Rhythm-symptom correlation in patients on continuous monitoring after catheter ablation of atrial fibrillation.

INTRODUCTION: Correlation between symptoms and atrial fibrillation (AF) episodes after catheter ablation may have clinical relevance, especially for anticoagulation usage. The aim of our project was to analyze the relationship between symptoms and AF recurrences in unselected patients following AF catheter ablation during long-term follow-up. METHODS AND RESULTS: One hundred and forty-three consecutive patients (mean age 59 ± 9 years, 85% male) were implanted with a continuous cardiac monitor (RevealXT, Medtronic Inc., Minneapolis, MN, USA) following first pulmonary vein ablation procedure. Device data were downloaded every 3 months and correlated to patients' symptom diary. AF was paroxysmal in 55% and persistent in 45%. At a mean follow-up of 14 ± 6 months, 98/143 (69%) patients had at least one AF recurrence. Among these, 53 (54%) reported AF-related symptoms while 45 (46%) were totally asymptomatic. Conversely, 13 (29%) out of 45 patients without AF recurrences reported symptoms. Globally, a significant reduction of symptoms (from 82% at baseline to 44% at last follow-up; P < 0.0001) was observed. SF-12 questionnaire showed a significant improvement of physical and mental functioning (respectively 44.5 ± 8.5 vs 51.0 ± 6.7, and 45.7 ± 9.3 vs 49.2 ± 6.1, P < 0.05 baseline vs last follow-up). At the 12-month follow-up, 80% and 77% of patients were on AAD and anticoagulant drugs, respectively. There were not differences in AAD usage in symptomatic and asymptomatic patients. CONCLUSIONS: Continuous ECG monitoring is a valuable tool for long-term follow-up after AF catheter ablation facilitating reliable assessment of symptomatic and asymptomatic AF episodes. This may have clinical implications with regards to anticoagulation therapy in high-risk patients.

Bystander cavo-tricuspid isthmus activation during post-incisional intra-atrial reentrant tachycardia.

We describe a case of post-incisional atrial tachycardia resembling typical atrial flutter on the surface ECG. Typical atrial flutter reentry was ruled out by the results of activation and entrainment mapping. Nevertheless, overdrive pacing from the lateral edge of the cavo-tricuspid isthmus produced tachycardia entrainment with concealed fusion associated with post-pacing and stimulus-to-P wave onset intervals exactly matching the tachycardia cycle length duration and the electrogram-to-P wave onset interval, respectively. Therefore, that site was firstly severed by sequential radiofrequency pulses. However, a transformation of the tachycardia P wave morphology and endocardial activation sequence, not associated with tachycardia termination or cycle length modification occurred. After additional mapping manoeuvres, a relatively small reentrant circuit was identified in the low and mid aspect of the lateral right atrium with the critical isthmus located between the lower border of a cannulation atriotomy and the crista terminalis, close to the inferior vena cava orifice. A single radiofrequency pulse at that site terminated the tachycardia. Both the electrocardiographic pattern and the endocardial mapping data obtained in our case might be explained by a split of the reentrant wavefront into a secondary wavelet which freely propagated through the cavo-tricuspid isthmus without completing the peritricuspid loop. In conclusion, bystander cavo-tricuspid isthmus activation during atrial tachycardia may simulate a typical atrial flutter pattern on the surface ECG. Further studies should evaluate the prevalence of this propagation pattern in post-incisional atrial reentry and atypical atrial flutters, and identify its implications for ablation strategy.

Iterative atrial tachycardia originating from the coronary sinus musculature.

A case of iterative atrial tachycardia leading to dilated cardiomyopathy is reported. During electrophysiologic study, the tachycardia showed a markedly irregular cycle length associated with changes in atrial activation breakthrough as demonstrated by coronary sinus (CS) recordings and frequently degenerated into self-terminating atrial fibrillation. Left atrial transseptal mapping demonstrated the earliest endocardial atrial activation close to the posterolateral mitral annulus, but this was invariably later than that recorded within the CS, where low-energy radiofrequency applications eliminated the tachycardia. No acute vessel damage was observed at postablation CS angiography. In accordance with previously published experimental data, we hypothesized that the muscular sleeves surrounding the CS might be involved in the genesis of this tachycardia. During 6-month follow-up, the patient remained asymptomatic without tachycardia recurrences and with complete recovery of left ventricular function, confirming the reversible nature of the tachycardia-induced cardiomyopathy.

