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Short-coupled idiopathic ventricular fibrillation (SC-IVF) is a rare, life-threatening arrhythmia, accountable for 5–10% of out-of-hospital cardiac arrests (OHCA). Catheter ablation of the short-coupled premature ventricular contraction (PVC) that triggers VF has been shown to prevent VF recurrences in outdated case series. Aim To evaluate the clinical outcome and summarize the recent experience of 3D electrophysiological mapping and radiofrequency catheter ablation (RFCA) of SC-IVFs in a tertiary high-volume referral centre. Methods from January 2016, we enrolled all consecutive patients diagnosed with SC-IVF and treated by RFCA. Structural heart disease was excluded in all patients by means of echocardiography, cardiac magnetic resonance, coronary angiography, and exercise test. Brugada syndrome and long QT syndrome were excluded by Ajmaline and Epinephrine tests, respectively. The CARTO system was used to construct detailed 3D electroanatomic maps of the right and left ventricle. Mapping and ablation were performed with a standard 3.5- irrigated tip catheter. The PVCs were localized by mapping the earliest bipolar electrogram relative to the onset of the ectopic surface QRS (confirmed by QS complex in the unipolar configuration). Pace mapping was used in patients with infrequent PVCs. The origin of PVCs from fascicles/Purkinje network was indicated by initial sharp potentials preceding the ectopic QRS complex. The procedural end point was the abolition of all clinical PVCs. Outcome (freedom from SC-PVCs and VF episodes) was assessed by Holter monitoring and defibrillator memory interrogation. Results eleven consecutive patients [8 men, 3 women; median age 41 (± 5 years)] were enrolled. 10/11 patients (91%) were asymptomatic prior the index VF event, while 1 patient (9%) experienced recurrent syncope. An aborted OHCA was the index event in all patients. Arrhythmic storm was observed at the index presentation in 2 patients (18%). No patient had family history of sudden cardiac death. All patients were implanted with an ICD after the index event. The delay in SC-IVF diagnosis was 3 (± 2 years) from the index event. 2 patients (18%) had ≥ 2 SC-PVC morphologies. The mean coupling interval (CI) of the SC-PVCs ranged from 230 to 330 msec (mean 303 ± 26 msec). The CI/QT ratio ranged from 0.6 to 1 (mean 0.81 ± 0.15). 10 patients underwent RFCA for recurrent VF/ICD shocks and 1 patient for refractory electrical storm. RFCA was based on activation mapping, pace-mapping, and both in 1 (9%), 1 (9%), and 9 (82%) patients, respectively. The sites of ablation were LV Purkinje, RV Purkinje, RV non-Purkinje (RV outflow tract and tricuspid annulus), and LV non-Purkinje (LV Summit) in 3 (27%), 4 (36%), 3 (27%), and 1 (9%) patient, respectively. The first ablation was acutely successful in all patients. 1 patient experienced recurrence of SC-PVCs and VF episodes after 5 days from the first ablation and underwent a second RFCA. There were no peri-procedural complications. After a median follow-up of 22 months (ranging from 6 to 39 months) all patients were free from sustained ventricular arrhythmia recurrences: 10 patients (91%) were free from VF and PVCs; 1 patient (9%) had recurrent SC-PVCs without VF episodes. Conclusions this retrospective study explored the effectiveness of RFCA combined with the advanced electroanatomic mapping in a current cohort of patients with history of OHCA diagnosed with SC-IVF. RFCA of SC-PVCs was safe and highly effective in abolishing VF episodes in all patients.

