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Biomedical subjects

G Swiatecka

Publications and source records attributed to G Swiatecka.

At least 19 recordsLinked to original sources
PubMed2001

Shortening the second phase duration of biphasic shocks: effects of class III antiarrhythmic drugs on defibrillation efficacy in humans.

INTRODUCTION: The specific waveform providing optimal defibrillation threshold (DFT) is unknown. We compared the defibrillation efficacy of biphasic pulses with second phases (P2) of 2 and 5 msec in a randomized prospective clinical study. METHODS AND RESULTS: Intraoperative DFTs of 62 patients (age 54 +/- 13 years; ejection fraction 43% +/- 17%; amiodarone 47%, d,l-sotalol 13%) were determined in random order using a binary search protocol. Anodal shocks of 60% tilt first phases (P1) and P2 of 2 msec/5 msec were delivered from two 100-microF capacitors between the right ventricular electrode and the test housing of a Phylax 06/XM device. Mean DFT was significantly lower using the shorter P2 (9.5 +/- 4.5 J vs 11.3 +/- 5.2 J; P < 0.0001). According to subgroup analysis, the effect of changing P2 duration was only influenced by antiarrhythmic treatment. DFT decreased markedly using the shorter P2 in patients treated with amiodarone (10.7 +/- 4.9 J vs 13.4 +/- 5.6 J; P < 0.00001) or d,l-sotalol (6.1 +/- 3.3 J vs 9.1 +/- 4.6 J; P < 0.05). The difference in patients not treated with Class III drugs was found to be insignificant. Chronic amiodarone treatment increased DFT only when the longer P2 was used. CONCLUSION: Biphasic shocks with shorter P2 should be used in patients undergoing Class III antiarrhythmic treatment.

Adult↗
PubMed2001

Efficacy and safety of dofetilide in the prevention of symptomatic episodes of paroxysmal supraventricular tachycardia: a 6-month double-blind comparison with propafenone and placebo.

BACKGROUND: Existing drug therapies for paroxysmal supraventricular tachycardia (PSVT) have potentially serious adverse effects. Dofetilide, a pure class III antiarrhythmic agent, may offer an effective and safe alternative for treating PSVT. This study compared the efficacy and safety of dofetilide with that of propafenone and placebo in the prevention of PSVT. METHODS: This multicenter, randomized, placebo-controlled, parallel-group study compared the effectiveness of oral dofetilide 500 microg given twice daily with that of propafenone 150 mg given 3 times a day and placebo in preventing the recurrence of PSVT in 122 symptomatic patients. Episodes of PSVT were documented by symptom diaries and Hertcard (Hertford Medical, Hertfordshire, UK) event recorders. RESULTS: After 6 months of treatment, patients taking dofetilide, propafenone, and placebo had a 50%, 54%, and 6% probability, respectively, of remaining free of episodes of PSVT (P <.001 for both dofetilide and propafenone vs placebo). Both dofetilide and propafenone also decreased the frequency of episodes of PSVT; the median numbers of episodes in the dofetilide- and propafenone-treated groups were 1 and 0.5, respectively, compared with 5 in the placebo-treated group. Dofetilide was well tolerated; no proarrhythmia occurred. Three patients taking propafenone had serious treatment-related adverse effects that required drug discontinuation. CONCLUSIONS: Dofetilide and propafenone were equally effective in preventing the recurrence of or decreasing the frequency of PSVT.

Administration, Oral↗
PubMed2001

Assessment of baroreflex sensitivity in patients with preserved and impaired left ventricular function by means of the Valsalva manoeuvre and the phenylephrine test.

