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A 62-year-old pacemaker-dependent patient presented to our department with a sudden onset of reduced physical capacity. While initial physical and pacemaker evaluations remained without specific findings, Holter-ECG monitoring revealed an abnormal rate response with unusual pauses during physical exercise. Consequently, closer evaluation of the pacemaker system revealed intermittent, exercise-related T-wave oversensing (TWOS). While TWOS remains a significant burden in ICD-patients, it might be an underestimated but clinically significant event in pacemaker patients. Further studies should evaluate the impact of TWOS in this patient population.

Background and aim: The complexity and success rate of right atrial flutter ablation is highly dependent on anatomical structures. Methods: The study comprised 35 consecutive patients (33–77 years old; 30 men) who underwent ablation of typical atrial flutter. The linear ablation line was measured offline as a surrogate for the cavotricuspid isthmus (CTI) length with the help of a three-dimensional mapping and navigation system (Ensite™). Biophysical parameters, such as total radiofrequency (RF) energy and time of the ablation procedure, were analysed to test the hypothesis that any of these variables show a correlation with the length of the ablation line. Results: Bidirectional isthmus block was achieved in all cases. The isthmus length had a mean value of 32 ± 12 mm with a range of 14–57 mm. The linear regression between the CTI length and the total RF energy was not significant. There was no significant difference in energy (32.281 ± 25.587 vs. 37.136 ± 24.250 W-s, p = NS) or in the total ablation time (759 ± 646 vs. 802 ± 533 s, p = NS) between the group with short (< 29 mm; n = 17) vs. long CTI (≥ 29 mm, n = 18). When comparing different ablation technologies, total RF energy delivered with 8-mm catheter technol­ogy (group I) was significantly lower than in patients with cross over from 8-mm to cooled ablation technology (group III) (29.615 ± 12.331 vs. 62.674 ± 28.735 W-s, p = 0.01). The same was true for the comparison between cooled ablation technology (group II) and group III (19.879 ± 13.669 vs. 62.674 ± 28.735 W-s, p = 0.002). Conclusions: The length of the CTI as measured with help of a three-dimensional mapping system may reflect only a weak indicator for the complexity of flutter ablation procedures. The thickness of musculature and specific anatomy of the CTI seem to be the main challenges in performing a linear ablation to achieve bidirectional block.

Objective: The aim of this retrospective study was to investigate the association of atrioventricular nodal reentrant tachycardia (AVNRT) with other forms of arrhythmia in individual patients and its consequences for treatment. Subjects and Methods: This study comprised 493 consecutive patients aged 16-88 years (296 women and 197 men) who were diagnosed with a form of AVNRT via a standard 4-catheter electrophysiological study (EPS). Patients were clinically followed (range 0.5-12 years) at a single center. Results: Coexistence of AVNRT with other types of tachycardias was observed in 197 (40%) patients. Atrial fibrillation was found most frequently in 94 (19%) patients as follows: focal atrial tachycardia, n = 40 (8%); atrial flutter, n = 32 (6%), and AV reentrant tachycardia, n = 22 (4%). Double tachycardia was present in 140 (30%) patients, and more than 2 different types of tachycardias were present in 57 (12%) patients. Transitions between AVNRT and other tachycardias occurred in 25 (5%) patients. Two or more tachycardias were ablated in 42 (9%) patients. The majority of patients were free of symptoms at the first follow-up, whereas 130 (26%) patients reported a variety of symptoms. Conclusion: Coexistence of AVNRT with other types of arrhythmias was a common finding among these patients. The most frequently observed double tachycardia was the combination of AVNRT with atrial tachyarrhythmias, such as atrial fibrillation, with a potential significance for further patient management.

Background: Atrial fibrosis or fatty deposition is known to increase the propensity for the development of atrial fibrillation (AF). Apart from the pulmonic veins, the interatrial septum (IAS) might play a role in the maintenance of AF. In contrast to left atrial anatomy and adjacent veins, the IAS cannot be visualized in detail with computed tomography. Thus, preprocedural transesophageal echocardiography (TEE) may provide important morphologic information beyond exclusion from atrial thrombi. Methods: The study comprised 108 consecutive patients (mean age 60 ± 11 years; 98 men). AF was paroxysmal in 91 (84%) and persistent in 17 (16%) patients. We investigated the morphological characteristics of the IAS by TEE in patients who underwent radiofrequency ablation of AF. Results: The IAS was structurally abnormal in 46 (43%) patients, showing the following echocardiograhic findings: atrial septal hypermobility or aneurysm (n = 27) associated with a patent foramen ovale (PFO) (n = 11) or with a small atrial septal defect (ASD) (n = 2), a septal flap associated with a PFO or an ASD (n = 8), and an abnormally thickened IAS (n = 12). A thrombus in the left atrial appendage was discovered in only 2 (2%) patients. Conclusions: A structurally abnormal IAS was diagnosed in nearly half of the patients undergoing ablation therapy for AF. The information obtained by TEE is mandatory to exclude left atrial thrombi prior the ablation procedure. Moreover, detailed knowledge of morphologic characteristics of the IAS facilitates an optimized and safe performance of the transseptal puncture using long sheaths with large diameters. (Echocardiography 2013;30:402-406)

