Hemodynamic effects of left ventricular pacing site in an animal model of heart failure.

BACKGROUND: This study investigates how different left ventricular epicardial and endocardial pacing sites influence hemodynamic performance in an animal model of heart failure (HF). METHODS: In six adult sheep, dilated HF was induced by rapid pacing. Subsequently, endocardial left ventricular stimulation was performed using a 64-electrode basket catheter. Epicardial pacing was achieved with temporary electrodes. RESULTS: Baseline cardiac output (CO) was 2.7 +/- 0.4 l/min and improved significantly with lateral wall epicardial and endocardial stimulation (3.6 +/- 0.7 and 3.8 +/- 0.65 l/min), whereas right ventricular pacing led to lower CO (2.1 +/- 0.5 and 2.0 +/- 0.9 l/min). In the optimal pacing location arterial pressure, pulmonary capillary wedge pressure (pcwp) and LV diameters improved significantly. Right ventricular pacing impaired hemodynamics, while no change was observed in the LV inferior wall and apex pacing. CONCLUSION: Endocardial and epicardial pacing of the lateral wall led to an improvement in LV function while right ventricular pacing induced a further reduction of LV performance. As this optimal pacing site cannot always be reached via the coronary sinus, surgical implantation of epicardial electrodes should be considered in all non-responding patients.

[Ambulatory electrocardioversion of atrial fibrillation by means of biphasic versus monophasic shock delivery. A prospective randomized study]. / Ambulante Elektrokardioversion von Vorhofflimmern mittels biphasischer versus monophasischer Schockabgabe. Eine prospektiv randomisierte Studie.

Transthoracic electrical cardioversion using a monophasic waveform is the most common method converting persistent atrial fibrillation into sinus rhythm. Recently, cardioversion with a new biphasic waveform has shown promising results for treatment of atrial fibrillation. We undertook a randomized prospective trial comparing the efficacy and safety of the two waveforms for ambulatory cardioversion of atrial fibrillation. A total of 118 consecutive patients (mean age 62 years [SD 11]) presenting with persistent atrial fibrillation (mean duration 8 months [SD 11]) for ambulatory electrical cardioversion were randomized to receive either monophasic (n = 57) or biphasic shocks (n = 61). We used a standardized step-up protocol with increasing shock energies (100-360 joules) in either group. In all patients an anterior-posterior shock electrode position was used. If sinus rhythm was not achieved with the third (360 joules) shock, cardioversion was repeated with the opposite waveform. The two groups did not differ in demographic or disease-related data. The success rate was 100% for the biphasic and 73.7% for the monophasic waveform (p < 0.001). Biphasic patients required fewer shocks (1.5 versus 2.9) and a lower mean cumulative energy (203 versus 570 joules) (p < 0.001). Twelve out of 15 unsuccessfully treated monophasic patients were converted with biphasic shocks. The success rate for all 118 patients was 97.5%. No major acute complications were observed. For ambulatory transthoracic cardioversion of persistent atrial fibrillation biphasic shocks are of greater efficacy and require less energy than monophasic shocks. The procedure can be performed ambulatory and is safe regardless of shock waveform used.

[Acute hemodynamic effects of biventricular and left ventricular pacing in chronic pacemaker-dependent patients with advanced heart failure]. / Akute hämodynamische Effekte einer biventrikulären und linksventrikulären Stimulation bei Patienten mit fortgeschrittener Herzinsuffizienz unter einer chronischen Herzschrittmachertherapie.

