Atrial electrogram amplitude variability during atrial fibrillation ablation.

INTRODUCTION: Variability of the bipolar atrial electrogram amplitude may affect voltage maps created during ablation procedures, and thus also the extent of ablations. Therefore, the aim of the study was to assess the beat-to-beat electrogram amplitude variability in the left atrium in patients undergoing atrial fibrillation ablation. METHODS: In 11 patients undergoing ablation for atrial fibrillation, 362 mapping points were collected in two series. At each point, three consecutive beats were recorded and verified including the bipolar electrogram amplitude, contact force (CF), and orientation of the catheter tip. The repeatability and reproducibility of obtained measurements between consecutive beats and series were assessed by the Pearson correlation coefficient (r), the Bland-Altman test, repeatability coefficient (RC), relative standard deviation (RSD), and concordance correlation coefficient (CCC). RESULTS: A total of 1086 beats were analyzed. The correlation coefficient for bipolar atrial electrogram amplitude for the first two beats, and for the first and the third beats were 0.94 and 0.86, respectively. The average of differences between the first two beats and between the first and the third beats were 0.06 and 0.13 mV with 95% limits of agreement (LoA) within ±0.98 and ±1.74 mV, respectively. For CF values ≤5 and ≥20 g, the 95% LoA were narrower compared to other CF ranges and were ±0.49 and ±0.71 mV from the average value, respectively. When the analyzes were performed within the predefined ranges of bipolar electrogram amplitude: 0.05-1; 1-2; 2-3 mV, the 95% LoA were within ±0.33, ±0.98, and ±0.84 mV from the average value, respectively. RC and RSD were 1.41 mV and 20.8%, respectively. For repeated measurement between series, CCC ranged from 0.67 to 0.71 and the 95% LoA were within ±2.7 to 2.9 mV from the average value. CONCLUSION: Bipolar atrial electrogram amplitude recorded at a given site during ablation procedures is variable to an extent that may be clinically relevant. The magnitude of the observed variability is greater during remapping.

Distances between transseptal puncture site and anatomical landmarks.

The aim of the study was to provide quantitative data and to look for new landmarks useful during transseptal puncture (TSP) using a fluoroscopy-guided approach. METHODS AND RESULTS: A total of 104 patients at mean age 57 ± 12 years, of whom 92% underwent pulmonary vein isolation, were analysed. Before TSP catheters were placed in the coronary sinus (CS) and His bundle region. A guidewire running from femoral vein through great veins was left loose in superior vena cava. Before TSP X-ray images were taken in right anterior oblique (RAO) 45° and RAO 53° projections. Locations posterior to TSP site in RAO were described with negative values and those anterior with positive values. The measured distances in millimeters were as follows: (a) between TSP site and posterior atrial wall (RAO 45 = -21 ± 7 mm; RAO 53 = -19 ± 6 mm (b) between TSP site and free guidewire (RAO 45 = -5 ± 4 mm, RAO 53 = -3 ± 4 mm (c) between TSP site and CS ostium (RAO 45 = 9 ± 6 mm; RAO 53 = 8 ± 5 mm (d) between TSP site and His region (RAO 45 = 29 ± 8 mm; RAO 53 = 30 ± 8 mm). We observed correlations between measured distances and age, body mass index and sizes of cardiac chambers. The distance between TSP site and the line projected by the guidewire running between great veins, measured in mid-RAO projections, was very small. CONCLUSION: The distances between TSP site and standard anatomical landmarks used during TSP vary with regard to age, physique and cardiac chamber dimensions. TSP site, as assessed in mid RAO, is in direct vicinity to the line projected by a guidewire running between the great veins.

Cryoballoon ablation without use of contrast for the treatment of paroxysmal atrial fibrillation.

