Ángel Ferrero

Ablation or conservative management of electrical storm due to monomorphic ventricular tachycardia: differences in outcome

AIMS Electrical storm (ES) is a life-threatening condition that predicts bad prognosis. Treatment includes antiarrhythmic drugs (AAD) and catheter ablation (CA). The present study aims to retrospectively compare prognosis in terms of survival and ES recurrence in 52 consecutive patients experiencing a first ES episode. METHODS AND RESULTS Patients were admitted from 1995 to 2011 and treated for ES by conservative therapy (pharmacological, 29 patients) or by CA (23 patients), according to the physicians preference and time of occurrence, i.e. conservative treatments were more frequently administered during the first years of the study, as catheter ablation became more frequent as the years passed by. After a median follow-up of 28 months, no differences either in survival (32% vs. 29% P = 0.8) or in ES recurrence (38% in ablated vs. 57% in non-ablated patients, P = 0.29) were observed between groups. Low left ventricle ejection fraction (LVEF) was the only variable associated with ES recurrence in ablated patients. When including patients with LVEF > 25%, ES recurrence was significantly lower in ablated patients (24 months estimated risk of ES recurrence was 21% vs. 62% in ablated and non-ablated patients, respectively); however, no benefit in survival was observed. CONCLUSION Our data suggest that in most patients, especially those with an LVEF > 25%, catheter ablation following a first ES episode, decreases the risk of ES recurrence, without increasing survival.

Value of Early Cardiovascular Magnetic Resonance for the Prediction of Adverse Arrhythmic Cardiac Events After a First Noncomplicated ST-Segment-Elevation Myocardial Infarction

Background— Infarct size (IS) determined by cardiac magnetic resonance (CMR) has proven an additional value, on top of left ventricular ejection fraction (LVEF), in prediction of adverse arrhythmic cardiac events (AACEs) in chronic ischemic heart disease. Its value soon after an acute ST-segment–elevation myocardial infarction remains unknown. Our aim was to determine whether early CMR can improve AACE risk prediction after acute ST-segment–elevation myocardial infarction. Methods and Results— Patients admitted for a first noncomplicated ST-segment–elevation myocardial infarction were prospectively followed up. A total of 440 patients were included. All of them underwent CMR 1 week after admission. CMR-derived LVEF and IS (grams per meter squared) were quantified. AACEs included postdischarge sudden death, sustained ventricular tachycardia, and ventricular fibrillation either documented on ECG or recorded via an implantable cardioverter-defibrillator. Within a median follow-up of 2 years, 11 AACEs (2.5%) were detected: 5 sudden deaths (1.1%) and 6 spontaneous ventricular tachycardia/ventricular fibrillation. In the whole group, AACEs associated with more depressed LVEF (adjusted hazard ratio [95% confidence interval], 0.90 [0.83–0.97]; P<0.01) and larger IS (adjusted hazard ratio [95% confidence interval], 1.06 [1.01–1.12]; P=0.01). According to the corresponding area under the receiver operating characteristic curve, LVEF ⩽36% and IS ≥23.5 g/m2 best predicted AACEs. The vast majority of AACEs (10/11) occurred in patients with simultaneous depressed LVEF ⩽36% and IS ≥23.5 g/m2 (n=39). Conclusions— In the era of reperfusion therapies, occurrence of AACEs in patients with an in-hospital noncomplicated first ST-segment–elevation myocardial infarction is low. In this setting, assessment of an early CMR-derived IS could be useful for further optimization of AACE risk prediction.

Implantation of single-lead atrioventricular permanent pacemakers guided by electroanatomic navigation without the use of fluoroscopy

