[Interatrial and atrioventricular conduction in dual chamber stimulation]. / Interatriální a atrioventrikulární vedení u dvoudutinové stimulace.

SAMPLE AND METHODOLOGY: 111 patients (54 men) with atrioventricular stimulation of an average age 56.5 +/- 14.3 were examined. Permanent cardiostimulation was indicated in 56 patients for sick sinus syndrome and in 55 patients for complete AV blockade. Average LV EF was 52.1 +/- 5.7% and LA endsystolic dimension was 39.8 +/- 4.0 mm. All patients were done esophageal electrocardiography under synchronous atrioventricular stimulation regimen. Values of interatrial conduction were compared in relation to placement of stimulation electrode in atrium. RESULTS: Interatrial conduction in the whole sample was 79.8 +/- 19.5 (40-150) ms, for placement of an electrode in heart auricle, in lateral or in anteroseptal wall of the right atrium it was 79.9 +/- 17.9 ms, 108.3 +/- 16.3 ms, 61.5 +/- 16.2 ms. Difference between programmed AV interval and AV interval set up via esophageal electrocardiography was 40.9 +/- 19.7 (5-95) ms. Value of interatrial conduction in the monitored sample depended on placement of the electrode in atrium and the size of the left atrium (r = 0.24, p < 0.009). We did not prove relation of the interatrial conduction value to LV EF or indication diagnosis. CONCLUSION: Interatrial conduction affects value of the real AV interval in atrioventricular stimulation, depends on placement of stimulation electrode in atrium and on the size of the left atrium. Interatrial conduction can be assessed via esophageal electrocardiography.

Prognostic value of the amount of dysfunctional but viable myocardium in revascularized patients with coronary artery disease and left ventricular dysfunction. Investigators of this Multicenter Study.

OBJECTIVES: The purpose of our study was to assess the prognostic importance of the amount of dysfunctional but viable myocardium in revascularized patients with coronary artery disease (CAD) and left ventricular (LV) dysfunction. BACKGROUND: The amount of dysfunctional but viable myocardium predicts the functional improvement after revascularization and may offer more precise risk stratification of patients referred for bypass surgery or coronary angioplasty. METHODS: Two hundred and seventy-four consecutive patients with CAD and LV ejection fraction < or =40% underwent low-dose dobutamine echocardiography for viability assessment. One hundred and thirty-three of them were revascularized using either coronary artery bypass surgery (118 patients) or coronary angioplasty (15 patients) and entered this study. To quantify the amount of dysfunctional but viable myocardium, wall motion was scored using 16-segment model. The dysfunctional segments were defined as viable if they exhibited improvement in their thickening by at least 1 grade with dobutamine infusion. The patients were followed up for a mean period of 20+/-12 months (range, 2 to 48) for cardiac mortality and nonfatal cardiac events including myocardial infarction, unstable angina pectoris requiring hospitalization and hospitalization for heart failure. Standard follow-up echocardiography was performed 3 to 6 months after revascularization. RESULTS: Twenty-nine patients exhibited a large amount of dysfunctional but viable myocardium (> or =6 segments, group A), 60 patients had a small amount of dysfunctional but viable myocardium (2 to 5 segments, group B) and 44 patients were found to have dysfunctional myocardium irreversibly damaged (group C). Similar prerevascularization LV ejection fractions of 35%+/-5%, 34%+/-4%, 36%+/-4% in groups A, B and C increased to 47%+/-6% (p < 0.01 vs. baseline, p < 0.01 vs. groups B and C), to 40%+/-5% (p < 0.01 vs. baseline) and to 37%+/-6% (p = NS vs baseline), respectively, after revascularization. The greatest functional improvement after revascularization in group A patients was accompanied by a lower rate of cardiac events during follow-up (2 vs. 18 in group B, p < 0.05, and vs. 17 in group C, p < 0.01) and better cardiac event-free survival according to Kaplan-Meier survival analysis (p < 0.05 vs. groups B and C, respectively). CONCLUSION: In revascularized patients with CAD and moderate or severe LV dysfunction, the presence of a large amount of dysfunctional but viable myocardium identifies patients with the best prognosis.

[Non-invasive programmed transthoracic ventricular stimulation]. / Neinvazívní programovaná transtorakální stimulace komor.

In 10 healthy volunteers programmed transthoracic stimulation of the ventricles was performed using two commercially available non-invasive pacemakers. The connection of the oesophageal stimulator SP-5 with the transthoracic ventricular stimulator NP-4D made it possible to obtain a two-lead ECG tracing without artefacts. The quality of the obtained tracings (surface tracing and oesophageal tracing) made it possible to assess accurately the ventriculo-atrial conduction. The examinations performed indicate the practical use of combined oesophageal and transthoracic stimulation during non-invasive diagnosis.

[Long-term effect of drug therapy in supraventricular dysrhythmia evaluated by diagnostic esophageal cardiac pacing]. / Dlouhodobý efekt medikamentózní lécby supraventrikulárních dysrytmií stanovený pomocí diagnostické jícnové kardiostimulace.

The authors investigated the long-term therapeutic effect in 33 patients after a medicamentous reversal of recent atrial fibrillation and 18 patients after reversal of an attack of supraventricular tachycardia (SVT). None of the patients had signs of cardiac failure. A change to sinus rhythm was achieved in the group with atrial fibrillation by digoxin with verapamil, in the group with SVT by verapamil. Treatment was then adjusted, based on testing by means of diagnostic oesophageal pacing. The basic drug for long-term use in atrial fibrillation was digoxin either as monotherapy or in combination; the majority of patients with SVT had verapamil treatment. At the end of the period 24.5 +/- 8.4 (12-36) months after the reversal in the group with atrial fibrillation 8 (25.8%) had permanent atrial fibrillation or different therapy on account of atrial fibrillation; short-term attacks of palpitation were recorded during the investigation period in 16 (51.6%), and the remaining 7 patients (22.6%) had no complaints. In the group with SVT none of the patients was hospitalized on account of persisting dysrhythmia and it was not necessary to alter treatment. Testing treatment of supraventricular dysrhythmias by means of diagnostic oesophageal pacing is of prognostic importance and the authors consider it the method of choice.

