Intracerebral arteriovenous malformations: evaluation with selective MR angiography and venography

Magnetic resonance (MR) angiography and spin-echo methods were used to evaluate intracerebral arteriovenous malformations (AVMs) in 10 patients. Spin-echo images obtained with flow presaturation demonstrated the nidus of the AVM in all cases, but it was difficult to determine feeding vessels. These vessels were directly visualized with three-dimensional MR angiography; their presence could be indirectly determined by means of selective presaturation of individual vessels, which resulted in a marked decrease in signal within the portion of the AVM supplied by that vessel. Vascular supplies from the internal carotid artery and anterior, middle, or posterior cerebral arteries were detected in all cases, but in three large malformations it was not possible to demonstrate small feeding vessels. MR angiograms were also helpful for further defining the nidus. The combination of MR angiographic and spin-echo methods provides information useful for therapeutic planning not provided by either technique alone.     

Selection of drugs in pursuit of rate control strategy

Atrial fibrillation is the most common sustained arrhythmia. Based on multiple large randomized trials, rate control therapy has been shown to be safe and effective and is gaining greater acceptance as a frontline alternative to drugs to maintain sinus rhythm. Adequate rate control can be achieved by atrioventricular nodal blocking agents both in the acute and chronic settings. In refractory patients, other methods such as atrioventricular node ablation can be used to control rate.     

Recurrent recurrent gallstone ileus

We describe the second reported case of three consecutive episodes of gallstone ileus and ask the question whether recurrent gallstone ileus justifies definitive surgery to the fistula itself or can be safely managed by repeated enterotomies.     

‘Working together’ - A new approach to Reviewing the Quality of Postgraduate Medical Training Posts in Northern Ireland?

Many of us are involved in the education and training of junior doctors. Maintaining and improving the quality of such training is the common goal of all medical educators, including those working in the Northern Ireland Medical and Dental Training Agency (NIMDTA) and within our hospitals – the Local Education Providers (LEPs). The development of NIMDTA’s Placement Quality Initiative (PQI) aims to create a more collaborative working relationship between NIMDTA and the LEPs, working together, to achieve a shared goal and develop and implement strategies to improve current practice. We review the PQI process, from both a trainee and trainer’s perspective, and ascertain if this approach has facilitated positive, reproducible changes in training programmes that are felt at ground level.     

Do ACE inhibitors or angiotensin II antagonists reduce total mortality and arrhythmic mortality? A critical review of controlled clinical trials.

ACE-inhibitors (ACE-I) represent effective drugs more and more widely used in acute myocardial infarction (AMI) patients, in post AMI patients and mainly, today, in CHF patients.A complete review of the scientific literature and of all the randomized controlled clinical trials (RCTs), where ACE-I have been tested directly or in association with other drugs, have been performed. ACE-I effects on total mortality (TM) and arrhythmic mortality (AM) and other composite clinical endpoints have been evaluated.It is well known that frequent ventricular arrhythmias (VA) and a high incidence of sudden death (SD) can be documented in CHF patients; nevertheless a direct relationship between VA, TM, and AM has not been clearly demonstrated; neither beneficial effects, on the same endpoints, of the treatment and suppression of ambient VA in CHF. Conversely, sometimes clear negative effects on both TM and AM have been observed.According to individual studies and two recent complete and large metanalysis, ACE-I were unable to reduce AM, but they reduced TM. Furthermore, they can affect and modify many, if not all, of the triggering factors of VA and SD in this context.Differently from ACE-I, betablockers (BB) have been clearly associated with a reduction in TM and AM, in the same context. Thus, at present time, ACE-I, with or without BB, should be considered the standard therapy in all patients with CHF, if not contraindicated.Angiotensin II antagonists (AII-a) probably represent a comparably effective treatment, in all CHF patients and mainly in those patients, suffering from side effects or showing intolerance to ACE-I, but we are still lacking definitive data from RCTs.In many RCTs, conducted with traditional antiarrhythmic drug therapy (ADT), these drugs have been widely used, contributing probably, in a consistent way, to some of the positive results of these studies. All primary and some secondary implantable defibrillators (ICD) RCTs, in the prevention of SD, have included these drugs as the standard treatment of the underlying cardiac disease, with or without CHF. The same therapeutical strategy is regularly applied in all biventricular pacing (BP) RCTs, with or without the ICD. These trials are supposed to assess the reduction in TM and AM, preventing deterioration or progression of CHF and improving the quality of the patients' s life.Finally, according to these clinical evidences, in the last part of the review, we stress the need for a more widespread implementation of ACE-I and AII-a in treating CHF patients.     

