Interventional prevention of paradoxical embolism as the gold standard: End of discussion?

Paradoxical embolism is one of the predominant causes of cryptogenic stroke and interventional secondary prevention, i.e., closure of the patent foramen ovale (PFO), is a much discussed issue. This review aims to provide a complex perspective on this topic, aggregates and comments on the available data and current guidelines. Several large trials were performed, some of which proved the superiority of PFO closure over pharmacotherapy while others have not. Studies detecting significant superiority of intervention worked with disproportionately high representation of large shunts compared to the general population. Other controversies also remain, such as the lack of comparison of the effect of modern anticoagulant/antiplatelet treatment to PFO closure or the risk of developing unwanted side effects after intervention, and these are discussed in detail. PFO closure is a suitable method for secondary prevention of paradoxical embolism and, therefore, cryptogenic stroke. However, this is only true for carefully selected patient populations and such selection is of the utmost importance in deciding on interventional or conservative treatment.

Radial artery pseudoaneurysm as a rare very late complication of transradial cardiac catheterization

AIMS

Here, we report a case of very late (70+ days) development of pseudoaneurysm on the site of sheath insertion in a 60- year old woman.

METHODS

The patient underwent cardiac catheterization using transradial approach.

RESULTS

Despite the transradial approach, which is generally considered as a suitable prevention of this problem, and despite absence of any periprocedural complications, the patient developed a pseudoaneurysm after more than 70 days from the procedure.

CONCLUSIONS

In some cases, a pseudoaneurysm may develop extremely late after cardiac catheterization. Such an extremely late development of pseudoaneurysm has not been described in literature so far.

[Dabigatran etexilate in clinical practice for prevention of thromboembolic events in patients with atrial fibrillation]

Dabigatrane is the first new generation antiacoagulant that at a dose of 150 mg twice daily was, in the RE-LY study, more effective in cerebrovascular event and systemic embolisation prevention than well-controlled warfarin and had comparable or better safety profile than well-controlled warfarin. The 110 mg twice daily dose showed comparable efficacy and superior safety against warfarin. Crucial and unique among modern anticoagulants is its ability to significantly reduce ischemic as well as hemorrhagic CVEs at a dose of 150 mg twice daily. In addition, dabigatran significantly facilitates management of patients with atrial fibrillation as it does not require laboratory monitoring, has predictable pharmacokinetics, simple dosing regimen that does not require complicated dose adjustments, and does not interact with food. However, it is important to remember that it is an anticoagulant. Care should, therefore, be exercised when the treatment is indicated, renal function has to be known and it needs to be kept in mind that, as with any anticoagulant, the treatment may be associated with bleeding. However, when indication criteria are observed, the above listed advantages considered and careful patient monitoring put in place, the bleeding will be, compared to standard warfarin treatment, minimized. Key words: dabigatran - atrial fibrillation - tromboembolism.

Symptoms of advanced heart failure—A case for radiofrequency catheter ablation?

A sixty-year-old man with previous history of coronary artery disease was admitted due to progressive worsening of dyspnoea at exertion (NYHA III functional class) and no angina. Coronary angiography confirmed occlusion of the right coronary artery which was naturally bypassed by homocollaterals with TIMI 3 flow to the peripheral branches. The lesion was not technically suitable for percutaneous angioplasty. The left coronary artery was without stenosis. On echocardiography, both the left ventricle and the left atrium were dilated and hemodynamically significant mitral regurgitation was present. Surface ECG showed a left bundle branch block with repeated runs of monomorphic ventricular ectopic beats (PVC). Radiofrequency catheter ablation of the focus in the posteroseptal region of the left ventricle underneath the mitral valve was performed using electroanatomical mapping system. After the procedure, mitral regurgitation decreased and reverse remodeling of the left ventricle and the left atrium occurred with concomitant significant clinical improvement of the patient. The authors discuss several treatment strategies: mitral valve repair surgery combined with revascularization, implantation of a biventricular ICD system or elimination of the focus of monomorphic VT runs by radiofrequency catheter ablation as a possible causal approach in the treatment of PVC-induced cardiomyopathy.

Endothelial Damage and Activation of the Hemostatic System During Radiofrequency Catheter Isolation of Pulmonary Veins

AIMS

To determine the systemic thrombogenic effect of radiofrequency catheter isolation of the pulmonary veins (PVI) in the treatment of atrial fibrillation.

