Pleomorphic Ventricular Tachycardia: Demonstration of Conduction Reversal Within the Reentry Circuit

A case is presented of a patient with incessant venfricular tacbycardia of left bundle branch block morphology. Endocardial mapping revealed the site of earliest activation during tachycardia to be the proximal right ventricular septum. Pacing at this site elicited the clinical tachycardia, whereas pacing at the proximal left ventricular septum induced a right bundle branch block morphology identical to that of a previously recorded spontaneous ventricuiar tachycardia. Electrophysiological evidence is given that both types of tachycardia originate from a single reentry circuit located in the proximal ventricular septum in which the reentrant wavefront may travel either orthodromically (during spontaneous tachycardia and right ventricular pacing) or antidromically (during left ventricular pacing).     

Preexcitation in Hypertrophic Cardiomyopathy: A Case of a Fasciculoventricular Mahaim Fiber

STELLBRINK, C., et al .: Preexcitation in Hypertrophic Cardiomyopathy: A Case of a Fasciculoventricular Mahaim Fiber . A patient with hypertrophic cardiomyopathy (HCM) who presented with preexcitation pattern on the surface ECG suggestive of the Wolff-Parkinson-White (WPW) syndrome is described. Intracardiac electrophysiological study revealed a fixed anomalous QRS complex and a short fixed His-ventricular interval indicating a fasciculoventricular Mahaim fiber. As this specific form of accessory connection does not cause reentrant tachycardias, no treatment was required. It is important to distinguish this entity from atriofascicular or nodoventricular Mahaim fibers or the WPW syndrome in patients with HCM showing a preexcitation pattern in the surface ECG, as these may cause life-threatening arrhythmias in this patient population.     

Smoking patterns at a British and at an American medical school

Cigarette smoking among medical students at the University of Bristol (Bristol) and the New York University School of Medicine (NYU) was investigated and differences were subjected to statistical analysis.
At Bristol 34–6% and at NYU 14–3% of respondents classified themselves as regular smokers. Among students in the pre-clinical phase of training the difference between the number of smokers at Bristol and at NYU was not significant. At both schools more clinical students smoked than preclinical students, but only at Bristol did the difference between the number of smokers in the two grade levels reach statistical significance.
There are fewer heavy smokers (consumers of more than twenty cigarettes per day) among the pre-clinical students at Bristol than among preclinicals at NYU. In the clinical year, however, there were slightly (insignificantly) fewer heavy smokers at NYU while there were significantly more at Bristol.
Smokers at NYU acquired the habit at a somewhat earlier age than the smokers at Bristol.
The majority of students at both schools indicated that medical education had not influenced their decision to smoke or not to smoke.
Most smokers—more among the clinical than the pre-clinical students—reported that they were displeased with their habit and that they wished to give it up. Somewhat fewer smokers at Bristol gave that response than students at NYU.
Factors contributing, at least in part, to the differences between smoking patterns observed may be variables of age and years of education.
The widely held but untested belief that precept and example by medical school teachers may be a potent force for modifying the smoking behaviour of health professionals, is in need of research.     

COMMMENTS

Germ cell tumours (CT) are no true carcinomas; therefore the term testicular intraepithelial neoplasia (IN) is probably more appropriate than “CIS”. The diagnostic accuracy of a single‐site biopsy is an open question. We experienced 9 false‐negative biopsies among 1859 cases. Thus, the proportion of a failed diagnosis is 0.5%. The main reason for diagnostic failure is the non‐random distribution of TIN within the testicle. Currently we are investigating whether a two‐site biopsy is more accurate than a single biopsy. In the ongoing trial, the over‐all prevalence of TIN is around 5.3%, so far. In one quarter of the positive cases the lesion was found in only one of the two specimens. Thus, a double biopsy appears to be more favourable than the traditional single biopsy. Surgical complications amount to 2.5% in that double biopsy study. Only one surgical re‐intervention was required among 983 patients. Serial imaging studies with scrotal sonography and magnetic resonance imaging (MRI) disclosed a transient intratesticular haematoma/oedema postoperatively. So, testicular biopsy, even when performed at two sites is in fact a low‐complication procedure. Low dose radiotherapy to the testis is the treatment of choice for TIN. However, more than one quarter of patients require testosterone supplementation secondary to androgen‐deficiency. Two dose‐reduction studies (Denmark and Germany) had to be terminated prematurely because unexpected relapse of TIN was encountered at 14 Gy and 16 Gy. Possibly, hyperfragmentation schedules can overcome the antagonism of androgenic compromise and oncological safety. In a nation‐wide survey, it was shown that contralateral biopsies were routinely performed in 66% of the urological departments in Germany. Another 19% offered the biopsy to particular “risk‐cases”; only 15% never did a biopsy. Among those refusing biopsies, there was a higher proportion of small hospitals and a significantly lower annual case‐number of GCT, when compared to those doing the biopsy. Thus, the contralateral biopsy is a well‐established procedure among German urologists; those with a high caseload of GCT particularly appreciate it.     

