21/107. Focal atrial tachycardia originating from the musculature of the coronary sinus. Focal atrial tachycardias originate predominantly from the right atrium along the crista terminalis and less commonly from the left atrium. Successful catheter ablation usually can be performed via an endocardial approach. We report the case of a 34-year-old patient in whom a focal atrial tachycardia was successfully ablated 4 cm within the coronary sinus after extensive mapping of the left atrial endocardium and coronary sinus using the three-dimensional CARTO mapping system. Rarely, atrial tachycardia can originate from the coronary sinus musculature and require ablation inside the coronary sinus. ( info) |
22/107. 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. ( info) |
23/107. Change in morphology of reentrant atrial arrhythmias without termination following radiofrequency catheter ablation. A 60-year-old woman who had previously undergone an atrial septal defect repair and had type I atrial flutter underwent electrophysiological study. After radiofrequency (RF) ablation to the isthmus between the inferior vena cava and the tricuspid annulus, type I atrial flutter was changed to atrial tachycardia following atriotomy without termination. This atrial tachycardia was eliminated by single-site RF ablation of a small lesion below the caudal end of the atriotomy scar, where continuous and fragmented potentials were recorded during tachycardia. We experienced a rare case in which RF energy changed tachycardia circuits. ( info) |
24/107. Ectopic tachycardia originating from the superior vena cava. We report a 65-year-old female patient with a 3-year history of symptomatic paroxysmal supraventricular tachycardia. Electroanatomic and basket catheter mapping revealed a focal tachycardia originating in the superior vena cava (SVC), 5 cm above the SVC-right atrium (SVC-RA) junction. An area of fractionated potentials and slow conduction was found on the anterior wall of the SVC. A line of conduction block extending downwardly and obliquely from the anteroseptal aspect to anterolateral aspect of the SVC forcing the impulse to enter the RA via the posterior aspect of SVC-RA junction was observed. Entrainment attempts from multiple sites within the SVC failed to demonstrate reentry as a mechanism of arrhythmia. The ablation approach consisted of isolation of the arrhythmogenic area from the rest of the SVC. ( info) |
25/107. Ectopic atrial rhythm with exit block following catheter ablation for focal atrial tachycardias in a patient with prior surgery for atrial septal defect. The patient was a 40-year-old woman with a history of surgery for atrial septal defect and catheter ablation for typical atrial flutter. An electrophysiological study was performed because she had palpitation and syncope. She had ectopic atrial rhythm originating from low lateral RA. Two focal atrial tachycardias ([1] superior vena cava-RA junction and [2] a lowposteroseptal RA) were successfully ablated. Following catheter ablation for the second atrial tachycardia, she developed junctional rhythm because ectopic atrial rhythm showed exit block. However, atrial activation of junctional rhythm could conduct into the ectopic atrial rhythm focus and reset the rhythm when atrial activation of junctional rhythm reached the blocked line after atrial refractoriness by preceding ectopic atrial rhythm. ( info) |
26/107. Extrinsic left atrial compression in a patient with achalasia. Left atrial compression by the esophagus, the stomach, or both is an uncommon but important cause of hemodynamic compromise. Achalasia is a disease of the esophagus with dilatation of the distal part and constriction of the lower oesophageal sphincter. Dilated esophagus is a rare cause of left atrial compression. Timely and precise diagnosis is of paramount importance in cases of left atrial compression and echocardiography enables clinicians to make a differential diagnosis successfully in most cases. Correction of primary pathology will usually lead to the return of normal hemodynamic function. We describe a case of extrinsic left atrial compression caused by the dilated esophagus due to achalasia that caused paroxysms of atrial tachycardia and hemodynamic compromise. ( info) |
27/107. Successful use of iv diltiazem to control perioperative refractory complex atrial tachyarrhythmias in a patient with pneumoconiosis. PURPOSE: To present a patient with pneumoconiosis who developed a complex, life-threatening atrial tachyarrhythmia during anesthesia. Intravenous diltiazem was effective in controlling the ventricular rate and hemodynamics after failure of other antiarrhythmic drugs and direct current cardioversion. CLINICAL FEATURES: A 79-yr-old man with pneumoconiosis complicated by cor pulmonale suffered from gout-related cellulitis of the left lower limb. debridement of the left gangrenous big toe was carried out under general anesthesia. During anesthesia, a wide-QRS tachycardia occurred suddenly and a complex atrial tachyarrhythmia was later diagnosed. hemodynamics deteriorated despite aggressive treatment with lidocaine, verapamil, direct current cardioversion, magnesium, digoxin and amiodarone. Correction of the underlying respiratory acidosis was not sufficient to control the rapid ventricular response. Eventually, iv diltiazem adequately controlled the rapid ventricular rate and quickly improved the deteriorating hemodynamics. CONCLUSION: life-threatening complex atrial tachyarrhythmias may occur in patients with chronic lung diseases perioperatively. Intravenous diltiazem was effective in the management of complex atrial tachyarrhythmia in a patient with underlying cor pulmonale. ( info) |
28/107. Radiofrequency ablation of incessant atrial tachycardia in an infant. Ectopic automatic atrial tachycardia, an uncommon type of supraventricular tachycardia in children and adults, has been reported to be resistant to medical therapy unlike reentrant supraventricular tachycardia. We report a case of incessant atrial tachycardia in an infant, which was successfully treated with radiofrequency catheter ablation. ( info) |
| The following case illustrates several important features: firstly, the occurrence of tachycardia-induced cardiomyopathy during sustained atrial tachycardia at a relatively modest heart rate of 130 beats per minute, in an elite athlete. Secondly, tachycardia may induce severe and occasionally life-threatening impairment of the systolic ventricular function without a history of palpitations. Finally, our patient is an excellent example of the complete recovery that may follow successful radiofrequency catheter ablation, performed promptly once the correct diagnosis has been confirmed. ( info) |
30/107. Sequential ablation of orthodromic atrioventricular tachycardia and ectopic atrial tachycardia with a single application of radiofrequency energy. A 62-year-old woman with wolff-parkinson-white syndrome had two types of tachycardia; ectopic AT and orthodromic-type AVRT. A radiofrequency application 2 cm inside the coronary sinus ostium eliminated ectopic AT and accessory pathway conduction at once. ( info) |