Aims The long-QT syndrome (LQTS) represents a leading cause of sudden cardiac death (SCD). The aim of this study was to assess the presence of an underlying electroanatomical arrhythmogenic substrate in high-risk LQTS patients. Methods and results The present study enrolled 11 consecutive LQTS patients who had experienced frequent implantable cardioverter-defibrillator (ICD discharges triggered by ventricular fibrillation (VF). We acquired electroanatomical biventricular maps of both endo and epicardial regions for all patients and analyzed electrograms sampled from several myocardial regions. Abnormal electrical activities were targeted and eliminated by the means of radiofrequency catheter ablation. VF episodes caused a median of four ICD discharges in eleven patients (6 male, 54.5%; mean age 44.0 ± 7.8 years, range 22–53) prior to our mapping and ablation procedures. The average QTc interval was 500.0 ± 30.2 ms. Endo-epicardial biventricular maps displayed abnormally fragmented, low-voltage (0.9 ± 0.2 mV) and prolonged electrograms (89.9 ± 24.1 ms) exclusively localized in the right ventricular epicardium. We found electrical abnormalities extending over a mean epicardial area of 15.7 ± 3.1 cm2. Catheter ablation of the abnormal epicardial area completely suppressed malignant arrhythmias over a mean 12 months of follow-up (median VF episodes before vs. after ablation, 4 vs. 0; P = 0.003). After the procedure, the QTc interval measured in a 12-lead ECG analysis shortened to a mean of 461.8 ± 23.6 ms (P = 0.004). Conclusion This study reveals that, among high-risk LQTS patients, regions localized in the epicardium of the right ventricle harbour structural electrophysiological abnormalities. Elimination of these abnormal electrical activities successfully prevented malignant ventricular arrhythmia recurrences.

Patients with COVID-19 frequently have non-typical ECG changes in the QRS and T-wave morphology. The novel CineECG uses using the mean temporal spatial isochrones (mTSI) to relate the activation and recovery pathway to the cardiac anatomy. The aim of this feasib ility study is to use the novel CineECG to separate normal from abnormal ECGs. The ECGs of 100 normal controls were used to obtain the normal mTSI paths values for the QRS, ST segment and T-wave. These normal CineECG values were used to classify the COVID-19 ECGs as either as normal or abnormal of 107 patients being treatedfor COVID-19 in the University Medical Center Utrecht. The CineECG was able to classify 98% of the normal ECG correctly and 94% of the abnormal ECG in comparison to expert ECG classifications. The ability of the CineECG to relate the ECG to the cardiac anatomy supports the detection of abnormal ECGs. The CineECG might be a novel ECG screening tool to detect potential cardiac involvement of the COVID-19 disease for non-ECG experts.

Background: The relationship between the typical electrocardiographic pattern and electromechanical abnormalities has never been systematically explored in Brugada syndrome (BrS). Objectives: The aims of this study were to characterize the electromechanical substrate in patients with BrS and to evaluate the relationship between electrical and mechanical abnormalities. Methods: We enrolled 50 consecutive high-risk patients with BrS (mean age 42 ± 7.2 years), with implantable cardioverter-defibrillator implantation for primary or secondary prevention of ventricular tachyarrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]), undergoing substrate mapping and ablation. Patients underwent 3-dimensional (3D) echocardiography with 3D wall motion/deformation quantification and electroanatomic mapping before and after ajmaline administration (1 mg/kg in 5 minutes); 3D mechanical changes were compared with 50 age- and sex-matched controls. The effect of substrate ablation on electromechanical abnormalities was also assessed. Results: In all patients, ajmaline administration induced Brugada type 1 pattern, with a significant increase in the electrical substrate (P

Aims Brugada syndrome (BrS) represents a major cause of sudden cardiac death in young individuals. The risk stratification to forecast future life-threatening events is still controversial. Non-invasive assessment of late potentials (LPs) has been proposed as a risk stratification tool. However, their nature in BrS is still undetermined. The purpose of this study is to assess the electrophysiological determinants of non-invasive LPs. Methods and Results Two hundred and fifty consecutive patients with (Group 1, n = 96) and without (Group 2, n = 154) BrS-related symptoms were prospectively enrolled in the registry. Signal-averaged electrocardiogram (SAECG) was performed in all subjects before undergoing epicardial mapping. Group 1 patients exhibited larger arrhythmogenic substrates (AS; 5.8 ± 2.8 vs. 2.6 ± 2.1 cm2, P Conclusion The results of this study support the role of the epicardial AS as an electrophysiological determinant of non-invasive LPs, which may serve as a tool in the non-invasive assessment of the BrS substrate, as SAECG-LPs could be considered an expression of the abnormal epicardial electrical activity. ClinicalTrials.gov number (NCT02641431; NCT03106701).

