Prospective Observations in the Clinical and Electrophysiological Characteristics of Intra‐Isthmus Reentry

ECG and EGM of IIR. Introduction: Intra‐isthmus reentry (IIR) is a circuit within the cavotricuspid isthmus (CTI). The purpose of this study is to prospectively define the electrogram and surface ECG characteristics of IIR, and its clinical implications. Methods and Results: Fourteen patients underwent electrophysiological studies and were found to have IIR. Detailed electrogram mapping of the CTI was available in all, electroanatomic mapping (EAM) in 8 of 14 (57%) patients. In all, entrainment mapping during tachycardia proved reentry, and showed that the anteroinferior CTI was out of the circuit and the septal CTI was in the circuit in 12 of 14 patients, whereas in 2, the circuit was confined within the mid and/or anteroinferior CTI. Fractionated potentials (FPs) spanning 34–71% of the tachycardia cycle length were recorded within the CTI in all, and double potentials were inscribed in 10 of 14 (71%). Analysis of the tricuspid annulus electrograms showed spontaneous shifts from a counterclockwise (CCW) to clockwise or fusion patterns. Surface ECGs showed either typical CCW pattern (12 patients) or atypical patterns (3 patients). The EAMs showed a focal pattern in 3, a CCW pattern in 5. The successful ablation site always occurred at the area with maximal FP duration. Over the same period, 33 of 384 (9%) patients who underwent ablation for CTI‐dependent flutter had prior successful CTI ablation, 7 of 33 (21%) were found to have IIR during the redo procedure. Conclusions: (1) Electrogram and ECG patterns of IIR frequently show atypical flutter. (2) IIR was successfully ablated in an area of the CTI associated with maximal duration of FPs. (3) IIR is a significant cause of “recurrent flutter” in patients with prior CTI ablation. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1099‐1106)     

Outcomes by Day and Night for Patients Bypassing the Emergency Department Presenting with ST‐Segment Elevation Myocardial Infarction Identified with a Pre‐Hospital Electrocardiogram

Background

Pre‐hospital ECG and emergency department (ED) bypass direct to the catheter laboratory may optimize reperfusion times for patients with ST‐segment elevation myocardial infarction. Questions remain over feasibility and safety during off hours.

Aims

To determine if presenting time of day is associated with differences in in‐hospital and 30‐day mortality and key reperfusion times.

Methods/Results

Seven hundred and twenty consecutive patients with STEMI triaged directly from the field to the catheter laboratory between June 2004–May 2013. Vital status was reported as of August 2013. The mean age was 65 ± 14 years, and 75.1% were male. Overall mortality (in‐hospital/30 days) did not significantly differ for patients (3.4% in hours and 3.1% off hours; P = N/S). Symptom onset‐to‐arrival to the heart attack was non‐significantly lower (100 minutes off hours (IQR 78–174) versus 110 minutes in hours (IQR 75–199), P = N/S). Call‐to‐balloon time was not significantly affected by the time of presentation: 150 min in hours (IQR 111–239) versus 154 minutes during off hours (IQR 115–225) P = N/S. Overall door‐to‐balloon time was 36 minutes (IQR 25–51), 34 minutes in hours (IQR 24–49) versus 40 minutes off hours (IQR 29–55) P = N/S. The overall false positive activation rate was only 13.1%, (in hours 12.2% vs. off hours 14.6%, respectively, P = N/S).

Conclusions

In a unit with an established field triage system facilitating ED bypass, reperfusion times and mortality are not significantly influenced by whether the patient presents during standard working hours or outside of these hours. (J Interven Cardiol 2015;28:24–31)

     

百日咳:可于任何年龄段发病的疾病

百日咳杆菌是具有高度传染性的革兰阴性杆菌，通过空气播散、飞沫传播，只有人类可感染该病原菌而发病。该菌所产生的抗原物质既可引起局部细胞损害，又可引起全身反应。     

Malignant peripheral nerve sheath tumor of the kidney

Malignant peripheral nerve sheath tumors are rare in the genitourinary organs, with few reports of occurrence in the kidney. We describe a patient with a renal malignant peripheral nerve sheath tumor, discovered after excision of a malignant peripheral nerve sheath scalp lesion, with additional masses in the lung and shoulder on metastatic evaluation. This patient underwent neoadjuvant intravenous doxorubicin therapy, followed by surgical resection of the scalp, lung and shoulder lesions in addition to a radical nephrectomy.     