METHODS AND RESULTS

We studied endothelial damage marker (von Willebrand factor [vWf]), fibrinolysis markers (tissue plasminogen activator [t-PA], plasminogen activator inhibitor-1 [PAI-1]) and coagulation activation markers (D-dimer [DD]) in 30 patients (pts) undergoing PVI. Heparin was administered continuously after double transseptal puncture in all pts. Concentrations of vWf and t-PA were significantly increased after accomplishing PVI compared to the baseline values, and elevated levels persisted 24 hours later ( p < 0.01). PAI-1 levels decreased following PVI compared to the baseline levels ( p = 0.02). PAI-1 levels normalized 24 hours after the procedure. DD increased continuously during the procedure with the peak following PVI ( p < 0.01). Higher DD concentrations persisted 24 hours later ( p = 0.02). In a multivariate analysis, total procedure time correlated significantly with the peak vWf and DD concentrations, while total RF energy dose correlated only with peak vWf ( r = 0.82). Time to heparin administration correlated with DD levels prior to the first RF pulse ( r = 0.83, p < 0.01) as well as after PVI ( r = 0.75, p < 0.01). A group of patients heparinized within the first hour of the PVI procedure had normal preablation DD levels and significantly mitigated DD levels following PVI compared to the group of patients heparinized later ( p < 0.01).

CONCLUSIONS

Pulmonary vein ablations cause an increased systemic procoagulant state as reflected by fibrin turnover, fibrinolysis activation and endothelial perturbation. The activation of the coagulation cascade could be decreased by early heparin administration.

[Endothelial injury and activation of the coagulation cascade during radiofrequency catheter ablation]

GOAL OF STUDY

To identify the extent of systemic activation of the coagulation cascade and to evaluate thrombogenic effect of the radiofrequency catheter ablation.

METHODS AND RESULTS

Markers of activation of the coagulation cascade (D-dimers [DD]), markers of activation of the fibrinolytic system (tissue plasminogen activator [t-PA] and its inhibitor [PAI-1]), and markers of endothelial damage (von Willebrand factor [vWf]) were monitored in 50 patients undergoing catheter ablation. Levels of these substances were identified in time T0--at the beginning of the examination, T1--after finishing diagnostic part of the electrophysiological study, T2--after finishing all applications of radiofrequency energy, and T3--24 hours after T2. Levels of vWf were significantly elevated in time T1 compared to values in T0 (p < 0.001) and were further elevating after finishing the procedure in time T2 (p < 0.05). Levels of t-PA were also elevated in time T1, however after application of the radiofrequency energy, further increase in T2 was nonsignificant. Concentrations of PAI-1 were in time T2 significantly lower compared to T1 values (p < 0.001). Levels of DD were significantly elevated during entire procedure and elevated levels persisted even 24 hours later (p < 0.001). Levels of vWf a t-PA in time T2 correlated with total time of application of radiofrequency energy. Significantly higher activation of the coagulation cascade was identified, in patients undergoing isolation of pulmonary veins compared to patients undergoing catheter ablation of other arrhythmias. In the subgroup of patients treated with anticoagulation before the intervention elevation of DD levels in times T1 and T2 was lower compared to patients who did not undergo any treatment (p < 0.05).

CONCLUSION

The radiofrequency catheter ablations activate the coagulation cascade. Moreover, application of the radio frequency energy increases systemic thrombogenic state and this effect "depends on the dose". A risk group make patients undergoing catheter isolation of pulmonary veins.

Triple-Site Pacing in Patients with Biventricular Device—Incidence of the Phenomenon and Cardiac Resynchronization Benefit

BACKGROUND

In patients with biventricular pacing (BIV), triple-site pacing (TSP), i.e. standard biventricular cathodal pacing of the right and the left ventricle plus additional anodal capture of the right ventricle, is sometimes present.

AIMS

To evaluate the incidence of TSP phenomenon, to examine TSP-related QRS changes, and to assess the effect of TSP on intraventricular resynchronization by means of tissue Doppler imaging (TDI).

METHODS AND RESULTS

23 patients with a first generation biventricular device (Medtronic 8040) and 16 patients with a new generation device (Medtronic 8042) were evaluated to look for the presence of TSP. TSP was found in 6 patients (26%) with the Medtronic 8040 (group I) and in 13 patients (81%) with the Medtronic 8042 device (group II). QRS duration decreased by 10 to 20 ms and QRS amplitude of leads I and aVL increased in almost all patients in group I during TSP modality. In group II, QRS morphology, duration and amplitude did not change as obviously. TDI analysis of the left ventricular (LV) basal segments showed significant shortening of the systole, together with a corresponding prolongation of the diastole, at the inferior wall of the LV, during TSP compared to standard BIV in all patients ( p < 0.01). Other LV segments did not show any change. Qualitative TDI electro-mechanical activation pattern of all LV segments improved in 22%, while it remained unchanged in 72%.

