Spontaneous, electrically, and cesium chloride induced arrhythmia and afterdepolarizations in the rapidly paced dog heart

Despite frequent arrhythmia and sudden death in heart failure, attempts to study arrhythmia mechanisms in patients are difficult. The dog heart, paced for several weeks at a fast rate to induce heart failure is prone to arrhythmia. The aim of this study was to determine the activation patterns of spontaneous and electrically induced arrhythmia and the susceptibility of the failing dog heart to arrhythmia and early afterdepolarization (EAD) induced triggered activity elicited by exogenous administration of cesium chloride (CsCl). The hearts of 56 mongrel dogs were paced at 240 beats/min for 3-5 weeks (heart failure group). Twenty-one similarly operated, but not paced dogs served as the control group. At baseline, all dogs were healthy as assessed electrophysiologically and hemodynamically. Spontaneous (bradycardia, tachycardia, and arrhythmic deaths) and electrically induced arrhythmia was frequent in dogs with heart failure. Also, the minimal dose of CsCl that produced ventricular tachycardia was significantly lower in the heart failure than the control dogs (1.02 +/- 0.02 vs 1.21 +/- 0.07 mMol/kg, P < 0.05). Epicardial mapping during spontaneous and electrically induced arrhythmia in the heart failure dogs showed initiation patterns with focal origin, often from multiple sites. This pattern was consistent with the patterns observed with CsCl induced ventricular tachycardia. In in vitro microelectrode studies, CsCl superfusion (2.5-5 mMol/L) induced triggered activity due to EADs within 30 minutes, in seven of the eight Purkinje fibers from four heart failure dogs. EADs were also found in ventricular myocytes of papillary muscle from two heart failure dogs. In contrast, 5 mMol/L CsCl induced EADs in only one of eight Purkinje fibers from the hearts of four control dogs and no papillary myocytes even with continuous superfusion for up to 60 minutes (P < 0.01). These results demonstrate that pacing induced heart failure in the dog has an increased tendency to develop ventricular tachycardia and triggered activity unmasked by CsCl.

Lack of norepinephrine--neuropeptide Y interactions in the hypothalamic control of cardiovascular regulation in urethane-anesthetized rats

Noradrenergic input to the hypothalamus is implicated in cardiovascular and behavioral regulation. The hypothalamus also contains high concentrations of neuropeptide Y (NPY), which often is colocalized in noradrenergic neurons. Systemically, NPY has been demonstrated to act synergistically with norepinephrine. Injections of concentrated solutions of NPY into the cerebral ventricles or hypothalamus have been found to alter ingestive behaviours, but the role of NPY in cardiovascular regulation is unknown. The objectives of this study were to determine if NPY injected directly into the hypothalamus elicits cardiovascular responses and (or) if the simultaneous administration of NPY with norepinephrine alters the cardiovascular responses elicited by norepinephrine alone. The hypothalamus of the urethane-anesthetized rat was mapped for heart rate and blood pressure responses to injections of one of the following: saline; NPY (1.9 or 0.6 pmol per injection site); norepinephrine (24, 81, or 243 nmol per injection site); or the combination of norepinephrine plus NPY. Site and drug selection were randomized. Injections of 0.25 microL were at 1.0 microL/min, bilaterally for bilateral structures and unilaterally for midline structures. Norepinephrine routinely elicited dose-dependent increases in blood pressure with latencies of approximately 1 min, which peaked by 3-5 min, accompanied or followed by tachycardia. Saline and NPY injections alone elicited no significant responses in any site. When NPY was injected together with norepinephrine, there were no significant alterations in cardiovascular variables except for attenuation of pressor responses when NPY was injected into the preoptic region and attenuation of tachycardia when NPY was injected into the caudal hypothalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

Injection therapy of superficial rheumatoid nodules

Although intralesional corticosteroid injection of subcutaneous rheumatoid nodules was mentioned in 1968, this simple procedure is not commonly practised. A placebo-controlled, double-blind trial of intralesional corticosteroid injection using 24 rheumatoid nodules from 11 patients was carried out to determine the efficacy and safety of the procedure. Nodules injected with methylprednisolone and lignocaine regressed significantly more than nodules injected with placebo (lignocaine alone). This was consistently shown in all modalities of assessments which included patients' assessments (P < 0.001) and investigator's assessments (P < 0.001) of the percentage change in nodule size, and gross measurements of nodule volumes using a pincer (P < 0.001). Nine of 12 active injections produced > or = 50% loss in nodular volume with complete disappearance of two nodules. This compares with only one out of 12 placebo injections which resulted in > or = 50% loss in nodular volume. The patients found all 12 active injections to be worthwhile compared to only two of 12 placebo injections being worthwhile. The only complication of injection therapy observed was that of pain during the procedure.

Childhood eosinophilic fasciitis presenting as inflammatory polyarthritis and associated with selective IgA deficiency

A 13 year old school boy presented with seronegative inflammatory polyarthritis after a flu-like illness. Four months later clinical features of eosinophilic fasciitis became apparent. After histological diagnosis treatment was started with prednisone 40 mg daily, with a good response. Routine investigations showed persistent selective IgA deficiency.

A controlled study of acupuncture in neck pain

Twenty-five out-patients with chronic neck pain participated in a prospective, randomized trial of acupuncture versus placebo transcutaneous nerve stimulation. A single-blind, non-cross-over design incorporated several outcome measures in an attempt to determine any particular facet of pain that responded to acupuncture. No significant difference between the two treatments was found either post-treatment or at follow-up. Whilst the small population studied limits the conclusions that may be drawn, these findings suggest that acupuncture may have no greater effect than that of a powerful placebo.

Giant cell arteritis diagnosed following arm claudication

A patient is described whose initial symptoms, though suggestive of polymyalgia rheumatica, were attributed to psoriatic arthritis, and whose subsequent development of claudication of the left arm led to the biopsy proven diagnosis of giant cell arteritis. Attention is drawn to widespread arterial involvement by giant cell arteritis which, though uncommon, must be considered in all patients with ischemic limb pain. In addition, the consequences of overlooking polymyalgia rheumatica as an early manifestation of giant cell arteritis are outlined.

Proximal dissection of the olecranon bursa in rheumatoid arthritis

A patient with rheumatoid arthritis and a distended olecranon bursa, which subsequently dissected subcutaneously in a proximal direction over the triceps muscle, is reported. Dissection of the olecranon bursa in a distal direction is not uncommon, but proximal dissection has not been reported.

Acupuncture in the treatment of chronic cervical pain. A pilot study

Thirteen patients with neck pain of at least two years' duration participated in the study. Patients were randomly assigned to either an acupuncture group or a placebo TNS (transcutaneous nerve stimulation) group. Initial pain scores revealed no significant difference between the groups with respect to pain severity. Patients were treated twice weekly for four weeks, at the end of which pain relief was measured using a simple descriptive scale. Even though an attempt was made to maximize the effect of placebo TNS using strong verbal suggestion, acupuncture still proved superior to placebo in the relief of cervical pain (p less than 0.01). The implications of these findings are discussed.