Biomedical subjects
Publications and source records attributed to J Pella.
In the submitted case-history the authors describe Conn's syndrome. A solitary cortical adenoma was involved manifested at first by so-called "lone" atrial fibrillation (idiopathic without organic causes). The trigger factor of the life threatening ventricular tachycardia were variable values of serum potassium and treatment of atrial fibrillation by anti-arrhythmic drugs.
Sudden cardiac death is in the majority of cases due to ventricular tachycardia (VT) developing into ventricular flutter or ventricular fibrillation. It is therefore very important to detect patients with the risk of sudden cardiac death because their mortality depends on the treatment selected. The authors tried to shift the problem of sudden cardiac death into the sphere of cardioendocrinology. They examined the serum levels of norepinephrine (NE) in 17 patients. They collected simultaneously blood samples from the left cubital vein and right atrium after 5 minutes stimulation of the apex of the right ventricle, the frequency of stimulation being 100/min. In ten patients during electrophysiological examination VT was induced (four patients had persisting VT). The authors found a declining NE serum value in the periphery and rising intracardial NE serum level after ventricular stimulation. These differences were statistically significant in patients with VT but not in patients without VT.
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On the basis of both literature data and our own experience, the review analyzes the problem of proarrhythmia. The origin of proarrhythmia is determined by: left ventricular function, coronary bloodflow, autonomous nervous system tonus, the presence of hidden lesions of the conductive system of the heart or the presence of accessory tracts, antiarrhythmic therapy or other therapy with cardiotropic preparations and the state of the internal environment. Each antiarrhythmic drug can evoke proarrhythmia. Regarding the therapy of current proarrhythmia, the competitive preference is ascribed to those antiarrhythmic drugs which are quickly eliminated. Regarding both the antiarrhythmic therapy and the possible occurrence of proarrhythmia in patients with ichaemic heart disease, the administration of Beta-blockers seems to be mostly prospective. (Fig. 3, Ref. 11).
Catheter ablation of the atrioventricular (AV) junction for due to refractory supraventricular tachycardias by means of the radiofrequency (RF) current is at present an accepted and widespread mode of therapy. Although pathomorphological findings of the early postablative period are well documented in animals, only few data are available on pathological postablative changes in humans. In this paper we present the necropsy findings in a woman who suddenly died 25 days after RF ablation of AV junction. In this case the ablative procedure has caused subendocardial necrosis revealing signs of advanced organisation with deposits of lipofuscin and haemosiderin. We have also found the necrosis of fat tissue in the vicinity of the tricuspid anulus in the stage of advanced resorption. The recent complication was the thrombotic occlusion of a small branch of coronary artery in the right atrial posterior wall causing a nonextensive acute infarction. We conclude that our findings are in agreement with the literature data on morphologic similarity of ablative lesions and reparative processes in experimental models and clinical practice. (Fig. 4, Ref. 8.)
The radiofrequency ablation (RFA) is advantageous due to gradual destruction of tissue which enables not only an interruption of conduction, but also its modification-retardation of conduction. This state is in most cases sufficient for the control of tachycardia. It is necessary to be aware that radiofrequency ablation does not coincide with barrotrauma, uncontrollable increase of temperature of electrodes and the requirement of general anaesthesis. This technique enables the RF ablation therapy: 1. ectopic atrial tachycardia, 2. intraatrial tachycardia, 3. atrial flutter of type Z by ablation of the lower posterolateral area. (Tab. 1, Fig. 5, Ref. 9.)