CONCLUSIONS

TSP phenomenon can be identified in approximately a quarter of patients with the first-generation biventricular devices on the basis of the QRS morphology changes. In the second-generation biventricular pacemakers it can be demonstrated in the vast majority of patients. TSP may increase the effectiveness of cardiac resynchronization therapy by counteracting the regional activation delay located at the inferior wall of the LV.

[The long QT interval syndrome]

The syndrome of long QT interval frequently follows to syncope or a sudden cardiac death on the basis of originated polymorphic ventricular tachycardia of the "torsade de pointes" type. The prolongation of the QT interval in the hereditary form is based on mutation of the genes responsible for the formation of sodium and potassium channels. The authors analyze the occurrence, clinical findings, therapy and genetic and electropathophysiological connections of the most frequently occurring genotype LQT1, LQT2 and LQT3 as well as the acquired forms of the syndrome of long QT interval.

[Long-term effect of catheter ablation of ventricular tachycardia in adult patients with previous surgery of congenital heart defects. 2 case reports]

Two case reports of catheter ablation of sustained monomorphic ventricular tachycardia in two adult patients after previous surgical correction of congenital heart disease are reported. In both patients catheter ablation led to long-term elimination of ventricular tachycardia during follow-up period of 38 and 20 months.

[Treatment of atrioventricular accessory pathways using catheter ablation: analysis of immediate and long-term results at the end of the learning curve period]

Immediate and long-term results of catheter ablation of atrioventricular accessory pathways (AP) are presented.

METHOD

One hundred and seventy-one patients aged 41.8 +/- 14.4 years underwent catheter ablation of 179 AP. Right and left AP occurred simultaneously in 3 patients; thus 65 ablation procedures for 57 rights AP in 57 patients were compared with 125 ablation procedures for 122 left AP in 117 patients.

RESULTS

Including repeated procedures ablation was successful in 116 (99%) patients with left AP and in 57 (100%) patients with right AP. First catheter ablation failed in 4 (7%) patients with right AP and in 4 (3.4%) patients with left AP (p = NS). Two of these patients with left AP and all 4 pts with right AP had successful reablation. AP conduction recurred after successful ablation in 7 (12.3%) patients with right AP and in u 5 (4.1%) patients with left AP (p = 0.1). Three patients with right AP did not undergo another ablation, other 9 patients with AP recurrence had successful reablation. Procedure time during left AP ablation was shorter (159.6 +/- 70.7 vs. 183.4 +/- 75.6 min.; p = 0.02) and number of RF current deliveries was lower during left AP ablation (9.3 +/- 8.5 vs. 13.3 +/- 11.8; p = 0.008) compared to right AP ablation. Fluoroscopy time during left AP ablation (22.4 +/- 19.1 min.) did not significantly differ from that during right AP ablation (20.9 +/- 17.1 min.). Concealed AP was present in 13 (22.8%) patients with right AP and in 59 (48.4%) patients with left AP (p = 0.002). Anatomico-functional variant of AP occurred in 5 (8.8%) patients with right AP and in 4 (3.3%) patients with left AP (p = NS). Atrial fibrillation complicated ablation procedure in 9 (15.8%) patients with right AP and in 7 (5.7%) patients with left AP (p = NS). During 30.3 +/- 17 (2-60) months follow-up period tachyarrhythmia associated with the presence of an AP occurred in 3 patients with right AP and in 1 patient with unsuccessful ablation of left AP. None of these patients underwent repeated ablation.

CONCLUSION

Successful ablation of AP can be achieved successfully in 100%. Catheter ablation of right AP is generally more difficult and primary ablation failure and AP conduction recurrence is nonsignificantly more often. Irregularity of the tricuspid annulus, instability of the ablation catheter, presence of the conduction system, higher occurrence of anatomico-functional AP variants and sustained atrial fibrillation during the ablation procedure represent the main causes of this finding.

[Determination of the end-point of the radiofrequency linear lesion in the subeustachian isthmus and its relation to treatment of atrial flutter and fibrillation. Acute and long-term results in 90 patients]

Complete subeustachian isthmus (isthmus) block created with radiofrequency (RF) linear lesion eliminates type I. atrial flutter (AFL). The end-point of the procedure is measurable.

PATIENTS AND METHOD

Ninety patients (21 F) aged 57.6 +/- 12.5 years underwent RF catheter ablation for AFL. Twenty patients had significant structural heart disease (SHD). Atrial fibrillation (AF) was previously documented in 34 (37.8%) patients. Complete isthmus block served as the end-point of the procedure.

