Incessant Tachycardia Research Articles

Atrioventricular Nodal Reentrant Tachycardia

Atrioventricular nodal reentrant tachycardia (AVNRT) represents the most common regular supraventricular arrhythmia in humans.1 The precise anatomic site and nature of the pathways involved have not yet been established, and several attempts to provide a reasonable hypothesis based on anatomic or anisotropic models have been made.2 There has been considerable evidence that the right and left inferior extensions of the human atrioventricular (AV) node and the atrionodal inputs they facilitate may provide the anatomic substrate of the slow pathway, and a comprehensive model of the tachycardia circuit for all forms of AVNRT based on the concept of atrionodal inputs has been proposed.2 Still, however, the circuit of AVNRT remains elusive. Recently, time-honored conventional schemes for the diagnosis and classification of the various forms of the arrhythmia have been refuted in part by evolving evidence. Recognition of the various types of AVNRT is important, however, to expedite diagnosis and allow implementation of appropriate ablation therapy without complications. We present an update on AVNRT with a particular emphasis on electrophysiological criteria used for the differential diagnosis of regular, supraventricular tachycardias. Typically, AVNRT is a narrow-complex tachycardia, ie, QRS duration <120 ms, unless aberrant conduction, which is usually of the right bundle-branch type, or a previous conduction defect exists. Tachycardia-related ST depression and RR-interval variation may be seen. RR alternans in AVNRT has been attributed to the proposed model of a figure of 8 reentry with continuous crossing over of antegrade activation through an inferior input to the contralateral superior input via the node.2 In the typical form of AVNRT (slow-fast), abnormal (retrograde) P′ waves are constantly related to the QRS and in the majority of cases are indiscernible or very close to the QRS complex (RP′/RR <0.5). Thus, P′ waves are either masked by the QRS complex or …

Catheter Ablation of Atrial Tachyarrhythmias in Patients With Tachycardia-Mediated Cardiomyopathy

Some of atrial tachyarrhythmias are deeply related to the onset of heart failure which has been known as tachycardia-mediated cardiomyopathy (TCM). Although prior animal studies have shown a relation between increasing tachycardia rate and duration and increased severity of LV dysfunction(1), only a small number of reports address the characteristics of atrial arrhythmias that cause TCM. 1. Atrial tachycardiaMedi C et al.(2) reported that incessant tachycardia occurred in approximately 25% of patients with focal atrial tachycardia (AT), and TCM developed in approximately one-third of these patients.

Ablation of Severe Drug‐Resistant Tachyarrhythmia During Pregnancy

The goal of this study was to describe mapping and ablation of severe arrhythmias during pregnancy, with minimum or no X-ray exposure. Treatment of tachyarrhythmia in pregnancy is a clinical problem. Pharmacotherapy entails a risk of adverse effects and is unsuccessful in some patients. Radiofrequency ablation has been performed rarely, because of fetal X-ray exposure and potential maternal and fetus complications. GROUP AND METHOD: Mapping and ablation was performed in 9 women (age 24-34 years) at 12-38th week of pregnancy. Three had permanent junctional reciprocating tachycardia, and 2 had incessant atrial tachycardia. Four of them had left ventricular ejection fraction < or =45%. One patient had atrioventricular nodal reciprocating tachycardia requiring cardioversion. Three patients had Wolff-Parkinson-White syndrome. Two of them had atrial fibrillation with ventricular rate 300 bpm and 1 had atrioventricular tachycardia 300 bpm. Fetal echocardiography was performed before and after the procedure. Three women had an electroanatomic map and ablation done without X-ray exposure. The mean fluoroscopy time in the whole group was 42 +/- 37 seconds. The mean procedure time was 56 +/- 18 minutes. After the procedure, all women and fetuses were in good condition. After a mean period of 43 +/- 23 months follow up (FU), all patients were free of arrhythmia without complications related to ablation either in the mothers or children. Ablation can be performed safely with no or minimal radiation exposure during pregnancy. In the setting of malignant, drug-resistant arrhythmia, ablation may be considered a therapeutic option in selected cases.

