Significance of the learning curve in left atrial appendage occlusion with two different devices.

OBJECTIVE: To evaluate the impact of learning on outcome with use of two different left atrial appendage (LAA) occlusion devices. BACKGROUND: Two self-expanding devices, the Watchman and the Amplatzer Cardiac Plug (ACP), have been used for LAA occlusion in the last few years. It has been demonstrated that complications associated with implantation decrease in frequency with operator experience. However, the role of operator experience has not been compared across the two device types. METHODS: The study comprises 31 consecutive patients who underwent LAA occlusion. We compare the first 10 patients in whom an ACP was implanted with the subsequent eleven patients who underwent ACP implantation and with 10 cases where a Watcthman device was implanted. The composite safety end point comprised procedure-related events and excessive bleeding events. We also performed 3 months echocardiographic and clinical follow-up. RESULTS: There were not significant differences in the basal clinical and echocardiographical characteristics across the three groups. Cardiac complications only occurred in the ACP initial experience group (9% vs. 0% vs. 0% P = 0.04). Echocardiographic and clinical follow-up at 3 months was completed in all patients. No significant residual leak was detected. One patient in the ACP initial experience group developed a thrombus on the device. One patient in ACP late experience presented an ischemic stroke. CONCLUSIONS: Complications associated with LAA occlusion cluster early in the peri-procedural period and significantly decrease in frequency with operator experience. Initial experience gained with one of device may improve outcome with use of alternative LAA occlusion devices.

Morphology of far-field electrograms and antitachycardia pacing effectiveness among fast ventricular tachycardias occurring in ICD patients: a multicenter study.

INTRODUCTION: Fast ventricular tachycardias (FVT) are less likely to be terminated by antitachycardia pacing (ATP). No information is available regarding the ability of far-field electrogram (Ff-EG) morphology (Ff-EGm) in predicting the result of the subsequent ATP. Our objective is to determine the relationship between Ff-EGm and ATP efficacy. METHODS AND RESULTS: In this multicenter study we analyzed 289 FVT (cycle length [CL]: 250-320 milliseconds) occurring consecutively in 52 ICD patients with Medtronic devices (LVEF: 37 ± 6; pacing site: right ventricular apex). FVT programming was standardized, including a single ATP burst as initial therapy. The configuration of Ff-EG was HVA versus HVB. FVTs were classified in QFVT or non-QFVT according to the presence or absence of a negative initial deflection in the Ff-EG. The mean CL was 291 ± 24 milliseconds. We observed 4 Ff-EGm: QS (n = 14, 5%), QR (n = 158, 55%), R (n = 93, 32%), and RS (n = 24, 8%). The ATP effectiveness was 80% (86% in QS, 85% in QR, 74% in R, 62% in RS). The frequency of successful ATP was higher in QFVT: 86 versus 71% (P = 0.002). By logistic regression analysis, a QFVT pattern (OR = 2.3; P = 0.015) remained as an independent predictor of effective ATP. ATP was safer in QFVTs, the frequencies of shock (14% vs 29%; P = 0.002), acceleration (5.1 vs 12.3%; P = 0.02), and syncope (4.6 vs 12.3%; P = 0.01) being lower. CONCLUSIONS: Since ATP is less effective in non-QFVTs, they are less well tolerated. Therefore, the substrate of non-QFVTs may need a specific treatment.

Influence of beta-blocker therapy on antitachycardia pacing effectiveness for monomorphic ventricular tachycardias occurring in implantable cardioverter-defibrillator patients: a dose-dependent effect.