Aims Continuous rhythm monitoring is valuable for adequate atrial fibrillation (AF) management in the clinical setting. Subcutaneous leadless implantable cardiac monitors (ICMs) yield an improved AF detection, overcoming the intrinsic limitations of the currently available external recording systems, thus resulting in a more accurate patient treatment. The study purpose was to assess the detection performance of a novel three-vector ICM device equipped with a dedicated AF algorithm. Methods and results Sixty-six patients (86.4% males; mean age 60.4 ± 9.4 years) at risk to present AF episodes, having undergone the novel ICM implant (BioMonitor, Biotronik SE&Co. KG, Berlin, Germany), were enrolled. External 48-h ECG Holter was performed 4 weeks after the device implantation. The automatic ICM AF classification was compared with the manual Holter arrhythmia recordings. Of the overall study population, 63/66 (95.5%) had analysable Holter data, 39/63 (62%) showed at least one true AF episode. All these patients had at least one AF episode stored in the ICM. On Holter monitoring, 24/63 (38%) patients did not show AF episodes, in 16 of them (16/24, 67%), the ICM confirmed the absence of AF. The AF detection sensitivity and positive predictive value for episodes' analysis were 95.4 and 76.3%, respectively. Conclusion Continuous monitoring using this novel device, equipped with a dedicated detection algorithm, yields an accurate and reliable detection of AF episodes. The ICM is a promising tool for tailoring individual AF patient management. Further long-term prospective studies are necessary to confirm these encouraging results.

Background: Guidelines recommend the use of implanted cardioverter-defibrillators in patients with Brugada syndrome and induced ventricular tachyarrhythmias, but there is no evidence supporting it. Objectives: This prospective registry study was designed to explore clinical and electrophysiological predictors of malignant ventricular tachyarrhythmia inducibility in Brugada syndrome. Methods: A total of 191 consecutive selected patients with (group 1; n = 88) and without (group 2; n = 103) Brugada syndrome–related symptoms were prospectively enrolled in the registry. Patients underwent electrophysiological study and substrate mapping or ablation before and after ajmaline testing (1 mg/kg/5 min). Results: Overall, before ajmaline testing, 53.4% of patients had ventricular tachyarrhythmia inducibility, which was more frequent in group 1 (65.9%) than in group 2 (42.7%; p < 0.001). Regardless of clinical presentation, larger substrates with more fragmented long-duration ventricular potentials were found in patients with inducible arrhythmias than in patients without inducible arrhythmias (p < 0.001). One extrastimulus was used in more extensive substrates (median 13 cm2; p < 0.001), and ventricular fibrillation was the more frequently induced rhythm (p < 0.001). After ajmaline, patients without arrhythmia inducibility had arrhythmia inducibility without a difference in substrate characteristics between the 2 groups. The substrate size was the only independent predictor of inducibility (odds ratio: 4.51; 95% confidence interval: 2.51 to 8.09; p < 0.001). A substrate size of 4 cm2 best identified patients with inducible arrhythmias (area under the curve: 0.98; p < 0.001). Substrate ablation prevented ventricular tachyarrhythmia reinducibility. Conclusions: In Brugada syndrome dynamic substrate variability represents the pathophysiological basis of lethal ventricular tachyarrhythmias. Substrate size is independently associated with arrhythmia inducibility, and its determination after ajmaline identifies high-risk patients missed by clinical criteria. Substrate ablation is associated with electrocardiogram normalization and not arrhythmia reinducibility. (Epicardial Ablation in Brugada Syndrome [BRUGADA_I]; NCT02641431; Epicardial Ablation in Brugada Syndrome: An Extension Study of 200 BrS Patients; NCT03106701)