RESULTS

Following the first ablation procedure complete isthmus block was achieved in 81 (90%) patients and incomplete isthmus block in 7 (7.8%) patients. First procedure failed in 2 (2.2%) patients. AFL recurred in 6 (6.8%) patients, in 4 (4.9%) out of 81 patients with complete isthmus block and in 2 (28.5%) out of 7 patients with incomplete isthmus block. After repeated successful ablation and creation of complete isthmus block in these 6 patients and in 1 patient with previous ablation failure, complete isthmus block was achieved in 84 (93.3%) patients, incomplete isthmus block in 5 (5.6%) patients and ablation was unsuccessful in 1 patient. During 21 +/- 10.6 (6-45) month follow-up since the last ablation AFL did not recur in any of 89 (98.9%) patients with complete or advanced incomplete isthmus block. AF occurred in 39 (43.3%) patients. Incidence of AF was significantly higher in patients without SHD and with AF previously documented or induced (group 2) (25/43; 58.1%) compared to patients without SHD and no AF documented or induced (group 1) (6/27; 22.2%) (p < 0.01). AF occurred in 40% patients with SHD (group 3), which did not significantly differ from any of the former two groups of patients. In this group AF occurred in 10 out of 12 (83.3%) patients with AF documented prior to ablation, which was significantly more compared to 1 (12.5%) patient out of 8 without documented AF (p < 0.01).

CONCLUSION

Complete conduction block over the subeustachian isthmus during catheter ablation has a clearly measurable end-point and represents effective method in permanent cure of AFL. Clinical benefit is reduced by AF, particularly in patients, in whom the arrhythmia was documented prior to ablation. In these patients catheter ablation of AFL can be considered a first step to combined treatment with previously ineffective antiarrhythmic drugs and with other ablation strategies.

[Ventricular tachyarrhythmias in patients without structural heart disease. Clinical and electrophysiologic characteristics of the tachyarrhythmias and long-term results of catheter ablation]

PURPOSE OF THE STUDY

Ventricular tachyarrhythmias without structural heart disease (SHD) form a heterogeneous group of unknown mechanism and different clinical and electrophysiological behavior. Purpose of the study was to analyze clinical and electrophysiological characteristics of the arrhythmias, and immediate and long-term results of catheter ablation.

PATIENTS

Nineteen consecutive patients without SHD (7 F) aged 44.5 +/- 14.1 (18-66) years had 23 ablation procedures. Documented arrhythmias varied from incessant ventricular premature beats (1 patient) through paroxysmal nonsustained ventricular tachycardia (5 patients), incessant "repetitive" (non)sustained ventricular tachycardia (4 patients) to paroxysmal sustained ventricular tachycardia (9 patients).

METHOD

Patients underwent standard electrophysiological examination. Mapping of focal arrhythmias was guided by earliest endocardial and epicardial activation, pace-mapping or both. In 1 patient with reentry tachycardia, mapping was guided by late potential during sinus rhythm and low-voltage fractionated diastolic potential during the tachycardia.

RESULTS

Catheter ablation was performed in 19 patients and 23 ablation procedures. Mean fluoroscopy time per procedure was 25.4 +/- 16.0 (7-65) minutes. The arrhythmia was targeted in the right ventricle in 13 patients, and in the left ventricle in 6 patients. All clinically significant ectopic activity was eliminated in 14 patients and significantly reduced in other 2 patients. Ablation procedure failed in 2 patients. In 1 patient sustained monomorphic ventricular tachycardia originating in the epicardial aspect of outflow tract close to the left anterior descending artery was not ablated. During the long-term follow-up 19.2 +/- 10.9 (2-42) months 14 (73.7%) patients are free of targeted ectopic activity, symptoms, and antiarrhythmic drugs. Other 2 patients experienced significant reduction of ectopic activity and previously ineffective antiarrhythmic therapy could be reduced. Thus, the clinical benefit was enhanced to 16 (84.2%) patients.

CONCLUSION

Ventricular tachyarrhythmias in patients without SHD form a heterogeneous group of different clinical and electrophysiological behavior and different pathophysiological mechanisms. Majority of the arrhythmias can be eliminated by focal catheter ablation with high efficacy and safety. Deep intramural and epicardial origin of the arrhythmic substrate is common reason for catheter ablation failure.