Tachycardia-Induced Cardiomyopathy.

This is a typical example of a tachycardia-induced cardiomyopathy due to incessant tachycardia with moderately increased ventricular rate. This was due to nonreentrant atrioventricular nodal tachycardia that gave rise to two ventricular complexes for every atrial complex. It describes a rare finding of the presence of retrograde concealed conduction in the fast pathway. Curative catheter ablation led to improvement of symptoms with reversal of tachycardia-induced cardiomyopathy.

Incessant Tachycardia Following Posteroseptal Pathway Ablation: A Pseudo-r′ or Pseudo-Pseudo-r′ Wave in V1?

Incessant Tachycardia Following Posteroseptal Pathway Ablation: A Pseudo-r′ or Pseudo-Pseudo-r′ Wave in V1?

Tachycardia-induced cardiomyopathy in childhood

MOTS CLES Tachycardie atriale focale ; Myocardiopathie rythmique ; Ablation par radiofrequence ; Insuffisance cardiaque A 14-year-old boy was referred to our institution for evaluation of heart failure potentially related to a tachycardia-induced cardiomyopathy. The condition was first diagnosed at the age of 7 years, because of frequent palpitations. Echocardiography excluded a congenital heart disease and the ejection fraction (EF) was 68% at this time, whereas Holter-electrocardiographic monitoring demonstrated incessant paroxysmal focal atrial tachycardia (FAT) (Fig. 1A). Various antiarrhythmic drugs were started, without any effect (verapamil, digoxin, propanolol, amiodarone). At the age of 13 years, the patient’s functional status had gradually worsened to reach stage 3 of the New York Heart Association. Echocardiography revealed altered left ventricular function (EF 35%) and significant dilation of the left ventricle, without any evidence for coronary disease or specific cause of cardiomyopathy. After discussion with his parents about the risk/benefit ratio of the procedure, it was decided to carry out ablation. The morphology of the ectopic P wave showed negativity in aVL, discrete positivity in V1 and strong positivity in leads II, III and aVF, pointing to an origin in the right upper part of the left atrium. The left atrium was mapped using a trans-septal approach, confirming the origin of the left tachycardia at the ostium of the right superior pulmonary vein. A single radiofrequency application at the site of ectopy was immediately effective (Fig. 1B and C). Close follow-up confirmed complete recovery of left ventricular function (EF 63%) 6weeks after ablation. After 4 years of follow-up to date, the patient remains asymptomatic and Holter monitoring remains unremarkable. Tachycardia-induced cardiomyopathy is a rare and potentially treatable cause of heart failure that should be considered systematically in cases of idiopathic ‘‘dilated cardiomyopathy’’. Radiofrequency ablation may be an efficient therapeutic approach when pharmacological therapy has failed to control the arrhythmia.

Image integration to guide ablation of incessant left atrial appendage tachycardia

Image integration to guide ablation of incessant left atrial appendage tachycardia

Dilated cardiomyopathy in children with ventricular preexcitation: the location of the accessory pathway is predictive of this association

Background Ventricular preexcitation may be associated with dilated cardiomyopathy, even in the absence of recurrent and incessant tachycardia. Methods This report describes the clinical and electrophysiologic characteristics of 10 consecutive children (6 males), with median age of 8 years (range, 1-17 years), who presented with dilated cardiomyopathy and overt ventricular preexcitation on the 12-lead electrocardiogram. Incessant tachycardia as the cause of dilated cardiomyopathy could be excluded. Coronary angiography, right ventricular endomyocardial biopsy (4/10 patients), and metabolic and microbiologic screening were nondiagnostic. Results The electrocardiograms suggested right-sided pathways in all patients. A right-sided accessory pathway was demonstrated in 8 patients during invasive electrophysiologic study (superoparaseptal, n = 5; septal, n = 2; fasciculoventricular, n = 1). All pathways were successfully ablated (radiofrequency ablation in 7, cryoablation in 1). Two patients had spontaneous loss of ventricular preexcitation during follow-up. Left ventricular (LV) function completely recovered after a loss of preexcitation in all patients. Conclusions Right-sided accessory pathways with overt ventricular preexcitation and LV dyssynchrony may cause dilated cardiomyopathy. An association between such pathways and dilated cardiomyopathy is suggested by the rapid normalization of ventricular function and reverse LV remodeling after a loss of ventricular preexcitation.

