Pathologic Findings Following Sudden Death in an Infant with Hypertrophic Cardiomyopathy and Supraventricular Tachycardia

Sudden Infant Death in Hypertrophic Cardiomyopathy. The cardiac conduction system from infants suddenly dying with hypertrophic cardiomyopathy has not been described. We studied by serial section examination the conduction system from a 13-month old infant also known to have had supraventricular tachycardia. At autopsy, there was cardiomegaly with asymmetric septal hypertrophy. Microscopic examination revealed myofiber disarray around an abnormally formed central fibrous body, numerous nodoventricular fibers to both sides of the ventricular septum, and fibrosis of the left bundle branch. We postulate that supraventricular tachycardia utilized a concealed pathway or the malformed AV Junction. Death may have resulted from deranged hemodynamics secondary to supraventricular tachycardia.     

Type II Atrial Flutter Interruption with Transesophageal Pacing: Use of Propafenone and Possible Change of the Substrate

Type II atrial flutter (AFII) is an arrhythmia which usually cannot be interrupted by atrial pacing: the underlying mechanism is considered to be a leading circle without an excitable gap. We investigated whether the administration of propafenone, an antiarrhythmic drug, which primarily decreases conduction velocity, has a beneficial effect on AFII interruption using transesophageal pacing. Twelve patients with an AFII were randomized into 2 groups in which pacing was performed without treatment (group A) or two hours after the administration of 600 mg of oral propafenone (group B). Sinus rhythm was attained in 0 of 6 patients in group A and in 4 of 6 patients in group B (P < 0.05). The baseline mean cycle length was the same in both groups (175 ± 7 (A) vs 168 ± 8 ms (B); it lengthened significantly after the administration of propafenone (219 ± 33 vs 168 ± 8 ms; P < 0.05). Propafenone did not significantly lengthen the cycle in the two patients in whom interruption of the arrhythmia was impossible. Our data show that propafenone has a facilitating effect on atrial pacing only when it significantly prolongs the cycle length of the arrhythmia, possible expression of a conversion of AFII into type I, with an anatomical substrate and an excitable gap allowing arrhythmia capture and interruption. In the two patients in whom sinus rhythm was not restored, the absence of a direct dependence of the cycle length on the change in conduction velocity induced by propafenone may be explained by the persistence of a functionally determined circuit, resistant to atrial pacing.     

Aged gastric mucosa: Mechanisms of vulnerability

Abstract The incidence, frequency of complications and mortality of gastric ulcer disease are increased four-fold in the elderly taking non-steroidal anti-inflammatory drugs (NSAID). There is controversy as to whether this reflects increased usage of NSAID or specific vulnerability associated with age. We have investigated two possible mechanisms for this increase in gastrointestinal effects in the elderly: (i) increased susceptibility to acute gastrotoxicity; and (ii) reduced adaptation to NSAID, in a model of young (2 month), mature (12 month) and aged (24 month) rats. Aspirin damaged 7.7% of the volume of gastric mucosa in the young rat. In mature and aged rats, this increased to 11.3% (P < 0.002 compared to control) and 21.9% (P < 0.005 compared to control), respectively. Thus, aspirin caused a three-fold increase in the severity of acute gastric mucosal injury in aged animals. However, indomethacin, ibuprofen and L745 337 did not produce any significant acute gastric mucosal damage in 2-, 12- or 24-month-old rats. Significant gastric adaptation to diclofenac treatment occurred in both aged and young rats as measured by gastric mucosal damage. The aged gastric mucosa adapted equally as well as the young gastric mucosa to diclofenac. The findings of this study provide only modest support to the hypothesis of increased vulnerability of the stomach in the aged. Aspirin was associated with greater damage in the aged. Adaptation to diclofenac-induced damage was not reduced in the aged and there was not an increased susceptibility to damage by the non-aspirin NSAID tested. The selective cyclo-oxygenase-2 inhibitor, L745 337, was the least toxic agent and may represent a group of NSAID which cause fewer gastrointestinal complications in the elderly.     