[Electrophysiologic parameters determining the success of radiofrequency ablation of atrioventricular reentry tachycardia]

The main objective was to assess electrophysiological parameters which may be important for effective radiofrequency ablation of accessory atrioventricular pathways. In a group of 66 patients a total of 490 applications of radiofrequency current were made, incl. 68 which led to successful severing of the accessory pathways. The ablations were successful in 65 patients (98.5%). The potential of the accessory pathways was present in effective ablations in 19 cases of 68 applications (28%), while in ineffective ablations it was present in 13 cases of 421 applications (3%, p < 0.001). Stability of the electrogram was found in all 68 effective ablations (100%), while in ineffective ablations a stable electrogram was found in 248 cases of 323 applications (77%, p < 0.001). In unstable electrograms the ablation was not effective in any of the patients. The V-delta interval was significantly longer in successful ablations (16 +/- 14.2 ms) than in unsuccessful ones (3 +/- 19.4 ms, p < 0.001). The ventriculoatrial interval was in successful ablations significantly shorter (57.5 +/- 22.5 ms) than in unsuccessful ones (74.5 +/- 20.9 ms, p < 0.001). In 90% applications the ventriculoatrial interval was less than 70 ms. Of 10 evaluated parameters the potential of the accessory pathway, stability of the electrogram, V-delta interval (equal or < or = 0) and short ventriculoatrial intervals (equal to or < or = 70 ms) proved important parameters for successful ablation of accessory pathways.

[Radiofrequency catheter ablation of left-sided atrioventricular accessory pathways. Immediate and long-term results using the trans-aortic approach]

Catheter mapping and ablation of left accessory pathways may be difficult if the pathway fibre orientation is oblique across the mitral annulus. This is particularly true in case of concealed accessory pathway that conducts only in ventriculoatrial direction. The purpose of the study was to compare catheter ablation safety, efficacy, procedure and fluoroscopy times and number of radiofrequency energy deliveries for manifest and concealed left accessory pathways using retrograde transaortic approach. 56 patients (26 females) aged 41.6 +/- 15.1 years underwent 59 ablation procedures for 59 left accessory pathways. 25 (44.6%) patients with 27 concealed accessory pathways and additional 2 patients with a manifest pathway mappable only during retrograde conduction formed group I and were compared to 29 patients with a manifest accessory pathway mappable during ventricular preexcitation (group II). Ablation was acutely successful in all patients. Reablation was necessary for the pathway recurrence in 2 patients and for a different pathway in 1 patient. Deep femoral venous thrombosis complicated ablation in 1 patient. During the 14.9 +/- 8.2 (3-30) month follow-up period all the patients remain free of a pathway related tachyarrhythmia. Both the groups (I vs II) did not differ in procedure (180 +/- 76.7 vs. 187 +/- 75.8; p = 0.36) and fluoroscopy (25.3 +/- 18.6 vs. 33.5 +/- 24.7; p = 0.08) times (min) and number of radiofrequency energy deliveries (10.0 +/- 9.2 vs. 10.2 +/- 9.8; p = 0.46).

CONCLUSION

Transaortic approach to the left concealed accessory pathways is safe and effective in virtually 100% of patients and, compared to manifest pathways, does not prolong procedure and fluoroscopy times nor the number of radiofrequency energy deliveries.

[Accessory atrioventricular pathways with decremental conduction (Mahaim connections). 2 case reports]

The so called Mahaim connections form a relatively scarce variant of the preexcitation syndrome. Antidromic atrioventricular reentry tachycardia with wide QRS complex of LBBB morphology represents a typical clinical manifestation of the condition. Nodofascicular and nodoventricular fibres in all the probability do exist, but only rarely. Most of these accessory pathways are located on the firht free wall and conduct only antegradely and decrementally. Majority of these pathways are formed by long bundles inserting in the terminal part of the right bundle branch or in the myocardium near the right ventricular apex. In this setting traditional mapping strategy is of little use and different approaches must be employed. Only minority of these right-sided accessory pathways are short inserting in the ventricular myocardium under the tricuspid annulus. We present two case reports of patients with accessory connections exhibiting the so called Mahaim electrophysiology. In the first case, the pathway was merely an innocent bystander that, however, masked serious low intrahissian conduction disturbance. In the second case, the patient had a long-standing characteristic symptomatology due to the right anterolateral short accessory pathway which was successfully mapped and ablated.

