Asystole Following Left Ventricular Pacing

During biventricular ICD implantation, pacing the epicardial inferior posterior-lateral surface of the left ventricle via the coronary sinus produced asystole. The proposed mechanism is a Bezold-Jarisch reflex manifested by a drop in heart rate and blood pressure through direct C fiber stimulation. (PACE 2004; 27[Pt. I]:815–817)     

An evaluation of the hypo-osmotic sperm swelling test as a predictor of fertilizing capacity in vitro

The ability of sperm to swell in hypo-osmotic conditions was examined in 211 semen samples from the partners of patients about to undergo oocyte retrieval for in-vitro fertilization (IVF). The test was performed using aliquots of semen, the remainder of which was then prepared for IVF. No significant difference was found, in either the percentage of swollen sperm or the type of swelling response, between samples that achieved fertilization in vitro and those that did not, or between any of the diagnostic categories of infertility (tubal damage, unexplained infertility, oligospermia). In samples which achieved fertilization in vitro there were correlations between sperm swelling and sperm motility (r = -0.51) and abnormal morphology (r = 0.33), but no such correlations were demonstrated in samples that failed to achieve fertilization. Moreover, there was no significant difference between the percentage of swollen sperm in semen (mean motility 64%), in samples immediately after preparation for IVF (mean motility 96%) or in capacitated sperm 24 h after preparation (mean motility 91%). These results demonstrate that the hypo-osmotic sperm swelling test does not assist in the prediction of the fertilizing capacity of human sperm in vitro.     

Six-Month Exposure of Strain A/J Mice to Cigarette Sidestream Smoke: Cell Kinetics and Lung Tumor Data

Male strain A/J mice were exposed to sidestream smoke (SS) generatedfrom burning Kentucky 1R4F reference cigarettes. Chamber concentrationswere 4 mg/m³ of total suspended respirable particulate matter(TSP). Animals were exposed 6 hr a day, 5 days a week. One-weekcumulative labeling indices were significantly increased inthe large intrapulmonary airways during the 1st week and inthe respiratory epithelium of the nasal and maxillar turbinatesduring the first 3 weeks of exposure and then returned to controlvalues. Subsequently, signs of increased cell proliferationwere again found in the nasal and maxillar turbinates duringthe 9th and 16th exposure weeks. The experiment was terminatedafter 6 months. The number of animals bearing lung tumors wasthe same in smoke-exposed as in filtered airexposed animalsas was the average number of tumors per lung. Analysis of theDNA of individual tumors obtained from exposed and control micefor K-ras mutations suggested that exon 2 might be a specifictarget for SS. It was concluded that (1) duration of exposurewas too short or (2) concentration of TSP was too low to reveala possible carcinogenic potential of SS in strain A/J mice orthat (3) SS is not carcinogenic in strain A mice.     

Retrograde ejaculation: a systematic approach to non-invasive recovery of spermatozoa from post-ejaculatory urine for artificial insemination

Summary. Retrograde ejaculation is an uncommon but treatable form of male infertility. Successful recovery of live spermatozoa from the post-ejaculatory urine for artificial insemination is dependent on careful regulation of pH and osmolarity of the urine into which ejaculation takes place, and separation of the motile spermatozoa from the debris and cells which are found in these samples. Three pregnancies established by artificial insemination of spermatozoa recovered by non-invasive means from the bladders of men suffering from retrograde ejaculation are described. The techniques for preparing the urine for spermatozoal survival, and for removal of cells and debris by sedimentation or buoyant density centrifugation are discussed.     

Hemiazygous Coil Placement for High‐Defibrillation Thresholds in a Patient with a Right‐Sided Implantable Cardioverter Defibrillator

A 41‐year‐old man underwent implantation of a right‐sided implantable cardioverter defibrillator after removal of an infected left‐sided system. Defibrillation threshold (DFT) testing on the right‐sided system failed to convert ventricular fibrillation at maximum device output (35 J) compared with a DFT of less than 15 J on the previous left‐sided system. A single‐coil lead was selectively placed into the hemiazygous vein, which courses leftward of the spine in a posterior‐anterior projection, resulting in an improved shocking vector and reduction in DFTs to less than 25 J. (PACE 2012; 35:e10–e12)     

I NTRODUCTION TO F IRE P REVENTION,F IFTH E DITION

Objectives: To determine whether members of a ski patrol, most of whom have no off-season medical responsibilities, can successfully complete an automated external defibrillator (AED) training program prior to the ski season, and retain AED skills at the end of the season and at the beginning of the following season. Methods: A prospective educational study was conducted with 61 ski patrol personnel: 51 (84%) had no other medical training, 44 (72%) had no off-season medical duties, and 57 (93%) had no prior exposure to AEDs. Prior to the ski season (December 1, 1998), all members were trained and tested using the standard American Heart Association (AHA) AED training package and a Life-Pak 500 AED and AED Trainer donated by the Medtronic Physio-Control Corporation. Both after the ski season (April 1, 1999) and prior to the following season (October 30, 1999), with no refresher training, participants were retested with the same written and practical exams. Cochrane's linear trend test was used to compare scores on the practical and written tests over time. Results: For the three testing sessions, practical test pass rates were 95%, 92%, and 97%, and written test pass rates were 100%, 98%, and 98%. There was no change in individuals' scores on either the written test (p = 0.914) or the practical test (p = 0.413) over time. Conclusions: A heterogeneous group of ski patrollers can successfully complete an AED training course, with good skill retention both after the ski season and at the beginning of the following season.     