[Comparison of the properties of spot and ring electrodes in transesophageal cardiac pacing]. / Srovnání vlastností bodové a prstencové elektrody pri jícnové kardiostimulaci.

The authors compare diagnostic oesophageal pacing of the left atrium by a ring and spot electrode using poles with an area of 20 mm2 oriented towards the left atrium. The examination was made in 15 volunteers, aged 37 +/- 5 years (range 28-43 years). In different depths of the oesophagus the threshold of stimulation was assessed (PS) and the threshold of perception of stimulation (PV) of the left atrium. At each of the examined levels the amplitude of waves A and V was determined as well as the A/V ratio. The change from a ring to a spot electrode reduces the PS from 12.2 +/- 2:3 (8.0-15.0 O) mA to 8.0 +/- 1.3 (6.0-10.0) mA. When the spot electrode is used, the difference between PS and PV is markedly reduced; one third of the examined subjects can be stimulated without subjective perception. The amplitude of the A wave recorded by means of the spot electrode was not reduced, as compared with the ring electrode and the optimal A/V ratio above 2:1 was recorded by the spot electrode on a longer section of the oesophagus. Evidence was also provided that the lowest PS is 3-4 cm beneath the site of recording of the maximum amplitude of wave A.

[Noninvasive evaluation of hemodynamics in changes in the atrioventricular interval in patients with dual-chamber pacemakers]. / Neinvazivní hodnocení hemodynamiky pri zmene sínokomorového intervalu u nemocných s dvoudutinovými stimulátory.

The authors evaluated in 19 patients with Dual Chamber pacemakers, using pulsed Doppler echocardiography, changes of the cardiac output after stimulation type DDD with an A-V interval of 100, 150, 175 and 200 ms. They evaluated also haemodynamic changes when changing the stimulation programme type DDD to ventricular stimulation type VVI. The group of patients was characterized by a left ventricular ejection fraction of 50.3 +/- 9.1%, a dimension of the left atrium of 37.1 +/- 5.6 mm and a end diastolic left ventricular dimension of 52.8 +/- 3.9 mm. The highest values of the cardiac output were recorded in 11 patients with an A-V interval of 175 ms, in 7 patients at 150 ms and in one patient at 200 ms. The difference of the cardiac output between the haemodynamically optimal and pessimal A-V interval assessed for individual patients during stimulation type DDD was 15.5 +/- 9.5%. The difference of the cardiac output during a change of stimulation type DDD with a haemodynamically optimal A-V interval to ventricular stimulation type VVI was 22.8 +/- 8.3%. Doppler echocardiography is a satisfactory non-invasive method for the evaluation of haemodynamic changes when assessing optimal parameters in patients with multiprogrammable dual chamber pacemakers.

[Testing the effectiveness of drug therapy in supraventricular dysrhythmias using diagnostic esophageal cardiac stimulation]. / Testování úcinnosti medikamentózní lécby supraventrikulárních dysrytmií pomocí diagnostické jícnové kardiostimulace.

The authors examined 33 patients aged 59.9 years with a new atrial fibrillation and 18 patients aged 45.6 years with attacks of supraventricular tachycardia. After medicamentous change to a sinus rhythm (in fibrillation after digoxin and verapamil i.v. and in supraventricular tachycardia after verapamil i.v.) the patients were changed to oral antiarrhythmic drugs. The method of diagnostic oesophageal stimulation was used after saturation with the oral form to test the effectiveness of long-term treatment. In the author's opinion the basic drug in atrial fibrillation is digoxin, possibly combined with verapamil or quinidine. In supraventricular tachycardia the basic drug is verapamil, in particular in case of a double AV node pathway. In the majority of patients combined treatment is indicated, selected individually by means of diagnostic oesophageal stimulation. The authors consider the described method due to its innocuous and repeatable character as the method of choice for optimization of antiarrhythmic treatment of supraventricular dysrhythmias.

[Esophageal stimulation of the heart: importance of the artifact inhibition system impulse in the quality of the ECG tracing from the stimulating electrode in the esophagus]. / Jícnová stimulace srdce: význam systému tlumení artefaktu stimulacního impulsu pro kvalitu EKG-záznamu z jícnové stimulacní elektrody.

The use of diagnostic possibilities of oesophageal stimulation of the heart depends on obtaining a readable and stable electrocardiogram from the stimulating electrode. The objective of the evaluating the importance of the electronic system eliminating the artefact of the stimulating impulse from the oesophageal tracing was to compare the quality of records obtained by the new and the traditional method. For stimulation an oesophageal cardiostimulator SP-5 manufactured by OBR, TEMED Zabrze was used. The atria and ventricles were stimulated by a fixed frequency and individual timed stimuli. In 58 subjects the tracings of the oesophageal ECG during stimulation of the atria were compared and in 45 subjects during oesophageal stimulation of the ventricles. The quality of the obtained tracings was evaluated by four grades where the first three grades include tracings not suitable for diagnostic interpretation. Contrary to the traditional method, the new method for obtaining tracings made it possible to obtain tracings the quality of which was in all instances suitable for interpretation. The assembled results provide evidence, due to the new system of recording, that there are great opportunities to extend diagnostic possibilities of oesophageal stimulation of the heart.