Quality-of-life during DDD and dual sensor VVIR pacing

Twenty-one patients (mean age 68 +/- 8 years) with dual-sensor (QT+activity) DDDR pacemaker were randomly assigned to a crossover, double-blind study in order to evaluate their quality-of-life scores. All pacemakers were implanted for sick sinus syndrome (8 patients) or complete heart block (13 patients). The pacemakers were randomly programmed to VVIR or DDD pacing modes for 2-week periods and then the pacing mode was switched for another 2-week period. At the end of each period, the quality-of-life was evaluated by a questionnaire with regard to cardiovascular symptoms, physical activity, psychosocial and emotional functioning, and self-perceived health. Nineteen questions were scored 0-5 points each. Significant improvement in the mean total quality-of-life score (20.5 +/- 14.9 vs 34.8 +/- 17.4) as well as in dyspnea on effort, dizzy spells, palpitation, sweating, fatigue, lethargy, emotional functioning, and self-perceived health was observed during DDD compared to VVIR pacing. No question was scored in favor of VVIR pacing mode. Significant improvements during DDD pacing was demonstrated in all subgroups of patients (sick sinus syndrome, chronotropically competent and incompetent patients, and patients with high degree AV block). Eighteen patients preferred DDD pacing mode, while only one preferred VVIR pacing mode. Two remaining patients expressed no preference. The results suggest that DDD pacing offers better quality-of-life than dual sensor VVIR pacing in all subgroups of patients commonly indicated for pacemaker implantation.

[The effect of amidepine on induction of ventricular tachycardia using programmed ventricular stimulation]

The authors investigated the electrophysiological and antiarrhythmic properties of a new preparation from the group of antiarrhythmic drugs-Amidepine-developed in the Research Institute for Pharmacy. Repeatedly 10 patients with persistent ventricular tachycardia (PVT) which could be induced by programmed stimulation of the ventricles were examined. Nine of them had confirmed spontaneous PVT and one had a syncope of obscure etiology. After i.v. administration of Amidepine no change was observed in the length of the effective refractory period. The induction of PVT was practically affected by Amidepine and conversely the frequency of PVT after Amidepine was 230/min. vs. 217/min. without treatment which is already a statistically significant difference. From the presented results it appears that Amidepine does not influence the induction of ventricular tachycardia, and the higher frequency of induced tachycardia suggests rather a proarrhythmic effect of this preparation.

[Dual-cavity pacing for maximal work capacity in patients with a chronic high-grade atrioventricular block]

Twenty-eight patients with a grade 2 and 3 atrioventricular block and an implanted DDD pacemaker were repeatedly subjected to a bicycle ergometric test with a maximum load of the AV block (VV30), ventricular stimulation (VVI70) and DDD stimulation. The maximum work capacity and maximum heart rate achieved on VVI30 were 92 + xi 38 W and 61 +/- 27/min. The maximum work capacity increased on DDD by 49% while on VVI70 only by 22% (p < 0.00001) and the maximum heart rate increased on DDD by 185%, while on VVI70 only by 41% (p < 0.00001). The authors found a significant correlation between the increment of the maximum work capacity on DDD, as compared with that on VVI70 (d maximum work capacity) and maximum work capacity at VVI70 (r = -0.53, p < 0.01), maximum work capacity on VVI30 (r = -0.437, p > 0.03), maximum heart rate at VVI70 (r = -0.415, p < 0.004) and age (r = 0.56, p < 0.005). The d maximum work capacity was significantly higher in patients without their own ventricular activity during the load on VVI70 (28 +/- 24% vs. 13 +/- 8%, p < 0.05 (in patients who did not attain the upper frequency limit of DDD stimulation (30 +/- 25% vs. 14 +/- 9%, p < 0.004) and in patients above 60 years of age (37 +/- 26% vs. 14 +/- 10%, p < 0.002).

[Permanent variable frequency cardiac pacing: which patients with chronic complete atrioventricular block profit most?]

The authors examined 27 patients with chronic complete atrioventricular block (AVIII) and an implanted pacemaker with rate responsive pacing (RRP), controlled by atrial frequency (DDD stimulation--19 patients) or the length of the QT interval (VVIR pacing--8 patients). The loading test in AVIII ventricular stimulation 70/min (VVI 70) and RRP proved a more than double asset of MKP in RRP, as compared with VVI 70 (55.5 +/- 43.3% vs. 24.3 +/- 34.1%, p less than 0.001). The difference was greater in acquired than in congenital AVIII (27.7 +/- 18.5% vs. 8.4 +/- 4.1%, p less than 0.002) and in patients where the maximum heart rate on VVI did not exceed 70/min, as compared with the remainder (29.3 +/- 19.1% vs. 12.7 +/- 8.1%, p less than 0.002). The difference of MPK in RRP and VVI 70 was inversely correlated with MPK on VVI 70 (r = -0.412, p less than 0.03). MPK on AVIII and MTF on VVI 70 (r = -0.386, p less than 0.05). RRP in patients with AVIII thus causes a double increase of MPK, as compared with VVI pacing. A greater asset can be expected in patients with acquired AVIII, with a lower working capacity and heart rate recorded during the loading test before implantation.