The Remote Monitoring (RM) technology has recently become available in insertable cardiac monitors (ICM) [(1)][1]. The purpose of this analysis was to assess feasibility, clinical reactions, and arrhythmic alerts burden of remote management for patients implanted with the novel long-dipole ICM (

Objectives: The aim of this study was to assess the performance of echocardiographic parameters to predict response to cardiac resynchronization therapy (CRT). Background: CRT reduces morbidity and mortality due to the proper selection of candidates for CRT. Methods: The 12-month trial was performed on 70 optimally medicated patients with standard inclusion criteria: NYHA class III or IV heart failure, left ventricular ejection fraction (LVEF) ≤ 35%, and QRS ≥ 120 ms. All parameters were evaluated by conventional and tissue Doppler-based methods. Indicator of positive CRT response was more than 20% in improvement of LVEF. Results: LVEF increased >20% in 42 patients. Out of 43 tested baseline echocardiographic parameters, 12 showed statistical difference between responders and nonresponders. Out of these 12 parameters, six (LVSV, LVSI, LVFS, RVd, VPMR, and PISA) had modest to moderately good ability to predict LVEF response with sensitivity ranging from 62.2% to 82.4%, and specificity ranging from 56.5% to 81.2%. For those parameters, the area under the receiver-operating characteristic curve for positive response to CRT was ≤0.76. Multivariate regression analysis resulted in selection of LVSI and LVFS as possible predictive independent parameters for a good response. The cutoff value for LVSI was 38.7 mL/m2 (P = 0.045) and for LVFS was 13% (P = 0.032). Conclusions: Contribution of LVSI and LVFS is to be confirmed in larger trials. Simplicity of their assessment by conventional echocardiography could be an argument for adding them to the inclusion criteria for CRT in severe heart failure patients. (Echocardiography 2012;29:267-275)

We thank Fenici et al for their interest in our experience on the natural history of the Wolff-Parkinson-White (WPW) syndrome.1 The authors, on the basis of their experience, suggest the routine use of ambulatory transesophageal atrial pacing (TEAP) as an intermediate approach to minimize “invasiveness” for risk assessment in the asymptomatic WPW population. It is well known that, unlike invasive electrophysiological testing (EPT), TEAP provides less accurate information about “the real electrophysiological profile of the risk” in WPW patients. Potential limitations are an approximate value of the anterograde refractory period of accessory pathways (APs), no identification of multiple APs, no reproducibility or inducibility of atrial fibrillation, no information on AP …

INTRODUCTION. Resynchronisation therapy with biventricular permanent pacing stimulation is one method of treating patients with systolic heart failure, with echocardiograph signs of ventricular asynchrony and a prolonged QRS of longer than 120 milliseconds. This method has been accepted in most medical centers around the world and was instigated in our Pacemaker Centre in December 2001, 3 months after FDA approval for human use. OBJECTIVE. The aim of the study was to present this new procedure and the results obtained from our own group of patients. METHOD. A multi-site, biventricular pacemaker, with a special electrode for left-half heart stimulation was implanted in the coronary sinus of 17 patients who had suffered systolic heart failure (12 male and 5 female, average age 59.9 years). For all of them, the duration of the QRS interval was longer than 120 ms, with left bundle branch morphology, and an ejection fraction below 30%. All the patients were NYHA class II or III. Prior to and after the implantation, a 12-channel ECG and ECHO were carried out, a b-minute hall walk test was performed, additionally, the total walked distance on a flat surface was measured, the general condition of the patient was evaluated, the number of medications being taken was noted, as was the number of days of hospitalization. RESULTS. The average time from diagnosis to implantation was 22 months, and the average post-operative follow-up was 14 months. Two of the patients died 10 and 7 months after the implantation, due to a new myocardial infarction and refractory heart failure. In addition, one patient did not show any improvement after the implantation of the multi-site pacemaker (there were three "non-responder" patients). All the other patients felt much better: decreased NYHA class for I - II class, increased left ventricle ejection fraction, reduced use of diuretics, increased b-minute hall walk distance and general walk distance on a flat surface, and decreased number of days of hospitalization. CONCLUSION. Resynchronisation heart failure therapy in the majority of patients with systolic left ventricular dysfunction and a prolonged QRS interval considerably improves cardiac function, in addition to reducing symptoms and hospital stays.