Transcatheter aortic valve implantation (TAVI) is a less invasive technique for the treatment of severe aortic stenosis in high-risk patients. Occurrence of conduction disturbances requiring permanent pacemaker (PPM) implantation after TAVI is frequently observed.The retrospective analysis comprised 153 patients (96 women, aged from 65 to 97 years) who underwent TAVI due to high-grade aortic stenosis. The aim was to evaluate the incidence of high-grade atrioventricular (AV) block after TAVI and the percentage of ventricular pacing and pacemaker (PM)-dependency at the first follow-up 6-8 weeks after implantation.Out of the 153 patients (age 81 ± 6 years) who underwent TAVI, 144 (94 %) had a transfemoral and 9 (6 %) patients a transapical approach. A PPM was implanted in 31 (20 %) patients, 24 (16 %) were implanted with the Medtronic CoreValve® and 7 (5 %) with the Edwards Sapien® valve (p = n.s.). Complete AV block was the indication in 21 patients (68 %), second-degree AV block in 1 patient (3 %), slow atrial fibrillation in 3 patients (10 %), new left bundle branch block (LBBB) plus sustained ventricular tachycardia (VT) in 1 patient (3 %), sick sinus syndrome in 2 patients (7 %), whereas in 3 patients (10 %) a PPM was inserted for safety reasons because of new LBBB and first-grade AV block. All of the nine patients (6 %) with a preexisting bundle branch block developed total AV block after TAVI. At follow-up PM-dependency (intrinsic rhythm 30 bpm) occurred in 11/30 patients (37 %), whereas an intrinsic rhythm 50 bpm was seen in 17 patients (57 %). At nominal device programming the percentage of ventricular stimulation (VP) during the short-term observation period was 60 ± 44 % in dual-chamber devices (N = 18), and 70 ± 36 % in single-chamber PPM (N = 5).The PPM implantation rate of about 20 % after TAVI is comparable to previously published data. The need for permanent pacing is linked to the valve type and preexistence of a right bundle branch block. At short-term more than half of the patients implanted with a device were not strictly PM-dependent, but presented an underlying intrinsic rhythm, indicating that temporary AV conduction disturbances may recover over time. This might justify a more conservative approach in some patients under watchful waiting. From another point of view, ventricular pacing at a regular or sensor-modulated rate may provide rhythm stability and chronotropy during the short-term period post-TAVI.

A young patient presented with hemodynamic instability due to wide QRS tachycardia occurring about 10 years after double valve replacement. Bilateral coronary artery fistulas draining into the pulmonary artery were documented by invasive coronary angiography as well as by computed tomography imaging. A calcified scar of the posterolateral left ventricle was considered to be the origin of the clinical ventricular tachycardia. Although additional pathological findings are rare in young patients with valvular heart disease, diagnostic imaging of the heart is mandatory prior to cardiac surgery.

Syncope is a complex clinical syndrome that may be challenging with respect to a definite diagnosis. The implantable loop recorder (ILR) is a useful tool to define but also to exclude an arrhythmic aetiology.To investigate the causes of recurrent syncope or near-syncope with respect to underlying arrhythmias in non-selected consecutive patients monitored with an ILR.A retrospective study was conducted including 55 patients (34 men, 21 women; age 60+/-19 years) with unexplained syncope who received an ILR for prolonged monitoring at our institution between April 1998 and October 2006.Forty (73%) patients had a recurrence of syncope or near-syncope. Structural heart disease was present in 18 (33%) patients, 4 of them having an ejection fraction35%. An arrhythmia was detected as the cause of syncope in 25 (46%) patients. The ILR was successful in establishing a symptom-rhythm correlation in 63%. The mean follow-up period from implantation to occurrence of the detected arrhythmias was 9+/-8 months. Bradyarrhythmias were recorded in 12 (22%) patients, whereas tachyarrhythmias were found in 13 (24%) patients. Narrow QRS tachycardia was the underlying arrhythmia in 6 patients and wide QRS tachycardia in 7 patients. A pacemaker was implanted in all 12 patients with bradyarrhythmias. Implantable cardioverter defibrillator (ICD) therapy was indicated in 6 patients with adjunctive catheter ablation in 3 of them. Four patients presenting with paroxysmal supraventricular tachycardia were treated with radiofrequency catheter ablation.The ILR helped efficaciously to determine the correct diagnosis and appropriate treatment of recurrent syncope. A considerably high proportion of tachyarrhythmias was detected in this non-selected consecutive population. The majority of patients with tachyarrhythmic syncope required defibrillator implantation and/or radiofrequency ablation.