[Serial testing of antiarrhythmic agents using programmed stimulation in recurrent ventricular tachycardia]

Serial testing of drugs (STL) by means of programmed electric stimulation (PES) was implemented in 41 patients with relapsing monomorphic persisting ventricular tachycardia (S-KT) of varying aetiology and severity. To reduce underrating of the action of antiarrhythmics, milder criteria were used for evaluation of the short-term and long-term effectiveness of therapy. By STL a total of 137 drugs and their combinations were tested. S-KT was not induced by 60 of them (44%) and in 35 patients (85%). In the remaining 6 patients STL could not be completed because of non-adherence of the patients to the method or because of serious proarrhythmic action of therapy. In the course of long-term follow up (mean 21 months) in positive therapy an arrhythmic episode did not occur during the first year in any of the patients, in the course of two years it occurred in 14%, in three years in 29% and in the course of four years in 33% of the patients. Treatment preventing S-KT had to be abandoned because of serious side-effects in four patients. In all of these four patients later an arrhythmic episode developed. Long-term treatment with antiarrhythmics selected by means of STL by programmed stimulation is a rational approach to pharmacotherapy of serious ventricular arrhythmias. In cases leading to combined treatment with amiodarone and antiarrhythmics class I it would be, however, better in view of the high incidence of serious effects of this treatment to use implantation of a defibrillator.

[Relative contribution of standard and physiologic stimulation for maximal work capacity in patients with complete atrioventricular block]

The influence of heart rate on the maximal work capacity was investigated in 18 patients (mean age 55 years) with a physiological pacemaker implanted on account of chronic complete atrioventricular block of different aetiology. Twelve patients with a dominating atrial sinus activity had a dual chamber DDD pacemaker and six patients with dominating atrial fibrillation or flutter had a single chamber QTVVIR pacemaker. The exercise test was made on a bicycle ergometer using three stimulation regimes in randomized order and without the patient's knowledge of the programmed mode of pacing: 1. VVI pacing with frequency of 30/min exercise on AV block, 2. VVI pacing with a frequency of 70/min, 3. Uhysiological DDD or QT pacing. Patients with atrioventricular block attained an average heart rate of 54 + 9/min and a work capacity of 81 + 31 W. During VVI pacing a mean frequency of 73 +/- 9/min was achieved (+35%, P less than 0.002) and a work capacity of 100 +/- 45 W (+24%, P less than 0.008). The load during physiological stimulation led to an increased heart rate, i.e. to 140 +/- 15/min (+169%, P less than 0.002) and work capacity to 130 +/- 52 W (+61%, P less than 0.002). The increment of work capacity was thus 2.5 times greater during physiological than during standard ventricular pacing (P less than 0.005), when compared with the work capacity of patients during AV block. A more extensive investigation is needed to identify patients who will benefit maximally from physiological pacing.

[Unstable angina pectoris and acute myocardial infarct]

In the course of nine years the authors investigated in 3570 patients hospitalized on account of acute coronary syndrome associations between unstable angina pectoris (UAP) and a acute myocardial infarction (NMI). A total of 1732 patients were admitted with UAP and 1912 patients were hospitalized on account of a NMI. In 74 patients admitted with UAP a NMI developed during hospitalization and 21 of them died from the complication of infarction. The risk of development of NMI was thus in patients admitted with UAP 4.3% and the probability of death was 1.2%. Statistical analysis did not reveal a different risk of development of infarction or death when comparing patients with UAP at rest or on exertion (p greater than 0.05). UAP preceded the development of NMI in 645 patients, i.e. in 33.7%. The great majority of infarctions (88.5%) developed in these patients before admission to hospital. The short-term prognosis of patients with UAP could thus be improved by earlier hospitalization.

[The spectrum of cardiovascular diseases at the cardiology section of the internal medicine department in Prostĕjov]

In 1981-1989 in the cardiological part of the medical department in Prostĕjov 6255 patients (mean age 62.8 years) were admitted on account of cardiovascular diseases. The most frequent cause for admission was acute coronary syndrome (57%). The hospital lethality differs markedly in new myocardial infarctions (19.5%) and unstable angina, where no death was recorded. The second most frequent disease are cardiac arrhythmias (20.5%) with a low lethality of 0.7%. These are followed by cardiac insufficiencies (incidence 9.2%, lethality 12.8%), pulmonary embolism incidence 5%, lethality 9.9%) and inflammatory heart diseases (pericarditis, myocarditis, endocarditis) with a mean incidence of 1.3% and lethality of 7.6%. The mean lethality of hospitalized cardiovascular diseases was 8%.