Radiofrequency catheter ablation of atrioventricular nodal reentry tachycardia: selective approach to the slow pathway via the superior vena cava.

Selective radiofrequency catheter ablation of the slow atrioventricular nodal pathway is currently considered the first-line therapy for patients suffering from recurrent symptomatic atrioventricular nodal reentry tachycardia. In most cases slow pathway conduction may be selectively eliminated or modified by the application of radiofrequency current at the posterior portion of Koch's triangle. The ablation site is usually targeted by careful mapping of this area performed using an ablation catheter advanced via the inferior vena cava approach. In this report we describe 2 cases in which the conventional approach to the target site was either impossible owing to the presence of an atresic inferior vena cava (case 1), or contraindicated in view of a history of common femoral vein thrombosis, subsequently extended up to the inferior vena cava (case 2). In both patients a superior vena cava approach was utilized and the slow pathway was successfully ablated. In case of arrhythmias necessitating slow pathway mapping and ablation, such an approach may be considered as a feasible and safe alternative whenever, owing to the presence of anomalies and/or diseases of the inferior vena cava, the conventional approach cannot be employed.

[Cardiac rhythm disturbances in hypertensive cardiopathy]. / Le alterazioni del ritmo cardiaco nella cardiopatia ipertensiva.

Patients with hypertensive heart disease are at a significantly increased risk for cardiovascular morbidity and mortality. Ultrastructural and gross anatomical cardiac changes, combined with hemodynamic and neurovegetative balance fluctuations, are frequently responsible for cardiac arrhythmias of atrial and/or ventricular origin. The prevalence, the pathophysiologic mechanism and the prognostic significance of cardiac rhythm disturbances occurring in hypertensive heart disease are discussed in this review.

Overdrive atrial stimulation during transesophageal electrophysiological study: usefulness of post-pacing VA interval analysis in differentiating supraventricular tachycardias with 1:1 atrio-ventricular relationship.

We evaluated the feasibility and usefulness of overdrive atrial pacing to identify the relationship between atrial and ventricular activation in supraventricular tachycardias with a stable 1:1 atrio-ventricular (AV) conduction ratio during a transesophageal electrophysiological investigation. Overdrive atrial stimulation was performed in 42 consecutive patients (11 males and 31 females; mean age 49 +/- 17 years) during AV junctional reentrant tachycardia, orthodromic AV reentrant tachycardia and ectopic atrial tachycardia (22, 13 and seven subjects, respectively). Trains of 12 stimuli at a constant rate were introduced starting at a cycle length 10 ms shorter than the tachycardia cycle length; stimulation was repeated with a 10-ms decrement in pacing cycle length at each step until tachycardia terminated and/or second-degree AV block occurred. The difference between the VA interval duration at baseline and in the first post-pacing tachycardia beat was measured at each step and provided identification of the AV relationship. At least one post-pacing VA interval was evaluable in 90% of the cases and measured 2 +/- 4 and 1 +/- 3 ms in AV junctional and AV reentrant tachycardia groups, respectively, and 83 +/- 42 ms in the ectopic atrial tachycardia group (P < 0.0000001 ectopic atrial tachycardia group vs. others). When three or more post-pacing VA intervals were obtained during the same tachycardia, a curve was constructed by plotting their values against the corresponding pacing cycle lengths. A curve could be constructed in 36% of the cases and was flat in all patients with AV junctional and AV reentry, while it was completely irregular in the ectopic atrial tachycardia group (P < 0.003). The analysis of post-pacing VA interval behaviour in response to overdrive atrial stimulation provides a rapid and reliable differentiation between supraventricular tachycardias with 1:1 AV conduction ratio during a transesophageal electrophysiological study.

["Double nodal pathway" as a common electrogenic pathway at the base of first and second degree paroxysmal atrioventricular node and nodal reentrant tachycardia]. / La "doppia via nodale" come comune substrato elettrogenetico alla base di blocchi atrioventricolari parossistici di primo e secondo grado e della tachicardia da rientro nodale.

