[Implantable pacemaker-cardioconverter-defibrillator]. / A beültethetö pacemaker-cardioverter-defibrillator.

The aim of this article is to introduce the automatic, implantable cardioverter-defibrillator (AICD) device in connection with the first two cases in Hungary. At present time, the indications of the AICD implantation in the European Community are as follows: recurrent sustained episodes of ventricular tachycardia ventricular fibrillation or aborted sudden cardiac (arrhythmic) death, when the treatment of the underlying heart disease and/or the application of antiarrhythmic drugs, antitachycardia surgery (or catheter ablation procedures) proved to be unsuccessful in the prevention of the ventricular tachyarrhythmias (guided by serial intracardiac electrophysiologic testing and exercise testing), Holter monitoring. On the one hand the implantation of an AICD is not a causative treatment, on the other hand the cost of an AICD is extremely expensive. On the 8th of January, 1992, the first AICD (PCD Medtronic 7217B) implantation was performed in the Hungarian Institute of Cardiology. At the first patient with dilatative cardiomyopathy, the cardioverter defibrillator discharged successfully at 16 times. Unfortunately, the implantation of this patient with AICD could prolong his life only with months due to the rapid progression of the underlying cardiomyopathy. The second patient with AICD implantation went home after the uneventful surgery. The implanted cardioverter defibrillator unit worked properly, spontaneous ventricular tachycardia was terminated successfully. The AICD treatment considerably decreases the risk of sudden cardiac (arrhythmic) deaths.

[The role of transesophageal echocardiography in the fibrinolytic treatment of thrombosis on the artificial mitral valve]. / A transoesophagealis echocardiographia szerepe a mitralis mechanikus mübillentyü thrombosis fibrinolytikus kezelésében.

UNLABELLED: Fibrinolytic treatment of mitral mechanical prosthetic valve thrombosis is still controversial. This treatment can only be justified if the incidence and severity of complications is relatively low compared to the expected success-rate. The purpose of this study was to assess the role of transesophageal echocardiography (TEE) in the selection of patients optimally suitable for fibrinolytic therapy. Five patients are reported in whom multiplane TEE revealed mitral prosthetic valve thrombosis. Two patients presented with valve obstruction, one patient with partial obstruction and earlier embolism, one with recent peripheral embolism and in 1 patient the thrombus was an unexpected finding on routine check-up. The oldest thrombus was first seen 5 months before fibrinolysis. There was no left atrial thrombus in any of patients. The thrombus was dissolved in all cases by Streptokinase given in a 200,000 unit bolus, followed by 100,000 unit per hour within 13-72 hours. The result of fibrinolysis was assessed by transthoracic echo-Doppler exam in 2 cases, by TEE in 2, and by both in 1 patient. Transient ischemic attack occurred in one case as the complication of treatment. IN CONCLUSION: the fibrinolytic treatment of mitral prosthetic valve thrombosis based on TEE findings is an effective and safe therapeutic modality.

Clinical predictors of electrophysiologic findings in patients with syncope of unknown origin.

Unexplained syncope is a common medical problem. Intracardiac electrophysiologic studies (EPS) have been used to uncover the underlying arrhythmic mechanisms. Electrophysiologic studies are especially helpful in the management of patients with inducible tachyarrhythmias, but is of limited usefulness in those with normal EPS findings. We investigated whether clinical and noninvasive laboratory variables can predict the results of EPS in 89 patients with unexplained syncope. The prevalence of inducible ventricular tachycardia (VT) was 15%; supraventricular tachycardia, 15%; bradyarrhythmias, 41%; and normal EPS, 29%. We used multivariate discriminant function analysis to predict the results of EPS. The variables selected for identification of patients with inducible VT by this analysis include New York Heart Association (NYHA) functional class, gender, digitalis use, nonsustained VT, and atrial fibrillation. Based on our statistical model, performing EPS on 45% of the patients with unexplained syncope would result in a 90% sensitivity in detecting patients with inducible VT. The variables selected for identification of patients with normal EPS findings include: New York Heart Association functional class, heart disease, digitalis use, and intraventricular conduction. Based on this model, it would require that all but 12% of patients with unexplained syncope be studied to achieve a 90% predictive accuracy for identification of patients with normal EPS. During follow-up, recurrence rates for the different EPS categories did not differ significantly. The five-year cumulative survival among the EPS groups were as follows: VT, 37% +/- 28%; SVT, 90% +/- 9%; bradyarrhythmias, 71% +/- 10%; and normal EPS, 96% +/- 4%. Survival of the VT group differed significantly from that of the normal group. In patients with unexplained syncope, EPS findings can be predicted from clinical and noninvasive laboratory data. Mortality during follow-up relates to EPS findings.