BACKGROUND: Cryoballoon ablation (CBA) for atrial fibrillation (AF) is usually preceded by demonstrating pulmonary vein (PV) occlusion using contrast. The aim of the study was to determine efficacy and safety of a simplified protocol for CBA performed without demonstrating PV occlusion and compare achieved results with conventional CBA. METHODS: Paroxysmal AF patients undergoing a first-time CBA were prospectively included. In the non-contrast (NC) group CBA was performed using standardized protocol without demonstrating PV occlusion. In the conventional contrast (CC) group ablations were performed after confirmation of PV occlusion. RESULTS: The NC and CC groups comprised 51 and 22 patients, respectively. PVI according to the group assignment was achieved in 34 (67%) and 21 (95.5%) patients from the NC and CC groups, respectively (p < 0.001). In the NC group, 184 (90%) out of 204 veins were isolated without venography. There were no differences between the NC and CC groups in terms of procedure duration (89.7 ± 22.6 vs. 90.0 ± 20.6 min; p = 0.7) and fluoroscopy time (15.3 ± 6.3 vs. 15 ± 4.5 min; p = 0.8). In the NC group, the use of contrast was significantly lower compared to the CC group (4.9 ± 10.1 vs. 19.4 ± 8.6 mL, p < 0.001). There were no serious adverse events in both groups. A 1-year freedom from AF was achieved in 73.5% and 71.5% of patients from the NC and CC groups, respectively (p = 1). CONCLUSIONS: Cryoballoon ablation without demonstrating vein occlusion with contrast is safe and feasible. Proposed simplified approach enables isolation of the vast majority of pulmonary veins with a significant reduction in the amount of contrast used.

Bipolar endo-epicardial RF ablation: Animal feasibility study.

BACKGROUND: Bipolar radiofrequency ablation (B-RFA) is a method used to treat the arrhythmia substrate resistant to unipolar ablation. Few studies have addressed endo-epicardial B-RFA. OBJECTIVE: The aim of the study was to evaluate chronic lesions resulting from endo-epicardial B-RFA and to determine optimal settings for such procedures in an animal model. METHODS: In 7 pigs, up to 5 radiofrequency applications per animal were performed with 2 electrodes placed on both sides of the left ventricular free wall. Current was delivered for 60 seconds by a generator dedicated for B-RFA with power settings of 25, 30, 35, 40, and 50 W. RESULTS: At 12 weeks after ablation, 31 lesions were assessed. Their maximal cross-sectional area ranged from 7.2 to 68 mm2 and correlated with total power delivered (r = 0.53), with temperature increment at the endocardial catheter (r = 0.65), and inversely with temperature decrement at the epicardial catheter (r = 0.54). For power values between 30 and 40 W, the lesion area did not differ significantly (P = .92). Lesion depth ranged from 1.9 to 11 mm and correlated with impedance decrement (r = 0.5). Lesions were transmural in 8 cases. Lesion depth/wall thickness ratio was on average 0.6 ± 0.3, with the smallest value for 25 W (0.5 ± 0.3) and the largest for 50 W (0.8 ± 0.3). Steam pops occurred at a power range of 30-50 W, with an incidence of 1 in 5 applications, with 1 case of fatal tamponade at 40 W. Impedance decrement, endocardial catheter temperature increment, and endocardial electrogram amplitude decrement were greater during applications with steam pops. CONCLUSION: Chronic lesions resulting from endo-epicardial B-RFA appear smaller and less often transmural compared with acute lesions described in the literature. The incidence of steam pops during endo-epicardial B-RFA is relatively high even at low powers.

Bipolar Endo-Epicardial Radiofrequency Ablation of Therapy-Resistant Ventricular Arrhythmias: A Brief Case Series.

Despite extensive conventional endoepicardial ablation, significant intramural arrhythmogenic substrate may remain out of reach of unipolar radiofrequency ablation (RFA). The authors present clinical findings and procedural workflow for bipolar radiofrequency ablation (B-RFA) with 1 catheter placed against the endocardium and the other in the pericardial sac to ablate refractory ventricular arrhythmias. No serious adverse events occurred during B-RFA procedures, and the short-term and midterm clinical results were satisfactory. Optimal catheter choice and ablation parameters settings for B-RFA remain to be determined.