The beneficial hemodynamic effects of cardiac resynchronization in patients with intraventricular conduction delay have been demonstrated. The potential hemodynamic effects of cardiac resynchronization to compensate the pacing-induced left ventricular conduction delay in chronically paced heart failure patients are not as well established. The aim of the study was to evaluate the acute hemodynamic effects of biventricular and left ventricular pacing in chronically paced patients with advanced heart failure. Fourteen consecutive pacemaker or defibrillator patients with permanent atrial fibrillation and AV block (11 male, 3 woman, mean age: 68 +/- 7 years) were enrolled in this study. There were 5 ischemic (36%) and 9 nonischemic (64%) patients (mean left ventricular ejection fraction: 19 +/- 5%; mean end-diastolic left ventricular diameter: 71 +/- 11 mm). In all patients a right ventricular and left ventricular (via coronary sinus) pacing lead was placed. The aortic and left ventricular hemodynamic measurements were performed using a two-channel micro-tip catheter. The measurements of the aortic pulse pressure (APP) and (dP/ dtmax) were performed during right ventricular apical pacing (RVP), left ventricular (LVP), and biventricular pacing (BVP) (70 bpm). Compared to RVP, LVP and BVP increased APP and dP/dtmax (35.8 +/- 4.2 vs 43.3 +/- 4.5 and 41.2 +/- 4 mmHg; p < 0.001) and (758 +/- 56 vs 967 +/- 60 and 961 +/- 62 mmHg/s; p < 0.001). LVP and BVP showed a comparable hemodynamic response. The hemodynamic effects were not related to the width of the paced QRS complex. Every patient showed improved hemodynamics during LVP and BVP unrelated to the underlying heart disease and to the baseline level of left ventricular dysfunction. BVP and LVP pacing acutely improve contractile left ventricular function in chronically paced patients with advanced heart failure.

Comparison of generic health survey SF-36 and arrhythmia related symptom severity check list in relation to post-therapy AF recurrence.

AIM: The effect of applied therapy on quality of life (QoL) in patients with atrial fibrillation (AF) was investigated in recent studies. However, no information on clinical relevance of QoL assessing instruments in relation to post-ablation recurrence of AF is currently available. The aim of this study was to evaluate the clinical relevance of SF-36 and Arrhythmia Related Symptom Severity Check List (SSCL) to post-procedure AF recurrences in patients with paroxysmal AF undergoing pulmonary vein isolation (PVI). METHODS AND RESULTS: Sixty consecutive patients with AF were enroled in the study. The QoL was measured using SF-36 scale and SSCL. The questionnaires were administered at baseline then 3, 6, 9 and 12 months after the procedure. In order to define statistical power in relation to AF recurrence the scores were dichotomized. Positive and negative predictive accuracy (PPA, NPA) and test efficiency (sum of PPA and NPA) were calculated. Twenty-one out of 60 patients experienced a total of 66 recurrences of AF during follow-up. The parameters of SF-36 provided maximum test efficiency of 1.36, whereas the test efficiency of SSCL was 1.79. CONCLUSION: We conclude that SSCL is more specific instrument for a measurement of PVI success or failure.

Automatic capture verification in ICD lead systems using intracardiac ventricular evoked response and reduced coupling capacitance.

AIM: Intracardiac ventricular evoked-response (ER) signals detected by implanted cardioverter defibrillator (ICD) lead systems were investigated for automatic capture verification (AC). METHOD: ER signals were evaluated with an external pacing system equipped with a reduced coupling capacitance (CC=2.2 microF) in the pacing output circuit during ventricular step-down threshold testing at 0.4 ms pulse duration. Real-time pacing markers, surface ECG and intracardiac electrograms pre- and post-filtering were digitally recorded. RESULTS: Twenty consecutive patients, age 61+/-12 years, with leads from two different manufacturers were tested - 10 were implanted with acute leads (AL) and 10 with chronic leads (CL). The analysis was based on the ER amplitude during capture and on the ER-to-afterpotential ratio (SAR), with SAR>2 as the criterion for successful capture detection. ER amplitudes (median and range) were 8.1 mV (2.1-19.5 mV) for AL and 8.3 mV (3.7-14.2 mV) for CL. SAR values (median and range) were 48.0 (2.5-682.6) for AL and 13.2 (6.3-35.9) for CL, indicating that AC could successfully be applied in all patients. CONCLUSIONS: Reducing the pacing CC allows adequate ER detection for automatic capture verification on non-selected ICD lead systems. The effect of high-voltage shock treatment on ER signal detection requires further investigation.

