Decreased amplitude of left ventricular posterior wall motion with notch movement to determine the left posterior septal accessory pathway in Wolff-Parkinson-White syndrome

OBJECTIVE—To determine preoperatively, by analysing asynchronous left ventricular wall motion, whether to approach through the right ventricle or the left ventricle when carrying out catheter ablation of the accessory pathway in Wolff-Parkinson-White syndrome, especially in patients with the pathway located on the septum.
METHODS—73 patients with manifest Wolff-Parkinson-White syndrome who underwent successful catheter ablation were studied. Location of accessory pathway was classified as right ventricular side: right anterior paraseptum, right anterior, right lateral, right posterior, anterior septum, midseptum, right posterior septum; left ventricular side: left posterior septum, left posterior, left lateral, left anterior. Asynchronous systolic wall motion was analysed by cross sectional echocardiography.
RESULTS—Echocardiography showed that the amplitude of left ventricular posterior systolic wall motion was reduced when the pathway was located on the left ventricular side as opposed to the right ventricular side (mean (SD), 11.1 (1.7) v 12.9 (1.1) mm, p < 0.001), especially in patients with left posterior septal accessory pathway (9.7 (0.8) mm). There were no overlapping values between the left posterior septal accessory pathway and the right ventricular side accessory pathway. Posterior wall notch motion was observed in all patients with a left posterior septal accessory pathway (9/9), but not at all in patients with pathways located on the right ventricular side of the septum. In patients with a septal accessory pathway, an ECG algorithm provided poor information (relatively low sensitivity, specificity, and predictive value) for determining whether the subsite faced either the left (left posterior septum) or the right ventricle (anterior septum, midseptum, right posterior septum).
CONCLUSIONS—Decreased amplitude of left ventricular posterior wall motion with notch movement is an important finding for accessory pathways located on the left posterior septum. These findings provided clinically useful information for determining whether to approach catheter ablation from the right or the left ventricle.


     

Coronary flow reserve and oxygen metabolism of the right ventricle

The flow reserve of the right coronary artery (RCA) and myocardial oxygen extraction are important tractors in any investigation of the mechanisms of impaired right ventricular function. The present study induced brief coronary occlusions and examined the effect on right coronary blood flow in normal dogs, and the effect on myocardial oxygen metabolism in dogs with right ventricular hypertrophy (RVH). Right coronary flow reserve, represented by occlusion duration causing a half maximum dilatation (T1/2), was greater in the RCA than in the left anterior descending coronary artery of normal dogs; 11.4 +/- 2.3 sec vs 5.9 +/- 1.4 sec. Myocardial oxygen extraction ratio (EO2) of the right ventricle (RV), 51.3 +/- 1.6%, was significantly (p less than 0.05) lower than the index of the left ventricle (LV), 60.6 +/- 1.0%, and the extraction of the RV increased significantly in association with an increase of myocardial oxygen demand. In dogs with RVH caused by chronic banding of the pulmonary artery, this dominant oxygen reserve was lost: the EO2 of the hypertrophied RV was high compared with the EO2 of the normal RV (57.3 +/- 3.4% vs 51.3 +/- 1.6%, p less than 0.05), and no further increase in EO2 was observed in the hypertrophied RV in response to the elevation of the myocardial oxygen requirement. Oxygen usage per 100g of the RV for a certain level of overall RV work, rate-pressure product, was significantly (p less than 0.02) lower in the hypertrophied RV (0.00054 mlO2/beat.mmHg) than in the normal RV (0.0012 mlO2/beat.mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Bronchoscopic approach to COPD

Chronic obstructive pulmonary disease (COPD) is a highly prevalent condition that has frequent morbidity and mortality, with associated costs of US $ 2.5 billion annually and nearly 14,000 deaths each year. In the most advanced stages it causes debilitating breathlessness which is not improved despite maximal medical therapy including smoking cessation, bronchodilators, steroids and supplemental oxygen. Limitations of medical therapy led to the development of several surgical techniques to improve quality of life. However, surgical techniques still carry substantial morbidity even if the mortality is low at centers with larger experience; hence investigators are vigorously pursuing research into innovative, alternative methods for achieving lung volume reduction (LVR), in recent years. Endoscopic techniques for LVR are proposed, based on two main approaches, either closing of anatomical airway passages into destroyed lobe/segment of the lung to affect a collapse and reduction in volume or opening extra-anatomical airway passages, aimed at improving expiratory collateral flow from hyper-inflated areas bypassing the flow limited segments of the emphysematous airways. This article reviews the available endoscopic devises and the evidence supporting their use in the treatment of COPD.     