AIMS Fluoroscopy is the standard and almost unique tool used for cardiac imaging during permanent pacemaker implantation, and its use implies exposure of patients and operators to radiation. The usefulness for this purpose of electroanatomic systems not based on fluoroscopy is unknown. Our aim was to study the feasibility of implanting single-lead VDD pacemakers without the use of fluoroscopy. METHODS AND RESULTS EnSite NavX, a catheter navigation tool based on the creation of a voltage gradient across the thorax of the patient, was used as an exclusive imaging tool during the implantation of single-lead atrioventricular (VDD) permanent pacemakers in 15 consecutive patients with atrioventricular block and normal sinus node function. A retrospective series of 15 consecutive patients in whom VDD pacemakers were implanted under fluoroscopic guidance was used as a control group. The pacemaker could be implanted in all patients. Time spent to obtain the right ventricle anatomy was 10.1 +/- 5.4 min and time to place the lead in an adequate position was 10.1 +/- 7.8 min. Total implant time was 59.3 +/- 15.6 min (51.5 +/- 12.3 min in the control group; P = 0.14). In one patient, a short pulse of radioscopy was needed for a correct catheterization of the subclavian vein. No complications were observed during the procedure. One lead dislodgement that required re-operation was detected 24 h after implantation. At 3 months follow-up, all pacemakers were functioning properly, with adequate pacing and sensing thresholds. CONCLUSION Electroanatomic navigation systems such as NavX can be used for cardiac imaging during single-lead atrioventricular pacemaker implantation as a reliable and safe alternative to fluoroscopy.

Predictors of short-term outcome in acute chest pain without ST-segment elevation

BACKGROUND Management of acute chest pain in the emergency room constitutes a challenge. METHODS Seven hundred and one consecutive patients were evaluated by clinical history (chest pain score and risk factors), ECG, troponin I and early (<24 h) exercise testing in low risk patients (n=165). A composite end-point (recurrent unstable angina, acute myocardial infarction or cardiac death) was recorded during hospital stay or in ambulatory care settings for patients discharged after early exercise testing. RESULTS The end-point occurred in 122 patients (17%). Multivariate analysis identified the following predictors: chest pain score > or =11 points (OR=1.8, 2-2.8, 95% CI, P=0.007), age > or =68 (OR 1.6, 1.1-2.4 CI 95%, P=0.03), insulin-dependent diabetes mellitus (OR 1.9, 1.1-3.4 CI 95%, P=0.02), a history of coronary surgery (OR 3.3, 1.5-7.2 CI 95%, P=0.003), ST-segment depression (OR 1.9, 1.2-3.0 CI 95%, P=0.009) and troponin I elevation (OR 1.6, 1.1-2.5, CI 95%, P=0.05). ST-segment depression produced a high end-point increase (31 vs. 13%, P=0.0001). Troponin I elevation increased the risk in the subgroup without ST-segment depression (20 vs. 11%, P=0.006) but did not further modify the risk in the subgroup with ST depression (31 vs. 28%, ns). Nevertheless, the negative ECG and troponin I subgroup showed a non-negligible end-point rate (16% when pain score > or =11 or 7% when pain score <11, P=0.004). Finally, no patient with a negative exercise test presented events compared to 7% of those with a non-negative test (RR=2.5, 2.1-3.1 95% CI, P=0.01). CONCLUSIONS Emergency room evaluation of chest pain should not focus on a single parameter; on the contrary, the clinical history, ECG, troponin and early exercise testing must be globally analysed.

Significance of tilt table testing in patients with suspected arrhythmic syncope and negative electrophysiologic study.

Background: The diagnostic significance of a tilt table test (TTT) in patients with a suspected arrhythmic etiology for syncope and negative electrophysiologic study (EPS) has not been previously assessed comparing the TTT results with the findings of prolonged monitoring using an implantable loop recorder (ILR). We sought to assess the diagnostic yielding of TTT in patients with suspected arrhythmic syncope and negative EPS.