[Cooled tip ablation of left ventricular outflow tract tachycardia through the aortic sinus of valsalva]. / Gekühlte HF-Stromkatheterablation epikardialer Ausflusstrakttachykardien über die Sinus valsalvae der Aorta.

BACKGROUND: Monomorphic tachycardia with an epicardial site of the arrhythmic focus in the left ventricular outflow tract (LVOT) usually cannot be ablated by an endocardial approach. We describe the use of cooled tip catheter ablation through the aortic sinus of valsalva to treat LVOT tachycardia. METHODS: In seven patients (four males, one with valvular cardiomyopathy, six patients without heart disease) with sustained and non-sustained ventricular tachycardia (VT) an epicardial focus of LVOT tachycardia could be identified by pace-mapping and earliest local activation within the aortic sinus of valsalva. Coronary angiography served to define the position of the coronary arteries with respect to the ablation catheter. High frequency current was delivered using a closed-loop cooled tip catheter system (Chilli Cool(R), Boston Scientific). ECG, Holter-ECG, echocardiography and transesophageal echocardiography were performed after the procedure and 3 months later. RESULTS: Foci were located in the left (two patients), in the right (three) and in the a coronary aortic sinus (two). Successful ablation could be achieved in six patients. No procedure-related complications could be observed during a mean follow-up of 4.2 months. CONCLUSION: Monomorphic VT with epicardial origin in the LVOT can be successfully treated by cooled tip ablation through the aortic sinus of valsalva. The use of a cooled tip ablation system may be favourable in several ways: 1) it allows the creation of deep lesions necessary to reach remote foci; 2) due to lower temperatures at the catheter/tissue interface surface tissue damage may be reduced; 3) lower catheter temperature may additionally reduce the risk of local clot formation which is crucial for all left-sided procedures and especially for ablation in the sinus of valsalva.

Inappropriate arrhythmia detection in implantable defibrillator therapy due to oversensing of diaphragmatic myopotentials.

Nonadequate arrhythmia detection and delivery of electrical therapy is still a main problem in current implantable cardioverter defibrillator therapy. Besides supraventricular arrhythmias extra-cardiac biosignals also can cause inadequate shock delivery. The present study focuses on nonadequate arrhythmia detection due to oversensing of diaphragmatic myopotentials. Their clinical characteristics, incidence and management are presented. Three-hundred-eighty-four recipients of a transvenous cardioverter-defibrillator who were implanted and followed-up at our institution between October 1991 and June 1999 were enrolled. During a mean follow-up of 32+/-25 months a total number of 139 nonadequate episodes of arrhythmia detection due to oversensing of diaphragmatic myopotentials were observed in 33 patients (8.6%). In 11 patients a total of 32 high energy shock deliveries occurred. Oversensing of diaphragmatic myopotentials was primarily observed in patients implanted with defibrillator leads providing "integrated bipolar" sensing. The vast majority of nonadequate arrhythmia detection were observed during intrinsic bradycardia heart rate and/or antibradycardia pacing. Electrical lead failure was ruled out in every patient. In 90% of the patients with a cardioverter-defibrillator providing programmable maximal sensitivity (n=16), the reduction of maximum sensitivity was effective in preventing further episodes of nonadequate arrhythmia detection. In 48% of the patients with devices without programmable maximal sensitivity (n=17), surgery revision was necessary to solve the problem.

Predictors for atrial transport function after mini-maze operation.

