Long-Term Prognostic Significance and Electrophysiological Evolution of Intraventricular Conduction Disturbances Complicating Acute Myocardial Infarction

Fifty-nine patients with post-infarctional, isolated intraventricular conduction disturbances (IVCD) who survived the acute stage of myocardial infarction were followed up after hospital discharge for a mean period of 11.4 ± 4.8 months. Fourteen patients (24%) had HV interval prolongation (>55 ms) during AMI (group A), and 45 patients had normal HV intervais (76%. group B). His bundle recordings were repeated during follow-up in 48 survivors after a mean period of 7.2 ± 0.7 months. Infranodal conduction delay in the acute stage of infarction was correlated with a higher incidence of heart failure during AMI (78% of patients in group A vs 22% in group B, p < 0.01), and with higher rate of cardiac mortality during follow-up (50% in group A vs 13% in group B. p < 0.01). Survivors of group A showed a higher functional NYHA class, a higher incidence of CHF, and a higher prevalence of complex ventricular arrhythmias at Holter monitoring. No statistically significant difference in late sudden death was evident between the two groups of patients, and the global incidence of late AV block was 2%. At repeat His bundle recording no significant change (>5 ms) in HV interval could be demonstrated in comparison to the acute phase recording, neither in patients with prolonged nor in patients with normal HV time. We conclude that HV prolongation in patients with isolated, post-infarctional IVCD is correlated with a worse prognosis, both during acute infarction and during the follow-up period, which presumably reflects wider anatomic damage in comporison to patients with normal HV time. The low incidence of late AV block and the electrophysiological demonstration of the stability of infranodal conduction several months after AMI indicate that these patients do not require permanent prophylactic pacing after acute myocardial infarction.     

Rhythm Discrimination by Rate Branch and QRS Morphology in Dual Chamber Implantable Cardioverter Defibrillators

BORIANI, G., et al. : Rhythm Discrimination by Rate Branch and QRS Morphology in Dual Chamber Implantable Cardioverter Defibrillators. Morphology Discrimination is a discriminator based on QRS morphology analysis that has been recently implemented in dual chamber implantable cardioverter defibrillators (ICDs). Detected events are initially classified according to median atrial and ventricular rates (Rate Branch). Then, a series of discriminators (Morphology Discrimination, Stability, Sudden Onset) analyze the rhythm according to specific criteria and the number of discriminators required for VT diagnosis (i.e., requiring "any" or "all" of the specific discriminators to indicate VT). The discriminating accuracy of the algorithm was evaluated in 645 detections recorded during the follow-up of 25 patients. The overall specificity for 397 supraventricular arrhythmias was 73.5% (292/397) with the tachycardia diagnosis criteria set to "any" and 90.9% (361/397) with the tachycardia diagnosis criteria set to "all." Sensitivity for VT was 100% and 98.7% (231/234) with the tachycardia diagnosis criteria set to "any" and "all," respectively. With the tachycardia diagnosis criteria set to "any," specificity for atrial fibrillation was 88.6%, for atrial flutter 40.3%, for atrial tachycardia 0%, and for sinus tachycardia 97.0%. With the tachycardia diagnosis criteria set to "all," specificity for atrial fibrillation was 92.40%, for atrial flutter 93.5%, for atrial tachycardia 54.7%, and for sinus tachycardia 99.0%. The contribution of Morphology Discrimination was crucial to improve the specificity of the Rate Branch algorithm. The implementation of Morphology Discrimination in a dual chamber ICD with Rate Branch rhythm classification allows the attainment of high specificity and high sensitivity for ventricular tachyarrhythmias. (PACE 2003; 26[Pt. II]:466–470)     

Low‐Risk Profile for Malignant Ventricular Arrhythmias and Sudden Cardiac Death after Surgical Ventricular Reconstruction