Atrial fibrillation in patients with Wolff-Parkinson-White syndrome: role of pulmonary veins.

AIM: We aimed to characterize electrophysiological properties of pulmonary veins (PVs) in patients with Wolff-Parkinson-White (WPW) syndrome and atrial fibrillation (AF), and to compare them to those in patients with WPW without AF. METHODS AND RESULTS: A total of 31 patients (mean age 40 ± 15 years, 23 males) with WPW were recruited: 16 patients with (AF group) and 15 without (controls) a history of AF. The basic electrophysiological (EPS) and echocardiographic data were not different between the 2 groups. Effective refractory periods (ERPs) of PVs were significantly shorter in the AF group compared to controls: left superior (LS) PV ERP 185±29 versus 230 ± 24 ms, P = 0.001; left inferior PV ERP 198 ± 25 versus 219 ± 26 ms, P = 0.04; right superior (RS) PV ERP 207 ± 25 versus 236 ± 19 ms, P = 0.001; right inferior PV ERP 208 ± 30 versus 240 ± 19 ms, P = 0.003. Maximal veno-atrial conduction delay (i.e., the maximal prolongation of interval from stimulus delivered at PV ostia to proximal coronary sinus after extrastimulus compared to the basic drive cycle) was longer in the AF group when pacing from LSPV (69.3 ± 37.9 vs 32.6 ± 16.1 ms, P = 0.01) and RSPV (74.1 ± 25.9 vs 50.2 ± 26.5 ms, P = 0.04). During EPS, AF was induced more often in the AF group (n = 7) compared to controls (n = 1; P = 0.04). Follow-up revealed that AF recurred in 3 patients in the AF group and none of the controls. CONCLUSION: Patients with WPW syndrome and AF have shorter ERPs of PVs and greater maximal veno-atrial conduction delay compared to patients with WPW without AF. These findings suggest a potential role of PVs in the development of AF in patients with WPW.

Safety and Efficacy of a Novel Blunt-Tip Concealed-Needle Epicardial Access Device: First-in-Human Feasibility Study.

Epicardial access is becoming increasingly important for various cardiovascular interventions. Access to dry pericardial space can be challenging and is often associated with significant complications. A novel concealed-needle blunt-tip device is designed to capture the parietal pericardium layer and retract it into the distal end of the device, which houses a fixated concealed needle, in a bid to minimize the likelihood of lacerating the visceral layer of the pericardium. This prospective single-arm study evaluated the feasibility of use of this device in 11 human subjects with successful access attained in 91% (10 of 11) of cases without adverse events. (Pericardial Access With ViaOne Device; NCT05006157).

Simultaneous Entrainment Response Assessment at Multiple Sites.

BACKGROUND: The entrainment response, defined as the difference between the postpacing interval and the tachycardia cycle length (TCL) recorded from a mapping catheter, allows to track down the components of the tachycardia loop. OBJECTIVES: The aim of this study was to evaluate if the postpacing interval measured simultaneously from multiple sites that are remote from the pacing site (PPIR) could be clinically useful in mapping re-entrant circuits. METHODS: Ninety-two episodes of entrainment response in 29 patients with different macro-re-entrant tachycardias were evaluated using a standardized entrainment protocol. The spatial distribution of different values of PPIR-TCL in a simulation and a computational model of an entrained re-entrant tachycardia was also analyzed. RESULTS: The PPIR exceeded TCL by more than 20 milliseconds only if both pacing and recording sites were outside the tachycardia circuit. The PPIR-TCL at in-circuit sites was always ≤20 milliseconds. Sites with negative PPIR-TCL values were found either outside or inside the tachycardia circuit. CONCLUSIONS: Assessment of entrainment response from catheters remote from the pacing site may enhance spatial mapping of the tachycardia circuit. The PPIR-TCL above 20 milliseconds has an excellent positive predictive value in identifying sites outside the tachycardia circuit.