BACKGROUND: Restoration of atrial transport function (ATF) is a major goal of the maze procedure. This prospective study was undertaken to evaluate predictors of left atrial transport function in patients undergoing a mini-variant of the maze III procedure 3 and 12 months postoperatively. METHODS: Mini-maze operation was performed in 72 patients with a mean age of 64 +/- 8.7 years during a 5-year period. Seventy of 72 (97%) had combined procedures. Clinical and electrophysiologic examination was carried out before surgery, and 3 and 12 months postoperatively. RESULTS: Early mortality was 1.4% (1 of 72 patients) and late death occurred in 5.6% (4 of 71 patients). After 3 months, 54 of 68 (80%) patients showed sinus rhythm, and 48 of 60 (80%) after 12 months. ATF was restored in 87% (echocardiography) and 82% (magnetic resonance imaging) after 3 months, and in 86% (echocardiography) and 78% (magnetic resonance imaging) after 12 months. Independent predictors for ATF restoration after 12 months were better preoperative left ventricular function (p = 0.02), and smaller preoperative left atrial diameter (p = 0.005). Correlation between echocardiography and magnetic resonance imaging was 80% after 12 months. CONCLUSIONS: Restoration of ATF after mini-maze procedure is achieved in over 80%. Independent predictors for ATF restoration are smaller preoperative left atrial diameter and better preoperative left ventricular ejection fraction.

Myocardial injury during radiofrequency catheter ablation: comparison of focal and linear lesions.

The aim of study was to investigate the extent of myocardial injury incurred by creation of continuous RF current induced linear ablation lesions (LL; ablation of atrial fibrillation, right atrial procedure) in comparison to focal RF lesions (FL; AV node reentry tachycardia, WPW tachycardia). In 23 patients with LL (age 51.3 +/- 11.2 years, 18 men, 5 women) and in 16 patients with FL (age 53.9 +/- 5.1 years, 8 men and 8 women), levels of creatine kinase (CK), myoglobin (MG), CKMB mass (CKMB M), CKMB activity (CKMB A), and cardiac troponin T (cTnT) were determined before and 2, 4, 8, 24, and 48 hours after ablation. CKMB A was normal in 87% in LL and 100% in FL (< 6% of CK) with median maximum CK values of 214 (45-1583) U/L in LL and 36 (29-212) U/L in FL. Peak values of all parameters were significantly higher in LL than in FL. The sensitivity of cTnT was 50% in FL and 100% in LL. In FL MG, total CK, and CKMB M were abnormal in only 12.5% of cases while in LL MG and CKMB M were pathological in 100% and total CK was abnormal in 91.3% of patients. The amount of energy and number of RF applications correlated with cTnT, MG, and CKMB M (P = 0.01). In conclusion, (1) long linear RF current lesions for ablation of atrial fibrillation are associated with significantly greater myocardial injury than focal ablations. (2) In focal lesions only cTnT provided a sensitivity of 50% in the detection of myocardial injury while in linear lesions cTnT, CKMBM, and CKMB M seemed suitable for detection of RF current induced myocardial damage with 100% sensitivity. All biochemical parameters do not differentiate patients with coronary ischemia up to 48 hours after an ablation. (3) Further investigations are necessary to determine if RF current linear lesions lead to impaired atrial contractility in cases of extensive tissue damage.

Dual-coil vs single-coil active pectoral implantable defibrillator lead systems: defibrillation energy requirements and probability of defibrillation success at multiples of the defibrillation energy requirements.

