Aorto-caval fistulas.

The surgical repair of 16 aorto-caval (A-C) fistulas (15 male and one female patient; average age of 61.3 years) is reviewed. Fourteen fistulas were caused by aneurysm's erosion, one by iatrogenic injury, while one followed abdominal blunt trauma. The interval from presumed occurrence to diagnosis ranged from 6 h to 2 years. The presence of an abdominal bruit (87.5%) was the most reliable physical finding. Congestive heart failure was prominent in three (18.7%) cases, while severe lower extremity edema in five (31.2%). Two patients (12.5%) had hematuria, two (12.5%) renal insufficiency, while four (25%) scrotal edema. The diagnosis was not recognized before the surgery in five (31.2%) cases. In all 16 cases after transaortic suture of the fistula, aortic reconstructions were performed. Four operative deaths (25%) occurred, in patients who were not correctly diagnosed before surgery. In one case the cause of death was massive bleeding, and in three MOFS. All other patients were followed from 1 to 17 years (mean 4 years and 2 months). All grafts are patent, and there is no lower extremity venous insufficiency or pelvic venous hypertension. Surgical repair of A-C fistulas is mandatory to prevent serious complications.

[Analysis of programmed pacing rate levels in patients with the carotid sinus hypersensitivity syndrome and implanted Clarity pacemakers]. / Analiza nivoa programisane frekvencije impulsa pejsmejkera kod bolesnika sa sindromom preosetljivosti karotidnog sinusa u ugradjenim pejsmejkerom "Klariti".

New Clarity DDDR pacemaker system (Vitatron Medical B.V.) Clarity DDDR, provides an option for recognizing sudden rate drop and responding by intervention pacing until it detects the recovering. In patients in whom syncopal episodes are mainly caused by occasional drops in heart rate, Sudden Rate Drop Intervention feature intends to provide high rate intervention pacing. We have implanted 10 of these devices in our Centre, 2 of which in patients with hypersensitive carotid sinus syndrome. In patients with carotid sinus syndrome it is possible to provoke this situation by sinus caroticus massage. In both patients, we activated Sudden Rate Drop Intervention on DDD mode pacing and used protocol for testing the necessary level of sudden Rate Drop Intervention Rate. Both patients gave their informed consent to be submitted to this testing. Pacemaker software assumes rate intervention level of 110 bpm. We tested our patients for rate levels of 90 and 110 bpm. Massaging the carotid sinus during 5 seconds, we provoked sudden Rate Drop Intervention 10 times, in each patient, 5 times at intervention rate of 90 and 5 times at 110 bpm. Patients were unaware of the programmed intervention rate and were merely expected to report any different sensations experienced during the testing. In all 20 tests, pacemaker responded to sudden rate drop elicited by carotid sinus massage (100%), that was verified by selected event recordings. After the massage, no patient experienced any sensation at sudden rate drop intervention rate level of 90 bpm in a total od 10 tests (100%), while 8 of 10 messages at 110 bpm intervention rate provoked palpitations (80%). We concluded that lowering of Sudden Rate Drop Intervention Rate Level from 110 BPM to 90 BPM did not affect the reliability of system reaction, but changes of patient's awareness of heart beats. As a final conclusion, it should be said that basic prerogatives of a pacing system are: safety and efficacy with minimal energy consumption, and in this case, quality of life option that a patient practically does not feel intervention when it occurs, are all met.

Sudden rate drop intervention rate level in patients with new 'clarity' pacemakers and carotid sinus syndrome.

BACKGROUND: In patients in whom syncopal episodes are mainly caused by occasional drops in heart rate, Sudden Rate Drop intervention feature intends to provide high rate intervention pacing. New Vitatron Medical B.V. pacemaker system Clarity DDDR, provides AN option FOR recognizing Sudden Rate Drop and responding by intervention pacing until it detects the recovering. MATERIAL AND METHODS: In patients with carotid sinus syndrome it is possible to provoke this situation BY sinus carotidus massage. We have implanted 10 of these devices in our center, 2 of which in patients with hypersensitive carotid sinus syndrome. In both patients, we activated sudden rate drop intervention on DDD mode pacing and applied protocol for testing the necessary level of Sudden Rate Drop Intervention Rate. Both patients gave their informed consent to be submitted to this testing. Pacemaker software assumes rate intervention level of 110 bpm. We tested our patients for rate levels of 90 and 110 bpm. Massaging the carotid sinus during 5 seconds, we provoked Sudden Rate Drop Intervention 10 times, in each patient, 5 times at intervention rate of 90 and 5 times at 110 bpm. Patients were unaware of the programmed intervention rate and were merely expected to report any different sensations experienced during the testing. RESULTS: In all 20 tests, pacemaker responded to sudden rate drop elicited by carotid sinus massage (100%), which was verified by selected event recordings. After the massage, neither of the patients registered any sensations at sudden rate drop intervention rate level of 90 bpm in a total od 10 tests (100%), while 8 out of 10 massages at 110 bpm intervention rate provoked palpitations (80%). On the grounds of this testing, we concluded that lowering of Sudden Rate Drop Intervention Rate Level from 110 BPM to 90 BPM does not affect the reliability of system reaction, but changes patient's awareness of heart beats. CONCLUSION: As a final conclusion, it should be said that basic prerogatives of a pacing system: safety and efficacy with minimal energy consumption, and in this case, quality of life option that a patients practically does not feel intervention when it occurs, are all met.