The purpose of the present study was to assess the agreement between measurements of baroreflex sensitivity (BRS) obtained by the Valsalva manoeuvre and by the phenylephrine test in patients with previous myocardial infarction and different degrees of left ventricular dysfunction. Patients with a previous myocardial infarction were enrolled consecutively into two groups according to their left ventricular ejection fraction (LVEF): 40% (n=52). All patients underwent BRS assessment by the phenylephrine technique (Phe-BRS) and by the Valsalva manoeuvre, with the latter using both the overshoot part of phase IV (Ov-VM-BRS) and the whole of phase IV (IV-VM-BRS). The linear association between methods was assessed by correlation analysis and the agreement was evaluated by computing the bias and the limits of agreement. IV-VM-BRS and Ov-VM-BRS could not be computed in 26% and 39% of patients respectively. For both indices a much higher percentage of non-computable Valsalva manoeuvre slopes was found in the group of patients with LVEF 40% the results were: r=0.91 (P<0.001), bias=0.1 ms/mmHg (P=0.84) and limits of agreement from -4.8 to 5 ms/mmHg. When comparing Phe-BRS and IV-VM-BRS, we found r=0.67 (P=0.001), bias=-1.5 ms/mmHg (P=0.06) and limits of agreement from -8.8 to 5.7 ms/mmHg in the group of patients with LVEF 40%. Dichotomizing Ov-VM-BRS, the best cut-off value to identify patients with a Phe-BRS of <3 ms/mmHg was found to be 7 ms/mmHg, giving 100% sensitivity and 69% specificity. In conclusion, estimation of BRS by the Valsalva manoeuvre in post-myocardial infarction patients is limited by a large number of non-measurable results. When computable, measurements are well correlated with those obtained by Phe-BRS, but, because of large limits of agreement, the two methods cannot be used interchangeably. If used as a screening test for risk stratification, the Valsalva manoeuvre could reduce by about one-third the need for phenylephrine injection.

Adult↗
PubMed2001

Permanent cardiac pacing and its influence on tricuspid valve function.

Implantation of transvenous devices is a widespread procedure in clinical cardiology. It is well known that the presence of the electrodes in the cardiovascular system can induce fibrosis or fibrous adhesions between them and cause tricuspid regurgitation. Moreover there are suggestions that the placement of the electrode in the tricuspid orifice may also play a role in the development of tricuspid insufficiency because of the thickening of reactive leaflets and the impairment of their mobility in morphological studies. There are no papers regarding the topography of the electrode in the right ventricle judged by means of transthoracic echocardiography. Moreover in literature we did not meet reports comparing the localisation of the lead on the tricuspid valve function. Therefore we decided to describe the detailed topographic relations between the lead and the structures of the right ventricle in a larger population and we compared the influence of the lead location for tricuspid valve function. Research was carried out on a group of 86 patients (52 M, 34 F), with a mean age of 64.7 +/- 14.9 years with permanent cardiac pacemaker or implantable cardioverter-defibrillator (ICD). On the basis of echocardiograms performed we assessed the position of the lead regarding the tricuspid valve leaflets or commissure, and judged the course of the lead beneath the tricuspid valve level. Moreover special attention was focused on the placement of the tip of the electrode. We qualified its position into three categories: apex of the right ventricle, right ventricle outflow tract, and "para-apex" position. The degree of the tricuspid valve insufficiency was assessed by means of semiquantitative method based on the Color-flow Doppler echocardiography. We measured the extension and the area of the tricuspid regurgitant jet using four-gradual scale. We compared the topography of the lead at the level of the valve with its function by means of the presence and degree of its regurgitation. We stated that in 35% of cases the pacing lead was located at the level of the anterior leaflet of the tricuspid valve, in 23% at the level of the septal leaflet and in 12% at the posterior one. Besides in 10% the electrode was placed between the leaflets just over the commissures. On the other hand in the remaining 20% the lead was positioned centrally in the right atrioventricular orifice without adherence to any leaflet. Next we assessed the course of the lead beneath the tricuspid valve level and stated that most frequently (45%) it run just across the centre of the right ventricle, and in other cases was lying along the interventricular septum (in 39% of cases) or along the anterior wall of the right ventricle (in 16%). The tip of the lead was positioned exactly in the apex of the right ventricle in 74%, in the right ventricular outflow tract in 9% and in 17% its position was "para-apical". We did not see any statistically significant differences between the presence and intensification of valve regurgitation and topography of the lead. We concluded that at the level of the tricuspid valve the lead was positioned in the anteroseptal part of tricuspid annulus and the proper apical position of the electrode's tip occurred in approximately 75% of cases. Localisation of the electrode at the level of the tricuspid orifice does not influence its insufficiency as detected by Doppler echocardiography.