AIMS: The aim of the study was to compare the defibrillation energy requirements and the probability of successful defibrillation at multiples of the minimum defibrillation energy requirements in active pectoral implantable defibrillators with single- and dual-coil lead systems. METHODS AND RESULTS: Eighty-three consecutive patients undergoing implantation of an active pectoral cardioverter-defibrillator were randomized to receive a dual- or single-coil lead system. Defibrillators of two manufacturers with a fixed tilt biphasic defibrillation waveform were used. Defibrillation energy requirements were determined using a step-down defibrillation testing protocol. According to the randomization protocol, the patients were assigned to three additional consecutive defibrillation attempts during device implantation and during pre-discharge testing of either 1.0, 1.5 or 2.0 times the determined defibrillation energy requirement. Patients presenting defibrillation energy requirements > 15 J were excluded from analysis. Eighty of 83 patients (96%) completed the study protocol. Three patients were excluded due to elevated defibrillation energy requirements. The defibrillation energy requirements in the dual- and single-coil patient groups were 8.0 +/- 3.6 J and 8.4 +/- 3.7 J (ns), respectively. A comparable percentage of study patients showed defibrillation energy requirements <10 J (dual-coil: 88% vs single-coil: 83%). Defibrillation impedance was significantly different (dual-coil: 50 +/- 5.8 Ohm; single-coil: 39.8 +/- 4.2 Ohm). Regarding the probabilities of successful defibrillation, there were no significant differences between the two patient groups. The probabilities of defibrillation at the three multiples of the defibrillation energy requirement using a dual- and single-coil lead system were 82, 89.7 and 93.6 and 77.8, 94.1 and 95.8%, respectively (P=0.88, P=0.42, P=0.62, respectively). CONCLUSIONS: Dual- and single-coil active pectoral defibrillator systems show no difference in defibrillation energy requirements and no difference in the probability of successful defibrillation at multiples of the minimum defibrillation energy requirement. The use of more simplified defibrillator lead systems may contribute to a future lead design focusing on improvement in lead durability.

Electrochemical potentials during radiofrequency energy delivery: a new method to control catheter ablation of arrhythmias.

AIMS: Thermal injury of subendocardial tissue leads to a release of electrolytes and free radicals from the intracellular site creating a change in electrochemical potential (eP) between the distal and the proximal catheter tip electrodes. The aim of the study was to verify the detection of ablation-induced release of electrolytes and free radicals and to assess the suitability of control-line energy delivery at ablation by measuring eP. METHODS AND RESULTS: In vitro tests under constant flow conditions were performed in a 101 bath of physiological saline solution or bovine blood. Endomyocardial preparations of fresh bovine hearts were used. Closed-loop temperature-controlled, irrigated and closed-loop eP-controlled ablations were performed. In vivo animal investigations were performed in six anaesthetized and ventilated pigs. The existence of the eP was established in the tank model and was confirmed in animal investigations. High correlations were found between eP and catheter tip temperature (r=0.87) and between maximum eP and induced lesion size (r=0.85). Also a high correlation (r=0.85, P<0.001) was found between eP and lesion volume. CONCLUSIONS: Control of energy delivery during RF ablation by the measurement of eP is feasible. In comparison with temperature controlled RF ablation, ablation guided by eP-measurement revealed a superior correlation with induced lesion size. Especially during cooled radiofrequency catheter ablation eP is the only parameter for control of energy delivery.

Possible role of epicardial left ventricular programmed stimulation in Brugada syndrome.

A patient with recurrent syncope due to polymorphic ventricular tachycardia was diagnosed with Brugada syndrome. Programmed right ventricular stimulation could not induce arrhythmia. Epicardial stimulation from a left ventricular site through the coronary sinus led to polymorphic VT. The stimulation protocol for risk stratification in Brugada syndrome is discussed.

Left ventricular leads used in cardiac resynchronization therapy for heart failure patients.

Cardiac resynchronization therapy (CRT) has been introduced as a treatment for selected heart failure patients, specifically those with symptomatic heart failure, left ventricular (LV) dysfunction, and intraventricular conduction delays. CRT is delivered by use of an implanted device and leads positioned in the right atrium, right ventricle, and left ventricle. In the early stages of CRT development, researchers affixed epicardial electrodes to the left ventricle by means of subxiphoid, thoracoscopic, or major surgical procedure. Currently there are a number of transvenous LV leads available that have undergone substantial evaluation. Reports indicate that such leads can be positioned safely by cannulating the coronary sinus and inserting the lead into the venous system. The leads are reported to have acceptable pacing/sensing thresholds and complication rates. Because of individual variations in the cardiac and venous anatomy, as well as sharp angulations in the venous system, maneuverability is an important consideration in lead selection.

Algorithmic complexity. A new approach of non-linear algorithms for the analysis of atrial signals from multipolar basket catheter.