AIMS: To determine, in a non-selected population of 282 implantable cardioverter-defibrillator (ICD) patients with left ventricular dysfunction, the influence of the dose of beta-blockers on antitachycardia pacing (ATP) effectiveness and on the incidence of shock due to monomorphic ventricular tachycardias (VT). METHODS AND RESULTS: We followed 282 ICD patients along 26 +/- 19 months. Antitachycardia pacing and shock programming were standardized. We determined the indexed dose equivalent of beta-blockers (IDE-BB), using metoprolol as a reference, at each VT presentation. The median of IDE-BB was 55 mg/m(2)/day. We analysed 846 VT occurred in 100 patients. The ATP success rate was 84%. Upon classification of the events into three groups (IDE-BB = 0, IDE-BB < 55, and IDE-BB > or = 55), the frequency of effective ATP increased with the IDE-BB: 75 vs. 83 vs. 92% (P < 0.001). According to logistic regression, IDE-BB remained as an independent predictor of effective ATP (P < 0.001) and VT-related shock (P = 0.001). Both the mean ATP effectiveness per patient (67 vs. 80 vs. 91%, P = 0.007) and the mean survival time free of VT-related shock (583 vs. 847 vs. 1158 days, P = 0.019, log-rank test) increased linearly with the dose of beta-blockers. CONCLUSION: Beta-blockers increase the effectiveness of ATP through a dose-dependent effect. As a result, they reduce the incidence of shocks due to VT.

Relationship between the duration of the basal QRS complex and electrical therapies for ventricular tachycardias among ICD patients.

BACKGROUND: In implantable cardioverter-defibrillators (ICD) patients, the duration of the basal QRS complex (QRSd) is not associated with a greater risk of developing ventricular tachyarrhythmias. QRSd could be inversely related to the effectiveness of antitachycardia pacing (ATP) because it may be associated with longer conduction times of the paced-impulses and hence, with a greater propensity to require shocks to terminate ventricular tachycardias (VTs). METHODS: We followed 216 ICD patients (pacing site: right ventricular apex; QRSd 100 remained as an independent predictor of receiving shocks to terminate VTs (P = 0.01). According to Kaplan-Meier analysis, the occurrence of VTs was similar regardless of the QRSd (30% vs 38%; P = 0.2), but the incidence of shock due to VTs was higher in patients with a QRSd > 100 (19% vs 7%; P = 0.01). CONCLUSION: Since QRSd is a negative and independent predictor of effective ATP, ICD patients with QRSd > 100 ms require shocks more frequently to terminate VTs.

Early reduction of QT dispersion after primary percutaneous intervention in ST-segment elevation acute myocardial infarction. Mechanisms and clinical implications.

OBJECTIVES: To determine, in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI), the mechanisms and clinical implications of the acute changes in QT dispersion (QTd). METHODS: In this prospective study we included 216 patients admitted with a STEMI of <12 h of evolution. All were treated with PPCI. QTd was measured prior to PPCI and within 1 h after. RESULTS: The ratio of QTd reduction after PPCI (QTd-R) - defined as [(QTd before PPCI - QTd after PPCI)/QTd before PPCI] x100 - was significantly correlated with the percentage of ST-segment elevation resolution (ST-R; p < 0.001). To determine the significance of the different values of QTd-R, we further subdivided our population into 3 groups according to the tertiles of QTd-R (<10, 11-49, > or =50%). Patients with longer QTd-R had higher percentages of ST-R: 32 +/- 43 for QTd-R <10% vs. 60 +/- 21 for 11-49% vs. 71 +/- 12 for > or =50% (p < 0.05). By logistic regression, patients with QTd-R > or =50% had a reduction of 75% in the adjusted frequency of death or severe heart failure during hospitalization (95% CI 13-73%, p = 0.03). CONCLUSION: QTd-R after PPCI occurs early, is closely related to the restoration of reperfusion at the microvascular level and provides additional prognostic information.

Association between -T786C NOS3 polymorphism and resistant hypertension: a prospective cohort study.

