早搏揭示位相型束支阻滞的心电图分析

目的探讨早搏对位相型束支阻滞的揭示作用和诊断价值。方法利用早搏的回归周期明显长于基础周期这一特征,对17例患者早搏后第1次窦性搏动形态改变进行分析,间接诊断位相型束支阻滞,并确定其类型。结果 17例患者早搏后的QRS形态均发生改变,依据位相型束支阻滞诊断标准,共发现3相右束支阻滞8例、3相左束支阻滞5例、3相左前分支阻滞1例、4相右束支阻滞1例、4相左束支阻滞2例。结论位相型束支阻滞多呈一过性改变,较难扑捉,借助于早搏后回转周期长于基础窦性周期来间接诊断是一种简洁、可靠的方法,无疑对基础疾病的预后判断以及对心律失常机制的理解是十分有益的。     

Simultaneous Endocardial and Epicardial Delineation of 3D Reentrant Ventricular Tachycardia

BackgroundMechanisms of scar-related ventricular tachycardia (VT) are largely based on computational and animal models that portray a 2-dimensional view.ObjectivesThe authors sought to delineate the human VT circuit with a 3-dimensional perspective from recordings obtained by simultaneous endocardial and epicardial mapping.MethodsHigh-resolution mapping was performed during 97 procedures in 89 patients with structural heart disease. Circuits were characterized by systematic isochronal analysis to estimate the dimensions of the isthmus and extent of the exit region recorded on both myocardial surfaces.ResultsA total of 151 VT morphologies were mapped, of which 83 underwent simultaneous endocardial and epicardial mapping; 17% of circuits activated in a 2-dimensional plane, restricted to 1 myocardial surface. Three-dimensional activation patterns with nonuniform transmural propagation were observed in 61% of circuits with only 4% showing transmurally uniform activation, and 18% exhibiting focal activation patterns consistent with mid-myocardial reentry. The dimensions of the central isthmus were 17 mm (12 to 28 mm) × 10 mm (9 to 19 mm) with 55% exhibiting a minimal dimension of <1.5 cm. QRS activation was transmural in 63% and located 43 mm (34 to 52 mm) from the central isthmus. On the basis of 6 proposed definitions for epicardial VT, the prevalence of an epicardial circuit ranged from 21% to 80% in ischemic cardiomyopathy and 28% to 77% in nonischemic cardiomyopathy.ConclusionsA 2D perspective oversimplifies the electrophysiological circuit responsible for reentrant human VT and simultaneous endocardial and epicardial mapping facilitates inferences about mid-myocardial activation. Intricate activation patterns are frequently observed on both myocardial surfaces, and the epicardium is functionally involved in the majority of circuits. Human reentry may exist within isthmus dimensions smaller than 1 cm, whereas QRS activation is often transmural and remote from the critical isthmus target. A 3-dimensional perspective of the VT circuit may enhance the precision of ablative therapy and may support a greater role for adjunctive strategies and technology to address arrhythmogenic tissue harbored in the mid-myocardium and subepicardium.     

Case Report: Severe Hypercalcemia Mimicking St-Segment Elevation Myocardial Infarction

The identification of ST-segment elevation on the electrocardiogram is an integral part of decision making in patients who present with suspected ischemia. Unfortunately, ST-segment elevation is nonspecific and may be caused by noncardiac causes such as electrolyte abnormalities. We present a case of ST-segment elevation secondary to hypercalcemia in a patient with metastatic cancer.     

La técnica de superposición de cúspides en TAVI con dispositivo autoexpandible optimiza la profundidad del implante y reduce la necesidad de marcapasos permanente

Introduction and objectivesThis study aimed to determine the safety and efficacy of modifying the classic implantation technique for aortic transcatheter heart valve (THV) implantation to a cusp-overlap-projection (COP) technique to achieve a higher implantation depth and to reduce the burden of new permanent pacemaker implantation (PPMI) at 30 days. Aortic self-expanding THV carries an elevated risk for PPMI. A higher implantation depth minimizes the damage in the conduction system and may reduce PPMI rates.MethodsFrom March 2017, 226 patients were consecutively included: 113 patients were treated using the COP implantation technique compared with the previous 113 consecutive patients treated using the classic technique. In all patients, implantation depth was assessed by 3 methods (noncoronary cusp to the THV, mean of the noncoronary cusp and the left coronary cusp to the THV, and the deepest edge from the left coronary cusp and the noncoronary cusp to the THV).ResultsThe COP group had a lower implantation depth than the group treated with the classic technique (4.8 mm ± 2.2 vs 5.7 mm ± 3.1; P = .011; 5.8 mm ± 3.1 vs 6.5 mm ± 2.4; P = .095; 7.1 mm ± 2.8 vs 7.4 mm ± 3.2; P = .392). Forty patients (17.7%) required a new PPMI after the 30-day follow-up but this requirement was significantly lower in the COP group (12.4% vs 23%, P = .036). The COP implantation technique consistently protected against the main event (OR, 0.45; 95%CI, 0.21-0.97; P = .043), with similar procedural success rates and complications.ConclusionsThe COP implantation technique is a simple modification of the implantation protocol and provides a higher implantation depth of self-expanding-THV with lower conduction disturbances and PPMI rates.     