Symbolic dynamics as a non linear method and computation of the normalized algorithmic complexity (C alpha) was applied to basket-catheter mapping of atrial fibrillation (AF) in the right human atrium. The resulting different degrees of organisation of AF have been compared to conventional classification of Wells. Short time temporal and spatial distribution of the C alpha during AF and effects of propafenone on this distribution have been investigated in 30 patients. C alpha was calculated for a moving window. Generated C alpha was analyzed within 10 minutes before and after administration of propafenone. The inter-regional C alpha distribution was statistically analyzed. Inter-regional C alpha differences were found in all patients (p < 0.001). The right atrium could be divided in high- and low complexity areas according to individual patterns. A significant C alpha increase in cranio-caudal direction was confirmed inter-individually (p < 0.01). The administration of propafenone enlarged the areas of low complexity.

[Clinical characteristics of patients with AV-nodal reentrant tachycardia (AVNRT): modification by high frequency catheter ablation. Study of 748 patients after high frequency catheter ablation]. / Klinische Charakteristika von Patienten mit AV-Knoten-Reentrytachykardie (AVNRT): Beeinflussung durch die Hochfrequenzkatheterablation. Untersuchung an 748 Patienten nach Hochfrequenzkatheterablation.

AIM: The aim of the study was to analyze the medical history of patients with AV-nodal reentry tachycardia (AVNRT). PATIENTS AND METHODS: Between 1990 and 1999 radiofrequency catheter ablation was performed in 1,024 patients suffering from AVNRT. Data of the previous history were comprehended by questionnaire. RESULTS: 748 (73%) patients replied to the questionnaire. The interval between the first appearance of the symptoms and the catheter ablation was 4.1 +/- 1.5 years. The mean age of the patients was 55.4 years (female) and 58.7 years (male). Merely 6% of all patients had a structural heart disease. The mean duration of case history was 16.8 years. In comparison to the male patients, the assignment for female patients to catheter ablation was after a significant 7 years longer lasting anamnesis. The distribution of age showed that the first tachycardia appeared in 16% of the female patients older than 50 years of age and only in 17% younger than 20 years of age; the corresponding percentages for men were 31% and 18%. With reference to the duration of the longest tachycardia episodes and arrhythmia-related presyncopes and syncopes, women showed a more defined symptomatic. On 20% of the patients a radiofrequency catheter ablation ensued without previous antiarrhythmic treatment; 80% of the patients were treated with 2.8 different antiarrhythmic medications. Medical consultations regarding AVNRT were named as follows (mean/range): family doctor 6.1/1-250, emergency physicians 1.1/0-15, hospital 1.0/0-20. The indication for catheter ablation was set by the family doctor in 13% and by the cardiologist in 77%. Patients got their information about catheter ablation in 2.9% from acquainted persons or news services. CONCLUSION: There is no "typical" anamnesis of AVNRT patients. There is an amazingly high rate of patients with an AVNRT begin in elder stage of age and the fact of therapy delay of 7 years in behalf of women.

Hemodynamic, antiischemic, and neurohumoral effects of tedisamil and atenolol in patients with coronary artery disease.