[Short QT syndrome--a case report]. / Zespól skróconego odstepu QT--opis przypadku.

We present two new cases of the short QT syndrome--a 23-year-old male and his 42-year-old mother. Invasive electrophysiological study was negative in both patients. Due to polymorphic ventricular tachycardia recorded during Holter ECG monitoring, an ICD was implanted in the male patient for primary prevention. Blood samples were collected for further genetic studies. Diagnosis and management of patients with the short QT syndrome are discussed.

[Ablation of right ventricular tachycardia with a bizarre QRS complex--a case report]. / Ablacja czestoskurczu z prawej komory o niezwyklym ksztalcie QRS--opis przypadku.

We describe a case of a 77-year-old patient with recurrent, symptomatic ventricular tachycardia with a bizarre QRS complex originating from the right ventricle lateral wall. The small region of slow conduction was the critical substrate for initiation and maintenance of ventricular tachycardia, confirmed by a successful one RF application.

Implantable cardioverter-defibrillators in patients with long QT syndrome: a multicentre study.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) therapy has been proven effective in the prevention of sudden cardiac death, but data on outcomes of ICD therapy in the young and otherwise healthy patients with long QT syndrome (LQTS) are limited. AIM: We sought to collect data on appropriate and inappropriate ICD discharges, risk factors, and ICD-related complications. METHODS: All LQTS patients implanted with an ICD in 14 centres were investigated. Demographic, clinical, and ICD therapy data were collected. RESULTS: The study included 67 patients (88% female). Median age at ICD implantation was 31 years (12-77 years). ICD indication was based on resuscitated cardiac arrest in 46 patients, syncope in 18 patients, and malignant family history in three patients. During a median follow-up of 48 months, 39 (58%) patients received one or more ICD therapies. Time to first appropriate discharge was up to 55 months. Inappropriate therapies were triggered by fast sinus rhythm, atrial fibrillation, and T-wave oversensing. No predictors of inappropriate shocks were identified. Risk factors for appropriate ICD therapy were: (1) recurrent syncope despite b-blocker treatment before ICD implantation, (2) pacemaker therapy before ICD implantation, (3) single-chamber ICD, and (4) noncompliance to b-blockers. In 38 (57%) patients, at least one complication occurred. CONCLUSIONS: ICD therapy is effective in nearly half the patient population; however, the rates of early and late complica-tions are high. Although the number of unnecessary ICD shocks and reimplantation procedures may be lowered by modern programming and increased longevity of newer ICD generators, other adverse events are less likely to be reduced.

[QRS and cycle length alternans during atrioventricular nodal reentry tachycardia: case report]. / Zmiennosc ksztaltu zespolów QRS i dlugosci cyklu w nawrotnym czestoskurczu wezlowym. Opis przypadku.

A 23-year old man with paroxysmal, poorly tolerated and spontaneously terminating palpitations, was referred to our department for electrophysiological study. Burst pacing from high right atrium using a cycle length of 350 ms induced a slowfast atrioventricular nodal reentry tachycardia. We excluded the presence of accessory atrioventricular tracts. During tachycardia a constant alternans of QRS morphology and cycle length was observed. The cycle length alternans could be due to the presence of three nodal pathways and activation circulating in a figure-of-eight pattern using alternatively two slow pathways as the antegrade arm of the reentry loop. The alternans could also originate from altering decremental properties of a single slow pathway that changed its conduction properties with relation to the length of the preceding cycle. The QRS alternans occurred both during burst pacing and tachycardia. As it was related to the rate and the changing cycle length, we concluded that it could reflect aberration in intraventricular conduction.

[RF ablation in a patient with recurrent post-infarction ventricular tachycardia requiring multiple cardioverter-defibrillator interventions]. / Ablacja RF u chorego z wielokrotnymi interwencjami kardiowertera-defibrylatora z powodu pozawalowego czestoskurczu komorowego.

