Prediction of Arrhythmic Events After Acute Myocardial Infarction Using Two Methods for Late Potentials Recording

One hundred consecutive patients recovering from an acute myocardiai infarction underwent, prior to home discharge, signal-averaged electrocardiography (ECG), left ventriculography. and 24-hour Holter ECG recording. The signal-averaged ECG was recorded and analyzed using two procedures: the orthogonal bipolar XYZ lead configuration with a bidirectional filter: and a precordial unipolar lead configuration with a uonrecursive digital filter. An abnormal signal-averaged ECG was seen in 40% of patients with the XYZ system and in 30% of patients in the precordial method, abnormal ejection fraction (< 40%) in 24% of patients and high grade ectopy activity in 22%. During the 24-month follow-up period, 12 patients (12%) had an arrhythmic event defined as either sudden death (11 patients) or sustained ventricular tachycardia (1 patient). Neither the signal-averaged ECG with the XYZ configuration, the abnormal ejection fraction, nor the high grade ectopy were able to statistically predict a higher arrhythmic event rate. The signal-averaged ECG with the precordial configuration was able to statistically predict a higher arrhythmic event rate, P < 0.03; odds ratio = 3.96. The combination of the orthogonal XYZ configuration signal-averaged ECG with the ejection fraction (P < 0.01, odds ralio = 7.33), or with ejection fraction and Holter monitoring (P < 0.06. odds ratio = 6.17) was able to predict a higher arrhythmic event rate. The combination of the precordial configuration signal-averaged ECG with the ejection fraction (P < 0.002, odds ratio = 14.4), or with ejection fraction and Holter monitoring (P < 0.06. odds ratio =10) was able to better predict a higher arrhythmic event rate. The combination of a normal or abnormal signal-averaged ECG and ejection fraction gave a sensitivity, specificity, positive, or negative value prediction of arrhythmic events of 60%, 90.6%, 37.5%, and 96%, respectively. It must be emphasized that the number of arrhythmic events during the 2-year follow-up was small and further study is required to determine the true predictive value of each method for arrhythmic events.     

Protein Losing Enteropathy as a Manifestation of Henoch-Schönlein Purpura

ABSTRACT. Gastrointestinal manifestations of Henoch-Schönlein purpura (HSP) commonly include abdominal pain and gastrointestinal bleeding. Hypoproteinemia and edema could be related to renal involvement. We report a 14-year-old boy with classical features of HSP manifestated with edema due to severe intestinal protein loss, measured by elevated fecal alpha 1 antitrypsin secretion. The protein losing enteropathy subsided with corticosteroid therapy.     

Single Lead VDD Pacing: Multicenter Study

Optimal treatment for patients with AV block and normal sinoatrial node (SA) function entails atrial sensing and ventricular pacing (VDD mode). Single-lead VDD pacing preserves AV synchrony, precludes the need to insert two leads, and makes the implanter's work simpler and quicker. Our objectives were to verify the performance of the Thera(tm) VDD pacing system (Medtronic, Inc., Minneapolis, MN, USA), and evaluate the effectiveness of its atrial sensing and its ventricular sensing and pacing. In 165 patients, 150 adults (mean age 62 ± 18 years) and 15 children (mean age 7 ± 5 years) with 1°–3° AV block and normal SA node function, a Thera VDD system (Models 8948 or 8968) was implanted. Intraoperative ventricular electrical measurements were not significantly different from those of VVI pacemakers. The mean amplitude of the atrial signal during implantation was 4.1 ± 1.9 mV. Optimal atrial signals during implantation were usually obtained in the mid or lower part of the right atrium by using a special technique. Adequate atrial measurements remained stable throughout 24 months. There was no difference between serial measurements of atrial signal amplitudes at predischarge and during follow-up visits. Reposition of the lead was done in 2 patients (1.4%), and reprogramming to VVI in 7 patients: due to atrial fibrillation in 3 (1.8%) and due to atrial undersensing in 4 patients (2.4%). Thera VDD pacing is reliable and easy to manage with dependable atrial sensing and ventricular pacing. The survival rate of VDD pacing at 2 years was 96%.     