The loss of circadian heart rate variations in patients undergoing mitral valve replacement and Corridor procedure--comparison to heart transplant patients.

We have presently demonstrated that when added to mitral valve replacement (MVR) the corridor procedure is 75% efficient in restoring and maintaining sinus rhythm in patients with chronic atrial fibrillation (AF), caused by rheumatic mitral valve disease, (follow up 13.9months). In the same patient population, we observed that the typical day-night cycle heart rate (HR) variations were lost and our present study concentrates on this subject. Heart rate variability analysis based on 24-h Holter ECG recording (StrataScan 563 DelMar Avionics) or hospital discharge (12th-14th postoperative days) was performed in 3 patient groups: Group I: Patients with a Corridor procedure added to MVR (12pts, m/f 10/2, mean age 47.3+/-7.5yr); Group II (control): with patients MVR performed through the left atrial approach, without additional antiarrhythmic procedures (10pts, m/f 3/7 mean age 51.5+/-6.7yr), and Group III: heart transplant recipients (5pts, mean age 46.4+/-11.22yr). We analyzed the hourly heart rate over 24-h period divided into three 8-h segments (07-14h; 15-22h and 23-06h). Statistical comparison of mean hourly heart rate values was made between the three time periods of Holter monitoring. The Corridor procedure performed with mitral valve replacement resulted in conversion of sinus rhythm in 75% of patients (Group I), but postoperative heart rate variability analyses based on Holter monitoring disclosed that the mean heart rate was not statistically significantly difficult between the three 8-h segments of the day-night (P>0.05). The same results were found in the group of patients after heart transplant (P>0.05). The same results were found in the group of patients after heart transplant (P>0.05). In the second group (classical MVR), statistically significant differences in mean HR variation existed between the three 8-h intervals (P<0.05), and although atrial fibrillation occurred postoperatively physiologic circadian heart rate variations were preserved. With the Corridor procedure, both atria were surgically and electrically isolated and chronotropic function of the ventricles was restored by creating a small strip of atrial tissue with isolated sinus node and atrio-ventricular node, connected to the ventricles. This technique produced heart denervation nervous system influence, producing the loss of circadian HR variations, similar to the transplanted heart.

Permanent endocardial pacing by cephalic vein access in new-borns and infants--surgical techniques.

Most centers worldwide use permanent endovenous cardiac electrostimulation in children requiring pacing whose body mass is over 10kg. The normal implantation route is via a subclavian vein puncture. In our Center, we have implanted permanent endovenous pacing systems for complete AV block in nine children with a mean body mass 7.4kg (range 2.45-10kg). The endovenous lead was placed using cephalic vein cutdown procedure. To allow 'sliding' during the child's growth, the lead was secured by absorbable sutures.

[Metabolic parameters in the evaluation of frequency-adaptive sensors in pacemakers]. / Metabolicki parametri u proceni senzora frekventno-adaptivnih pejsmejkera.

