Tchavdar N. Shalganov

Preventing complicated transseptal puncture with intracardiac echocardiography: case report.

BackgroundRecently, intracardiac echocardiography emerged as a useful tool in the electrophysiology laboratories for guiding transseptal left heart catheterizations, for avoiding thromboembolic and mechanical complications and assessing the ablation lesions characteristics. Although the value of ICE is well known, it is not a universal tool for achieving uncomplicated access to the left atrium. We present a case in which ICE led to interruption of a transseptal procedure because several risk factors for mechanical complications were revealed.Case presentationA case of a patient with paroxysmal atrial fibrillation and atrial flutter, and distorted intracardiac anatomy is presented. Intracardiac echocardiography showed a small oval fossa abouting to an enlarged aorta anteriorly. A very small distance from the interatrial septum to the left atrial free wall was seen. The latter two conditions were predisposing to a complicated transseptal puncture. According to fluoroscopy the transseptal needle had a correct position, but the intracardiac echo image showed that it was actually pointing towards the aortic root and most importantly, that it was virtually impossible to stabilize it in the fossa itself. Based on intracardiac echo findings a decision was made to limit the procedure only to ablation of the cavotricuspid isthmus and not to proceed further so as to avoid complications.ConclusionThis case report illustrates the usefulness of the intracardiac echocardiography in preventing serious or even fatal complications in transseptal procedures when the cardiac anatomy is unusual or distorted. It also helps to understand the possible mechanisms of mechanical complications in cases where fluoroscopic images are apparently normal.

Mid-term echocardiographic follow up of left ventricular function with permanent right ventricular pacing in pediatric patients with and without structural heart disease

BackgroundChronic right ventricular apical pacing may have detrimental effect on left ventricular function and may promote to heart failure in adult patients with left ventricular dysfunction.MethodsA group of 99 pediatric patients with previously implanted pacemaker was studied retrospectively. Forty-three patients (21 males) had isolated congenital complete or advanced atrioventricular block. The remaining 56 patients (34 males) had pacing indication in the presence of structural heart disease. Thirty-two of them (21 males) had isolated structural heart disease and the remaining 24 (13 males) had complex congenital heart disease. Patients were followed up for an average of 53 ± 41.4 months with 12-lead electrocardiogram and transthoracic echocardiography. Left ventricular shortening fraction was used as a marker of ventricular function. QRS duration was assessed using leads V5 or II on standard 12-lead electrocardiogram.ResultsLeft ventricular shortening fraction did not change significantly after pacemaker implantation compared to preimplant values overall and in subgroups. In patients with complex congenital heart malformations shortening fraction decreased significantly during the follow up period. (0.45 ± 0.07 vs 0.35 ± 0.06, p = 0.015). The correlation between the change in left ventricular shortening fraction and the mean increase of paced QRS duration was not significant. Six patients developed dilated cardiomyopathy, which was diagnosed 2 months to 9 years after pacemaker implantation.ConclusionChronic right ventricular pacing in pediatric patients with or without structural heart disease does not necessarily result in decline of left ventricular function. In patients with complex congenital heart malformations left ventricular shortening fraction shows significant decrease.

The presence of extensive atrial scars hinders the differential diagnosis of focal or macroreentrant atrial tachycardias in patients with complex congenital heart disease

AIMS Atrial tachycardias (ATs) frequently develop in patients with congenital heart defects (CHDs). This study aimed to evaluate the effects of extensive atrial scar formation on the total atrial activation time (TAAT) and its relation to the tachycardia cycle length (CL) to classify AT. METHODS AND RESULTS Seventy-one patients were included and divided into two groups: patients without CHD (Group I, 35 patients) and with CHD (Group II, 36 patients). All patients underwent CARTO electroanatomical activation mapping. Two subgroups were created: centrifugal (CAT) or macroreentrant AT (MRAT). Total atrial activation time, CL, and mean bipolar signal amplitude (BiSA) were analysed. In Group I, 18 patients (51.4%) had CAT and 17 (48.6%) MRAT. The mean BiSA for Group I was 1.30 ± 0.32 mV. Total atrial activation time/CL ratios were different between CAT and MRAT (28.4 ± 16.9 vs. 66.6 ± 14.3%, P < 0.001). In Group II, 18 patients (50%) had CAT and 18 patients (50%) MRAT. The mean BiSA was 0.94 ± 0.50 mV and was not different for CAT and MRAT subgroups (1.04 ± 0.64 vs. 0.85 ± 0.29, P = 0.243). Total atrial activation time/CL ratios were comparable between CAT and MRAT patients (69.0 ± 40.4 vs. 83.6 ± 8.3%, P = 0.243). A significant lower BiSA was found for CAT with TAAT/CL ratios above 40% (0.62 ± 0.11 vs. 1.90 ± 0.18 mV, P < 0.001). A strong negative correlation was identified between the BiSA and the TAAT/CL ratio in patients with CAT in Group II (-0.742; P < 0.001). CONCLUSION Low mean BiSA values in CHD patients are associated with altered impulse propagation, making TAAT- and CL-based diagnostic tools inaccurate. Further diagnostic tests are needed to determine the correct mechanism of ATs.