Remote Navigation Guided Ablation of Incessant Atrial Tachycardia in a Patient with Restricted Venous Access

We report a case of a 45-year-old man with incessant supraventricular tachycardia (SVT) in the setting of intrahepatic inferior vena cava thrombus and a left upper extremity arteriovenous fistula. A diagnostic electrophysiology study (EPS) was performed via the right internal jugular and right subclavian veins. After confirming the mechanism of SVT was atrial tachycardia (AT), mapping, and successful ablation was performed using remote catheter navigation. This case demonstrates that remote navigation can facilitate the therapy of complex arrhythmias in challenging clinical situations.

Tachycardia-Mediated Cardiomyopathy Secondary to Focal Atrial Tachycardia: Long-Term Outcome After Catheter Ablation

This study aimed to characterize the incidence, clinical and electrophysiologic features, and long-term outcomes of patients with tachycardia-mediated cardiomyopathy (TCM) secondary to focal atrial tachycardia (AT). TCM is known to complicate atrial tachyarrhythmias. Little is known of the patient and tachycardia characteristics associated with the development of left ventricular (LV) dysfunction and the long-term outcomes after cure of tachycardia. A total of 345 patients with focal AT underwent radiofrequency ablation between January 1997 and July 2008. A retrospective analysis was performed to identify patients with LV dysfunction, defined as an ejection fraction <50% on echocardiography. Patients with pre-existing structural heart disease (n = 14) were excluded. Patients with TCM (n = 30) and without TCM (n = 301) were compared. Recovery of LV function was also assessed. The incidence of TCM was 10%. Incessant or very frequent paroxysmal tachycardia was strongly associated with TCM, compared to patients without TCM (100% vs. 20%, p < 0.001). Patients in the TCM group were younger (mean age 39 +/- 22 years vs. 51 +/- 17 years, p = 0.0006) and more frequently male (60% vs. 38%, p < 0.001). Patients with TCM had a longer mean tachycardia cycle length (502 +/- 131 ms vs. 402 +/- 105 ms, p < 0.0001) and slower ventricular rate (117 +/- 21 beats/min vs. 141 +/- 33 beats/min, p = 0.0007) during tachycardia compared with patients who did not have TCM. Appendage sites are associated with a high incidence of incessant tachycardia (84%) and LV dysfunction (42%). After successful ablation, LV function was restored in 97% of patients at a mean of 3 months. Cardiomyopathy occurs in 10% of patients with focal AT. A slower incessant tachycardia is more frequently complicated by cardiomyopathy. Long-term restoration of LV function can be achieved after successful catheter ablation of the tachycardia focus.

Surgical Catheter Ablation of Ventricular Tachycardia Using Left Thoracotomy in a Patient with Hindered Access to the Left Ventricle

We report the case of a patient presenting with incessant monomorphic ventricular tachycardia resistant to antiarrhythmic drugs, and in whom usual percutaneous vascular or pericardial access to the left ventricle was hindered by mechanical aortic and mitral prosthetic valves. Because an epicardial location was suspected by electrocardiogram features and because access to the target area through the coronary sinus was not possible, we decided to perform a surgically based radiofrequency (RF) ablation. Catheter mapping of the epicardial surface through surgical left lateral thoracotomy in the operating room confirmed the epicardial location of the arrhythmogenic substrate and allowed successful RF ablation of the clinically incessant tachycardia. Combined surgical and electrophysiological approach should therefore be performed when RF ablation is needed in case of unadvisable, difficult, or failed nonsurgical percutaneous access.