Background— The management of Wolff-Parkinson-White is based on the distinction between asymptomatic and symptomatic presentations, but evidence is limited in the asymptomatic population. Methods and Results— The Wolff-Parkinson-White registry was an 8-year prospective study of either symptomatic or asymptomatic Wolff-Parkinson-White patients referred to our Arrhythmology Department for evaluation or ablation. Inclusion criteria were a baseline electrophysiological testing with or without radiofrequency catheter ablation (RFA). Primary end points were the percentage of patients who experienced ventricular fibrillation (VF) or potentially malignant arrhythmias and risk factors. Among 2169 enrolled patients, 1001 (550 asymptomatic) did not undergo RFA (no-RFA group) and 1168 (206 asymptomatic) underwent ablation (RFA group). There were no differences in clinical and electrophysiological characteristics between the 2 groups except for symptoms. In the no-RFA group, VF occurred in 1.5% of patients, virtually exclusively (13 of 15) in children (median age, 11 years), and was associated with a short accessory pathway antegrade refractory period ( P P P Conclusions— The prognosis of the Wolff-Parkinson-White syndrome essentially depends on intrinsic electrophysiological properties of AP rather than on symptoms. RFA performed during the same procedure after electrophysiological testing is of benefit in improving the long-term outcomes.

Background— The available amount of detailed long-term data in patients with Wolff-Parkinson-White syndrome is limited, and no prospective electrophysiological studies looking at predictors of malignant arrhythmia are available. Methods and Results— Among 8575 symptomatic Wolff-Parkinson-White patients with atrioventricular reentrant tachycardia referred for electrophysiological test, 369 (mean age, 23±12.5 years) declined catheter ablation and were followed up. The primary end point of the study was to evaluate over a 5-year follow-up the predictors and characteristics of patients who develop malignant arrhythmias. After a mean follow-up of 42.1±10 months, malignant arrhythmias developed in 29 patients (mean age, 13.9±5.6 years; 26 male), resulting in presyncope/syncope (25 patients), hemodynamic collapse (3 patients), or cardiac arrest caused by ventricular fibrillation (1 patient). Of the remaining 340 patients, 168 (mean age, 34.2±9.0 years) remained asymptomatic up to 5 years, and 172 (mean age, 13.6±5.1 years) had benign recurrence, including sustained atrioventricular reentrant tachycardia (132 patients) or atrial fibrillation (40 patients). Compared with the group with no malignant arrhythmias, the group with malignant arrhythmias showed shorter accessory-pathway effective refractory period ( P P P P P Conclusions— Symptomatic patients with Wolff-Parkinson-White syndrome generally have a good outcome, and predictors of malignant arrhythmias are similar to those reported for asymptomatic patients with ventricular pre-excitation.