The combined occurrence of conduction disturbances and reentry in subjects with a dual atrioventricular nodal pathway is extremely rare and poorly documented, only by means of short electrocardiographic strips. This case report deals with a young woman with frequent episodes of paroxysmal first- and second-degree type I atrioventricular block due to a dual atrioventricular nodal pathway at Holter monitoring, and atrioventricular nodal reentrant tachycardia inducible at transesophageal electrophysiologic study. This case confirms that some paroxysmal first- and second-degree atrioventricular block and the atrioventricular nodal reentrant tachycardia may share the same electrogenetic substrate represented by a dual atrioventricular nodal pathway. This finding may be of clinical significance because of its potential therapeutical implications. Further studies are needed in order to explain the rarity of this association.

Unusual resetting patterns in response to single atrial extrastimuli during AV junctional reentrant tachycardia.

INTRODUCTION: Two unusual resetting patterns were observed in two patients with slow-fast AV junctional reentrant tachycardia (AVJRT) submitted to an electrophysiologic study. METHODS AND RESULTS: After AVJRT induction, resetting was evaluated by introducing single extrastimuli at progressively shorter coupling intervals from the high right atrium (HRA) and the proximal coronary sinus (CS). An alteration in the return cycle length duration allowed demonstration of resetting. In the first patient, during and AVJRT with a large excitable gap, properly timed extrastimuli delivered both from the HRA and CS simultaneously reset the tachycardia and advanced the H electrogram of the preceding tachycardia beat. In the second patient, both HRA and CS stimulation apparently failed to reset AVJRT (return cycle length unchanged), but, at critical coupling intervals, the cycle length duration of the tachycardia beat following the return cycle was consistently shortened. CONCLUSION: During slow-fast AVJRT, single atrial stimulation from sites remote to the reentrant circuit may result in unusual resetting patterns. Further studies are required to evidence the full spectrum of resetting in AVJRT.

Radiation-induced heart disease.

The recent improvement in radiation techniques and the associated significant prolongation of survival have resulted in a widespread utilization of mediastinal irradiation in patients with various neoplasms. However, a large number of experimental and clinical studies have clearly demonstrated that high-dose therapeutic mediastinal irradiation can produce delayed, severe cardiovascular disease. This review presents the data from the Literature regarding the pathogenesis, pathology, prevalence and clinical manifestation of the radiation-related heart disease.

Intra-atrial and atrioventricular nodal reentrant tachycardia in the same subject diagnosed at transesophageal electrophysiologic study.

The case report deals with a young woman with frequent episodes of paroxysmal narrow QRS tachycardia of uncertain etiology at Holter monitoring in whom a transesophageal electrophysiologic study was carried out in order to identify the electrogenetic mechanism of the presenting arrhythmia. During the electrophysiologic study, 2 different types of supraventricular tachycardia were induced and diagnosed as intra-atrial and atrioventricular nodal reentrant tachycardia. This association represents a rare finding and can provide a possible explanation to the intriguing electrocardiographic pattern observed at Holter monitoring. Therefore, transesophageal electrophysiologic study proved to be a valuable method for evaluating subjects with complex supraventricular tachycardias.

Ventricular premature beats in young subjects without evidence of cardiac disease: histological findings.

This report describes the results of right ventricle endomyocardial biopsies from 26 subjects (mean age 27 +/- 10 years) with premature ventricular beats and normal cardiac anatomy and mechanical function. Light microscopy examination revealed normal myocardium in 10 subjects (38%), acute myocarditis in two (7%), borderline myocarditis in one (3.5%), non-specific histological abnormalities including cellular hypertrophy, fibrosis and degenerative changes in 11 (42%), vasculitis in one (3.5%) and findings compatible with right ventricular dysplasia in the final subject (3.5%). The frequency of ventricular premature beats, as assessed by Holter monitoring, and the results of electrophysiological testing did not correlate with histopathological findings and their severity. These data indicate that some young subjects with premature ventricular beats of unknown origin have abnormal right ventricular biopsy findings. Adequate follow-up will probably demonstrate the clinical utility of these observations.

Anti-HCV antibody presence in hemodialyzed patients: assessment after one year regarding some preventive measures chosen.

The authors report on the presence of anti-HCV antibodies in a uremic chronic (UC) patient population after 6 months and 1 year with regard to certain selective preventive measures. The nonincreased number of HCV-positive subjects among the UC population could lead to the conclusion that the risk of environmental spreading of HCV is less than the risk of HBV diffusion.