Selective slow pathway ablation using transseptal approach in a patient with surgically corrected partial atrioventricular canal defect and atrioventricular nodal reentrant tachycardia of the common type

A 26-year-old woman with partial atrioventricular (AV) canal defect surgically closed with pericardial patch in a mode that the triangle of Koch had become part of the left atrium underwent successful slow pathway ablation for slow-fast AV nodal reentrant tachycardia. Transseptal approach was used because of the atypical post-operative anatomy. Transseptal catheter ablation of the slow pathway can be a reasonable and safe alternative in patients subjected to this type of operation.

Ice mapping during tachycardia in close proximity to the AV node is safe and offers advantages for transcatheter ablation procedures.

Background — Ablation during ongoing orthodromic reentry tachycardia (AVRT) and atrioventricular nodal reentry tachycardia (AVNRT) is not recommended using radiofrequency energy when the arrhythmia substrate is located in close proximity to the atrioventricular (AV) node due to a significant risk for inadvertent AV block. The aim of the study is to test the feasibility of ice mapping during tachycardias involving arrhythmia substrate located in close proximity to the AV node. Methods — This was a single-centre, prospective, randomized study. A total of 65 patients was screened and 30 patients with supraventricular arrhythmias were assigned either to a cryo or RF energy group after diagnosis of AVNRT (17 pts) or AVRT (13 pts) with an anteroseptal accessory pathway. RF ablation was performed using standard ablation techniques. In the cryo group, ice mapping was performed during tachycardia with cooling of the catheter tip temperature to a maximum of —40°C. Ablation was performed only if ice mapping terminated the tachycardia without prolongation of the AV conduction. Results — The overall acute success rate was 84%, and was not different in the cryo and RF groups (85% vs. 82.4%, P = 0.43). Both fluoroscopy and the procedure times were comparable.There was a marked reduction in the mean number of applications in the cryo group [2 (1-6) vs. 7 (1-41), P = 0.002]. In one patient ablation was not attempted in the cryo group because of AV prolongation, and in two patients temporary second-degree AV block was observed in the RF group. After 12 months follow-up the long-term success rate was similar between the two groups. Conclusions — (1) Ice mapping is a feasible method to determine the exact location of accessory pathways and of the slow pathway during tachycardia. (2) Ice mapping performed during tachycardia causes less ablation lesions without increasing the procedure and fluoroscopy times.

Electrogram analysis at the His bundle region and the proximal coronary sinus as a tool to predict left atrial origin of focal atrial tachycardias

AIMS Early activation at the His bundle (HB) region or proximal coronary sinus (CS) during focal atrial tachycardias (FATs) often necessitates biatrial mapping. Analysis of CS electrograms (EGMs) consisting of a near-field (N) component from CS musculature and a far-field (F) component from left atrial (LA) myocardium can uncover LA activation preceding right atrial (RA) activation. A similar pattern might be observed at the HB. METHODS AND RESULTS Eight patients underwent RA and LA pacing testing the hypothesis that N and F components originating from the RA and LA septum are present in the HB atrial EGM (Pacing group). In this group N preceded F (N-F sequence) in all, while F preceded N (F-N sequence) in seven of eight patients during RA and LA pacing, respectively. Twenty-seven patients with FAT demonstrating earliest activation at the HB or proximal CS during limited RA mapping were also studied (FAT group). Two observers analysed the EGMs at the earliest site during FAT. They found an N-F sequence in 17 (94%) and 16 (89%) of 18 RA FAT and an F-N sequence in seven (78%) and eight (89%) of nine LA FAT, respectively. The F-N sequence predicted the need for LA access with a sensitivity of 78 and 89% and a specificity of 94 and 89%. CONCLUSION Near-field and F components from RA and LA activation can be identified in the HB atrial EGM. Earliest atrial EGM analysis at the HB or CS can predict the need for LA access during FAT ablation.

Correlation between the sudden jump-like increases of the atrio-Hisian interval induced during burst atrial pacing and during programmed atrial stimulation in patients with atrioventricular nodal reentrant tachycardia