[Treatment of postinfarction ventricular tachycardia based on the results of programmed stimulation]

Serial testing of antiarrhythmic agents (group I and III or their combination) by means of programmed pacing using a simple protocol (1-3 premature stimuli during stimulation from the apex of the right ventricle at a rate of 100 [120] and 140/min) and milder criteria of the effectiveness of treatment (does not produce significant ventricular tachycardias of a frequency above 150/min and with a duration longer than 30 s) was performed in 21 patients with significant post-infarction ventricular tachycardia (same definition of significance). Effective treatment was found in serial testing in 17 patients, i.e. in 80%. According to the results of serial test and long-term adherence to treatment the patients were divided into two groups. Group I comprised 14 patients taking effective treatment up to the completion of the investigation and group II, seven patients, where effective treatment was not revealed during testing (4 patients) or was discontinued because of side-effects (3 patients). During long-term follow up (15.2 +/- 13.5 months) no significant ventricular tachycardias or sudden deaths were recorded in group I but in five patients of group II P less than 0.0003). A correct prediction of ventricular tachycardia or sudden death during long-term treatment was made in 19 patients, i.e. 90%. Serial testing of drugs by programmed stimulation is thus, when the above stimulation protocol is used in patients with significant ventricular tachycardia and with a myocardial infarction in the case-history, an effective method leading to a relatively low incidence of serious ventricular arrhythmic attacks.

[Experience with ablation of the bundle of His using electrical discharge]

Ablation of the bundle of His by an electric discharge was made in 10 patients (average age 64 years, range 48-80) unsuccessfully treated with 3-14 antiarrhythmic drugs or their combinations (average 8.7) on account of supraventricular tachycardia occurring repeatedly for 3-44 years (average 12.5 years). By means of a bipolar electrode inserted into the area of the bundle of His a nonsynchronized defibrillation discharge with a mean energy of 323 J (40-380) was administered. On average 2.9 discharges were used (1-9) per patient, in 1-3 sessions. The patients were followed up for a period of 15.3 months (10-19). Permanent complete a-v block was achieved in 6 patients, the remaining 4 patients are also free from complaints with have antiarrhythmic treatment. To all patients a pacemaker was implanted, four times "physiological" stimulation was used. One month after the operation the authors observed once the development of a transient phatic disorder and once the slow development of cardiac tamponade in conjunction with anticoagulant treatment, resolved by pericardial puncture. Ablation of the bundle of His by a defibrillation discharge is thus in carefully selected patients a highly effective method of treatment of stubborn supraventricular tachycardias.

[The effect of procainamide on the inducibility of ventricular tachycardia using programmed stimulation]

The effect of intravenously administered procainamide (0.5-1 g, mean 0.966 g) on the inducibility of sustained ventricular tachycardia by programmed ventricular stimulation was tested in 15 patients (12 men and 3 women, mean age 57.2 +/- 16.6 years) with confirmed sustained ventricular tachycardia. Eleven patients had a previous myocardial infarction and two had congestive heart failure. The programmed ventricular stimulation (1-3 premature stimuli following after ventricular stimulation at a rate of 100/120 and 140/min. and a number of quick stimuli with a rising frequency from the apex of the right ventricle at an intensity equal to twice the diastolic threshold) was administered before and after procainamide administration. Sustained ventricular tachycardia was induced during the controlled examination in all 15 patients (100% sensitivity). Induced ventricular tachycardia had a haemodynamically important course with a rapid onset of unconsciousness in three patients whose index of risk of ventricular tachycardia (ratio of its frequency and the ejection fraction at rest) was significantly higher than in the remaining 12 patients (9.0 +/- 2.2 as compared with 4.9 +/- 1.2). Procainamide prevented the induction of sustained ventricular tachycardia in six patients (group I), i. e. in 40%. In the remaining nine patients (group II) ventricular tachycardia induced after procainamide had a significantly lower frequency (192 +/- 34/min.), as compared with controls (214 +/- 42/min.), but its haemodynamic impact was not affected. Patients of group I had, as compared with group II, a significantly higher ejection fraction (47 +/- 14% as compared with 35 +/- 10%) and a significantly lower index of the risk of tachycardia (4.5 +/- 1.3 as compared with 6.5 +/- 2.4).(ABSTRACT TRUNCATED AT 250 WORDS)