Blood pressure assessment in haemodialysis patients: Comparison between pre-dialysis blood pressure and ambulatory blood pressure measurement

Aim: Hypertension is common in haemodialysis (HD) patients. Determining the most appropriate method of blood pressure (BP) measurement, representative of target organ damage, is still an issue. BP variations between pre‐ and post‐HD treatment, or between on‐dialysis day and off‐dialysis day, are common. The aim of this study was to examine the possible differences between pre‐HD office BP (OBP) levels, inter‐HD (iHD) or HD day 24 h ambulatory BP measurement (ABPM) with 48 h ABPM, where the latter was considered the gold standard. Methods: 163 HD patients were studied. BP was monitored consecutively for 48 h with a Takeda TM2421 device, then sub‐analysed into two periods of 24 h: HD and iHD day. An average of 12 sessions pre‐HD OBP measurements was determined. Results: OBP significantly overestimates systolic (SBP) and diastolic BP (DBP) when compared with 48 h ABPM. SBP and DBP are significantly higher on iHD day than on HD day: 141.2 ± 20.8 versus 137.9 ± 20.9, and 77.1 ± 11.1 versus 76.1 ± 10.9 (P < 0.01). No differences of SBP night/day ratio were reported between 48 h ABPM and iHD 24 h ABPM or HD 24 h ABPM. The highest correlations were reported between 48 h SBP/DBP with iHD or HD 24 h ABPM (r² = 0.95, P < 0.001), while the lowest between 48 h SBP/DBP and OBP (r² = 0.40, P < 0.01, r² = 0.12, P < 0.01). The narrowest limits of agreement using the Bland and Altman test were reported between 48 h SBP or DBP and 24 h iHD or HD day ABPM. Considering 48 h ABPM, 80.5% of patients had BP higher than the norm, compared with 61.7% of patients in the case of OBP (χ² = 13.28, P < 0.001). The sensibility for detecting hypertension for iHD day 24 h ABPM was 98.4%, with specificity of 90%. The sensibility of 24 h HD day ABPM was 90.3%, with specificity 96.6%. In the case of OBP, sensibility and specificity were considerably lower, that is, 72.6% and 83.3% respectively. Conclusion: Significant differences are shown between OBP and 48 h ABPM in the recognition of a hypertensive state. OBP measurement has a lower sensibility and specificity than 24 h ABPM, which remains a valid alternative approach to 48 h ABPM in HD patients. Errors of OBP estimation should be taken into account, with possible negative impact on treatment strategies and epidemiology studies.     

Time course of continuous positive airway pressure effects on central sleep apnoea in patients with chronic heart failure

Continuous positive airway pressure (CPAP) causes a variable immediate reduction in the frequency of central apnoeas and hypopnoeas in patients with congestive heart failure (CHF) and central sleep apnoea (CSA), but has beneficial mid-term effects on factors known to destabilize the ventilatory control system. We, therefore, tested whether CPAP therapy leads, in addition to its short-term effects on CSA, to a significant further alleviation of CSA after 12 weeks of treatment on the same CPAP level in such patients. CPAP therapy was initiated in 10 CHF patients with CSA. During the first night on CPAP, the pressure was stepwise increased to a target pressure of 8–12 cmH₂O or the highest level the patients tolerated (<12 cmH₂O). Throughout the second night (baseline CPAP), the achieved CPAP of the first night was applied. After 12 weeks of CPAP treatment, we performed a follow-up polysomnography (12 weeks CPAP) on the same CPAP level (8.6 ± 1.1 cmH₂0). We found a significant reduction of the apnoea-hypopnoea index (AHI) between the diagnostic polysomnography and baseline CPAP night (41.8 ± 19.2 versus 22.2 ± 12.6 events per hour; P  = 0.005). The AHI further significantly decreased between the baseline CPAP night and the 12 weeks CPAP night on the same CPAP level (22.2 ± 12.6 versus 12.8 ± 11.0 events per hour; P  = 0.028). We conclude that, in addition to its immediate effects, CPAP therapy leads to a time-dependent alleviation of CSA in some CHF patients, indicating that in such patients neither clinical nor scientific decisions should be based on a short-term trial of CPAP.     

After antagonization of acute opiate overdose: a survey at hospitals in Vienna

This study describes the clinical management and characteristics of people who, following acute opioid overdose, are taken to hospital after efficient antagonization by the pre-hospital emergency service. In addition, it defines areas of interest for further research. Over a 4-month period (September-December 1993) we collected data by a structured protocol sheet on patients' characteristics, anamnestic data on abuse and emergencies, clinical presentation, treatment by specific antidote and routine laboratory investigations. Outcome leas verified by retrospective review of prehospital and forensic data. We studied 77 subjects, predominantly young males, who were involved in 83 emergencies, mostly occurring at weekends. In more than 60% of cases a single administration of specific antidote sufficed to stabilize the patients; 64% of patients left hospital against medical advice after an average stay of less than 6 hours; 46% denied daily opioid abuse and half the subjects, especially younger drug-users, seemed interested in counselling. This hospital-based study did not provide reliable data on the epidemiology of opioid overdose. Clinical management is determined by experience, pragmatism and beliefs. Efforts towards secondary prevention of drug problems at emergency departments might be warranted, and further research on pattern and management of opioid overdose is needed.