Multivariate Analysis of Left Ventricular Mass Determinants in Adults

Echocardiographic left ventricular mass (LVM) estimates are strong predictors of subsequent mortality and cardiovascular events. It is known that blood pressure (BP), weight (WT), and age are significantly correlated with LVM. We hypothesized that stroke volume (SV) measured by Doppler echocardiography would also be correlated with LVM. Two hundred and thirteen patients referred for routine echocardiography had determination of LVM, cuff BP, and Doppler SV. Those with localized LV disease, valvular disease, or cor pulmonale were excluded. In both men and women, systolic BP (SBP) was more closely correlated with LVM than was diastolic blood pressure or mean arterial pressure, and SV was more closely correlated with LVM than cardiac output or cardiac index. Stepwise regression, followed by multiple regression showed that four variables (WT, SV, SBP, and AGE) explained 32.3% of the variability in LVM in men and 48.5% of the variability in LVM in women. WT and SV were significant determinants of LVM in both men and women. Age was also significant in men and SBP was also significant in women. For both men and women, SV was more significantly correlated with LVM than was SBP. The changes in LVM associated with 1 SD increments of SV and SBP, respectively, were 8 and 5 g for men and 13 and 11 g for women. We conclude that men and women have different patterns of variables influencing LVM. Doppler echocardiographic SV is a newly described determinant of LVM that has a greater correlation with LVM than does SBP. This study reemphasizes the importance of WT as the major determinant of LVM.     

Comparison Between Patients with and without Reliahle Ventricular Escape Rhythm in the Presence of Long Standing Complete Atrioventricular Block

The underlying heart rhythm was evaluated in 74 patients with complete atrioventricular block and had a permanent pacemaker implantation. The pacing was inhibited for 10 seconds or until the patient developed symptoms of presyncope or syncope. Fifty-six patients (74%) had a reliable escape with a mean cycle length of 2010 ± 596 msec and a mean escape interval of 2335 ± 971 msec. In 93% of these piatients the escape interval was < 4 seconds. The patients without reliable escape (24%), developed symptoms only after a mean of 7153 ± 1875 msec. The duration of the conduction disorder was longer in the patients without escape and the intraventricular conduction was slower. More patients without escape were treated with antiarrhythmic agents. Forty-eight patients were followed for 1 year and underwent at least two different studies and 13% had different results at different tests. In conclusion, patients without reliable escape have a longer history of conduction disorder, a slower intraventricular conduction, and are frequently treated with antiarrhythmic agents. Even patients with reliable escape occasionally may show a greater pacemaker dependence; therefore, they should also be considered as pacemaker dependent.     

Rocuronium (Org 9426) for Caesarean section

This was a prospective, non-randomized, multi-centre study ofrocuronium (Org 9426) in 40 elective Caesarean section patientsat full term without fetal distress. Anaesthesia was inducedwith thiopentone 4–6 mg kg^–1 i.v. and rocuronium0.6 mg kg^–1 and maintained with isoflurane and nitrousoxide in oxygen. Monitors included ECG, arterial pressure, pulseoximeter and train-of-four (TOF) produced by ulnar nerve stimulation.In all patients, full neuromuscular block at the hand indicatingthe maximum effect of rocuronium (T1 = 0) occurred at a meantime of 98.1 (SE 9.4) s. However, after 79.3 (2.9) s, excellentto good intubating conditions were achieved in 90% of patients.Injection to delivery time was 12.7 (0.9) min and the surgicalprocedure tasted 53.1 (3.5) min. After administration of rocuronium,T2 appeared after 32.7 (1.8) min (indicating duration of effect).At the end of the surgical procedure in 39 patients, glycopyrronium0.2 mg and neostigmine 1 mg were given every 5 min to antagonizeresidual neuromuscular effect. The mean dose of neostigminerequired was 1.54 (0.1) mg. Rocuronium had no clinically significanteffect on maternal heart rate or arterial pressure. After administrationof thiopentone and rocuronium in two patients, temporary erythemaoccurred, one along the site of injection and the other on thechest wall. Rocuronium had no untoward effects on the neonates,evaluated by 1- and 5-min Apgar scores, time to sustained respiration,total and muscular neuroadaptive capacity scores, acid-basestatus and blood-gas tensions in umbilical arterial and venousblood. At delivery in 32 patients, concentrations of rocuroniumin maternal venous (MV) and umbilical venous (UV) plasma were2412 (180) ng ml^–1 and 389.6 (27.8) ng ml^–1, respectively(UV/MV ratio 0.16). In 12 patients, the mean concentration ofrocuronium in umbilical arterial (UA) plasma was 271.2 (34.7)ng ml^–1 with a UA/UV ratio of 0.62. 17-Desacetylrocuronium(Org 9943), the main metabolite of rocuronium, was below thesensitivity level (25 ng ml^–1) in umbilical venous andarterial plasma; the maternal venous plasma concentration was178 (31) ng ml^–1.     