At the Third Medical Clinic, which acts as a cardiostimulation centre for the eastern Slovak area, in 1978 to 1994 1 581 primary implantations and 996 reimplantations of pacemakers were made. In the group of primary implantations the mean age of patients was 70.7 +/- 10.9 years, the male/female ratio was 850/731. In the group of reimplantations the mean age was 71.3 +/- 11.6 years, incl. 483 men and 513 women. There is an almost linear rise of primoimplantations. In the group of reimplantations we can observe a two-peak shape of the curve with a maximum in 1986 and in 1990. While in 1978 atrioventricular block grade III accounted for almost 90% indications for primary implantations, during subsequent years its ratio declined gradually and at present it has reached a steady level of 30-40%. The second most frequent dysrhythmia in the group is dysfunction of the sinoatrial node which in 1978 accounted for 6% of the indications, while in 1994 it accounts for 28% of the primary implantations. In 1978 only non-programmable pacemakers VVI/V00 were implanted. In 1989 on a wider scale multiprogrammable ventricular single electrode systems VVIM were introduced which in 1994 accounted for 58% of the implanted pacemakers. Stimulation with adaptable frequency (VVIR, AAIR) and physiological stimulation of two cavities incl. VDD stimulation accounted for 42% in 1994. It can be summarized that during the last five years marked extension of physiological stimulation occurred with an opportunity to select the optimal mode of stimulation, to increase reliability and keeping qualities of the implanted pacemakers and to improve the perspectives of patients needing cardiostimulation therapy.
The authors describe their own experience with the administration of recombinant alpha 2c interferon in the treatment of Loefller's endocarditis. Based on their analysis (as well as in keeping with the spares data in the literature-as a rare disease is involved), the authors consider this procedure as a qualitative advance of treatment. They consider their account as preliminary because of the short period of time, and therefore in future strict dispensary care of the patient is essential.
Ablation therapy of tachycardias refractory to pharmaceutical preparations is considered in recent years the method of choice. In the submitted paper the authors give an account of 12 years experience with ablation treatment of supraventricular tachycardias. The group comprises 23 patients, who were subjected to ablation therapy by radiofrequency current (RF) on account of relapsing supraventricular dysrhythmias, resistant to medicamentous treatment (between May 1994 and February 1996). The mean age of the patients was 60.4 +/- 9.2 years. The historical control group is formed by 13 patients who were subjected to ablation of the AV junction by direct current (DC) between March 1984 and April 1994, their mean age being 68.4 +/- 10.4 years. After DC ablation the operation was successful in 8 cases (62%) where complete AV block was achieved, while it was partially successful in two cases where modification of the conductivity was achieved (15%) and it failed in three cases (23%). The levels of AST and CK enzymes at the investigated time intervals are significantly higher than in the RF method. During RF ablation the mean duration of successful ablation sequence was 36 s, the mean energy 1 042 +/- 726 J, the median number of sequences was 10.5. In ablation of the AV junction the success was 95%. In one of two patients who were subjected to ablation of arterial flutter a relapse of tachycardia was recorded after an interval of 24 hours. Subsequently complete ablation of the AV junction was performed. In a female patient with atrioventricular reciprocal tachycardia due to a latent accessory pathway in the area of the free left ventricular wall temporarily tachycardia could not be induced, however, after discharge from hospital the paroxysms of supraventricular tachycardia with a substantially lower frequency reappeared. Comparison of the two methods does not suggest a significant difference of their effectiveness, the RF method causes, however, less extensive myocardial damage.
In the submitted case-history the authors describe a hitherto unknown proarrhythmic effect of adenosine. Adenosine was administered on account of supraventricular tachycardia and the undesirable proarrhythmic effect was so-called "sine wave-like tachycardia" and ventricular fibrillation. Proarrhythmia was resistant to electric cardioversion and resuscitation was successful probably only after the breakdown of adenosine. The very short half-life of breakdown of this antiarrhythmic is thus useful not only for antiarrhythmic strategy but, because of the possible occurrence of rare proarrhythmias, adenosine holds a preferential position among other antiarrhythmic drugs.
The administration of an implantable cardioverter-defibrillator (ICD) is the method of choice in life-threatening ventricular tachyarrhythmias. This effective non-pharmacological intervention was a great advance in the prevention of sudden cardiac death. As to ventricular tachycardias, relapsing ventricular tachycardias based on ischaemic alone need not influence ventricular tachycardia. The mechanism of ventricular tachycardia in ischaemic heart disease is reentry and therefore this arrhythmia can be terminated not only by a defibrillation discharge but also by antitachycardiac stimulation. Various types of antitachycardiac stimulation are part of modern types of ICD. Evidence of the effectiveness of antitachycardiac stimulation (electrophysiological examination) permits to use it also by the transoesophageal approach. This treatment can be very effective and we can thus overcome the period before the definite administration of an ICD, as indicated by the case described.