Incidence and Implications of Obstructive Sleep Apnoea in Patients Presenting for Atrial Fibrillation Ablation: A Prospective Study

Background: Incessant focal atrial tachycardia (AT)may be complicated by LV dysfunction. The aim was to characterise the incidence, ECG and EP features of incessant focal AT and identify predictors of tachycardia mediated cardiomyopathy (TCM). Methods: 82 of 345 (24%) pts with focal AT presenting for radiofrequency ablation between 1997 and 2008 were incessant. Incessant AT was defined as continuous tachycardia or recurrent paroxysms of tachycardia separated by ≤2 sinus beats. Results: The mean age was 42± 20 years, 57% were male and mean symptom duration was 5± 7 years. TCM was present in 30/82 (37%), defined as LVEF <50%. Pts with incessant AT and TCM were more likely to be younger (mean 39± 22 year vs. 45± 18 year, p= 0.02); have a slower tachycardia cycle length (TCL) (502± 131ms vs. 446± 106ms, p= 0.05) and slower mean heart rate in tachycardia (117± 21 bpm vs. 132± 33 bpm, p= 0.05) than incessant pts without TCM. Incessant tachycardia was more frequent from atrial appendage (AA, 16/19 (84%)) and pulmonary vein (PV, 26/44 (59%)) sites compared to other anatomic locations (combined, 15%) (p< 0.001). Appendage and PV sites were therefore associated with a higher incidence of TCM (AA: 42%; PV: 18%; other: 6%, p= 0.008). RFA was successfully performed in 76/82 (93%) pts at mean follow up of 22± 26months. In pts with TCM recoveryofLV functionwas seen in 29/30 (97%)pts atmean of 2.8 months. Conclusion: Incessant tachycardia is frequently complicated by TCM. AA and PV foci were more likely to be incessant and complicated by TCM. Incessant tachycardia and TCM was characterized by a slower TCL and mean heart rate than pts without TCMpossibly delaying clinical presentation.

Two Cases of Pilsicainide Intoxication showing the Brugada-type Electrocardiographic Findings and Incessant Wide QRS Tachycardia

We have experienced two patients with the Brugada-type electrocardiographic abnormalities and incessant wide QRS tachycardia (presumed ventricular tachycardia) induced by intoxication of a class IC antiarrhythmic drug pilsicainide. They were elderly men with impaired renal function. Plasma concentration of pilsicainide was elevated to a toxic level in both patients. After cessation of pilsicainide, incessant wide QRS tachycardia spontaneously subsided and intraventricular conduction delay with coved type ST segment elevation in V1 and V2 disappeared. In the elderly or patients with renal dysfunction, we should be very careful regarding dose adjustment of pilsicainide or it may be better to avoid using this drug.

A case of unstable atrial tachycardia due to intermittent firing focus from the right inferior pulmonary vein following cavo-tricuspid isthmus dependent atrial flutter

This case report describes a patient with incessant atrial tachycardia (AT) who underwent catheter ablation. During electrophysiological study, the stable AT circuit spontaneously shifted to unstable AT due to intermittent frequent firing from the right inferior pulmonary vein (PV) after termination of cavo‐tricuspid isthmus dependent atrial flutter. A macroreentrant AT circuit was observed after electrical isolation of right inferior PV potentials. These findings suggest that the presence of rapid activated firing is likely to be associated with the development of instability in the AT circuit. This may lead to a greater understanding of the physiology of atrial tachyarrhythmia as a simple clinical model.