BACKGROUND: It is estimated that 5% of the hypertensive patients are resistant to conventional antihypertensive therapy. Polymorphisms in the endothelial nitric oxide synthase (NOS3) gene have been associated with high blood pressure levels, but not with resistant hypertension. The aim of the present study was to investigate if the -786T>C and G894T (Glu298Asp) polymorphisms of the NOS3 gene were associated with resistant hypertension. METHODS: A prospective case-control observational study was performed. From a series of 950 consecutive patients followed up during 42 months, 48 patients with resistant hypertension were detected. 232 patients with controlled high blood pressure were also included. RESULTS: No differences were observed in the distribution of G894T (Glu298Asp) NOS3 genotypes between the resistant hypertension group and the controlled hypertension patients. However, genotype -786CC was more frequent in the group of patients with resistant hypertension (33.3%) than in the group of patients with controlled high blood pressure (17.7%) (p 0.03). Furthermore carriers of allele T (-786TC and -786TT) were more frequent in patients with controlled hypertension (82.3%) than those with resistant hypertension (66.7%) (Multivariate analysis; RR 2.09; 95% CI 1.03-4.24; p 0.004). CONCLUSION: Our results indicate that genotype -786CC of the NOS3 gene increase the susceptibility to suffer resistant hypertension, which suggest that resistance to conventional therapy could be determined at the endothelial level.

[Hemodynamic and inflammatory markers of sleep apnea-hypopnea syndrome and nocturnal hypoxemia: effects of treatment with nasal continuous positive airway pressure]. / Marcadores hemodinámicos e inflamatorios del síndrome de apneas-hipopneas durante el sueño e hipoxemia nocturna. Efectos del tratamiento nasal con presión positiva continua de la vía aérea nasal.

OBJECTIVE: In this study, we assessed factors associated with cardiovascular risk in patients with sleep apnea-hypopnea syndrome (SAHS) through analysis of plasma concentrations of N-terminal prohormone brain natriuretic peptide (NTproBNP) and high-sensitivity C-reactive protein (hsCRP). In addition, we analyzed the effect of nasal continuous positive airway pressure (nCPAP) on these markers. PATIENTS AND METHODS: Forty-two patients with SAHS (mild to moderate in 15 cases and severe in 27) were compared with 14 individuals without SAHS. The participants were not receiving drug treatment and they did not have diabetes, hypertension, marked dyslipidemia, or cardiovascular disease, which was ruled out both clinically and by echocardiography and (99m)Tc-tetrofosmin scintigraphy at rest and during exercise. The effects of nCPAP in patients with severe SAHS were analyzed after 6 months of treatment. RESULTS: Following adjustment for age, body mass index, and smoking habit, the mean concentrations of markers were not significantly higher in patients with severe SAHS than in those with mild-to-moderate SAHS or in control subjects. Nevertheless, in patients with SAHS the main factor influencing NTproBNP concentrations was the percentage of time with a nocturnal arterial oxygen saturation of less then 90% (r=0.37, P=.017). No variables predictive of hsCRP concentration were identified. The concentrations of the markers were reduced by nCPAP, but the differences were not statistically significant. CONCLUSIONS: While nocturnal hypoxemia in SAHS is responsible for variations in the plasma concentration of NTproBNP (as a result of cardiovascular changes), SAHS appears not to be associated with the inflammatory marker hsCRP when patients with heart disease, cardiovascular risk factors, or those receiving pharmacologic treatment are excluded.

Importance of the relationship between sinus cycle length and junctional rhythm cycle length (occured during radiofrequency ablation) in predicting the successful modification of the slow pathway in Atrioventricular Nodal Re-entrant Tachycardias.