Aged↗
PubMed2000

The terminal portion of the T wave: a new electrocardiographic marker of risk of ventricular arrhythmias.

Experimental studies have shown that transmural dispersion of repolarization (DoR), defined as the difference in action potential duration between mid-myocardial M-cells, epicardial, and endocardial cells is reflected in the duration of the terminal portion of the T wave (TpTe) on the surface ECG. Since DoR is an important factor associated with the propensity for reentrant arrhythmias, this study examined if TpTe may serve as a marker of risk of ventricular arrhythmias. Data from 18 patients with coronary artery disease and inducible sustained ventricular tachycardia (VT group) were compared with those of 16 survivors of myocardial infarction without inducible VT (control group). TpTe was automatically measured in each beat of 24-hour ECG recordings, and programmed ventricular stimulation was performed in the antiarrhythmic drug-free state. TpTe was expressed as the absolute interval in milliseconds, and relative to the duration of QTe (TpTe/QTe x 100%). TpTe duration was 74 +/- 14 ms in the VT group versus 63 +/- 16 ms in the control group (P < 0.004). The TpTe interval expressed as a percent of the QT interval was 21 +/- 4% in the VT group versus 17 +/- 3% in the control group (P = 0.02). In patients with coronary artery disease. TpTe was longer in patients with, versus without, inducible VT. The results of this study support the hypothesis that TpTe reflects transmural dispersion of repolarization.

Aged↗
PubMed2000

Implantation and follow-up of ICD leads implanted in the right ventricular outflow tract.

Unipolar ICD electrodes are routinely implanted at the right ventricular apex (RVA). However, inappropriate pacing/sensing parameters and/or high DFT may limit the appropriateness of the lead's implantation at the RVA. This study examined the effects on DFT of ICD leads implanted in the RVOT, attached to the high interventricular septum as an alternate location. DFT, defibrillation impedance, and sensing and pacing characteristics were measured at the time of implantation in 28 consecutive patients. Group A consisted of 12 patients in whom the ICD implantation criteria in the RVA were not satisfied, and whose lead was placed in the RVOT. Group B consisted of 16 patients with ICD electrodes implanted at the RVA. Mean DFT in group A was 11 +/- 4 J (4.5-20 J) versus 12 +/- 6 J (4-20 J) in the group B (P = 0.58). Defibrillation impedance was 81 +/- 9 omega (69-92 omega) in group A versus 77 +/- 15 omega) (46-93 omega) in group B (P = 0.43). R wave amplitude, slew rate, pacing threshold, and pacing impedance were comparable in both groups. In the perioperative period, the electrode needed to be repositioned in two patients from group A. There was no further dislodgment of RVOT defibrillation leads or other lead related complications during a follow-up of 23 +/- 9 months. The placement of ICD leads in the RVOT is an alternative to the RVA position. However, active-fixation ICD leads should be considered to limit the risk of electrode dislodgment.

Adult↗
PubMed2000

The localisation of the electrode in permanently paced heart--an echocardiographical study.