Clinical drawbacks of beta-blocker treatment in stable angina have motivated researchers to provide alternative heart-rate-lowering agents, such as tedisamil, which additionally exerts antiischemic and antiarrhythmic effects by blockade of cellular repolarizing K+ currents. Forty-eight patients with stable angina pectoris were investigated (doubleblind, randomized, parallel grouped) comparing the hemodynamic, antiischemic, metabolic and neurohumoral effects of tedisamil 100 mg b.i.d. and atenolol 50 mg b.i.d. after a single dose and over 6 days of treatment. Tedisamil and atenolol produced a decrease in heart rate both at rest [day 1:-13.6 versus - 15.4 bpm; day 6: - 14.8 versus - 22.2 bpm, resp.; p > 0.05] and exercise [day 1: - 9.1 versus - 18.3 bpm; p = 0.001; day 6: - 12.0 versus - 24.8 bpm, resp.; p = 0.001], while anginal threshold increased. Cardiac output decreased with tedisamil and atenolol at rest [day 1: -1.01 versus -1.19 l/min; p > 0.05; day 6: - 0.86 versus - 1.10 l/min, resp.; p > 0.05] and exercise [day 1: - 0.82 versus - 1.28 l/min; p > 0.05; day 6: - 0.65 versus - 2.68 l/min, resp.; p = 0.03], while stroke volume remained unchanged. Right atrial pressure changed during exercise only: it decreased with tedisamil (-1.7 mmHg) and increased with atenolol (+ 3.7 mmHg) (p < .001). Mean pulmonary capillary wedge pressures decreased both at rest (- 0.5 mmHg) and exercise (- 6.9 mmHg) in the tedisamil group but tended to increase with atenolol on day 6 of treatment [rest: + 1.7; exercise: + 3.7 mmHg) (p = 0.03). Arterial pressure decreased under atenolol treatment only. Exercise-induced plasma norepinephrine levels were reduced by tedisamil (- 93 pg/ml) but elevated by atenolol (+ 172 pg/ml) (p = 0.001). As compared to atenolol, tedisamil produced a prolongation of QTc interval [+ 31 versus 8 ms] at initial values of 0.408 +/- 0.018 s with PQ and QRS remaining unaltered. In patients with stable angina, tedisamil (100 mg b.i.d.) as compared to atenolol (50 mg b.i.d.) generated similar hemodynamic, neurohumoral and antiischemic effects. The antiischemic efficacy of tedisamil, as measured by ST segment depression and angina threshold, was comparable to that of atenolol.

[Recurrent syncope of unknown origin. Diagnosis with implantable "loop" recorders]. / Rezidivierende Synkopen unklarer Genese. Diagnostik mittels implantierbaren "Loop"-Recorders.

BACKGROUND: In about a third of cases of recurrent syncope a diagnosis cannot be established despite extensive cardiovascular and neurologic testing. In patients without underlying heart disease the sensitivity of conventional diagnostic testing is low. CASE REPORT: A 33-year-old male patient underwent implantation of a loop recorder (Reveal) after negative neurological and cardiovascular testing. One month after implantation sinus node arrest could be documented during a presyncope. The patient underwent pacemaker implantation and remains asymptomatic since then. CONCLUSION: In patients with syncope and a negative conventional diagnostic workup the implantable loop recorder is a helpful and cost-effective diagnostic tool.

[Recurrent syncope in a 34-year-old woman triathlete]. / 34-jährige Triathletin mit rezidivierenden Synkopen.

HISTORY: Some weeks previously a 34-year old athlete, specializing in the triathlon, had 6 syncopes in one day. They had caused abrasions and contusions resulting from the falls. At another hospital paroxysmal atrial fibrillation had been diagnosed and treatment with disopyramide (2 x 200 mg) initiated, but she had about 15 further syncopes within 2 weeks. She was admitted for establishing their cause. INVESTIGATIONS: Initial ECGs and neurological examination failed to provide a diagnosis and she was discharged with an "event recorder". DIAGNOSIS, TREATMENT AND COURSE: Three weeks after discharge she had another syncope. The event recorder was activated by the patient's partner and revealed polymorphous ventricular tachycardia. She underwent extensive invasive cardiological tests, including a right ventricular biopsy, but no abnormality was demonstrated. However, a provocation test with ajmaline produced ST segment elevations in V1 and V2 typical of the syndrome previously described by the Brugadas (right bundle branch block, precordial ST elevations in V1-V3 and sudden cardiac death). A cardioverter-defibrillator was implanted. During the subsequent observation period of 2 month the ICD delivered one countershock, triggered by the onset of polymorphous ventricular tachycardia with syncope. CONCLUSION: In patients with serious ventricular arrhythmias but no diagnostic findings, including a normal resting ECG, a drug provocation test should be performed to exclude a Brugada syndrome.