Oral amiodarone loading therapy. I. The effect on serial signal-averaged electrocardiographic recordings and the QTc in patients with ventricular tachyarrhythmias.

The effect of amiodarone loading (1400 mg/day for 7 days) and maintenance therapy (400 mg/day) on the signal-averaged electrocardiogram (SAECG) and the QTc were evaluated in 14 patients. Daily recordings were taken for the first 7 days of loading and on the ninth, twelfth, fourteenth, and twenty-first day of maintenance therapy. All patients had inducible sustained ventricular tachycardia (VT), 10 of them had late potential (LP) positive recording, and four were LP negative during control measurements. Amiodarone loading significantly changed all SAECG indices and prolonged the QTc. Changes induced by amiodarone were present within 24 hours of administration. The time to reach peak effect varied from 6 to 9 days. The maximum increase in late potential duration (LPD) was threefold greater than the increase in filtered QRS duration or QTc (61% vs 18% vs 14%, respectively), suggesting a more pronounced effect on the reentrant pathway than on the remaining myocardium. Of the four LP negative patients, three became LP positive while receiving amiodarone. In conclusion, amiodarone affects all SAECG indices. However, the magnitude of the changes varies, being most pronounced on the LPD. Amiodarone affects the SAECG and the QTc within the first 24 hours. The time of onset of the peak effect varies from 6 to 9 days. LP negative patients with inducible VT frequently became LP positive during amiodarone therapy.

Short-term effect of coronary artery bypass grafting on the signal-averaged electrocardiogram.

Ventricular late potentials at the end of the QRS can be detected on the body surface during sinus rhythm by recording a signal-averaged electrocardiogram (SAECG). In patients with coronary artery disease, these late potentials have been shown to be markers for spontaneous or inducible ventricular tachycardia, or both. The short-term (before and 10 +/- 4 days after coronary revascularization) influence of coronary artery bypass grafting (CABG) on the quantitative SAECG variables was studied in 40 patients with chronic coronary artery disease. Twenty-five of these patients had a previous myocardial infarction. In the 15 patients without previous myocardial infarction, no abnormal SAECG indexes were recorded before CABG and no change in the quantitative SAECG variables was observed after surgery. In the patients with a previous myocardial infarction, 7 (28%) had a late potential before CABG. After CABG, 5 (71%) patients remained late potential-positive, whereas the other 2 (29%) lost their late potential. The mean values of their SAECG variables improved after coronary revascularization. In the entire group of postmyocardial infarction patients, the high-frequency QRS duration had shortened (p less than 0.01) after CABG (the other SAECG indexes did not change). The postoperative arrhythmic complications (transient atrial fibrillation, new onset of ventricular couplets) tended to be more frequent in the postmyocardial infarction group and in patients with late potentials. Our findings suggest that the reported increase in ventricular arrhythmias after CABG is probably not related to a change in the arrhythmogenic substrate for ventricular reentry but is associated with changes in the arrhythmogenic milieu.

Correlation between the signal-averaged electrocardiogram and electrophysiologic study findings in patients with coronary artery disease and sustained ventricular tachycardia.

Ventricular late potentials at the end of the surface QRS, detected on the signal-averaged electrocardiogram (SAECG) have been shown to be markers for spontaneous and/or inducible ventricular tachycardia (VT) in patients with coronary artery disease (CAD). We examined the correlations between electrophysiologic study (EPS) findings and SAECG indexes in 50 patients with chronic CAD with documented spontaneous VT/ventricular fibrillation (VF), who had either syncope (24 patients) or aborted sudden cardiac death (SCD). The prevalence of late potentials was significantly higher in the syncope patients (75%) compared with the SCD group (46%) (p less than 0.05). No correlation was found between the ventricular refractoriness and the SAECG indexes. There was a significant difference in quantitative SAECG indexes comparing the induction mode of the sustained VT/VF by single and double versus triple extrastimuli; the types of the induced VT (sustained monomorphic, sustained pleomorphic or VF, noninducible); and the cycle length of the induced sustained monomorphic VT with the high frequency QRS duration (QRSD). In conclusion, differences in prevalence and characteristics of ventricular late potentials were found between patients with syncope and with SCD. The degree of abnormality of SAECG indexes correlated with the type and the mode of induction of sustained VT. The magnitude of QRSD of the SAECG correlated with the cycle length of monomorphic VT. The above findings suggest that in patients with CAD and sustained VT/VF the SAECG variables are related to the area of reentry.