Purpose To study the correlation between the sudden prolongations of the atrio-Hisian (AH) interval with ≥50 ms during burst and programmed atrial stimulation, and to define whether the AH jump during burst atrial pacing is a reliable diagnostic criterion for dual AV nodal physiology. Methods Retrospective data on 304 patients with preliminary ECG diagnosis of AV nodal reentrant tachycardia (AVNRT), confirmed during electrophysiological study, was analyzed for the presence of AH jump during burst and programmed atrial stimulation, and for correlation between the pacing modes for inducing the jump. Wilcoxon signed-ranks test and Spearmans bivariate correlation coefficient were applied, significant was P-value <0.05. Results The population was aged 48.5 ± 15.7 (12-85) years; males were 38.5%. AH jump occurred during burst atrial pacing in 81% of the patients, and during programmed stimulation – in 78%, P = 0.366. In 63.2% AH jump was induced by both pacing modes; in 17.8% – only by burst pacing; in 14.8% – only by programmed pacing; in 4.2% there was no inducible jump. There was negative correlation between both pacing modes, ρ = –0.204, Р<0.001. Conclusion Burst and programmed atrial stimulation separately prove the presence of dual AV nodal physiology in 81 and 78% of the patients with AVNRT, respectively. There is negative correlation between the two pacing modes, allowing the combination of the two methods to prove diagnostic in 95.8% of the patients.

Bi-atrial and right atrial activation times help to differentiate focal from macroreentrant right atrial tachycardias

Objective — The objective was to study atrial activation intervals and their relation to the tachycardia cycle length (TCL) as electrophysiologic parameters differentiating focal (FAT) from macroreentrant atrial tachycardias (MRAT) originating in the right atrium. Methods — In 21 patients (8 men) with 30 successfully ablated right atrial tachycardias (15 focal) the endocardial activity during tachycardia was registered using multipolar catheters in the right atrium and the coronary sinus. Using this catheter configuration we measured the tachycardia cycle length (TCL), biatrial activation (BAA), right atrial activation (RAA), left atrial activation (LAA), as well as the proportion of those intervals to TCL. In 14 patients, the measurements were repeated in sinus rhythm as well. The diagnostic accuracy of the ratio of BAA to TCL was assessed. Results — TCL was longer, but all other intervals and ratios were significantly shorter in FAT compar dto MRAT (P < 0.05 for all parameters, except for LAA – P= NS). During sinus rhythm, patients with MRAT had prolonged RAA (P = 0.003), but not BAA and LAA (P= NS), compred to patients with FAT. A discriminating value of 40% for the ratio of BAA to TCL, compared to 50% and 30%, was found to have the best sensitivity, specificity, positive and negative predictive values for MRAT, as well as for FAT. Conclusions — BAA, RAA, LAA and their relation to the TCL are significantly shorter in FATs compared to MRATs arising from the right atrium. The ratio of BAA to TCL obtained using a simple 2-catheter configuration, allows a rapid and reliable differentiation between FAT and MRAT.

Transseptal access to the left atrium from the left femoral vein.

Transseptal (TS) access to the left atrium (LA) is obtained routinely via right femoral vein approach. Alternative approaches have been reported occasionally. A 66-year-old female patient was referred to our institution for wide QRS complex tachycardia workout. She had no angina or heart failure, although severely depressed left ventricular function was described on echocardiography. Multiple episodes of sustained tachycardia with LBBB morphology were recorded on ambulatory Holter-ECG. The QRS complex and electrical axis during tachycardia and during sinus rhythm were identical. The tachycardia was refractory to the available drugs. The patient had an electrophysiologic study and LA tachycardia was diagnosed. Ablation was attempted, with difficult passage of the TS needle through the right iliac vein and subsequent difficult rotation of the TS set. The procedure was prematurely stopped because of inadvertent puncture of the aortic root without any hemodynamic sequel. She was discharged in incessant tachycardia with drug-controlled ventricular rate. One month later the patient presented again with uncontrolled ventricular rate. A second ablation procedure was undertaken. An EnSite NavX (St. Jude Medical, St. Paul, MN, USA) system for electroanatomic mapping was used. This time the TS needle stopped at the level of the right iliac vein. After several unsuccessful attempts to surmount the iliac vein, the introducer was withdrawn. Several tiny bulges were seen on its wall (Figures 1A and B). A contrast injection described right iliac vein without any marked tortuosity. After replacing the TS set it was again not possible to get past the iliac vein and ultimately the needle stylet was seen to go outside the contour of the introducer. After removal of the introducer, a tearing on its wall was seen (Figure 1B). A new contrast injection did not show any leak out

Unusual wenckebach phenomenon due to an atrial tachycardia arising from the apex of koch's triangle in the presence of dual AV nodal physiology

A case of a patient with narrow QRS tachycardia and without structural heart disease is presented. The electrophysiologic study revealed an atrial tachycardia in the presence of dual atrioventricular (AV) nodal physiology and AV block at suprahisian level, the latter two leading to an unusual Wenckebach periodicity. The entire septal area was mapped as was the coronary sinus (CS) os and the earliest atrial activation was found at the apex of Koch’s triangle in close vicinity to the His bundle (HB). Cryomapping at that point reproducibly terminated the tachycardia without impairing AV conduction. Cryoablation rendered the tachycardia non-inducible. Discontinuous AV conduction persisted but AV nodal reentrant tachycardia (AVNRT) was not inducible. Six months later the patient is arrhythmia-free.