UNLABELLED: Permanent cardiac pacing is a widely applied procedure in invasive cardiology. The aim of our study was the analysis of the localisation of the tip of the pacemaker lead and its course in the right ventricle. Research was carried out on a group of 12 patients (5F, 7M), from 40 to 93 years of age (average 70 +/- 15 yrs) with permanent cardiac pacing or implantable cardioverter-defibrillator (ICD). Subsequent echocardiographic views were applied: an apical four chamber view, a subcostal one and a parasternal right ventricular inflow tract view. At the level of the tricuspid annulus the electrode was positioned: the anterior leaflet--41.7% (5 pts), the anteroseptal commissure 25% (3 pts), the posterior leaflet 8.3% (1 pt) and the septal one--8.3% (1 pt). In 16.7% (2 patients) the lead was positioned centrally in the right atrioventricular orifice. Regarding the further positioning of the electrode in the ventricle, in 41.7% (5 pts) the leads were placed along the interventricular septum, in 16.7% (2 pts) along the anterior wall of right ventricle and in 41.7% (5 pts) across the centre of the right ventricle. The tip of the lead was positioned in the apex of the right ventricle in 83.4% (10 pts). In the remaining 16.7% (2 pts) the position was not apical--in 1 patient the anterior wall of the right ventricle and in 1 patient the interventricular septum. In the VVI pacing mode the electrode did not lie on the interventricular septum. In contrast to this in 80% of patients (4 pts) having the DDD pacing mode the lead was situated on the interventricular septum on its course downwards to the ventricle. CONCLUSIONS: 1) On the level of the leaflets of the tricuspid valve the lead most often was positioned at the level of the anterior leaflet and the anteroseptal commissure. 2) Most patients had an apical localisation of the tip of the lead. 3) Differences between morphological and echocardiographic studies are related to the intravital and the two-dimensional character of echocardiography, and probably to the small population of the group examined.

Adult↗
PubMed1999

Multicenter randomized trial and a systematic overview of lidocaine in acute myocardial infarction.

BACKGROUND: More than 20 randomized trials and 4 meta-analyses have been conducted on the use of prophylactic lidocaine in acute myocardial infarction (MI). The results suggest that lidocaine reduces ventricular fibrillation (VF) but increases mortality rates in acute MI. METHODS AND RESULTS: Patients with ST-elevation MI who were examined <6 hours after symptom onset (n = 903) were randomly assigned to either lidocaine or no lidocaine and to either streptokinase and heparin or heparin alone. Lidocaine was given as 4 boluses of 50 mg each every 2 minutes, then an infusion of 3 mg/min for 12 hours, then 2 mg/min for 36 hours. We compared the incidence of in-hospital death and ventricular arrhythmias. We then performed a meta-analysis of prophylactic lidocaine in acute MI that included these and prior trial results. The rates of VF and death with and without lidocaine were calculated for each trial, then odds ratios (OR) with confidence intervals (CI) were calculated for the risk of these events overall with and without lidocaine. Patients given lidocaine in the randomized study had significantly less VF (2.0% vs 5.7% without lidocaine, P =.004) and a trend toward increased mortality rates (9.7% vs 7.0%, P =.145). Meta-analysis revealed nonsignificant trends toward reduced VF (OR 0.71, 95% CI 0.47 to 1. 09) and increased mortality rates (OR 1.12, 95% CI 0.91 to 1.36) with lidocaine. CONCLUSIONS: Lidocaine reduces VF but may adversely affect mortality rates. The routine use of prophylactic lidocaine in acute MI is not recommended.

Anti-Arrhythmia Agents↗
PubMed1999

[Recurrent ventricular fibrillation in a patient with Prinzmetal angina pectoris--case report].

The description of the case of 35 years old patient with paroxysmal ventricular fibrillation in a course of Prinzmetal angina pectoris treated unsuccessfully with antiarrhythmic drugs who required implantation of cardioverter/defibrillator. The via-venous cardioverter/defibrillator was implanted (ICD). During 6 months observation ventricular tachycardia and ventricular fibrillation occurred four times and was effectively interrupted by the cardioverter/defibrillator.

Adult↗
PubMed1998

New insight into repolarization abnormalities in patients with congenital long QT syndrome: the increased transmural dispersion of repolarization.