A case of a 51 year old patient with a history of myocardial infarction (MI) and recurrent ventricular tachycardia (VT) is presented. Three months after MI the patient underwent coronary angioplasty and one year later received prophylactic implantable cardioverter-defibrillator (ICD) due to complex ventricular arrhythmias, detected on Holter ECG monitoring, and depressed left ventricular ejection fraction. Later on the patient started to experience palpitations and ICD shocks during physical activity (cycling). Interrogation of the ICD memory showed appropriate shocks due to slow (160 betas/min) VT. The device was reprogrammed and new antitachycardia pacing (ATP) algorithms were enabled, however, it occurred proarrhythmic due to the ATP-induced acceleration of VT rate. Finally, in April 2005 he received 37 appropriate ICD shocks during a few hours. The patient was selected for RF ablation and underwent successful procedure with the use of the electro-anatomical CARTO mapping system.

Atrial resynchronization in patients after heart transplantation.

UNLABELLED: Lower-Shumway technique (atrioatrial anastomosis) is the most frequently used technique for orthotopic heart transplantation and such a patient has two right atria and two sinus nodes. Sinus node dysfunction (SND) is a frequent finding in pts. after OHT; taking advantage of the frequency of innervated sinus node of recipient's atrial remnant as a natural biosensor for triggered pacing of donor atrium is an interesting option for these pts. THE AIMS OF OUR STUDY: 1. the analysis of possibility of utility of recipient atrial sinus node as natural biosensor for triggered donor atrium permanent pacing in transplanted patients with SND. 2. the evaluation of pacing and sensing conditions of the recipient's atrium in the some pts.. 3. long-term observation of effectiveness A2A2T(/D) pacing mode. METHODS: 10 out of 37 pts. received A2A2T (8 pts.) and A2A2T/D (2 pts) pacing systems. In pts. with NSR of recipients atrium, we evaluated acceleration of its frequency during slight exercise and atropine. RESULTS: In recipient's atrium among 37 pts we recognized NSR only in 15/37 pts.; in the remaining 22 pts. we found: sinus bradycardia--in 3, atrial flutter--in 3, low voltage AF--in 12 and no electrical activity--in 4 pts. Positive response to isometric exercise and atropine was observed in 12/15 pts. and 8 of them received A2A2T or A2A2T/D pacing system. We found much better sensing and pacing conditions in donor (A wave 2.1 mV, p. threshold 0.8 V) than in recipient atrium (1.1 mV and 1.4 V respectively). We observed some problems with sensing of recipient atrium in 4 of 10 pts. and changes SST to AAI-R mode solved the problem without loss of atrial resynchronization. 9 out of 10 pts. preferred AAT to AAI-R pacing program. One dislodged lead required revision during postoperative period (1/44, 2%). There was no dislodgement related to endomyocardial biopsy. In one patient, atrial flutter in recipient atria was transmitted to atrium of transplanted heart by pacing system with 2:1 conduction; arrhythmia was interrupted with drugs and did not return. CONCLUSIONS: 1. Atrial resynchronization is possible only in about 1/4 patients with SND after OHT due to frequently noted electrophysiological changes in recipient atrium. 2. In transplanted heart patients sensing and pacing conditions are much more favorable in donor's than recipient's atrium. 3. Atrial resynchronization can be subjectively (positively) recognised by most of patient after OHT and it still remains a promising pacing mode for selected patients after OHT with SND.

Atrial pacing of transplanted heart.