Catheter ablation of atrioventricular junction using radiofrequency current in 17 patients. Comparison of standard and large-tip catheter electrodes

BACKGROUND. Two catheter electrode systems were compared for delivering radiofrequency current for ablation of the atrioventricular junction. Seventeen patients with drug-resistant supraventricular tachyarrhythmias were studied. METHODS AND RESULTS. A 6F or 7F catheter with six or eight standard electrodes (1.25 mm wide, 2.5-mm spacing) was used in the first seven patients (group 1). A 7F quadripolar catheter with a large-tip electrode (4 mm long; surface area, 27 mm2) was used in the final 10 patients (group 2). Both ablation catheters were positioned to record a large atrial potential and a small but sharp His bundle potential from the distal bipolar electrode pair. Radiofrequency current was applied between a large skin electrode on the left posterior chest and either 1) each individual electrode on the standard-tip electrode catheter at 40 V (group 1) or 2) the large-tip electrode at 50-60 V (group 2). Radiofrequency current was limited to 40 V in group patients because of the strong potential for an early impedance rise when higher voltage is applied through standard electrodes. Complete atrioventricular block was achieved in six of seven group 1 patients and all 10 group 2 patients. A junctional escape rhythm followed ablation in five or six group 1 patients (mean cycle length, 1,066 +/- 162 msec) and eight of 10 group 2 patients (mean cycle length, 1,281 +/- 231 msec). Atrioventricular block was produced in a mean of 4.7 +/- 4.6 radiofrequency current applications delivered over a period of 42 +/- 45 minutes using the large-tip electrode (group 2) compared with 46 +/- 22 applications using standard electrodes (15.9 +/- 10.2 applications delivered through the standard-tip electrode) over a period of 147 +/- 59 minutes (group 1). For the application producing atrioventricular block, the large-tip electrode used higher voltage (58 +/- 17 versus 38 +/- 5 V, p less than 0.03) and had lower impedance (103 +/- 22 versus 148 +/- 40 omega, p less than 0.01), resulting in greater power (33.0 +/- 13.0 versus 10.2 +/- 0.6 W, p less than 0.003) and shorter time to block (8 +/- 3 versus 22 +/- 3 seconds, p less than 0.001). Current delivery through standard electrodes was limited by an impedance rise occurring 7 +/- 7 seconds after the onset of one or more radiofrequency current applications at 10 +/- 1 W in six of seven patients. Using the large-tip electrode, an impedance rise occurred in five of 10 patients, but at 25 +/- 10 W and after 21 +/- 9 seconds. Atrioventricular block occurred before the impedance rise in three of these five patients. Complete atrioventricular block persisted in 15 of 16 patients at a mean follow-up of 8.7 months. Atrioventricular conduction returned at 1 month in one group 2 patient and was successfully ablated by a second procedure. Three group 1 patients died 0.5-2 months after ablation, and a fourth patient underwent cardiac transplantation after 10 months. Pathological examination of the heart in two of these patients showed necrosis of the atrioventricular node and origin of the His bundle, without injury to the middle or distal His bundle. All 10 group 2 patients are alive and subjectively improved after ablation. CONCLUSIONS. We conclude that catheter-delivered radiofrequency current effectively produces complete atrioventricular block (94%) without requiring general anesthesia or the risk of ventricular dysfunction or cardiac perforation. The large-tip electrode allows a threefold increase in delivered power and markedly decreases the number of pulses and time required to produce atrioventricular block.     

Role of electrophysiologic testing in managing patients who have ventricular tachycardia unrelated to coronary artery disease

This study examined the usefulness of programmed electrical stimulation in managing 83 patients who had ventricular tachycardia not due to coronary artery disease. Among 39 patients with a history of sustained ventricular tachycardia, programmed stimulation induced ventricular tachycardia in 14 of 14 patients with mitral valve prolapse or primary electrical disease (arrhythmias without evidence of structural heart disease) and in 13 of 25 with cardiomyopathy (total 27 of 39, 69 percent). Programmed stimulation induced nonsustained ventricular tachycardia in 15 (34 percent) of 44 patients with a history of nonsustained tachycardia (5 of 13 with mitral valve prolapse, 6 of 19 with primary electrical disease and 4 of 12 with cardiomyopathy). Seventy-three of the 83 patients were treated with antiarrhythmic drugs and then followed up for 14.4 ± 11.4 months (mean ± standard deviation). Drug therapy was determined with serial electrophysiologic testing in 31 patients. Twenty-four of these 31 patients had a history of sustained ventricular tachycardia, and drugs prevented induction of ventricular tachycardia in 9 (none of whom manifested symptomatic events) but did not prevent it in 15 (6 of whom had symptomatic events). Among seven patients with a history of nonsustained ventricular tachycardia, drugs prevented induction of ventricular tachycardia in five (none of whom had symptomatic events) and did not prevent it in two (none of whom had symptomatic events). Forty-two patients were treated using the results of noninvasive testing. Drugs suppressed spontaneous ventricular tachycardia in 15 of 15 patients with a history of sustained tachycardia (7 of whom had symptomatic events including one sudden death), and in 26 of 27 with a history of nonsustained tachycardia (6 of whom had symptomatic events including one sudden death).Thus, in patients with ventricular tachycardia unrelated to coronary artery disease: (1) programmed electrical stimulation induced ventricular tachycardia less often than in patients whose tachycardia was due to coronary artery disease; (2) programmed stimulation induced ventricular tachycardia less often in patients with a history of nonsustained versus sustained tachycardia; and (3) suppression of inducible ventricular tachycardia appeared to predict effective drug therapy but drug therapy predicted with noninvasive testing appeared to be unreliable.