The aim of this study was to assess the performance of echocardiographic parameters to predict response to cardiac resynchronization therapy (CRT).CRT reduces morbidity and mortality due to the proper selection of candidates for CRT.The 12-month trial was performed on 70 optimally medicated patients with standard inclusion criteria: NYHA class III or IV heart failure, left ventricular ejection fraction (LVEF) ≤ 35%, and QRS ≥ 120 ms. All parameters were evaluated by conventional and tissue Doppler-based methods. Indicator of positive CRT response was more than 20% in improvement of LVEF.LVEF increased20% in 42 patients. Out of 43 tested baseline echocardiographic parameters, 12 showed statistical difference between responders and nonresponders. Out of these 12 parameters, six (LVSV, LVSI, LVFS, RVd, VPMR, and PISA) had modest to moderately good ability to predict LVEF response with sensitivity ranging from 62.2% to 82.4%, and specificity ranging from 56.5% to 81.2%. For those parameters, the area under the receiver-operating characteristic curve for positive response to CRT was ≤0.76. Multivariate regression analysis resulted in selection of LVSI and LVFS as possible predictive independent parameters for a good response. The cutoff value for LVSI was 38.7 mL/m(2) (P = 0.045) and for LVFS was 13% (P = 0.032).Contribution of LVSI and LVFS is to be confirmed in larger trials. Simplicity of their assessment by conventional echocardiography could be an argument for adding them to the inclusion criteria for CRT in severe heart failure patients.

Background— Information on comparative outcome between radiofrequency catheter ablation (RFA) and antiarrhythmic drugs (AADs) >1 year after randomization is important for clinical decision-making. Methods and Results— A total of 198 patients (age, 56±10 years) with paroxysmal atrial fibrillation were randomly assigned to RFA (99 patients) or to AADs (99 patients). We evaluated efficacy of RFA or AADs in a comparable 48-month follow-up period according to intention-to-treat analysis. Cardiac rhythm was assessed with daily transtelephonic transmissions. Quality of life was also analyzed. At 4 years, among the 99 patients first assigned to RFA, the procedure was repeated because of recurrent atrial fibrillation/atrial tachycardia in 27 patients (27.3%). Among the 99 patients randomly assigned to AADs, 87 (87.9%) crossed over to undergo RFA and 4 years after random assignment only 12 (12.1%) were in sinus rhythm with AAD alone without ablation. Despite the high level of crossovers, at 4 years the intention-to-treat analysis showed that 72.7% of patients in the ablation arm and 56.5% of those initially randomly assigned to AADs were free of recurrent atrial fibrillation/atrial tachycardia ( P =0.017). During the follow-up, 19.2% of AAD patients progressed to persistent atrial fibrillation before switching to RFA. RFA significantly improved quality of life ( P Conclusions— With follow-up extended to 4 years after randomly assigned, ablation remains superior to antiarrhythmic drug in these patients with paroxysmal atrial fibrillation. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00340314.

Cardiac resynchronization therapy (CRT) has important role in the contemporary treatment of heart failure, systolic dysfunction and mechanical disynchrony. Classical indications for CRT are severe heart failure (NYHA class III or IV), a broad QRS (more than 120 ms) and left ejection fraction less than 35% despite optimal medical therapy. Several have studies demonstrated the important role of echocardiography in patient selection for CRT, follow up and estimation of CRT effects, as well as the optimization of biventricular pacemaker. Basically, there are three types of cardiac asynchrony: interventricular asynchrony, between the right and left ventricle, intraventricular asynchrony, between the myocardial segments within the left ventricle and atrioventricular asynchrony, between the atria and ventricles. Although many echocardiographic techniques are used in patient selection for CRT, no ideal approach has yet been found. There are several techniques and parameters used in the assessment of myocardial asynchrony: two dimensional (2D) echocardiography, one dimensional echocardiography (M-mode), Doppler echocardiography, different modalities of tissue Doppler including Colour Coded Tissue Doppler Imaging - TDI, measurements of local tissue deformation indices (strain and strain rate), speckle tracking, 3D echocardiography, semiquantitative assessment of myocardial border, vector velocity imaging. Each of these techniques has advantages and limitations. A special accent in this revue is on the consensus report from the American Society of Echocardiography Dyssynchrony Writing group. According to this consensus report color coded tissue Doppler is the most appropriate technique for myocardial asynchrony estimation and patients selection for CRT. The same group recommended that definitive decision for CFT implantation should not be based only on echocardiographic analysis, but rather on the whole clinical aspect of the patient.