BACKGROUND: In atrioventricular nodal re-entrant tachycardias (AVNRT), the achievement of Junctional Rhythms (JR) during Radiofrequency Ablation (RF) is a sensitive but non-specific marker of success. Our aim is to analyze prospectively the predictors of non-inducibility of AVNRT, focusing on the characteristics of the JR. METHODS: We included 75 patients with reproducibly inducible AVNRT. Ablation was performed following an electro-anatomical approach. After each application, the induction protocol was repeated. RESULTS: A total of 341 applications were performed. Although the achievement of >/=1 JR was necessary to obtain the non-inducibility, and the cumulative number of junctional beats (CJB) was higher in effective applications, no CJB cut-off was associated with a success rate higher than 75%. After the observation of a significant correlation between the sinus cycle length (CL) pre-RF and the CL of the JR (JR-CL) (c=0.52; p<0.001), the sinus CL pre-RF/JR-CL ratio (CL-ratio) adequately differentiated the successful vs. unsuccessful applications: 1.41+/-0.23 vs. 1.17+/-0.2 (p<0.001). In a multivariate analysis, a CBJ 11 (p<0.001) and a CL-ratio 1.25 (p<0.001) were found to be the only independent predictors of success. The combination of >/= 11 of CJB with a CL ratio >/= 1.25 achieved non-inducibility in 97% of our patients. CONCLUSION: 1) The specificity of the occurrence of JR as a marker of the successful ablation of AVNRT is increased by the CL-ratio. 2) The achievement of >/= 11 of CJB with a CL ratio >/= 1.25 predicts non-inducibility in almost all patients.

Short- and long-term prognostic value of the corrected QT interval in the non-ST-elevation acute coronary syndrome.

BACKGROUND AND PURPOSE: Myocardial ischemia prolongs the QTc interval. Very little data exists about its prognostic implications in the non-ST-elevation acute coronary syndromes (NST-ACS). METHODS: This is and observational and prospective study in which we evaluated the prognostic implications of the QTc obtained at admission (AQTc) in the short- and long-term of the NST-ACS. The median of the follow-up was 17 months. RESULTS: AQTc correlated adequately with the incidence of adverse events in the short- and long-term (P < .001), with the best cut-off point in 450 milliseconds. Patients with AQTc > or =450 presented higher frequency of in-hospital death: 8.8% vs 1.2%; P = .001, and MACE (death, recurrent ischemia, or urgent coronary revascularization): 72% vs 25%; P < .001. In a Cox regression analysis, we found 3 independent predictors of cardiovascular death after discharge: AQTc > or =450 (14.7% vs 2.1%; P < .0001), age >65 years and left ventricular ejection fraction <40%. Coronary revascularization reduced the risk of posthospitalary cardiovascular death in AQTc > or =450 milliseconds (5% vs 24%; P < .0001) but had no significant effect in AQTc<450 milliseconds. CONCLUSION: These findings provide a new evidence supporting the prognostic value of the AQTc in predicting unfavorable events in the short- and long-term of the NST-ACS.

Relation of circulating C-reactive protein to progression of aortic valve stenosis.

C-reactive protein (CRP) is a marker of inflammation and predicts outcome in apparently healthy subjects and patients with coronary artery disease. Systemic inflammation is present in patients with aortic valve stenosis (AS). The aim of this prospective study was to assess whether CRP levels predict the progression of AS severity. Blood samples for high-sensitivity CRP measurements and echocardiographic data were obtained in 43 patients (70% men; mean age 73 +/- 8 years) with asymptomatic degenerative AS at study entry. On the basis of repeat echocardiographic assessment at 6 months, patients were grouped as (1) slow progressors (a decrease in aortic valve area [AVA] <0.05 cm2 and/or an increase in aortic peak velocity <0.15 m/s) and (2) rapid progressors (a decrease in AVA > or =0.05 cm2 and/or an increase in aortic peak velocity > or =0.15 m/s). Plasma CRP levels were significantly higher in rapid progressors than slow progressors (median 5.1 [range 2.3 to 11.3] vs 2.1 [range 1.0 to 3.1] mg/L, p = 0.007). In multivariate analysis, CRP levels >3 mg/L were independently associated with rapid AS progression (odds ratio 9.1, 95% confidence interval 2.2 to 37.3). In conclusion, CRP levels are higher in patients with degenerative AS who show rapid valve disease progression. These findings suggest that inflammation may have a pathogenic role in degenerative AS.

[Kinetics of C-reactive protein release in different forms of acute coronary syndrome]. / Cinética de la proteína C reactiva en las distintas manifestaciones clínicas del síndrome coronario agudo.

