Investigation of childhood central nervous system vasculitis: magnetic resonance angiography versus catheter cerebral angiography

Aim We compared the clinical utility of magnetic resonance angiography (MRA) to catheter cerebral angiography (CA) in the investigation of children with suspected central nervous system (CNS) vasculitis. Method Single‐centre retrospective review of children with a suspected diagnosis of CNS vasculitis studied with both MRA and CA. MRA and CA‐detected abnormalities (location, multiplicity, and morphology) were compared; sensitivity and specificity were calculated on a per lesion and per patient basis for MRA, with CA as the reference standard. Results Findings in fourteen patients (median age at presentation of 5y 10mo [range 1y 5mo–14y 5mo]; eight males, six females) relating to sixteen paired studies of MRA and CA were reviewed. CA‐detected lesions were commonly bilateral (13/16 studies, p<0.05), and likely to be proximally distributed (15/16 studies, p<0.05).The sensitivity and specificity of MRA for CA lesion detection was 63% (95% confidence interval [CI] 48–78) and 89% (95% CI 81–93), respectively with moderate agreement between the two modalities (κ=0.51, 95% CI 0.37–0.66). The majority of the false negative observations involved the posterior circulation (9/14). The overall sensitivity for MRA diagnosis of vasculitis per patient was 94% (95% CI 67–99). Interpretation MRA failed to identify all lesions detected on CA, particularly those in the posterior circulation. MRA is a reasonable initial modality in the investigation of suspected CNS vasculitis but in cases of abnormal parenchymal MRI and normal MRA, CA should be considered.     

Intracoronary Radiation Post PTCA Prevents Late Arterial Constriction

Vascular constriction post PTCA is a major component in the mechanism of restenosis following intervention. Ionizing radiation demonstrated reduction of neointima formation after injury in animal models and lowered the restenosis rates in pilot clinical studies. To determine the effect of intracoronary radiation therapy on vascular remodeling, angiograms from two radiation trials were analyzed by QCA methods. Patients in these trials had de novo lesions and were treated with balloon angioplasty followed by either beta or gamma radiation. All patients were studied angiographically at 6 months; patients with total occlusion at the treated artery were excluded from the analysis. In the gamma trial, 192-Iridium was utilized in 14 patients (15 lesions) with doses between 20-25 Gy. In the beta trial, 90-Sr/Y was utilized in 17 patients (17 lesions) with doses between 12-16 Gy. The QCA analysis from these studies demonstrated negative late loss and late loss index at six months for patients from the beta (-0.02 ± 0.3) and the gamma (-0.19 ± 0. 3) study. The effect of positive remodeling was maintained at 24 months, -0.16 ± 0.4 in the gamma group. Larger MLD at follow-up compared to the immediate post MLD were demonstrated in 50% of the patients from both studies. Thus, intracoronary radiation resulted in lower late loss and late loss index rates than previously reported following balloon angioplasty alone suggesting a positive vascular remodeling effect of intracoronary radiation.     

High Voltage Shock Induced Cellular Electrophysiological Effects: Transient Refractoriness and Bimodal Changes in Action Potential Duration

LI, H.G., et al .: High Voltage Shock Induced Cellular Electrophysiological Effects: Transient Refractoriness and Bimodal Changes in Action Potential Duration . The cellular electrophysiological effects of defibrillation shocks on the myocardium during ventricular fibrillation are not clear. The present study investigated the effects of high voltage shocks on membrane potentials of isolated guinea pig and pig papillary muscles during rapid activations simulating ventricular fibrillation. High voltage shocks induced an action potential with a prolonged duration, followed by a transient refractory state. Subsequent action potentials following this refractory state had shortened durations. The duration of the transient refractory state varied in proportion to shock intensity and stimulation rate, whether the shock was biphasic or monophasic. Shock induced prolonged depolarization was not a consistent finding and mainly observed with slow stimulation rates. In conclusion, high voltage shocks induce bimodal changes of the action potential duration associated with a transient refractory state during rapid activation. The rate dependency of this refractory state suggests that the duration of the shock induced refractory state may be longer in the fibrillating than the normal beating heart, and may contribute to successful defibrillation.     

Effects of Autonomic Manipulation on Ventricular Fibrillation and Internal Cardiac Defibrillation Thresholds in Pigs

Autonomic tone may contribute to cardiac arrhythmogenesis and influence the efficacy of implantable defibrillators. Fifty-two anesthetized pigs were randomized to: (1) methacholine (n = 12); (2) nitroprusside (n = 12); (3) phenylephrine (n = 12); (4) carbachol (n = 8); and (5) saline (n = 8). Ventricular fibrillation threshold (VFT) and triplicate defibrillation thresholds (DFT) were obtained before and during each intervention. Mean (± SE) VFT was increased with: methacholine (76 ± 10.6 V vs 39 ± 7.1 V, P < 0.001); phenylephrine (68 ± 10.5 V vs 38 ± 6.2 V, P < 0.001); and carbachol (106 ± 11.5 V vs 30 ± 6.5 V, P < 0.0001). Nitroprusside and saline failed to alter VFT. Mean (± SE) DFT was decreased with: methacholine (7.7 ± 0.8 J vs 9.7 ± 0.8 J, P < 0.001); phenylephrine (9.8 ± 0.9 J vs 11.3 ± 1.0 1, P < 0.05); and carbachol (9.2 ± 0.7 J vs 12.2 ± 0.8), P < 0.0001), remaining unchanged following nitroprusside and saline infusion. Thus, modulation of autonomic tone modified arrhythmia susceptibility and the energy necessary for defibrillation, increased parasympathetic tone, increased VFT, and decreased DFT. Evaluation of autonomic balance, particularly parasympathetic tone, may be useful with the implantation of automatic defibrillators.     