Background: Although it has been recently demonstrated that there was no significant difference in total survival and clinical outcomes between patients who underwent coronary artery bypass grafting (CABG) with or without surgical ventricular reconstruction (SVR), the question of whether or not SVR decreases the arrhythmic risk profile in this population has not been clarified yet. Objective: To determine the real incidence of sudden cardiac death (SCD) and sustained ventricular tachycardia/ventricular fibrillation (sustained VT/VF) in patients following CABG added to SVR and to define their clinical and echocardiographic parameters predicting in‐hospital and long‐term arrhythmic events (SCD + sustained VT/VF). Methods: Pre‐ and postoperative clinical and echocardiographic values as well as postoperative electrocardiogram Holter data of 65 patients (21 female, 63 ± 11 years) who underwent SVR + CABG were retrospectively evaluated. Results: Mean follow‐up was 1,105 ± 940 days. At 3 years, the SCD‐free rate was 98% and the rate free from arrhythmic events was 88%. Multivariate logistic analysis identified a preoperative left ventricular end‐systolic volume index (LVESVI) > 102 mL/m² (odds ratio [OR] 1.4, confidence interval [CI] 1.073–1.864, P = 0.02; sensitivity 100%, specificity 94%) and a postoperative pulmonary artery systolic pressure (PASP) > 27 mmHg (OR 2.3, CI 1.887–4.487, P = 0.01; sensitivity 100%, specificity 71%) as independent predictors of arrhythmic events. Conclusions: Our and previous studies report a low incidence of arrhythmic events in patients following SVR added to CABG, considering the high‐risk profile of the study population. A preoperative LVESVI > 102 mL/m² and a postoperative PASP > 27 mmHg had a good sensitivity and specificity in predicting arrhythmic events. (PACE 2010; 33:1054–1062)     

PANCURONIUM ALLERGY: A CASE REPORT

A case of anaphylactic shock to pancuronium bromide is describedin which a type l immunological reaction occurred. A 33-yr-oldmale anaesthetist, with no family or personal history of allergy,collapsed soon after induction of anaesthesia. The drugs usedincluded fentanyl, droperidol, thiopentone and pancuronium.Diffuse erythema occurred, with probable cardiac arrest. Thepatient was treated with cardiac massage, sympathomimetics andcortisone, and made a complete recovery. Examination (skin tests,passive transfer according to Prausnitz and Küstner, invitro lymphocyte transformation test, total lgE assay) revealedthat the allergic reaction was to pancuronium bromide.     

Characterization of Transition Sleep Episodes in Baseline EEG Recordings of Adult Rats

By scoring 5-s EEG epochs and calculating spectral power of consecutive EEG segments as short as 1 s, transition sleep (TS) episodes were identified in baseline recordings of adult rats. TS episodes were characterized by the abrupt appearance of theta and alpha waves within an ongoing period of slow-wave sleep (SS). They were followed by paradoxical sleep (PS) or, somewhat more frequently, by a period of wakefulness (W) that often led to an additional SS. Statistical values of the main variables of TS → (W) and TS → (PS) episodes are presented, together with comparable data concerning previous SS and following W or PS episodes. On the whole, TS episodes were more numerous than PS episodes, and less numerous than SS episodes. Their average duration was considerably shorter. As a consequence of the identification of TS and of brief W or PS epochs intervening within SS, the number of SS episodes was estimated to be considerably higher than previously assessed, and their average duration considerably shorter.     

Dysplastic naevus in non-familial melanoma. A clinicopathological study of 101 cases

In 101 patients with non-familial cutaneous melanoma (CM), melanocytic naevi were counted and classified according to clinical criteria. Only 8% of the patients had very atypical naevi. These atypical naevi were few in number and only one patient exhibited dysplastic naevus syndrome. An histological study was undertaken on the hypothesis that, in a given individual, if the most clinically atypical naevus is not histologically dysplastic it is unlikely that any of the others are. The most clinically atypical naevus in each patient was biopsied. Estimated in this way the prevalence of dysplastic naevi in patients with non-familial CM was only 18%. Comparison of patients with and without dysplastic naevi did not suggest that they constituted two different subsets. An attempt to correlate clinical diagnosis and histological features in this group of patients showed that the diagnosis of dysplastic naevi on the basis of clinical criteria alone is difficult and not reliable.