The prognosis and expected outcome of apical surgery

Clinicians should possess current knowledge about the prognosis and expected outcome of endodontic treatment, including apical surgery. This knowledge cannot be acquired by indiscriminate review of the many available studies because they vary in the level of evidence they provide. Therefore, seven studies that best comply with methodology criteria defining the levels of evidence were selected and used as the basis of this review. In spite of their methodological consistency, the outcomes reported in these studies still differ considerably, mainly because of differences in inclusion criteria. According to these studies, 37–91% of teeth can be expected to be healed, while up to 33% can still be healing several years after surgery. Importantly, 80–94% of teeth can remain in symptom‐free function, even if they are not healed. Several pre‐operative factors may influence the outcome of treatment; the outcome may be better in teeth with small lesions and excessively short or long root canal fillings, and it may be poorer in teeth treated surgically for the second time. With regard to intra‐operative factors, the choice of the root‐end filling material and the quality of the root‐end filling may influence the outcome, while the retrograde retreatment procedure clearly offers a better outcome than the standard root‐end filling. In summary, the expected outcome of apical surgery is good and therefore, before considering tooth extraction and replacement, apical surgery should be attempted when it is feasible.     

Dynamic Beat-to-Beat QT-RR Relationship During Physiotherapy Effort in Elderly Patients Without Primary Heart Disease

The ECGs from 18 patients hospitalized in a rehabilitation setting, following surgery for hip fracture, were examined to characterize the dynamic behavior of uncorrected QT interval in relation to changing RR interval during physiotherapy effort. ECG waveforms were analyzed to extract beat-to-beat QT and RR intervals using a computerized ECG Analyzer (CEA-1100). The method of defining the QT and RR intervals is based on performing multiple cross-correlations that enable rejection of artifacts from the analysis. The relationship between the RR and QT intervals was found using the following general formula QTi = cRRi-1b. Linear regression was performed on the logarithms of QT and RR measurements obtained to estimate the constant (a = log c) and the slope (b) values, reflecting the dynamic change of QT during physiotherapy effort. Having these two values, the dynamic QT extrapolated to a heart period of 1 second (QTcd) was calculated. The results were compared to the conventional corrected static QT according to the Bazzet formula (QTcs). The mean values of constants (a = log c) and slopes (b) over all patients were found to be 1.61 +/- 0.23 and 0.33 +/- 0.08, respectively, giving a QT (ms) heart-period (ms) dynamic relation of QTi = 41 x RR(i-1)0.33. The correlation between the dynamic QT and the static QT intervals was not significant. The mean values of the QTcd and QTcs intervals were significantly different (392 +/- 25 ms vs 434 +/- 28 ms; P < 0.0001). This dynamic measurement method of QT intervals may provide additional information on normal and abnormal cardiac repolarization in health and disease, helping in the diagnosis of cardiac disorders and arrhythmia risk.     

The Effect of Electrode Configuration on the Unipolar His-Bundle Electrogram

Although "unipolar electrograms" recorded from the His-bundle position have been used to help position catheters for His-bundle ablation, the techniques used to record such electrograms have not been standardized. The effects of five anode locations (right chest wall, anterior chest wall, left chest wall, posterior chest wall, and inferior vena cava) on unipolar atrial, His bundle and ventricular electrograms recorded from the His-bundle position were examined in ten patients undergoing clinical electrophysiology studies. Electrograms were recorded at filter settings of 50-500 as well as 0.05-1000 Hz. The location of the anode had no consistent effect on the amplitude, duration or morphology of any of the electrograms at either filter setting, but signals recorded with the inferior vena cava anode had the highest signal-to-noise ratio. A filter setting of 50-500 Hz decreased the amplitude of atrial (0.72 to 0.33 mV-P less than 0.01), His bundle (0.38 vs 0.32 mV-P less than 0.01) and ventricular electrograms (3.71 vs 2.01 mV-P less than 0.001) compared to a filter setting of 0.05-1,000 Hz. The filter setting did not affect electrogram duration. We concluded that the use of an electrode catheter in the inferior vena cava as the anode when recording "unipolar electrograms" from the His-bundle position yields a better signal-to-noise ratio than a skin patch on the chest and appears to be the optimal method for recording unipolar electrograms.