Tracheal or esophageal compression due to benign thyroid disease

Tracheal or esophageal compression was present in 91 (33 percent) of 273 consecutive patients with benign goiter during a 7 year experience. The underlying disease was nodular colloid goiter in 66 percent, adenoma in 21 percent, thyroiditis in 9 percent and Graves' disease in 4 percent. The incidence of tracheoesophageal compression was higher in patients with thyroiditis (67 percent) than in those with colloid goiter (46 percent). Thirty of 91 patients were completely asymptomatic but had marked tracheal deviation on roentgenography. Two thirds presented with significant dyspnea, or dysphagia or both. A long history of goiter preceding the onset of symptoms and progressive worsening of compression symptoms after its onset were common in the latter group. Previous radiographs demonstrating significant tracheal deviation during a previous presymptomatic period were available in 11 of 36 dyspneic patients. Sudden tracheal occlusion developed in 3 percent and required emergency treatment.Tracheal compression occurred more often and when present was a more ominous symptom. Compression manifestations were more frequent in patients with multinodular goiter, were more likely to appear when the underlying disorder was thyroiditis, affected the trachea more often than the esophagus and were generally gradually progressive with time.A clinical spectrum ranging from a presymptomatic tracheal compression stage to one wherein progressive worsening of symptoms occurs is suggested. After symptoms of tracheal compression become clinically manifest, the occurrence of complete airway occlusion may be sudden and unpredictable. Early operation whenever roentgenographic evidence of tracheal deviation becomes manifest is recommended.     

The efficacy of bupropion in winter depression: results of an open trial.

BACKGROUND: Seasonal affective disorder (SAD) refers to regularly recurring episodes of affective illness bearing a fixed relationship to season. Wintertime depression is its most widely recognized form. This study was undertaken to assess the efficacy of bupropion as a treatment for this disorder. METHOD: Fifteen consecutively presenting patients were treated with bupropion (200 to 400 mg/day). All met DSM-III-R criteria for major depression with a seasonal pattern. All were moderately to severely depressed. A modified version of the Hamilton Rating Scale for Depression (mHAM-D) including ratings of hypersomnia, increased appetite and carbohydrate craving, and weight gain was used to quantify the severity of illness. Up to 5 weeks of treatment was allowed before the subjects were categorized as nonresponders, partial responders, or responders. RESULTS: The mean +/- SD mHAM-D scores before and after treatment were 25.5 +/- 6.4 and 4.1 +/- 3.1, respectively. Ten (66.7%) of the subjects had a complete response to treatment (mHAM-D score less than or equal to 5). The other 5 (33.3%) had a partial response (mHAM-D score = 6-10). Five of the subjects had chronic pain and 3 had panic attacks restricted to episodes of depression. These problems resolved simultaneously with the symptoms of depression. CONCLUSION: The results of this open trial suggest that bupropion is an effective treatment for winter depression. However, controlled studies are required to confidently determine whether this is the case.     

Lung mitochondria in experimental asbestosis

Alterations in lung mitochondria were followed in guinea pigs at different periods after a single intratracheal injection of chrysotile dust. Cytochrome c oxidase and succinic dehydrogenase activities showed gradual increase after 90 days, whereas monoamine oxidase remained unaffected throughout the study. There was an increase in glutamate dehydrogenase activity in postmitochondrial as well as in mitochondrial fractions, the latter being accompanied by decreased latency of the enzyme. Mitochondria from asbestotic lung appeared to be more swollen than in normal animals at and after 90 days of exposure. There were fluctuations in the contents of different phospholipids as a result of asbestosis. Beyond 90 days, collagen and mucopolysaccharides also increased. The results confirm the contention that pulmonary mitochondria are among the major target sites in asbestosis.     

Exercise induced QRS broadening as a potential marker for significant coronary artery disease

We describe a 33-year-old male with angina pectoris who was found to have abnormal origin and course of right coronary artery from left aortic cusp. The abnormal origin was identified by conventional coronary angiography but the abnormal course of the vessel between ascending aorta and the main pulmonary artery was precisely delineated by high resolution CT angiography. Patient underwent successful surgical transposition of the anomalous vessel with complete resolution of symptoms.     

Tobacco smoke exposure induces nicotine dependence in rats

Rationale

Tobacco smoke contains nicotine and many other compounds that act in concert on the brain reward system. Therefore, animal models are needed that allow the investigation of chronic exposure to the full spectrum of tobacco smoke constituents.

Objectives

The aim of these studies was to investigate if exposure to tobacco smoke leads to nicotine dependence in rats.

Methods

The intracranial self-stimulation procedure was used to assess the negative affective aspects of nicotine withdrawal. Somatic signs were recorded from a checklist of nicotine abstinence signs. Nicotine self-administration sessions were conducted to investigate if tobacco smoke exposure affects the motivation to self-administer nicotine. Nicotinic receptor autoradiography was used to investigate if exposure to tobacco smoke affects central α7 nicotinic acetylcholine receptor (nAChR) and non-α7 nAChR levels (primarily α4β2 nAChRs).

Results

The nAChR antagonist mecamylamine dose-dependently elevated the brain reward thresholds of the rats exposed to tobacco smoke and did not affect the brain reward thresholds of the untreated control rats. Furthermore, mecamylamine induced more somatic withdrawal signs in the smoke-exposed rats than in the control rats. Nicotine self-administration was decreased 1 day after the last tobacco smoke exposure sessions and was returned to control levels 5 days later. Tobacco smoke exposure increased the α7 nAChR density in the CA2/3 area and the stratum oriens and increased the non-α7 nAChR density in the dentate gyrus.

Conclusion

Tobacco smoke exposure leads to nicotine dependence as indicated by precipitated affective and somatic withdrawal signs and induces an upregulation of nAChRs in the hippocampus.