Role of Antitachycardia Pacing in Patients with Third Generation Cardioverter Defibrillators

The most effective antitachycardia pacing (ATP) mode is still a matter of debate. Randomized prospective testing of 3 different ATP modes was performed in B5 patients (pts) prior to and after cardioverter Defibrillator implantation (Ventak PHx 36 pts, Cadence V 100 29 pts). All 3 ATP modes included 4 stimulation attempts with 4–7 adaptive scanning burst pulses. Adaptive burst coupling interval was 75% in mode A, 81% in mode B and 69% in mode C. Autodecremental scanning within bursts was 8 msec in all, decremenial scanning between bursts was 8 msec in modes B and C. Each ATP mode had to be tested 3 times; all 3 ATP modes were randomly applied to each pt. During preoperative testing 91 of 133 VT episodes (68%) could be terminated by ATP. Termination was achieved in 68% with mode A, 68% with mode B and 73% with mode C, During predischarge testing, 251 VTs were induced and ATP was successful in 147 VTs (59%). Termination rate was 56% with mode A, 68% with mode B and 50% with mode C. During the mean follow-up of 12 months, 2301 arrhythmia episodes (AE) occurred. ATP was performed in 2097 AE (91%) and successful in 1920 AE (92%). Acceleration of VT occurred in 65 AE (3%) and unsuccessful ATP was observed in 112 AE (5%). It is concluded that ATP in general is highly effective in pts with sustained VT. None of the tested ATP modes, however, proved to be superior to the other.     

Advanced endometrial adenocarcinoma following endometrial ablation: a case report and review of the literature

Endometrial ablation is an alternate method to hysterectomy when treating dysfunctional uterine bleeding (menorrhagia, metrorrhagia and postmenopausal) that does not respond to hormonal treatment or curettage among a carefully evaluated and selected patient population. Its safety and efficacy have been confirmed in large studies. We present a case of advanced staged endometrial carcinoma diagnosed after endometrial ablation that followed uneventful preoperative work-up.     

Malposition of Transvenous Pacing Lead in the Left Ventricle

Malposition of pacemaker leads has been described in several locations but rarely in the left ventricle. The incidence and clinical course of this pacemaker complication are unknown. We describe clinical, electrocardiographic, chest X ray, and echocardiographic findings in four patients in whom the transvenous pacing lead was inadvertendy placed through the interatrial septum and mitral valve into the left ventricle, in these patients, lead misplacement was not recognized at the time of implantation and lead malposition was diagnosed a mean of 2 years later. All four patients had right bundle branch block configuration paced complexes. In retrospect, chest X rays suggested atypical lead position in all, but the initial posterioranterior and lateral chest X rays were misinterpreted and contributed to the delay in diagnosis. When lead misplacement in the left ventricle was considered it was confirmed by two-dimensional echocardiography. One patient subsequently presented with a stroke and the remainder were diagnosed when they presented with other unrelated problems. Pacing thresholds were normal at the time of implantation and behaved normally during follow-up. The patient presenting with stroke was anticoagulated and the other three have been managed expectantly without anticoagulafion. Diagnosis of left ventricular lead malposition is not difficult but requires a high index of suspicion. A 12-lead ECC and posterior-anterior and lateral chest X rays after implantation can be diagnostic. Patients with pacing lead in the left ventricle may remain asymptomatic with normal lead function during long-term follow-up. Anticoagulation should be considered when this problem comes to attention for the first time during follow-up.     

PULSATILE GnRH-THERAPY IN OLIGOZOOSPERMIC MEN DOES NOT IMPROVE SEMINAL PARAMETERS DESPITE DECREASED FSH LEVELS

In order to evaluate GnRH administration for the treatment of infertile men with elevated serum FSH levels we administered GnRH in pulses via portable electronic infusion pumps initially to seven patients with low sperm counts and high FSH values over 12 weeks and later to nine further patients over 24 weeks who also underwent testicular biopsies. Fifty microlitres containing 5 micrograms GnRH were infused subcutaneously for 1 min every 120 min in the short-term study and every 90 min in the long-term study. Although FSH levels could be lowered in both groups of patients, none showed any improvement in sperm count or other seminal parameters. Therefore, pulsatile GnRH treatment cannot be recommended for therapy of severe oligozoospermia with elevated FSH levels.