INTRODUCTION AND OBJECTIVES: Better knowledge of C-reactive protein (CRP) kinetics could lead to improved clinical application of this biomarker. METHODS: We studied 110 patients: 42 had ST-elevation acute myocardial infarction (STEMI), 35 had non-ST-elevation acute myocardial infarction (NSTEMI), and 33 had unstable angina. Patients were admitted to our institution within 6 hours of symptom onset. The levels of CRP, troponin-I, and creatine kinase MB fraction (CK-MB) were measured on admission and every 6 hours during the first 48 h. The CRP level was also measured daily until hospital discharge. RESULTS: The median (interquartile range) CRP level increased relative to baseline from 6 hours after admission, from 5 (2-9) mg/L to 6 (3-10) mg/L (P=.004). Although, CRP levels on admission were similar in all groups, there was a significant difference in peak CRP level: it was 67 (36-112) mg/L in the STEMI group, 29 (20-87) mg/L in the NSTEMI group, and 18 (12-36) mg/L in the unstable angina group. The maximum CRP level was observed 49 (38-53) hours after the onset of symptoms, but occurred later in patients with STEMI. Although there was only a weak non-significant correlation between CRP and troponin levels (r=0.135) at admission, the maximum CRP level was found to be influenced by the degree of myocardial damage (r=0.496; P< .001). CONCLUSIONS: The pattern of CRP release observed was clearly different in different forms of acute coronary syndrome. Although the CRP level measured at admission was similar in all patient groups, it was influenced by the degree of early myocardial tissue necrosis. This variation in CRP kinetics should be taken into consideration when designing future studies.

[Imbalance between the supply and demand for cardiologists in Spain. Analysis of the current situation, future prospects, and possible solutions]. / Desequilibrio entre la oferta y las necesidades de cardiólogos en España. Análisis de la situación actual, previsiones futuras y propuestas de solución.

Planning cardiology provision in Spain requires knowledge of the resources available and the demand, both now and in the future. In this report, we present the results of a study carried out by the Spanish Society of Cardiology on the availability of and demand for cardiologists in the country. The current situation is characterized by an imbalance of around 14% between the number of active cardiologists and the estimated number required. The demographic distribution of cardiologists shows that they are predominantly male and middle-aged. Expectations are that the situation will get worse until the year 2020. To correct this imbalance, alternative forms of training or clinical department organization, or both, are required. Some possible alternatives are presented in the final part of this document, as proposals for open discussion.

[Hypoxemia and stroke in a patient with a pacemaker]. / Cianosis y accidente cerebrovascular en una paciente con marcapasos.

We report a woman with a VVI pacemaker and a history of stroke and severe hypoxemia due to a right-to-left shunt. Anomalous blood flow was through a patent foramen oval, and was related directly with severe tricuspid regurgitation because the ventricular pacemaker electro de was adhered to the tricuspid valve. She was treated successfully with surgery. We review the role of patent foramen ovale from a clinical point of view, and current therapeutic options.

[Clinical safety and efficacy of single-chamber atrial pacing in sick sinus syndrome: long-term follow-up]. / Seguridad y eficacia clínica de la estimulación con el modo AAI en la disfunción del nodo sinusal: seguimiento a largo plazo.

INTRODUCTION AND OBJECTIVES: Although atrial pacing is a more physiological mode of stimulation in sinus node dysfunction, the pacing modes most often are used DDD and VVI. The aim of our study was to demonstrate that AAI/AAIR pacing is effective and safe by analyzing the complications and mortality of this pacing mode in a long-term follow-up study. PATIENTS AND METHOD: Between 1982 and 2000 definitive AAI-mode pacemakers were implanted for sinus node dysfunction in mode AAI in 160 patients. We analyzed the clinical characteristics, evolution, and complications of the AAI pacing mode during a follow-up of 5.4 4.5 years. RESULTS: The sample was made up of 104 women and 56 men with an average age of 72 12 years. During follow-up, it was necessary to change the pacing mode for symptomatic bradycardia in 11 patients (annual incidence 1.2%), which was caused by second or third-degree atrioventricular block in 7 patients (annual incidence 0.8%), and chronic atrial fibrillation with bradycardia in 4 patients (annual incidence 0.4%). During follow-up, atrial arrhythmias occurred in 32 patients (annual incidence 3.7%), stroke in 4 patients (annual incidence 0.4%), and 27 patients (annual incidence 3.1%) died. CONCLUSIONS: The AAI/AAIR pacing mode was safe and effective in sinus node dysfunction, with a low percentage of pacing changes required for progression to atrioventricular block, low incidence of atrial arrhythmias, stroke and low mortality during long term follow-up.