UNLABELLED: Intravenously administered adenosine triphosphate (ATP) converts some supraventricular tachycardias to a sinus rhythm. Temporary atrioventricular block can help with the differentiation of different forms of supraventricular tachycardia. METHOD: Twenty-one patients with different forms of supraventricular tachycardia were subjected to electrophysiological examination for diagnostic or therapeutic (ablation) purposes. During tachycardia (after 5 minutes duration) ATP Spofa was administered by the i.v. route within 3 s into the cubital vein--0.3 mg per 1 kg body weight. RESULTS: One patient had two forms of supraventricular tachycardia. In the first group with auricular fibrillation (AF, n = 10), with auricular flutter (AFL, n = 5) and with automatic auricular tachycardia (AAT, n = 1) tachycardia was not eliminated by intravenously administered ATP. In the second group the authors were always able to eliminate paroxysmal supraventricular tachycardia, AV nodal reciprocal (AVNRT, n = 4) and atrioventricular reciprocal tachycardia (AVRT, n = 2) by intravenously administered ATP. CONCLUSIONS: 1. The authors conclude that ATP exerts an antiarrhythmic effect by blocking the reentry circuit in the AV node, i.e. it converts reentry supraventricular tachycardias (AVNRT and AVRT) to a sinus rhythm after reciprocal atrial activity. 2. The effect on atria can be proarythmogenic. 3. The authors did not confirm the effect on abnormal automaticity.
The authors investigate the degree of alteration of large vessels in newly detected not treated hypertension, using a series of non-invasive indicators of vascular function and their association with selected parameters of systolic and diastolic left ventricular function in a group of 23 hypertonic patients and 23 subjects with normal blood pressure. The mean age of the examined subjects was 51.1 +/- 16.6 years. In the echocardiographic indicators a significant difference was found between the groups as regards the weight of the LV and in the ratios of amplitudes and time integrals of waves E and A of the Doppler record of transmitral flow. Comparison of functional and morphological indicators of large vessels revealed significant differences between groups as regards tension in the aortic arch, value of the elastic module (EMp), rate of pulse wave (RPVcf) and relative systolic rate of the arteriovelocitogram. Correlation analysis revealed positive relations between age, blood pressure and weight of the LV on the one hand and EMp, diameter of the femoral artery and RPVc on the other hand. The ratio of E/A waves and their time integrals displayed the same correlation with the pulse change and the tension of the aortic arch, with the peak and relative systolic rate of the arteriovelocitogram and a negative correlation with the EMp values. These results provide evidence of a reduced elasticity of the large vessels in the group of newly detected hypertonics, associated with left ventricular hypertrophy and a reduction of its diastolic function. This finding implies the necessity to focus treatment not only on normalization of blood pressure readings but to consider also other components of the hypertensive syndrome.