Análisis tiempo-frecuencia de la fibrilación ventricular. Estudio experimental

INTRODUCTION AND OBJECTIVES The analysis of frequency variability during ventricular fibrillation has yielded inconsistent results. We used an experimental model of ventricular fibrillation, with a short timescale, to analyze variations in frequency and their associated spatial distribution. METHODS Epicardial recordings of ventricular fibrillation were made in 10 perfused isolated rabbit heart preparations using a multiple electrode system (i.e., 240 unipolar electrodes). Both spectral and time-frequency analysis were used to derive the dominant frequency in the anterolateral wall of the left ventricle. RESULTS Linear regression analysis showed that there was a good correlation between the dominant frequency obtained using the two signal analysis methods: frequency (spectral analysis) = 1.01 x frequency (time-frequency analysis) -- 0.4 (r=0.9; P< .0001; standard error of the estimate, 2.2 Hz). In all cases except one, the dominant frequency exhibited a significant temporal variation on a short timescale (time-frequency analysis); the coefficient of variation was between 0.19 (0.06) and 0.24 (0.07) (NS). In all cases, there were significant differences between regions. The location at which the frequency was highest varied according to the timepoint considered, though it was predominantly in the apical or anterior zone. CONCLUSIONS In the absence of external modulating factors, the frequency of ventricular fibrillation exhibits temporal and spatial variations which can be observed at short timescales. In the free wall of the left ventricle, the dominant frequency is highest in the apical and anterior zones, and the maximum frequencies are most often found in these zones.Introduccion y objetivos El analisis de la variabilidad de la frecuencia durante la fibrilacion ventricular ha aportado resultados no uniformes. En un modelo experimental de fibrilacion ventricular se analiza, en una escala temporal reducida, las variaciones de la frecuencia y su distribucion espacial. Metodos En 10 preparaciones de corazon aislado y perfundido de conejo, se efectuan registros epicardicos de la fibrilacion ventricular con un electrodo multiple (240 electrodos unipolares) y se aplican metodos de analisis espectrales y de tiempo-frecuencia para obtener la frecuencia dominante en la pared anterolateral del ventriculo izquierdo. Resultados La recta de regresion obtenida al relacionar los valores de la frecuencia dominante obtenidos con los 2 metodos de analisis muestra una buena correlacion entre ambos: frecuencia (metodo espectral) = 1,01 × frecuencia (metodo tiempo-frecuencia) – 0,4 (r = 0,9; p Conclusiones En ausencia de factores moduladores externos, la fibrilacion ventricular presenta variaciones temporales y espaciales de la frecuencia que se objetivan en escalas de tiempo reducidas. En la pared libre del ventriculo izquierdo, la frecuencia dominante es mayor en las zonas apicales y anteriores, zonas en las que se ubican con mayor frecuencia los valores maximos.

Prognostic Value of Serum Creatinine in Non-ST-Elevation Acute Coronary Syndrome

INTRODUCTION AND OBJECTIVES Cardiovascular disease is the main cause of death in patients with kidney failure. Moreover, the presence of impaired renal function is an important prognostic factor in patients with heart disease, and is a determinant of outcome during follow-up. The main aim was to investigate the relationship between kidney failure at admission and one-year mortality in patients with non-ST-elevation acute coronary syndrome. PATIENTS AND METHOD We studied 1029 consecutive patients admitted to our institution. The serum creatinine level and glomerular filtration rate were determined at admission, and classical risk factors and biochemical markers were assessed. The primary endpoint was all-cause mortality at one year. RESULTS Patients who died were older, more frequently had a history of diabetes or coronary artery disease, were more likely to have heart failure at admission, had higher troponin-I, myoglobin and creatinine levels, and were less likely to have dyslipidemia or to be a smoker. Multivariate analysis showed that the independent predictors of all-cause mortality at one year were age, diabetes, troponin-I level, Killip class > 1, male gender, creatinine level, and glomerular filtration rate. There was a linear correlation between increased risk and creatinine level. CONCLUSIONS Creatinine level at admission is one of the most important covariates in early prognostic stratification in these patients. A high serum creatinine level (or a low glomerular filtration rate) increases the probability of death due to all causes. The serum creatinine level is, moreover, an inexpensive, easy-to-use, and widely available prognostic marker.

Efecto del estiramiento miocárdico sobre las frecuencias de activación determinadas mediante análisis espectral durante la fibrilación ventricular

