ABSTRACT
INTRODUCTION: The presence of notches in the paced QRS complex (P-QRS) from the right ventricular apex (RVA) reflects delays in the activation of the left ventricle and may therefore be associated with longer times of stimulus conduction. Our objective was to determine prospectively the relationship between the duration of a notch ≥0.1 mV in the P-QRS (DN) and the effectiveness of antitachycardia pacing (ATP). METHODS AND RESULTS: We followed 286 implantable cardioverter-defibrillator (ICD) patients with left ventricular dysfunction (pacing site: RVA) for 41 ± 27 months. ICD programming was standardized. P-QRS (100 bpm) was obtained at implant (50 mm/s). A total of 955 monomorphic ventricular tachycardias (VTs) with a cycle length of 335 ± 32 milliseconds occurred consecutively in 108 patients. ATP was successful in 84% of VTs. DN correlated with the probability of ineffective ATP (C = 0.67; P < 0.001), the cutoff point with the best sensitivity and specificity being 50 milliseconds. The adjusted mean ATP effectiveness per patient was 76% (95% CI: 72-85). Patients with a DN ≥ 50 milliseconds had a lower ATP efficiency: 67% (56-77) versus 92% (87-97) and a higher proportion of VTs terminated with shocks (SH): 31% (21-42) versus 8% (2-14); P < 0.001 for both. Although the occurrence of VT was similar (41% vs. 40%), the incidence of VT-related SH was higher in patients with a DN ≥ 50 (25% vs. 14%; P = 0.01) in the overall study population (n = 286). CONCLUSIONS: When ATP is applied to the RVA, a DN ≥ 50 milliseconds is associated with a lower ATP effectiveness and a higher risk of SH due to VT.
Subject(s)
Defibrillators, Implantable , Diagnosis, Computer-Assisted/methods , Electrocardiography/methods , Tachycardia/diagnosis , Tachycardia/prevention & control , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/prevention & control , Aged , Female , Humans , Male , Reproducibility of Results , Sensitivity and Specificity , Tachycardia/complications , Treatment Outcome , Ventricular Dysfunction, Left/etiologyABSTRACT
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.
Subject(s)
Angina, Unstable/diagnosis , Troponin I , Adult , Aged , Aged, 80 and over , Angina, Unstable/blood , Angina, Unstable/mortality , Biomarkers/blood , Coronary Care Units/statistics & numerical data , Creatine Kinase/blood , Creatine Kinase, MB Form , Female , Humans , Isoenzymes/blood , Male , Middle Aged , Predictive Value of Tests , Prognosis , Prospective Studies , Survival Analysis , Time Factors , Troponin I/bloodABSTRACT
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.