There is evidence from experimental studies that the time interval from the peak to the end of T-wave reflects the transmural dispersion in repolarization (electrical gradient) between myocardial "layers" (epicardial, M-cells, endocardial). Since Congenital Long QT Syndrome (LQTS) is considered to be classical disease or repolarisation abnormalities, we performed the present study to assess the transmural dispersion of repolarization in LQTS patients. The study group consisted of 17 patients: 7 LQTS pts and 10 pts from the control group. In each patient the 24-hour ECG recording was performed on magnetic tape. The interval from the peak to the end of the T-wave (TpTo) was automatically measured by Holter system during every hour as a measure of transmural dispersion of repolarisation. Thereafter the mean TpTo from 24-hours was calculated. In addition the spatial QT dispersion was measured from 12 lead ECG and 3 channel Holter tape as a difference between the shortest and the longest QT interval between leads. The values were compared between groups using the Anova test. TpTo was 79.6 +/- 9.6 ms (72-92 ms) in LQTS group and 62.4 +/- 7.5 ms (51-70) in the control group (p < 0.001). In LQTS group TpTo was significantly longer at night hours 72.5 +/- 2 when compared to day hours 87.4 +/- 8 (p < 0.01). The spatial QT dispersion was significantly higher in LQTS patients when compared to control, both in 12-lead standard and Holter ECG. Congenital long QT syndrome is associated with increase in both transmural and spatial dispersion of repolarization. The extent of prolongation of the terminal portion of QT in patients with congenital long QT syndrome is greater at night sleep hours compared to daily activity.

Adult↗
PubMed1998

Electrical atrial remodeling assessed by monophasic action potential and atrial refractoriness in patients with structural heart disease.

UNLABELLED: The present study was performed to assess the effect of induced atrial fibrillation (AF) on atrial monophasic action potentials (MAPs) and atrial refractory period (ERP) in patients with structural heart disease. An electrode MAP catheter was placed in the right atrium to continuously measure atrial potential duration (APD90) in 13 patients (coronary artery disease, 10 patients; dilated cardiomyopathy, 2 patients; hypertrophic cardiomyopathy, 1 patient) without spontaneous AF episodes. AF was induced by rapid atrial stimulation (300-1500/min). If sinus rhythm returned within 10 minutes, AF was reinduced. The atrial ERP was measured during atrial pacing at a basic cycle length of 550 ms before AF induction and after its conversion. RESULTS: The mean atrial ERP and the atrial APD90 before AF was 242 +/- 34 ms and 256 +/- 23 ms, respectively. ERP and APD90 shortening was observed after 3 minutes of AF. After 11 +/- 0.5 min (10 min 20 s-13 min 10 s) of AF, ERP and APD90 reached their minimal values of 72% +/- 13% and 71% +/- 10% of baseline, respectively. ERP and APD90 returned to their initial values within 10 minutes after conversion of AF. A tendency toward longer duration of consecutive AF episodes and facilitation of their induction was observed. CONCLUSION: The present study confirms that short episodes of AF modify the electrophysiological properties of the atria in humans. In patients with structural heart disease, induced atrial fibrillation shortens the atrial ERP as well as the atrial APD90. The changes were reversible within 10 minutes after arrhythmia termination.

Action Potentials↗
PubMed1996

[Evaluation of efficacy and mechanism of action of angioplasty and directed atherectomy assisted by intravascular ultrasonography].

Intravascular ultrasound (IVUS) is a unique method of coronary lumen visualization enabling also examination the structure of the artery wall. Aim of this study was to assess efficacy and mechanisms of action of balloon angioplasty (PTCA) and directional atherectomy by means of IVUS. IVUS examination was performed before and after mechanical revascularization procedure in 37 pts (DCA-19 pts, PTCA-18 pts). Both PTCA and DCA resulted in enlargement of the coronary artery lumen (2.29 +/- 1.19 mm2 vs 2.93 +/- 1.55 mm2) but, also external diameter of the vessel increased after the procedure (1.94 +/- 1.10 mm2 and 0.74 +/- 1.01 mm2 retrospectively). In 55.6% of cases after PTCA plaque rupture or artery wall dissection was observed, mainly in eccentric lesions (70%). IVUS allowed to recognize details of artery lumen and define efficiency of procedure. In about 15% cases decision to continue PTCA or DCA was made on the basis of IVUS images only. The mechanism in which PTCA modifies the artery lumen is diverse and depends on the structure of lesion. Factors possibly responsible for enlargement of the lumen are: stretching, squeezing and translocation of atheroma as well as cracking and dissections along the arterial wall. DCA effectiveness depends on the withdraw of the atheromatous deposit, however, in over one-half of cases also stretching has some effect.