Introduction: Cardiac resynchronization therapy (CRT) is relatively new tool in treatment of chronic heart failure (HF), especially in dilated cardiomyopathy (DCM) with the left bundle branch block (LBBB). Objective: The Objective of our study was to assess the success of CRT in treatment of severe HF and the role of echocardiography in the evaluation of Results of such therapy. Method: The group consisted of 19 patients, 13 males and 6 females, mean age 58.0?8.22 years (47-65 years) with CRT applied for DCM, severe HF (NYHA III-IV), LBBB and ejection fraction (EF)

R A L A B ST R A C T S Results: Groups were comparable with regards to baseline characteristics. The duration of QRS complex was significantly lower in III group (117 28 ms) compared to II group (154 46 ms, p

Introduction: Cardiac resynchronization therapy (CRT) with biventricular pacing improves acute cardiac hemodynamics. We investigated the correlation of different hemodynamic parameters commonly used to assess acute response. Methods: Forty-four patients (pts) receiving CRT implant with a quadripolar left ventricular (LV) lead and multisite LV pacing-enabled device underwent LV hemodynamic assessment using a PV loop system. PV loops were recorded during biventricular pacing with each of two single LV sites, 4-7 multisite LV pacing settings, and RV pacing (BASELINE). Correlations between dP/dtMax, stroke work (SW), and stroke volume (SV) during different pacing interventions were quantified for each patient with Spearman's rank coefficient (ρ). Results: Evaluable recordings were obtained in 42 pts. SW and SV were positively correlated (ρ > 0.3 in 33 pts, ρ 0.3 in 18 pts, -0.3 0.3 in 11 pts, -0.3 < ρ < 0.3 in 19 pts, and ρ < -0.3 in 12 pts. In one example patient (see Fig.), strong positive correlation existed between SW and SV (ρ = 1.0, p-value < 0.001), while both SW and SV correlated negatively with dP/dtMax (SW: ρ = -0.73, p-value = 0.03, SV: ρ = -0.73, p-value = 0.03). ![Figure][1] Conclusion: Correlation of different hemodynamic parameters varies between pts. Understanding the relationship between hemodynamic parameters could help individualize the selection of a parameter for CRT optimization. [1]: pending:yes

Introduction. The implantable loop recorder (ILR) is a new diagnostic tool in cardiology for establishing The causes of unexplained syncope in patients where standard conventional tests, invasive tests included, have failed. The device is a diagnostic "pacemaker," surgically implanted underneath the skin of the chest, with leads attached to the case of the device, not requiring endovenous lead implantation. Heart rhythm is monitored continuously on the basis of an endless loop, up to a maximum period of 14 months. Recording is carried out either by applying an outside activator whenever symptoms occur, or automatically, according to a preset algorithm for bradycardia, tachycardia, and/or asystolic detection. Objective. The aim of this study was to present this new diagnostic method as well as our first experiences with its implementation. METHOD We followed 5 patients (3 male, 2 female, mean age: 46.4?19) who had ILRs ("Reveal Plus," Medtronic Inc., USA) implanted at our centre, over a period of 14 months (7.6 ?5.5], concentrating on their clinical course, symptom occurrence, and electronically monitored heart rhythm at the time of ILR auto activation and/or recordings triggered by outside activation whenever a patient's symptoms were discernible. Results. In three patients, the ILR revealed syncope aetiology by documenting heart rhythm at the time of its occurrence. In one patient, involving a lethal outcome, the ILR was not explanted, so that the rhythm at the time of the fatal syncope, although assumed, remained undocumented, in one, most recently implanted patient, follow-up is still in progress. Conclusion. The implantable loop recorder represents an important innovation and a step forward in establishing the causes of recurrent syncope, which cannot be determined by standard invasive and non-invasive testing.