Percutaneous Catheter Ablation at the Mitral Annulus in Canines Using a Bipolar Epicardial-Endocardial Electrode Configuration

For potential application in ablating left free-wall accessory AV pathways with direct current shocks, a new epicardial-endocardial electrode configuration, designed to focus the current field across the mitral annulus, was tested in dogs. A catheter electrode in (he coronary sinus (epicardial electrode) was used as the cathode, and a catheter electrode in the left ventricle (endocardial electrode) placed beneath the mitral valve, high against the mitral annulus and directly across from the epicardial electrode formed the anode. Two shocks, each of 30, 40, or 50 joules (J) were delivered in nine, three, and four dogs, respectively. The first shock was applied to the anterior or lateral wail and the second shock to the posterior wall, except in one dog which received one anterior and one lateral shock. Two dogs receiving 50] shocks died acutely, one due to rupture of the coronary sinus and cardiac tamponade and the other had unexplained electromechanical dissociation. The remaining 14 dogs tolerated the two shocks well and were sacrificed 3–5 days later for pathological examination of the heart. Shocks in the anterior and lateral regions produced atrial necrosis (height 1.5–11 mm, width 1.5–12 mm and depth 1–3 mm) in 10 of 14 dogs and ventricular necrosis (height 4–27 mm, width 4–33 mm, and depth 5–14 mm) in all 14 dogs. Ideal lesions with atrial necrosis extending down to the annulus and ventricular necrosis extending to the epicardial aspect of the ventricular crest occurred in five dogs in which the endocardial electrode was positioned high against the annulus. In the other nine dogs, the endocardial electrode was located 6–18 mm below the annulus, as estimated by the center of ventricular necrosis. In these dogs, the ventricular lesions did not extend to the epicardial aspect of the crest and, in four dogs, no atrial necrosis was found. Shocks delivered to the posterior wall produced no atrial or ventricular necrosis except in one dog receiving a 50 J shock. It is concluded that, using the epicardial-endocardial electrode configuration with the LV catheter positioned high against the annulus, shocks of less than 50 J in dogs safely produce atrial and ventricular necrosis adjacent to the mitral annulus in the anterior and lateral regions but not in the posterior regions. Similar lesions in man may be capable of interrupting left anterior and lateral accessory AV pathways.     

Short-duration ('minutes') therapy with dithranol for psoriasis: a new out-patient regimen

Eighty-five patients with widespread psoriasis were treated with daily short-term applications of dithranol and salicylic acid in yellow soft paraffin. Two different schedules were used: (1)‘3-h’ therapy using increasing dithranol concentrations (0.1, 0.25, 0.5, 1, 2%) for 3 h; (2)‘minutes’ therapy using high dithranol concentrations (1, 2, 3%) for only 10–20 min. In comparison with the standard dithranol therapy, applied for 24 h each day, the‘3-h’ therapy showed equal efficacy clinically and histologically, and the‘minutes’ therapy was significantly hotter than the standard therapy, reducing the mean clearing time by 6.8 days. Daily short-term (‘minutes’) therapy combines all the advantages of dithranol with a convenient and readily acceptable mode of application for home use.