UNLABELLED: Orthotopic heart transplantation (OHT) is most effective method for treatment of irreversible heart failure. Patients after OHT considered for permanent pacing consist still present a challenge for the implanting physician due to distorted atrial geometry and specific electrophysiological conditions of atrium. The aim of our study was to analyse the effectiveness of permanent atrial pacing in these patients. PATIENTS AND METHODS: We implanted atrial lead in 37 SND pts., 2 months--7 years after OHT, (3 pts with coexisting AV block received ventricular lead). Only straight BP screw-in leads and manually formed stylets were used; we found satisfactory pacing/sensing conditions in 25 pts in RA appendage or anterior/lateral wall, in 10 pts--in CS ostium region and in 2--in proximal part of CS. RESULTS: All implantations were successful and no patient received VVI pacing system. One dislodged lead required revision (1/37, 3%) but this was not related to endomyocardial biopsy. In 2 pts, due to unacceptable low RA potential and/or high PTh values atrial lead was implanted to CS for sensing/pacing of left atrium. The average acute value of A wave were 2.4 mV and chronic 2.2 mV; values of pacing threshold were 0.9 V and 1.6 V respectively. Only in 13/37 pts native A waves were recorded but with amplitude < 0.6 mV. Wenckebach point was 120/min only in 2 pts., in borders 130-160 bpm in 15 pts. and exceeded 170 bpm. in remained 20 pts. Retrograde VA conduction was intact in 33/37 pts, but in 4 pts exceeded 260/min. During long term follow-up in no patient we observed AV conduction disturbances. In 6 pts. treadmill exercise (Bruce's protocol) was repeated three times during: sinus (spontaneous) rhythm, AAI pacing 70/min, AAI-R (DDD-R) pacing. AAI 70 bpm did not influence significantly attained workload, heart rate on peak exercise or duration of exercise. But atrial rate modulated pacing increased values of examined parameters significantly. CONCLUSIONS: 1. Atrial pacing (and atrial based pacing modes) are possible in majority of transplanted heart patients. 2. Frequency of atrial lead dislocation, appearance of atrial sensing problems and AV conduction disturbances (all in about 3%) are comparable to non-transplanted patients. 3. In most patients with SND after OHT AV conduction remains within normal limits; it indicates safety of rate responsive pacing modes in these patients. 4. Rate modulated atrial pacing improves exercise tolerance in heart transplanted patients with SND. 5. High ("supra-normal") values of Wenckebach's point observed in most of patients with transplanted (dennervated) heart may have clinical importance in cases of atrial arrhythmias in these patients.

[Acute coronary syndrome during dissection of left main as a complication of radiofrequency ablation]. / Ostry zespol wiencowy w przebiegu rozwarstwienia pnia lewej tetnicy wiencowej jako powiklanie zabiegu ablacji pradem o wysokiej czestotliwosci.

We present a case of 44 year-old female who was admitted to the hospital due to performed radio frequency ablation because of VF during WPW syndrome, which was complicated by dissection of left main. The dissection was treated with success by primary percutaneous coronary intervention with two metal stents.

[Arrythmogenic right ventricular cardiomyopathy in patient with abnormal origin of right coronary artery and ventricular tachycardia during exercises]. / Arytmogenna kardiomiopatia prawej komoryu chorego z anomalia tetnic wiencowychi czestoskurczem komorowym wywolanymwysilkiem fizycznym.

A 18-year-old patient with abnormal origin of right coronary artery and ventricular tachycardia during exercises is presented. Myocardial biopsy revealed arrhythmogenic right ventricular cardiomyopathy.

[Reentrant ventricular tachycardia treated with RF ablation delivered through coronary sinus - a case report]. / Burza elektryczna w przebiegu ustawicznego nawrotnego czestoskurczu komorowego o lokalizacji epikardialnej skutecznie leczonego ablacja RF z dojscia przez zatoke wiencowa.

A case of a 58 year-old man with epicardially located reentrant ventricular tachycardia treated with RF ablation delivered through coronary sinus is presented. Based on multiple electrophysiological parameters (surface ECG, electroanatomical map collected from the endocardium, bipolar and unipolar endocardial recordings, and unsuccesful ablation attempts from the endocardial side) the tachycardia loop was found to be located epicardially. This allowed for successful ablation approach.