Aged↗
PubMed1995

[Advantages and controversies regarding physiologic electrostimulation of the heart in sinus node disease].

UNLABELLED: Pacing mode in sinus node disease (SND) is one of controversies in cardiac pacing. We evaluated atrial pacing mode (AAI) in SND patients (pts). Between 1985 and 1994 AAI pacemaker was inserted in 179 pts due to symptomatic SND of varied etiology. RESULTS: The majority of pts (91.6%) were free from syncopal episodes after AAI implantation, in 15 pts (8.4%) syncopes were occasionally observed due to disturbances in pacemaker function, AVB III degrees, vaso-vagal syndrome, orthostatic hypotonia or atherosclerotic insufficiency of the cerebral circulation. In 49 (51%) out of 96 pts with brady-tachy syndrome (BTS), episodes of supraventricular tachyarrhythmia were not observed after AAI insertion and in the majority of the remaining pts the frequency of the episodes decreased significantly. Chronic atrial fibrillation developed in 5 (5.2%) pts. In some of the pts the symptoms related to chronic heart failure decreased or disappeared. A reoperation was performed in 44 (24%) pts due to electrode dislocation or fracture, atrio-ventricular conduction disturbances, an increase in pacing threshold or due to local infections. During the follow-up period 13 (7.3%) pts died of reasons unrelated to cardiac pacing therapy. CONCLUSION: In the majority of SND pts AAI pacing mode prevents from syncopal episodes caused by sinus node disfunction. It decreases the symptoms of heart failure in SND pts and stabilizes the sinus rhythm in the majority of BTS pts. Complications accompanying AAI do not post a major threat for the pts and can be easily resolved. They should by no means discourage from AAI implantation in SND.

Cardiac Pacing, Artificial↗
PubMed1993

[Hypertrophic cardiomyopathy occurring in the family. Rare coexistence with oligophrenia. Clinical examinations, cytogenetic and HLA system].

Familial hereditary ventricular hypertrophy (HCM) is classified as a genetically determined disease (autosomal dominant trait) characterized by generalized ventricular hypertrophy, specific heart sounds and echocardiography images, characteristic ECG changes. Sudden death occurs in some cases. Clinical data and laboratory findings in a family of twelve, in which three brothers (aged 17, 21 and 25) displayed typical features of hypertrophic cardiomyopathy, are presented. In addition to the HCM symptoms, all brothers displayed unique, characteristic phenotype: long upper and lower extremities, microcephaly and different in degree mental retardation. Echocardiography and Holter monitoring revealed types III and IV (according to Maron's classification) with complex ECG disturbances. In other members of the family the following changes were found: supra and ventricular arrhythmias appeared in the ECG of the mother (45 years old) in the forth decade of her life and ST disturbances ("silent ischaemia") in the ECG of the father (44 years old). Arrhythmias were present in the father's brother and sister, but without any clinical signs of HCM. Cytogenetic analysis was performed on the peripheral blood lymphocytes derived from the mother and all her sick sons--the karyotypes were normal. Additional cytogenetic studies detecting the presence of chromosome fra (16) were negative. Analyses of the HLA antigens were performed on 13 members of the three generations in the family. The HLA antigens of classes I-A, B and C were identified and results suggest some linkage between HCM and B12 (44) antigen. To our knowledge, the present study provides the first description of a family displaying simultaneously ventricular hypertrophy and a specific phenotype with mental retardation.

Adolescent↗
PubMed1993

[Left ventricular stroke volume in individuals with dual chamber pacemaker (DDD). Effect of atrioventricular delay].