Introduction and objectives. The aim of this study was to analyze the effects of myocardial stretching on excitation frequencies, as determined by spectral analysis, during ventricular fibrillation. Methods. In 12 isolated rabbit heart preparations, ventricular activation during ventricular fibrillation was recorded with multiple electrodes. Recordings were obtained before, during and after ventricular dilatation produced with an intraventricular balloon. The dominant frequency of the signals obtained with each of the electrodes was determined by spectral analysis. Results. During the control phase, the mean, minimum and maximum dominant frequencies were, respectively, 14.3 ± 1.7, 12.5 ± 1.7, and 16.2 ± 1.4 Hz, and the average difference between the maximum and minimum frequencies was 3.6 ± 2.1 Hz. This difference was over 4 Hz in four cases, and in no case did it exceed 8 Hz. During ventricular stretching, the mean dominant frequency increased significantly (21.1 ± 6.1 Hz; p < 0.0001), as did the minimum values (14 ± 2.6 Hz; p < 0.05) and especially the maximum values (26.6 ± 7.7 Hz; p < 0.0001). The difference between the maximum and minimum frequencies (12.6 ± 6.4 Hz; p < 0.001) was over 4 Hz in all cases except one, and over 8 Hz in 9 cases. The maximum values were distributed heterogeneously during ventricular stretching. Upon suppressing ventricular stretching, the dominant frequency did not differ from controls. Conclusions. Myocardial frequency maps during ventricular fibrillation show limited variations in the dominant frequency of the signals recorded in the lateral wall of the left ventricle. During stretching, the patterns were heterogeneous, due mainly to the marked increase in the maximum dominant frequency. In the experimental model used, the effects of stretching remitted after suppressing ventricular dilatation.

Influencia del tipo de registro (unipolar o bipolar) en las características espectrales de los registros epicárdicos de la fibrilación ventricular. Estudio experimental

Introduction and objectives. The aim of this study was to examine the hypothesis that the recording mode (ie, unipolar or bipolar) affects the information obtained using spectral analysis techniques during ventricular fibrillation by carrying out an experiment using epicardial electrodes. Methods. Recordings of ventricular fibrillation were obtained in 29 isolated rabbit hearts using a multipleelectrode probe located on the left ventricular free wall. The parameter values obtained in the frequency domain (by Fourier analysis) using unipolar or bipolar electrodes, different interelectrode distances, and different orientations (ie, horizontal, vertical, or diagonal) were compared. Results. Changing the recording mode (ie, unipolar to bipolar) or the interelectrode distance significantly altered the mean frequency (P<.0001) and the normalized energy of the spectrum (±1 Hz) around the dominant frequency (P<.05), though the changes were small relative to the dominant frequency. Cross-spectral analysis showed that the coherence between unipolar recordings decreased as the interelectrode distance increased, while the opposite occurred with the coherence between unipolar and bipolar recordings. The 2 coherences were inversely correlated such that the greater the former coherence, the less the coherence between unipolar and bipolar recordings (r=0.29; P<.0001; n=348). Conclusions. The recording mode (ie, unipolar or bipolar) used influenced the information obtained using spectral analysis techniques from epicardial recordings of

Significance of the Morphological Patterns of Electrograms Recorded During Ventricular Fibrillation

Mapping techniques are used to study the significance of the morphological patterns of the electrograms (EGMs) obtained during VF in an experimental model. In 24 isolated rabbit heart preparations recordings were made of activation during VF using a multiple electrode (121 unipolar electrodes) positioned on the lateral wall of the left ventricle. Three types of activation maps were selected: (A) with functional block of an activation front; (B) with epicardial breakthrough; and (C) with a single broad wavefront without block lines. The EGMs were classified as negative (Q), positive‐negative with a predominance of the negative (rS) or positive wave (Rs), and positive (R). In 60 type A maps the morphology in the zone limiting the block line corresponded to an R wave in 55 (92%) cases and to Rs in 5 (8%) cases. In 67 type B maps, the EGM in the earliest activation zone most often showed Q wave morphology (48 [72%] cases), followed by rS (18 [27%] cases), and Rs morphology (1 [1%] case); in no case was R wave morphology seen. Finally, in 78 type C maps the morphology corresponded to a Q wave in 15 (19%) cases, rS in 38 (49%), Rs in 24 (31%), and R in a 1 (1%) case. The differences between the three types of maps were significant (P < 0.0001). Q wave EGM sensitivity for indicating the existence of an epicardial breakthrough pattern was 72%, with a specificity of 89%, and positive and negative predictive values of 76% and 87%, respectively. R wave EGM sensitivity for indicating the existence of conduction block was 92%, with a specificity of 99%, and positive and negative predictive values of 98% and 97%, respectively. R wave morphology is highly sensitive and specific for indicating conduction block. EGM recordings with initial positivity predominance are infrequent in the earliest activation zones of epicardial breakthrough during VF. The recording of the EGM with Q wave morphology indicates centrifugal activation from the explored zone. (PACE 2003; 26:1262–1269)