is maintained by a small number of high-frequency sources that interact with the surrounding myocardium to generate fibrillatory conduction.
    Heart Rhythm. 11/2012; 9(11):1919.
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    ABSTRACT: AIMS: β-adrenergic stimulation has profound influence in the genesis and maintenance of atrial fibrillation (AF). However, the effects of β-adrenoceptors stimulation on repolarizing currents and action potential (AP) characteristics in human atrial myocytes from left (LAA) and right atrial appendages (RAA) obtained from sinus rhythm (SR) and chronic AF (CAF) patients have not been compared yet. METHODS AND RESULTS: Currents and APs were recorded using whole-cell patch-clamp in RAA and LAA myocytes from SR and CAF patients.Isoproterenol concentration-dependently decreased the Ca(2+)-independent 4-aminopyridine-sensitive component of the transient outward current (I(to1)) and the inward rectifying current (I(K1)). CAF significantly enhanced this inhibition, this effect being more marked in the left than in the right atria. CAF dramatically enhanced β-adrenoceptor-mediated increase of the slow component of the delayed rectifier current (I(Ks)), whose density was already markedly increased by CAF. Conversely, the ultrarapid component of the delayed rectifier current (I(Kur)) of both SR and CAF myocytes, was insensitive to low isoproterenol concentrations. As a consequence, stimulation of β1-adrenoceptors in SR myocytes lengthened, whereas in CAF myocytes shortened, the AP duration.Quantitative PCR revealed that CAF up-regulated β1-adrenoceptor expression, preferentially in the left atria. CONCLUSION: The present results demonstrate that CAF increases the effects of β1-adrenoceptor stimulation on repolarizing currents by means of a chamber-specific up-regulation of the receptors. This, together with the ion channel derangements produced by CAF, could contribute to the long-term stabilization of the arrhythmia by shortening the AP duration.
    Cardiovascular research 10/2012; · 5.80 Impact Factor
  • Felipe Atienza, Raphael P Martins, José Jalife
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    ABSTRACT: Atrial fibrillation (AF) is the most common arrhythmia seen in clinical practice and is associated with increased risk of stroke, heart failure and death.(1) However, currently available treatments for AF are less than satisfactory. Many drugs have been tried with very limited success.(2) On the other hand, the demonstration of AF triggers in the atrial sleeves of the pulmonary veins (PVs)(3) has led to a significant improvement in therapy. Today PV isolation by means of radiofrequency (RF) ablation is a gold standard treatment for paroxysmal AF.(4) However, the success rate of RF ablation in the more prevalent and highly heterogeneous persistent and long-term persistent AF populations has been disappointing.(5) The reasons are probably multifactorial, but undoubtedly incomplete understanding of the mechanism(s) underlying this complex arrhythmia has contributed substantially to such a poor outcome...
    Circulation Arrhythmia and Electrophysiology 09/2012; · 5.95 Impact Factor
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    ABSTRACT: BACKGROUND: Identification of electrocardiographic (ECG) criteria for para-Hisian accessory pathways (APs) is based on a small series of patients. The presence of a negative delta wave in leads V(1) and V(2) has been suggested as an ECG marker of this AP location. OBJECTIVE: To validate these ECG findings in a large series of patients with strict invasive criteria for that location. METHODS: We included 105 patients (39 women, 66 men; mean age 26±12 years, range 5-82 years) with an ECG pattern compatible with preexcitation through an anteroseptal or midseptal AP following established ECG criteria. A para-Hisian AP was defined when the location of its successful catheter ablation coincided with either the largest recordable His bundle electrogram or a His bundle potential of>0.1 mV. Patients without that definition were included in the control group. RESULTS: A para-Hisian location of the AP was found in 52 patients. AP locations of the remaining 53 patients (control group) were anteroseptal (n = 39), midseptal (n = 9), and fasciculoventricular (n = 5). A negative delta wave in leads V(1) and V(2) was observed in 13 patients with para-Hisian APs (sensitivity 25%; specificity 92%). However, the sum of initial r-wave amplitudes in those leads was<0.5 mV in 44 of the patients with para-Hisian APs and in 13 patients of the control group (sensitivity 85%; specificity 75.5%; area under receiver-operator characteristic curve 0.85). CONCLUSIONS: The presence of negative delta waves in leads V(1) and V(2) indicates a poor sensitivity and high specificity to detect APs with a strict definition of para-Hisian location. The sum of initial r-wave amplitudes in those ECG leads could be a useful, adjunctive marker in the noninvasive identification of these challenging APs.
    Heart rhythm: the official journal of the Heart Rhythm Society 09/2012; · 4.56 Impact Factor

Publication Stats

757 Citations
285.32 Total Impact Points


  • 2014
    • Instituto de Investigación Sanitaria Gregorio Marañón
      Madrid, Madrid, Spain
  • 2004–2014
    • Hospital General Universitario Gregorio Marañón
      • • Servicio de Cardiología
      • • Department of Cardiology
      Madrid, Madrid, Spain
  • 2013
    • Polytechnical University of Valencia
      Valenza, Valencia, Spain
  • 2009–2012
    • Complutense University of Madrid
      • Departamento de Medicina
      Madrid, Madrid, Spain
  • 2006–2008
    • State University of New York Upstate Medical University
      • Department of Pharmacology
      Syracuse, NY, United States
  • 2000–2004
    • Consorcio Hospital General Universitario de Valencia
      • Departamento de Cardiología
      Valencia, Valencia, Spain