Effect of interferon gamma on intrahepatic haemodynamics of the cirrhotic rat liver

Sublethal injury of the liver with carbon tetrachloride (CCI₄) induces the modulation of hepatic stellate cells to their myofibroblast (MFB) phenotype. Pretreatment or concomitant treatment with interferon gamma (IFNγ) has been shown to inhibit this phenomenon. The aim of this study was to investigate the influence of IFNγ treatment (50 000 IU s.c. each day for 5 days) in rats with an established cirrhosis. Cirrhosis was induced with nine doses of CCI⁴. Comparison of biopsies before and after treatment with IFNγ showed that the number of MFB present, identified by their α-smooth muscle actin immunoreactivity, was markedly reduced. Pressure-flow curves were constructed in isolated perfused liver preparations from IFNγ-treated and saline-treated cirrhotic rats and analysed to obtain the extrapolated zero-flow intercept (P⁰, an index of hepatic vascular distensibility) and the vasodilator-induced change in resistance at a flow rate of 1 mL/min per g (ΔR₁ an indication of the level of intrinsic vascular tone). In IFNγ-treated rats, portal venous pressure measured in vivo was significantly reduced compared with controls (11.9±1.2 vs 16.0 ± 0.5 mmHg, P < 0.05), P₀ was lower (2.03 ± 0.18 vs 2.87 ± 0.32 mmHg, P < 0.05) and ΔR₁ was decreased (0.39 ± 0.15 vs 1.02 ± 0.19 mmHg/mL per min per g, P < 0.05). The findings indicate that treatment with IFNγ is effective in reducing MFB density in established CCI₄-cirrhosis in the rat and results in a marked improvement in intrahepatic haemodynamics.     

OBSERVATIONS ON THE EFFECT OF MASSIVE DOSES OF IRON GIVEN INTRAVENOUSLY TO PATIENTS WITH HYPOCHROMIC ANEMIA

Massive doses of iron (from 0.608 to 1.32 Gm. as colloidal terric hydroxide orcolloidal ferric oxide) were given intravenously in single infusions to 8 differentpatients with hypochromic microcytic anemia. One patient was given a secondinjection after an interval of four months, so that nine administrations were made.The following observations were made:

1. The reticulocyte response was higher in each instance than would be expectedin oral therapy. In 3 additional patients in whom injection had to be discontinuedafter 0.070, 0.180, and 0.123 Gm. of elemental iron had respectively been given, thereticulocyte rises were higher than were the average responses reported by Heath¹⁸after optimal oral therapy. This at least suggests that "optimal" oral therapy doesnot provide a maximal stimulus to outpouring of reticulocytes from the bone marrow. Comparable doses of iron given to 3 control subjects with normal hemoglobinlevels did not cause a reticulocytosis.

2. The average rate of hemoglobin regeneration per 100 cc. of blood per day was0.224 Gm.; the lowest value was 0.16 Gm. and the highest 0.27 Gm. These figureswere calculated for the rise that occurred from the day of iron administration to thetime at which the rate of hemoglobin increase was obviously becoming slower.Since correction was not made for blood loss in 3 of the patients during the periodof regeneration, the figures for the rate of hemoglobin formation are lower thanthey otherwise would have been. Even so they are distinctly greater than thoseusually obtained following oral therapy (table 2), but no greater than is found in anoccasional patient given iron by mouth. The data suggest that the fastest rate ofhemoglobin regeneration that can be stimulated by iron in subjects with hypochromic anemia approximates 0.3 Gm. per 100 cc. per day.

3. Calculations indicated that from 71.8 to 99.7 per cent of the injected iron wasapparently used for the synthesis of hemoglobin. These figures are likewise lowerthan they would have been if several of the patients had not lost blood during therecovery period. The observation of other workers that parenterally administerediron is almost completely retained by the body and converted into hemoglobin wastherefore confirmed.

4. Toxic reactions to the injected iron are described in detail. They were severein all but two instances, and in 3 patients were so alarming that injection of ironhad to be discontinued. There can be no doubt that the reactions to iron parenterally administered in large doses are great enough to contra-indicate use of thismeasure as a therapeutic procedure.

     

Signal-Averaged ECG Prior to and Serially After Thrombolytic Therapy for Acute Myocardial Infarction

Signal averaging has been performed to evaluate late potentials following infarction and the administration of thrombolytic therapy. Most studies have recorded signal-averaged electrocardiograms (SAECGs) at least 12 hours after the onset of the infarction. In this study, SAECGs were recorded before thrombolytic therapy and serially over 7–10 days following infarction in 21 patients. The high frequency QRS duration was significantly shortened at 1 and 24 hours compared to presentation (96.8 ± 11.3 ms and 93.4 ± 8.0 ms vs 103.3 ± 14.3 ms, respectively, P < 0.05) and there was an increase in the terminal voltage over time, significant at 1 hour and 3 days (57.3 ± 29.1 μV and 58.6 ± 44.7 μV vs 44.4 ± 35.5 μV, respectively, P < 0.01). Five patients met criteria for ventricular late potentials on at least one SAECG. The prevalence of late potentials was higher in patients with Q wave infarctions, or with occluded infarct related arteries. These changes in myocardial activation may be related to ischemia and reperfusion, and may not correlate with the development of a fixed substrate for reentry.