A comparison was made between metabolic parameters during exercise in patients with implanted dual sensor VVIR pacemakers. We analyzed two groups of patients with implanted dual sensor responsive pacemakers. The first group was composed of 14 patients (mean age 37.7 years) who had implanted Topaz pacemakers. The second group of 9 patients had a Legend Plus (mean age 44.7 years). A control group consisted of 54 healthy individuals (mean age 40.4 years). Testing was performed on treadmill, using a stepwise staircase loading CAEP protocol. Directly measured and mathematically calculated parameters used in assessment of metabolic impact of pacemaker function were: minute ventilation (MV), MV/body surface, MV/body mass unit, oxygen consumption, oxygen consumption/body surface, oxygen consumption/heart rate (oxygen pulse), oxygen consumption/body mass unit, carbon dioxide production, respiratory index. The majority of the observed parameters revealed no statistically significant difference between the control group and the patients with dual sensor or single sensor controlled rate response. However, oxygen pulse showed a statistically significant difference when comparing the group with single sensor controlled rate response with dual sensor controlled rate response and control group (p < 0.05). Other parameters indicating an advantage of dual sensor controlled rate were the time period of reaching anaerobic threshold (respiratory index) and exercise duration. They both displayed a statistically significant difference between dual sensor controlled rate response and single sensor rate response (p < 0.05) with no significant difference compared to control group (p > 0.05).

Multisensory principle of heart rate regulation.

We analyzed metabolic parameters during exercise in two groups of patients with implanted dual sensor VVIR. The first group was comprised of 14 patients (mean age 37.7 years) with implanted Topaz pacemakers and the second of 9 patients with a Legend Plus pacemaker (mean age 44.7 years). A control group consisted of 54 healthy individuals (mean age 40.4 years). Testing was performed on treadmill, using a stepwise staircase loading CAEP protocol. The following directly measured and mathematically calculated parameters we used in assessing the metabolic impact of pacemaker function: minute ventilation (MV), MV/body surface, MV/body mass unit, oxygen consumption, oxygen consumption/body surface, oxygen consumption/heart rate (oxygen pulse), oxygen consumption/body mass unit, carbon dioxide production, respiratory index. For the majority of the observed parameters statistically significant difference was not found between the control group and the patients with dual sensor nor single sensor controlled rate response. However, oxygen pulse showed a statistically significant difference when comparing the group with single sensor controlled rate response with dual sensor controlled rate response as well as to the control group (p < 0.05). Also, the time of reaching the anaerobic threshold, as well as the duration of the exercise test were significantly longer in dual sensor guided rate. Since these pacemakers are particularly aimed at a population of still active patients, this finding confirms their contribution to the better quality of life and justifies their use in these patients.

Absorbable suture technique: solution to the growth problem in pediatric pacing with endocardial leads.

Endocardial pacing system implantation has been performed in 15 children of mean age 37 months (ranging from 1 day to 89 months). Endocardial lead fixation was performed by means of slowly resorbable suture (Dexon) to allow spontaneous lead migration as the child grows. During a mean follow-up period of 61 months (range 17-108 months), none of the patients needed reintervention for correcting the lead length to allow growth.

Corridor procedure--surgical option for treatment of chronic atrial fibrillation in patients undergoing mitral valve replacement.

The aim of this study was to determine the effectiveness of the 'corridor' procedure when added to mitral valve replacement in restoring and maintaining sinus rhythm in patients with chronic atrial fibrillation resulting from rheumatic mitral valve disease. Twenty-two patients with rheumatic mitral valve disease and chronic atrial fibrillation with fast, irregular ventricular response were divided into two groups. In the first group (n = 12), mitral valve replacement was combined with sinus node-AV node isolation ('corridor'): in the second, control group (n = 10), mitral valve replacement was performed through the left atriotomy. The effectiveness of the 'corridor' procedure on heart rhythm was analysed by: (i) 24-h Holter monitoring performed before and during 72 h after surgery, at hospital discharge, and 2 months later; and (ii) postoperative electrophysiological studies using temporary epicardial wires on each isolated atrial compartment. Immediately after surgery and in the following 2 months, heart rate variability analysis showed significantly lower hourly ventricular rates and rate variations in the 'corridor' group compared with those of the control group (P < 0.01). A significant difference was also found when comparing postoperative to preoperative findings in the corridor group (P < 0.05). In the control group, however, no significant differences (P > 0.05) were found concerning pre- and postoperative ventricular rate variations. At hospital discharge, nine of 12 patients with 'corridor' procedure were in sinus rhythm. Control patients remained in atrial fibrillation with irregular ventricular rate. The 'corridor' procedure, when added to mitral valve replacement, prolonged surgery, but led to restoration and long-term maintenance of sinus rhythm in 75% of patients with chronic atrial fibrillation and rheumatic mitral valve disease.

Evaluation of asynchronous left ventricular relaxation by Doppler echocardiography during ventricular pacing with AV synchrony (VDD): comparison with atrial pacing (AAI).