Memory template comparison processes in anhedonia and dysthymia

Anhedonic subjects, potentially at risk for psychopathology because of a deficient ability to experience pleasure, have demonstrated a large N200 component in the event-related brain potential (ERP). The present experiment attempted to determine the psychological significance of this finding in light of Näätänen's (1990) distinction between N2a and N2b subcomponents. Anhedonics were contrasted with controls and dysthymics, an at-risk group reporting depression. Across groups, N2a was larger when a tone mismatched a longer run of preceding identical tones. Thus, an involuntary mismatch process appears to be intact in both at-risk groups. However, the three groups produced distinct N2bs as a function of stimulus sequence. The N2b finding for anhedonics is consistent with Knight's (1984, 1992) model of early stimulus processing deficits in schizophrenia.     

Clinical Electrophysiological Effects of Intravenous Recainam: An Antiarrhythmic Drug Under Investigation for the Treatment of Ventricular and Supraventricular Arrhythmias

This open-label, multicenter study was designed to assess the electrophysiological properties of intravenous recainam, an investigational Class I antiarrhythmic agent. In 25 patients undergoing electrophysiological studies for the evaluation of arrhythmias, recainam was administered intravenously in a loading infusion (0.1 mg/kg/min) for 40 minutes, followed by a maintenance infusion (0.02 mg/kg/min) until the completion of the study. Electrophysiological measurements were obtained at baseline, 30 minutes after initiation of the loading infusion, and 30 minutes after termination of the infusion during washout. Conduction intervals, refractory periods, and sinus node recovery times were measured during sinus rhythm and during atrial or ventricular pacing. Vital signs were obtained and recorded before, during, and after recainam infusion. The results showed no change in mean arterial pressure, but heart rate increased slightly by 4 beats/min following recainam infusion. Recainam produced a generalized slowing of intracardiac conduction. The mean intraatrial conduction time, measured at an atrial paced cycle length of 600 msec, increased during recainam loading infusion by 44%, from 38.8% +/- 2.8 to 53.0 +/- 5.4 msec; intranodal conduction time increased by 10%, from 102.0 +/- 5.5 to 112.1 +/- 5.2 msec; and infranodal conduction time increased by 31% from 53.1 +/- 3.0 to 70.7 +/- 3.8 msec. Slowed conduction persisted during washout. The mean right atrial effective refractory period was significantly prolonged (+7% at 600 msec cycle length and +8% at 450 msec cycle length, P less than 0.05 and P less than 0.01, respectively) during recainam loading and remained so during washout.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rapid Atrial Pacing Does Not Decrease the Atrial Defibrillation Threshold

The aim of the study was to evaluate the effect of preshock atrial pacing on the atrial defibrillation threshold (DFT) during internal cardioversion of AF. The implantable atrial defibrillator has been added to the therapeutic options for patients with recurrent episodes of persistent AF. Although the device is efficient in restoring sinus rhythm, patient discomfort is a limitation. Methods that lower the ADFT are needed. Eleven patients with AF underwent internal cardioversion. In a randomized, crossover design, ADFT testing was performed, applying a step-up protocol starting at 100 V. Rapid atrial pacing was performed with a right atrial catheter for 20 seconds at 90% of the average cycle length of the fibrillatory waves and was immediately followed by a biphasic defibrillation shock. At each energy level, pacing + shock was compared to shock only, until the level at which sinus rhythm was restored by both modes. The step-up protocol was thereafter repeated using the inverse sequence of the two modes. A total of 19 ADFTs were obtained. For 10 the ADFT was lower with pacing + shock, in 4 equal and in 5 higher, than with shock only. The ADFT (mean ± SD) with pacing + shock was   260 ± 84   V   (3.4 ± 2.9 J)   and did not differ from shock only:   268 ± 85   V   (3.8 ± 3.0 J) (P > 0.05)   . The coefficient of variation and the coefficient of reproducibility for pacing + shock was 16% and 60 V, respectively, and for shock only 17% and 61 V. Rapid atrial pacing did not influence the internal ADFT in AF. The randomized, crossover protocol used was reproducible between different modes, and seems useful when testing the impact of different interventions on the ADFT. (PACE 2003; 26[Pt. I]:1461–1466)