[Long-term prognostic value of troponin I in patients admitted to a coronary unit for unstable angina]. / Valor pronóstico de la troponina I en los pacientes ingresados en una unidad coronaria por angina inestable.

INTRODUCTION AND OBJECTIVES: Troponin I (TnI) is a useful marker of myocardial damage for the diagnosis and prognosis of acute coronary syndrome. The purpose of this study was to analyze the long-term prognostic value of the peak TnI concentration obtained within 48 h of admission to the coronary unit for unstable angina. METHODS: The study included 149 consecutive patients. Serial determinations were made of the MB fraction of creatine kinase (CK-MB) and TnI. Patients without CK-MB elevation were classified into two groups depending on the presence of high (n = 58) or normal (n = 91) troponin I values. We prospectively analyzed the clinical and evolutive factors related to the probability of death, new acute coronary event, or coronary revascularization at one-year of follow-up. RESULTS: There were no differences in the clinical characteristics between groups, except that patients in the group with high TnI values were older (69 vs. 64 years, p = 0.01). At one year of follow-up there were no differences in the incidence of new acute coronary events or coronary revascularization procedures; however there was a higher mortality in the group with high TnI (13 vs. 4%; p = 0.01). The independent predictors of mortality were prior myocardial infarction (RR = 3), elevated troponin I (RR = 3.2), left ventricular ejection fraction < 35% (RR = 10), and age > 70 years (RR = 15). CONCLUSIONS: In patients with unstable angina a high troponin I value in the first 48 h of admission was associated with a higher mortality rate at one-year of follow-up.

[Recurrent coronary thrombosis, factor V Leiden, primary antiphospholipid syndrome and HIV]. / Trombosis coronaria recurrente, síndrome antifosfolipídico primario, factor V Leiden y virus de la inmunodeficiencia humana.

We describe a 54-year-old man who was HIV-positive, admitted for cardiogenic shock complications inferior myocardial infarction. He was treated with primary percutaneous transluminal angioplasty (PCTA) and stent deployment in mid right coronary artery. After a few days thrombotic occlusion of the stent occurred, and the problem recurred during implantation of a new stent in the course of a second PTCA. We detected coinheritance of factor V Leiden, primary antiphospholipid syndrome and antithrombin deficiency. We discuss the role of these coagulation disorders in acute myocardial infarction as well as the treatment and course of the coronary syndrome in this context.

[Inflammation markers and risk stratification in patients with acute coronary syndromes: design of the SIESTA Study (Systemic Inflammation Evaluation in Patients with non-ST segment elevation Acute coronary syndromes)]. / Marcadores de inflamación y estratificación de riesgo en pacientes con síndorome coronario agudo: diseño del estudio SIESTA (Systemic Inflammation Evaluation in patients with non-ST segment elevaton Acute coronary syndromes).

