Clinical Characteristics and Electrophysiological Mechanisms Underlying Brugada ECG in Patients With Severe Hyperkalemia.

Background Several metabolic conditions can cause the Brugada ECG pattern, also called Brugada phenotype (BrPh). We aimed to define the clinical characteristics and outcome of BrPh patients and elucidate the mechanisms underlying BrPh attributed to hyperkalemia. Methods and Results We prospectively identified patients hospitalized with severe hyperkalemia and ECG diagnosis of BrPh and compared their clinical characteristics and outcome with patients with hyperkalemia but no BrPh ECG. Computer simulations investigated the roles of extracellular potassium increase, fibrosis at the right ventricular outflow tract, and epicardial/endocardial gradients in transient outward current. Over a 6-year period, 15 patients presented severe hyperkalemia with BrPh ECG that was transient and disappeared after normalization of their serum potassium. Most patients were admitted because of various severe medical conditions causing hyperkalemia. Six (40%) patients presented malignant arrhythmias and 6 died during admission. Multiple logistic regression analysis revealed that higher serum potassium levels (odds ratio, 15.8; 95% CI, 3.1-79; P=0.001) and male sex (odds ratio, 17; 95% CI, 1.05-286; P=0.045) were risk factors for developing BrPh ECG in patients with severe hyperkalemia. In simulations, hyperkalemia yielded BrPh by promoting delayed and heterogeneous right ventricular outflow tract activation attributed to elevation of resting potential, reduced availability of inward sodium channel conductance, and increased right ventricular outflow tract fibrosis. An elevated transient outward current gradient contributed to, but was not essential for, the BrPh phenotype. Conclusions In patients with severe hyperkalemia, a BrPh ECG is associated with malignant arrhythmias and all-cause mortality secondary to resting potential depolarization, reduced sodium current availability, and fibrosis at the right ventricular outflow tract.

The Feasibility and Safety of Ambulatory Percutaneous Coronary Interventions in Complex Lesions.

BACKGROUND: The safety and feasibility of ambulatory PCI has been demonstrated in selected patients with "simple" lesions, but it is not well known whether it could be applied in more "complex" scenarios. METHODS: Main objective is to assess the feasibility and safety of ambulatory complex PCI. Prospective multicentre registry of 1047 consecutive patients planned for ambulatory trans-radial PCI. Outcomes in patients with "complex angioplasty" (CA group: 313 (30%)) were analysed and compared with those of "simple angioplasty" (SA group: 734, 70%). The feasibility (% of patients finally discharged) and safety (MACE at 24 h and at 1 month) were compared between groups. We also analyse admissions, visits to the emergency department and minor vascular complications. RESULTS: Feasibility was higher for SA (80.6% vs. 63.6%, OR 1.89, 95% CI 1.52-2.35, p < 0.001). Ambulatory PCI was very safe in both groups. In CA no MACE occurred at 24 h (vs. 0.17% SA) or 30 days (vs. 0.68% in SA). There were also no differences in re-admissions, visits to the emergency department or minor vascular complications (there was a non-significant tendency to higher rate of radial occlusion at 1 month in the CA group, 5.5% vs. 2.7%, p: 0.07). CONCLUSIONS: The feasibility of ambulatory PCI in selected patients with complex lesions is lower than in simple lesions, however when it is possible, it is as safe as in selected patients with simple lesions.

Prevalence of Microvascular and Endothelial Dysfunction in the Nonculprit Territory in Patients With Acute Myocardial Infarction.

BACKGROUND: Approximately half of the patients presenting with ST-segment-elevation myocardial infarction (STEMI) have multivessel disease. The physiology of the nonculprit artery has not been thoroughly studied to date. We sought to characterize the coronary physiology of the nonculprit artery in the early phase after STEMI and determine the real prevalence of microvascular and endothelial dysfunction. METHODS AND RESULTS: Patients with STEMI and another coronary artery lesion in a different territory were prospectively included in an observational single-center study. The protocol took place after revascularization of the culprit artery and comprised 3 phases: first, epicardial endothelial functional assessment using intracoronary acetylcholine; second, epicardial severity quantification based on fractional flow reserve, and nonendothelial microvascular function with coronary flow reserve and the index of microvascular resistance; third, endothelium-dependent microvascular function assessment based on the endothelial coronary flow reserve. Eighty-four patients were included. Mean age was 62±10 years, and 86.9% were men. Only 6 subjects had a nonpathological study: macrovascular endothelial dysfunction was present in 60% of the patients; fractional flow reserve ≤0.8, coronary flow reserve <2, and index of microvascular resistance >25 were evident in 34%, 37%, and 28% of the subjects respectively; and microvascular endothelial dysfunction (endothelial coronary flow reserve <1.5) was observed in 44%. In hospital-mortality was 0%, and no major complications occurred. At 6-month follow-up, there were no events related to the nonculprit artery. CONCLUSIONS: Microvascular and endothelial dysfunction in the nonculprit artery territory in patients with STEMI are very common. In 93% of the patients, we found functional abnormalities. Acetylcholine administration in the early phase post-STEMI in patients with multivessel disease is safe.

Safety and Feasibility of Outpatient Percutaneous Coronary Intervention in Selected Patients: A Spanish Multicenter Registry.

INTRODUCTION AND OBJECTIVES: The exponential increase in coronary interventions plus the generalization of the radial approach represent the ideal scenario for starting outpatient angioplasty programs with the aim of reducing the costs while maintaining safety. This article reports data from a multicenter Spanish registry on fully ambulatory transradial angioplasty in selected patients for the first time. METHODS: Prospective registry of elective outpatient transradial-ulnar angioplasty in patients with stable coronary disease. Patients were discharged the same day and were followed up at 24hours and 30 days. Safety and feasibility were analyzed. RESULTS: Of the 723 patients included (76% male; age, 66.6±10.5 years), 533 (73.7%) were finally discharged after 4 to 12hours of surveillance. Among the remaining 190 (26.7%) patients, the most common reason for hospitalization was clinical instability after the procedure (60.5%). Independent predictors of admission were a history of peripheral artery disease, a higher baseline creatinine level, ad hoc performance of the procedure, and multivessel disease. At 24hours, there was 1 major adverse event in 1 patient (0.19%), who required hospitalization for major bleeding not related to vascular access. At 30 days, there were 3 major adverse events (0.56%): 1 subacute stent thrombosis, 1 revascularization of a vessel other than the treated vessel, and 1 minor stroke. Eight patients (1.5%) required admission at 30 days. CONCLUSIONS: The application of an outpatient transradial-ulnar angioplasty program with discharge after 4 to 12 hours' surveillance is safe and feasible in well-selected patients.