UNLABELLED: Programming of atrioventricular delay in patients with dual chamber pacemaker is very important for left ventricular filling and has a consequence for its stroke volume. The aim of this study was to evaluate the influence of atrioventricular delay for left ventricular stroke volume during pacing at two different rates. The study was performed in 36 patients with DDD pacemaker aged from 30 to 81 years, mean 56.1 +/- 14.6. Using Doppler echocardiography we have assessed left ventricular stroke volume during two pacing rates (70 and 100 ppm) with four atrioventricular delays (100, 150, 200 and 250 ms). We have found statistically significant difference between stroke volume with various atrioventricular delays. During pacing rate of 70 ppm the maximal difference was 19% and 15% during 100 ppm. Comparing both pacing rates the distributions of hemodynamically optimal atrioventricular delays was also significantly different. The best atrioventricular delay from the hemodynamic point of view was 36 ms longer during 70 ppm of pacing rate than during 100 ppm (p = 0.0009). The most often optimal delay at 70 ppm was 190-200 ms, and the rarest optimal delay was 90-100 ms; during 100 ppm pacing respectively: 140-150 ms and 240-250 ms. We have observed considerable personal variability in the hemodynamic response for atrioventricular delay changing as well as in the hemodynamically optimal values of this parameter during both pacing rates. CONCLUSIONS: 1. Atrioventricular delay programming has significant influence on left ventricular stroke volume. 2. Programming of atrioventricular delay should be performed individually in every patient because of personal variability of optimal values of this parameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Complications associated with use of atrial electrodes].

The higher complication rate with atrial than ventricular leads make the physiological mode of pacing less popular. The aim of this study was to assess the complications associated with atrial leads. Between July 1985 and December 1991 we inserted 174 atrial leads in 165 patients (pts) with sick sinus syndrome or/and a-v block (AAI and DDD system respectively). A variety of different types of unipolar leads have been used: passive fixation simple or J shaped with the porous tip of vitreus-carbon (n = 49) and platinum-iridium (n = 78) or polished tip of Elgiloy (n = 18), active fixation (n = 29). The leads were manufactured by Siemens-Elema, CPI, Biotronik, Medtronic and Vitatron. All leads have similar acute electrical characteristics. The mean follow-up period lasted 28 months (12-83) until June 1992. We observed the following complications: displacement of electrode tip in 16 pts (9.7%), the disturbances of sensing in 10 pts (6%), 3rd degree of a-v block in 6 pts (5.4%) of 111 pts with AAI pacing, the exit-block in 3 pts (1.8%), suppuration in 3 pts (1.8%) in pacemaker area, various in 1 pt (0.6%). Total complication rate, which required reoperation was 20.6%. Complications associated with atrial leads implantation are not dangerous, may be easily treated and should not limit the indication for physiological pacing.

Adult↗
PubMed1992

Atrioventricular conduction disturbances in patients with sinoatrial node disease and atrial pacing.

In sinoatrial node disease (SND) atrial pacing may be limited by progression of AV block. The incidence of AV block after AAI systems implantation range, according to various authors, from 0% to 12%. The aim of this study was to examine the AV conduction disturbances that forced a change in the mode of pacing in patients with AAI pacemakers. The information was collected retrospectively from a cohort of 122 patients. The follow-up period ranged from 5 to 83 months (mean = 35). Among these patients there were 37 with sinus bradycardia and 85 with bradycardia-tachycardia syndrome. Their mean age was 63 years. Before AAI pacemaker insertion, all patients had normal AV conduction on 12-lead ECG, and all but five had a Wenckebach cycle length shorter than 500 msec. Seven out of these 122 patients (5.7%) developed symptomatic conduction disturbances (second-degree type I AV block in five, second degree type II AV block in one, and third-degree AV block in one), necessitating a change from AAI to another mode of pacing. We conclude that progression of AV block after atrial pacemaker implantation in patients with SND is infrequent and mild in the majority of cases. Intraventricular disturbances such as left anterior hemiblock represent contraindication to AAI pacing particularly in patients who may be in need of antiarrhythmic drugs.

Arrhythmia, Sinus↗