The effect of right ventricular pacing on left ventricular relaxation was studied in 13 patients (age 62 +/- 3 years), with the atrial sensing ventricular pacing mode (VDD). A control group of similar age (64 +/- 4 years) consisted of 11 patients with atrial pacing (AAI). The timing of events was determined in both groups at similar R-R intervals (921 +/- 77 ms vs 967 +/- 37 ms). The loading conditions as estimated by peak systolic wall stress (afterload) and end-diastolic left ventricular dimensions (preload) were approximately the same in both groups. The ratio of late to early filling velocities were similar in both groups. Dominant changes were: increased preejection period (142 +/- 13 ms vs 95 +/- 15 ms); and higher velocities of isovolumic relaxation flow (60 +/- 34 cm/s vs 25 +/- 4 cm/s) in patients with ventricular pacing. The isovolumic relaxation time was longer in patients with VDD pacing (127 +/- 14 ms vs 108 +/- 12 ms). Anterior systolic interventricular septal motion (paradoxal motion) was recorded in nine patients with VDD pacing and in none of the patients with AAI pacing. Isovolumic relaxation flow was detected during atrial pacing in five (45%) patients and in 13 (100%) patients during atrial sensing ventricular pacing, indicating asynchronous left ventricular relaxation. This data shows that VDD pacing compared to atrial pacing resulted in an altered activation pattern of the left ventricle, associated with delayed onset, asynchronous contraction with interventricular septal motion abnormalities and prolonged asynchronous left ventricular relaxation with abnormal motion manifested by the presence of isovolumic relaxation flow.

Control of ventricular rate by interatrial septal incision and crista terminalis myotomy in the patients with atrial fibrillation undergoing mitral valve replacement.

The aim of the study was to analyze the effect of surgical moderation of conduction from the atrium to the atrio-ventricular (AV) node on ventricular response in 30 patients with atrial fibrillation (AF) undergoing mitral valve replacement (MVR). Besides the usual diagnostics, echocardiographic evaluation of the size of the left atrium was performed in all patients, as a parameter of stability of rhythm conversion by drugs. Surgical treatment was applied exclusively in cases where, judging by these parameters, there was little chance for drug treatment to be effective. All patients (mean age 50 years) had severe mitral valve disease (NYHA III and IV), chronic AF and irregular ventricular rate, and underwent mitral valve replacement with mechanical valve. The patients were divided into three groups of ten patients each. In group I: MVR was combined with interatrial septal incision (IASI) to study the effect of the moderation of conduction from the interatrial septum to the AV node; in group II: after MVR, IASI was combined with crista terminalis myotomy (CTM) to study the additional effect of the moderation of conduction along the crista terminalis to the AV node; in group III (control): MVR was performed through left atriotomy, without antiarrhythmic incisions. Ventricular response was studied in two phases: In the immediate postoperative period (up to 7 days), using continuous electrocardiographic (ECG) monitoring, and 2 months postoperatively, using 24 h Holter monitoring with the results compared to a preoperative 24 h recording. Postoperative AF occurred in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The etiology of syncope in pacemaker patients.

A total of 46 patients with syncopal episodes after VVI pacemaker implantation were studied. Of these, 92% had one to three syncopal episodes and 8% more than three. All underwent a thorough clinical examination, which included chest X ray, echocardiogram, neurological exam, and the following protocol: 24-hour Holter monitoring, EEG, blood pressure (BP) measurement in three positions, Doppler exam of the carotid vessels, fasting blood glucose, and head-up tilt table test (60 minutes, 60 degrees). Holter monitoring showed exit block in two patients (4.3%) and failed sensing in one (2.1%). In two patients there was unilateral slowing on EEG. Orthostatic hypotension was found in four patients (8.6%), and hypoglycemia in three insulin-dependent diabetics. An occlusive atherosclerotic plaque in the carotid artery was found in three patients (6.5%). Syncope was induced in 17 patients (36.9%) by the tilt table test, after a mean standing time of 47 +/- 11 minutes. The mean resting systolic BP of these patients was 140 +/- 24 mmHg, and fell to a mean level of 56 +/- 8 mmHg (mean systolic BP drop was 79 +/- 8 mmHg). Sixteen of these 17 patients with positive tilt table were being paced at the time of syncope and one had a spontaneous heart rate of 73 beats/min. In 14 cases (30.4%) the cause of syncopal episodes after this extensive workup remained unexplained. These results indicate that pacemaker dysfunction is not a major cause of syncopal episodes in pacemaker patients and that these are most often due to vasovagal syncope. Long-term follow-up is warranted to determine the prognostic significance of various types of syncope in pacemaker patients.