BACKGROUND AND OBJECTIVE: Evidence is growing regarding the prognostic value of markers of inflammation in unstable angina/non-ST segment elevation myocardial infarction (UA/NSTEMI). However, the independent value of these variables has not been systematically investigated in prospective studies. The main objective of the SIESTA study is to assess the relative prognostic roles of C-reactive protein, fibrinogen, neopterin, interleukins 6, 8, 10 and 18, tumor necrosis factor, e-selectin, endothelin 1, tissue factor, VCAM-1, ICAM-1, pregnancy-associated plasma protein-A, B-type natriuretic peptide, leukocytes, troponin I or T and serum creatine kinase-MB (CKMB) in UA/NSTEMI patients. PATIENTS AND METHOD: SIESTA is a prospective, multicenter trial involving patients with chest pain suggestive of acute coronary syndrome (ACS) within 48 hours of enrolment and at least one of the following: abnormal troponin levels, electrocardiographic signs of ischaemia or previously documented vascular disease. Clinical outcome data and serial biochemical determinations will be assessed during hospital admission and at 30, 180 and 365 days of follow-up. The TIMI (Thrombolysis In Myocardial Infarction) and PEPA (Proyecto de Estudio del Pronóstico de la Angina) risk scores will be also validated. Study variables will include death due to any cause, cardiac death, non-fatal myocardial infarction, unstable angina requiring re-admission, emergency revascularization and a composite of death, myocardial infarction and need for emergency hospitalization or myocardial revascularization. Each of these conditions will be treated as secondary end-points when assessed individually. This study will provide valuable prospective information about the prognostic value of inflammatory markers in real life ACS patients of Mediterranean origin.

Influence of cycle length variations on antitachycardia pacing effectiveness among ICD patients.

BACKGROUND: Antitachycardia pacing (ATP) fails to terminate 5% to 25% of ventricular tachycardias (VTs) occurring in implantable cardioverter-defibrillator patients. We speculated that small fluctuations in VT cycle length (CL) may be related to the efficacy of subsequent ATP. OBJECTIVE: The purpose of this study was to determine the relationship between the R-R variations of the last 12 R-R intervals before ATP and the efficacy of the first ATP attempt. METHODS: We studied 551 VTs (CL 329±35 ms) occurring in 67 patients. We also analyzed the percentage of variation (P-RR), which was calculated by dividing the mean difference between each R-R interval and the next one by the CL (×100), and the acceleration index (AI), which was calculated by dividing the CL of the first 6 R-R intervals by the CL of the next 6. RESULTS: The effectiveness of the first ATP therapy was 81%, being higher in VTs with AI<1 (85% vs 64%; P<.001). After classifying the events according to the tertiles of P-RR, ATP efficiency was better in higher values of P-RR (VTs with AI<1): 99% (third tertile) vs 85% (second tertile) vs 76% (first tertile), P<.001; and for VTs with AI≥1: 94% vs 68% vs 42% (P<.001). By logistic regression, P-RR (%; odds ratio 2.37; P<.001), and AI<1 (odds ratio 4.17; P<.001) were found to be independent predictors of successful first ATP attempts. CONCLUSION: Small changes in CL increase the effectiveness of ATP significantly. VTs with lower degrees of R-R fluctuations, especially when the pattern is a progressive CL shortening, are infrequently terminated by ATP.

Prognostic significance of heart rate in hospitalized patients presenting with myocardial infarction.

AIM: To investigate the prognostic significance of resting heart rate in patients with acute coronary syndrome (ACS), independent of other known factors. METHODS: Patients 40 years of age or older who had been admitted with acute coronary syndrome (ACS) to one of the 94 hospitals participating in the Prevalence of Peripheral Arterial Disease in Patients with Acute Coronary Syndrome (PAMISCA) study were included. Patients were divided into two groups based on their resting heart rate (HR ≥ or < 70 bpm). Complications were recording during a follow-up period of 1 year. RESULTS: There were 1054 ACS patients analyzed (43.5% with ST segment elevation and 56.5% without elevation). Mean age was 66.6 ± 11.7 years, 70.6% were male and 29.4% of subjects were female. During follow-up, more patients in the HR ≥ 70 bpm group were hospitalized for heart failure and they also had a higher mortality rate. In the multivariate analysis, a heart rate of ≥ 70 bpm was independently related to overall mortality during the follow-up period (hazard ratio 2.5; 95% confidence interval, 1.26-4.97, P = 0.009). CONCLUSION: A resting heart rate ≥ 70 bpm in patients who survive an ACS is an indicator of a high risk of suffering cardiovascular events during follow-up.