Supraventricular bigeminy originating from the mitral annulus: What is the mechanism?

We present a case of a 67‐year‐old female with a previous history of pulmonary vein isolation for paroxysmal atrial fibrillation who presented with supraventricular bigeminy with a constant coupling interval. The supraventricular bigeminy originated from the anterior mitral annulus with initial mapping suggestive of a focal mechanism. However detailed mapping using an ultrahigh resolution mapping system (with the manual shifting of the annotation window) revealed very low amplitude potentials connecting the previous sinus beat with continuous activation along the mitral annulus. Our observations were indicative of a re‐entry mechanism underlying the supraventricular bigeminy.     

常规标测与球囊电极三维标测指导右室间隔部室性早搏射频消融比较

目的：比较常规电生理标测与Ensite array球囊标测指导下对特发性右室间隔部室性早搏导管射频消融的效果。方法将88例右室间隔部室早患者分为2组,39例室早采用常规电生理标测、49例室早采用Ensite array球囊标测。比较射频消融治疗时2组靶点标测时间、X线曝光时间、消融时间、手术总时间,观察随访疗效。结果与常规电生理标测相比, Ensite array 球囊标测室早靶点标测时间、X线曝光时间、消融时间、手术总时间均显著缩短（P＜0．01）;2组的即刻成功率均为100％;术后1个月随访时,常规电生理标测组有5例室早复发;Ensitearray球囊标测组有1例复发。结论 Ensitearray球囊标测可缩短手术时间、降低术后复发率。     

Redefining Diastolic Dysfunction Grading: Combination of E/A ≤0.75 and Deceleration Time >140 ms and E/ε′ ≥10

ObjectivesThis study sought to examine left atrial (LA) mechanics and the prognostic impact of patients with echocardiographic findings of E/A ratio ≤0.75, deceleration time (DcT) of mitral E-wave >140 ms, but E/ε′ ≥10.BackgroundTraditional diastolic dysfunction (DD) grading system could not classify every patient into a specific group. We considered the group of patients with E/A ≤0.75, DcT >140 ms, but E/ε′ ≥10 (proposed new DD grade) as a new group in the DD grading system.MethodsA total of 1,362 consecutive patients were stratified according to the new DD grading system, and the LA volumes, strain, and strain rates were measured by 2-dimensional speckle-tracking analysis. All patients were followed up to determine cardiac death and major adverse cardiac events.ResultsAn E/A ≤0.75, DcT >140 ms, but E/ε′ ≥10 was observed in 227 patients (17%). LA volumes in patients with the new DD grade were between those of the impaired relaxation group and the pseudonormal group. LA strain of the new DD grade was similar to that of the pseudonormal group, whereas LA booster function was preserved as in the impaired relaxation group. During a mean follow-up of 3.0 ± 1.1 years, 25 patients had cardiac death and 61 had major adverse cardiac events. Event-free survival for major adverse cardiac events of the new DD grade was worse than that of the impaired relaxation group but similar to that of the pseudonormal group.ConclusionsThe new DD grade is frequently observed and has a prognosis similar to that of the pseudonormal group but significantly worse than that of the impaired relaxation group. However, LA booster function was maintained at the expense of LA volume enlargement. Thus, the new grade should be a distinct entity for routine DD grading.     

肝硬化大鼠胃肠运动及胃动素受体表达的实验研究

目的探讨肝硬化大鼠胃肠运动障碍与胃动素受体表达的关系。方法测定大鼠胃肠运动及十二指肠肌收缩力,测定胃肠道胃动素受体的表达。结果肝硬化大鼠与正常大鼠相比,在体胃肠排空时间明显延长(P0.05),离体十二指肠肌条平均收缩力明显减小(P0.05);肝硬化大鼠与正常大鼠相比胃动素受体染色浅,分布较少(P0.05)。结论肝硬化大鼠胃肠运动障碍与胃动素受体表达具有相关性。     

Extreme sarcoplasmic reticulum volume loss and compensatory T-tubule remodeling after Serca2 knockout

Cardiomyocyte contraction and relaxation are controlled by Ca(2+) handling, which can be regulated to meet demand. Indeed, major reduction in sarcoplasmic reticulum (SR) function in mice with Serca2 knockout (KO) is compensated by enhanced plasmalemmal Ca(2+) fluxes. Here we investigate whether altered Ca(2+) fluxes are facilitated by reorganization of cardiomyocyte ultrastructure. Hearts were fixed for electron microscopy and enzymatically dissociated for confocal microscopy and electrophysiology. SR relative surface area and volume densities were reduced by 63% and 76%, indicating marked loss and collapse of the free SR in KO. Although overall cardiomyocyte dimensions were unaltered, total surface area was increased. This resulted from increased T-tubule density, as revealed by confocal images. Fourier analysis indicated a maintained organization of transverse T-tubules but an increased presence of longitudinal T-tubules. This demonstrates a remarkable plasticity of the tubular system in the adult myocardium. Immunocytochemical data showed that the newly grown longitudinal T-tubules contained Na(+)/Ca(2+)-exchanger proximal to ryanodine receptors in the SR but did not contain Ca(2+)-channels. Ca(2+) measurements demonstrated a switch from SR-driven to Ca(2+) influx-driven Ca(2+) transients in KO. Still, SR Ca(2+) release constituted 20% of the Ca(2+) transient in KO. Mathematical modeling suggested that Ca(2+) influx via Na(+)/Ca(2+)-exchange in longitudinal T-tubules triggers release from apposing ryanodine receptors in KO, partially compensating for reduced SERCA by allowing for local Ca(2+) release near the myofilaments. T-tubule proliferation occurs without loss of the original ordered transverse orientation and thus constitutes the basis for compensation of the declining SR function without structural disarrangement.     

Isolation of the phrenic nerve to suppress diaphragmatic contraction induced by cardiac resynchronization

Left phrenic nerve stimulation is a well-known complication of cardiac resynchronization therapy (CRT). We report a case where electronic or anatomical repositioning of the left ventricular (LV) electrode (within the coronary sinus tributaries) was not feasible/effective. Surgical graft interpositioning was performed to successfully isolate the phrenic nerve from the previously implanted coronary sinus epicardial LV lead.     

胆胃舒颗粒对胆囊血管活性肠肽受体基因表达的影响

[目的]观察胆胃舒颗粒对胆囊血管活性肠肽(vasoactive intestinal peptide,VIP)受体基因表达的影响及预防胆囊结石的作用.[方法]雄性豚鼠90只,随机分为3组,每组30只,空白组喂养普通饲料40 g/(d·只);模型组喂养胆固醇结石诱石饲料40 g/(d·只);治疗组喂养胆固醇诱石饲料40 g/(d·只),加胆胃舒颗粒溶液1.5ml(含300mg胆胃舒颗粒)灌胃.实验2个月后观察3组胆囊结石情况、胆囊收缩功能及胆囊壁VIP受体基因表达.[结果]胆囊结石形成率:空白组3.33％(1/30),模型组92.59％(25/27),治疗组10.71％(3/28);胆囊收缩功能:空白组胆囊收缩率为(66.83± 5.34)％,模型组(43.06±4.27)％,治疗组(67.93±6.82)％;胆囊壁VIP受体基因表达:空白组0.30±0.07,模型组0.45±0.12,治疗组0.33±0.06.差异均有统计学意义(P＜0.05).[结论]胆胃舒颗粒可降低胆囊结石的形成,其作用机制可能通过降低胆囊壁VIP受体基因表达,从而加强胆囊收缩功能,促使胆汁排泄,防止胆囊结石的发生.