Atrial fibrillation (AF) is associated with a higher morbidity and mortality because of the risk of systemic or pulmonary embolism as well as the negative impact on cardiac function. The authors investigate in the submitted paper factors influencing the vulnerability of atria during transoesophageal atrial stimulation (TESP). The group comprised 68 patients with a sinus rhythm, mean age 56.9 +/- 17.9 years. Depending on the response to rapid atrial stimulation, the patients were divided into three groups. In group I (small disposition to AF) they revealed a significantly lower age, the relative thickness of the left ventricular wall assessed by echocardiography and the dimension of the left atrium, as compared with groups with a medium increased (II) and high disposition (III) for AF. In group III hypertonic changes on the fundus were found more frequently, as well as anamnestic data on hypertension, diabetes and pathological values of the recovery period of the sinoatrial node. At the same time significantly lower values of the rate of the E wave were observed and of the ratio of amplitudes and E/A integrals from the Doppler record of the mitral valve. The weight of the left ventricle and its index by groups increased, however the changes did not attain statistical significance. Indicators of left ventricular systolic function did not differ. The authors conclude that the main independent factors which determine the response to provoked AF by the TESP method are the diastolic left ventricular function documented by the Doppler method, the diameter of the left atrium, the automation of the SA node. Less important factors are left ventricular hypertrophy and age.(ABSTRACT TRUNCATED AT 250 WORDS)
The objective of the submitted prospective study was to assess the influence of intravenously administered aminophylline on the sinoatrial node. The authors examined by electrophysiological methods 20 patients (16 without dysfunction of the sinoatrial node and 4 with dysfunction of the sinoatrial node). From the investigation patients were eliminated with an apparent and obvious cause of elevated uric acid serum levels and patients where on electrophysiological examination limited values of the corrected recovery time of the sinoatrial node were found (from 650 ms to 999 ms). To all 20 patients 240 mg aminophylline were administered by the i.v. route with in 2 mins. The following parameters were recorded: age, serum level of uric acid, basal heart rate in ms, corrected recovery time of the sinoatrial node in ms, heart rate and corrected recovery time of the sinoatrial node 5 min after completed administration of aminohpylline in ms. As regards age and uric acid serum levels there was no significant difference between dysfunction of the sinoatrial node and normal function of the sinoatrial node. Intravenously administered aminophylline hastened significantly the heart rate in patients without dysfunction of the sinoatrial node (p < 0.05). The value of the corrected recovery time of the sinoatrial node was shorter but the difference was not statistically significant. In patients with dysfunction of the sinoatrial node aminophylline did not affect the heart rate and corrected recovery time of the sinoatrial node.
The authors present a group of 67 patients, mean age 63 +/- 15 years, where they applied on account of suspected dysfunction of the sinoatrial node (SA) the atropine test (AT), 24-hour Holter monitoring and transoesophageal stimulation of the atria (TESP). The objective of the investigation was to test the reliability and yield of the mentioned methods and to investigate more closely the relations of their final indicators. Correlation analysis revealed a positive relationship between the maximal frequency during AT and the mean daily (r = 0.553, p < 0.001) and minimal frequency during Holter monitoring (r = 0.349, p < 0.0025). The recovery periods of the SA node were negatively related to the mean, minimal and maximal frequency during Holter monitoring. The relative rise of SF during the atropine test did not correlate with any Holter parameter nor with the recovery periods of the SA node. The length of the pause (Holter) did not correlate with any of the evaluated parameters. Based on the mentioned findings, the authors conclude that the diagnostic value of the mentioned non-invasive tests, when used separately, is limited but increases when the tests are combined.
The authors submit a retrospective analysis of 140 patients with an affection of the sinoatrial node who had a permanent cardiac pacemaker. The analysis comprises an 18-month period; the patients were from the eastern Slovakian region. The authors emphasize different affections of the sinoatrial node and discuss various ways of permanent cardiac pacing and other types of non-pharmacological treatment (e.g. electric ablation). Diseases of the sinoatrial node account for as much as 40% of implantations of a permanent pacemaker on account of bradyarrhythmia. At the clinic this implies a quantitative increase of cardiac pacing on account of diseases of the sinoatrial node by 18%, as compared with a previous period (e.g. the average for 1978-1987). A qualitative change is the introduction of physiological permanent cardiac pacing.
The aim of the paper was to assess the contribution of transesophageal atrial stimulation in bradyarrhythmic derangements of the heart rhythm. The main purpose was to make the diagnostic simpler and safer. Since the series of patients involved is small, our results are to be considered as a preliminary report. (1) When only dysfunction of the sinoatrial node is involved, the method yields results comparable to those obtained by invasive electrophysiological examination. Compared to the latter, invasive approach, the great advantage of the presented method is its repeatability and simplicity. (2) Greater caution is required on evaluating the conductivity, as it can not be reliably determined in the His-Purkinje system. (Tab. 2, Fig. 5, Ref. 12.)