Ticagrelor to Reduce Myocardial Injury in Patients With High-Risk Coronary Artery Plaque

ObjectivesThe goal of this study was to determine whether ticagrelor reduces high-sensitivity troponin I concentrations in patients with established coronary artery disease and high-risk coronary plaque.BackgroundHigh-risk coronary atherosclerotic plaque is associated with higher plasma troponin concentrations suggesting ongoing myocardial injury that may be a target for dual antiplatelet therapy.MethodsIn a randomized, double-blind, placebo-controlled trial, patients with multivessel coronary artery disease underwent coronary ¹⁸F-fluoride positron emission tomography/coronary computed tomography scanning and measurement of high-sensitivity cardiac troponin I. Patients were randomized (1:1) to receive ticagrelor 90 mg twice daily or matched placebo. The primary endpoint was troponin I concentration at 30 days in patients with increased coronary ¹⁸F-fluoride uptake.ResultsIn total, 202 patients were randomized to treatment, and 191 met the pre-specified criteria for inclusion in the primary analysis. In patients with increased coronary ¹⁸F-fluoride uptake (120 of 191), there was no evidence that ticagrelor had an effect on plasma troponin concentrations at 30 days (ratio of geometric means for ticagrelor vs. placebo: 1.11; 95% confidence interval: 0.90 to 1.36; p = 0.32). Over 1 year, ticagrelor had no effect on troponin concentrations in patients with increased coronary ¹⁸F-fluoride uptake (ratio of geometric means: 0.86; 95% confidence interval: 0.63 to 1.17; p = 0.33).ConclusionsDual antiplatelet therapy with ticagrelor did not reduce plasma troponin concentrations in patients with high-risk coronary plaque, suggesting that subclinical plaque thrombosis does not contribute to ongoing myocardial injury in this setting. (Dual Antiplatelet Therapy to Reduce Myocardial Injury [DIAMOND]; NCT02110303)     

体表心电图慢性ST—T改变对冠心病的诊断价值

目的探讨体表心电图慢性ST—T改变对冠心病的诊断价值。方法对216例体表心电图慢性ST～T改变的冠状动脉造影结果进行回顾性分析。结果216例患者中冠状动脉造影阳性者125例（57．87％），男性92例，女性33例。其中冠状动脉狭窄单支病变69例，双支病变25例，多支病变31例。106例合并高血压的患者中冠状动脉造影阳性者48例（45．28％），男性36例，女性12例。结论临床依据体表心电图慢性ST—T改变诊断冠心病有一定的局限性，要慎重。     

Predictors of venous obstruction following pacemaker or implantable cardioverter-defibrillator implantation: a contrast venographic study on 100 patients admitted for generator change, lead revision, or device upgrade.

AIM: Venous obstruction following transvenous device implantation rarely cause immediate clinical problems. When lead revision or device upgrade is indicated, venous obstruction become a significant challenge. The aim of this study was to determine the predictors of venous obstruction after transvenous device implantation, and to asess likely effects of antiplatelet/anticoagulant drugs in preventing venous thrombosis. METHODS AND RESULTS: Between March 2005 and July 2006, contrast venography was performed in 100 patients who were candidates for generator change, lead revision, or device upgrade. Vessel patency was graded as either completely obstructed, partially obstructed (>70%), or patent. The incidence of venous obstruction was 26%, with 9% of patients having total obstruction and 17% of patients exhibiting partial obstruction. No statistically significant differences between obstructed and non-obstructed patients were seen for age, sex, indication for device implantation, atrial fibrillation, cardiothoracic ratio, insulation material, operative technique, device type, and manufacturer (all Ps > 0.05). In a univariate analysis, multiple leads (P = 0.033), and presence of dilated cardiomyopathy (P = 0.036) were associated with higher risk of venous obstruction, whereas anticoagulant/antiplatelet therapy (P = 0.047) significantly reduced incidence of venous obstruction. Multivariate logistic regression analysis showed that only number of the leads (P = 0.039, OR: 2.22, and 95% CI: 1.03-4.76) and antiplatelet/anticoagulant therapy (P = 0.044, OR: 2.79, and 95% CI: 0.98-7.96) were predictors of venous obstruction. CONCLUSION: Total or partial obstruction of the access veins occurs relatively frequently after pacemaker or ICD implantation. Multiple pacing or ICD leads are associated with an increased risk of venous obstruction, whereas antiplatelet/anticoagulant therapy appears to have a preventive effect on development of access vein thrombosis.