The automatic implantable cardioverter-defibrillator. Clinical experience, complications, and follow-up in 25 patients.

Twenty-five patients with recurrent ventricular tachyarrhythmias underwent implantation of an automatic implantable cardioverter-defibrillator. The mean length of follow-up was 11.9 +/- 10.8 months. Before the implantation, the patients had survived one or more cardiac arrests (mean, 1.7; range, 1 to 4) and episodes of syncope (mean, 2.2; range, 2 to 3) and had received 6.0 +/- 1.0 antiarrhythmic drug trials. The in-hospital complications included death (two patients), reoperation (one patient), intraoperative myocardial infarction (one patient), sensing-failure (one patient), infection (five patients), and pocket seroma (two patients). The posthospital complications included device failure (four patients), device deactivation (one patient), and inappropriate discharge (two patients). The device discharged appropriately in seven patients due to sustained ventricular tachycardia. During electrophysiologic measurements, the energy requirement for successful cardioversion-defibrillation was related to the type of ventricular arrhythmia induced (monomorphic or pleomorphic ventricular tachycardia or fibrillation). Ventricular tachycardia acceleration occurred in ten patients (40%). No significant changes were found in the size of the electrograms or in the cardioversion threshold during early and late follow-up measurements. Life table analysis showed a 12-month survival rate of 86% and an arrhythmic death survival rate of 100%. We confirm the improved rate of survival in this high-risk group of patients, despite significant complications.

The clinical value of the His-bundle electrogram in intraventricular conduction defects.

A study concerned with the clinical significance of the His-bundle ECG was carried out in association with upper atrial stimulation in 20 patients with intraventricular conduction defect. On the ground of the results the His-bundle ECG is regarded as a procedure of diagnostic value in intraventricular conduction defects by contributing to the accuracy of information on the severity and extent of the lesion. In the framework of published observations, including the present findings, questions relating to prognosis and to the necessity for pacing in bifascicular block are discussed.

The secondary poststimulative phase after rapid atrial pacing: its importance in the diagnosis of sinus node dysfunction.

The effect of atropine and the beta-blocker Tobanum was studied on intrinsic heart rate (IHR) and on rapid atrial pacing carried out before and after administration of the drugs. The primary and secondary postpacing parameters were examined in both circumstances. In patients with normal IHR, return to the basic heart frequency after the drugs showed an exponential characteristic while in patients with abnormal IHR, the cycles of PPC 2-10 have lost this characteristic feature. The latter was a more characteristic electrophysiological sign of sinus node dysfunction than the recovery time of the sinus node. In patients with abnormal IHR, maximum CPPC1 is sometimes normal.

Application of His bundle recording to study disorders of atrioventricular and intraventricular conduction.

This paper briefly describes the techniques available for evaluation of conduction in our catheterization laboratory. The application of the technique for recording His-bundle potentials has greatly enhanced our understanding of rhythm and conduction disturbances and has provided useful and important information in the management of atrioventricular and intraventricular conduction disorders.

Application of His bundle recording in different rhythm disturbances of the heart.

The new intracardiac electrophysiological method: His bundle electrocardiography, combined with the electrophysiological examination used in routine clinical practice, has considerably improved our knowledge of the cardiac dysrhythmias. It helps to localize the focus of the atypical junctional and other supraventricular premature beats complicated with either organic or functional intraventricular conduction disturbance. The various forms of paroxysmal tachycardias can be differentiated more exactly from each other. In pre-excitation syndrome, it has become possible to detect the abnormal pathway and to screen the patients susceptible to life-threatening arrhythmias. By means of this the diagnosis of sick sinus syndrome and estimation of its severity can be made more exactly. In addition to the diagnosis, the electrophysiological examinations connected with pharmacological tests give valuable information whether medical or pacemaker therapy should be applied. Six cases of various forms of cardiac dysrhythmias are presented to demonstrate the superiority of this method.