Catheter Ablation of Ectopic Atrial Tachycardia Originating from the Left Atrial Appendage using CARTOMERGE® System

A 70‐year‐old woman was referred because of drug resistant and daily incessant palpitation attack. She had undergone two previous unsuccessful radiofrequency catheter ablations at another hospital. The physical examination, chest X‐ray, and echocardiogram were all normal. The 12‐lead ECG during tachycardia showed narrow QRS, short PR tachycardia and negative polarity of the P wave in leads I and aVL (Fig. 1A). The ECG monitor showed incessant tachycardia with warming‐up phenomenon. Three dimensional electroanatomical map integrated with CT imaging (CARTOMERGE®, Biosense Webster Inc.) clearly revealed the radial activation pattern originating from the basalo‐postero‐inferior aspect of the left atrial appendage. Radiofrequency energy application at this site eliminated tachycardia permanently.

Incessant tachycardia with wide and narrow QRS complexes: What is the mechanism?

Incessant tachycardia with wide and narrow QRS complexes: What is the mechanism?

Incessant Non‐Reentrant Supraventricular Tachycardia Interrupted By Apparent Simultaneous Wenckebach Sequences along Both Nodal Pathways

We report a new case of non-reentrant supraventricular tachycardia, associated with tachycardia-induced cardiomyopathy fully reversible after radiofrequency (RF) ablation, together with striking features of apparent concomitant Mobitz type 1 atrioventricular (AV) block in both AV node pathways. Further analysis of the conduction patterns during the incessant non-reentrant tachycardia raised unresolved hypothesis about the involved mechanisms and further interrogations on AV node physiology.

The challenge of fetal dysrhythmias: echocardiographic diagnosis and clinical management

The present study aimed to evaluate the management of fetal cardiac dysrhythmias based on prior identification of the underlying electrophysiological mechanism. We studied 36 consecutive fetuses with cardiac dysrhythmia. Rhythm diagnosis was based on M-mode, pulsed wave Doppler and tissue Doppler imaging (TDI). Only fetuses with: (i) incessant tachycardia (> 12 h) and mean ventricular rate > 200 beats/min, (ii) signs of left ventricular dysfunction, or (iii) hydrops, were treated using oral maternal drug therapy. The mean gestational age at diagnosis was 24.3 +/- 4.5 weeks. Twenty-one fetuses had tachycardia with a 1: 1 atrial-ventricular (AV) conduction. Based on ventricular-atrial interval, prenatal diagnosis was: permanent junctional reciprocating (n = 6), atrial ectopic (n = 6) or atrial-ventricular re-entry tachycardia (n = 9). One had atrial flutter, one ventricular tachycardia and four congenital AV block. Nine showed premature atrial or ventricular beats. Fifteen fetuses with incessant tachycardia, left ventricular dysfunction or hydrops were prenatally treated with maternal administration of digoxin, sotalol or flecainide. The total success rate (sinus rhythm or rate control) was 14/15 (93%). Seven fetuses were hydropics. Three of these died (one at 28 weeks of gestation, two in the first week of life). The prenatal diagnosis of dysrhythmia was confirmed at the birth in 31 of 35 live-born. No misdiagnosis was made using TDI. At 3 +/- 1.1-year follow-up, 33/35 children were alive and well. Fetal echocardiography could clarify the electrophysiological mechanism of fetal cardiac dysrhythmias and guide the therapy.

Narrow QRS incessant tachycardia in a patient with recent myocardial infarction: What is the mechanism?

Narrow QRS incessant tachycardia in a patient with recent myocardial infarction: What is the mechanism?

A case of unstable atrial tachycardia due to intermittent firing focus from the right inferior pulmonary vein following cavo-tricuspid isthmus dependent atrial flutter

This case report describes a patient with incessant atrial tachycardia (AT) who underwent catheter ablation. During electrophysiological study, the stable AT circuit spontaneously shifted to unstable AT due to intermittent frequent firing from the right inferior pulmonary vein (PV) after termination of cavo-tricuspid isthmus dependent atrial flutter. A macroreentrant AT circuit was observed after electrical isolation of right inferior PV potentials. These findings suggest that the presence of rapid activated firing is likely to be associated with the development of instability in the AT circuit. This may lead to a greater understanding of the physiology of atrial tachyarrhythmia as a simple clinical model.