Reversibility of tachycardia-induced cardiomyopathy after cure of incessant supraventricular tachycardia

Seven of 17 patients with incessant supraventricular tachycardia caused by an accessory pathway with a long retrograde conduction time were seen with symptoms or echocardiographic signs of a tachycardia-induced cardiomyopathy. Three patients were in New York Heart Association functional class II with dyspnea and four were in class III. Eight patients (six with tachycardia-induced cardiomyopathy) underwent surgery because of failure of medical treatment (including one patient in functional class I) and one underwent direct current catheter ablation of the atrioventricular (AV) node. In six patients echocardiograms recorded before and after the procedure were available. Before surgery or direct current ablation the mean left ventricular ejection fraction was 36.3 +/- 8.7%, the left ventricular end-diastolic diameter 55.7 +/- 7.6 mm and the left ventricular end-systolic diameter 44.3 +/- 7.8 mm. A mean of 21.6 +/- 6.8 months after the procedure the mean left ventricular ejection fraction increased to 58.6 +/- 8.0%, the left ventricular end-diastolic diameter decreased to 49.0 +/- 3.6 mm and the left ventricular end-systolic diameter decreased to 32.2 +/- 2.7 mm; all six patients were in functional class I. These results confirm that control of incessant tachycardia leads to a regression of symptoms and signs of cardiomyopathy and progressive normalization of the dimensions of the heart. Because of these findings, surgery should be considered early in patients with an accessory AV pathway and incessant tachycardia. The presence of a tachycardia-induced cardiomyopathy should therefore be an indication for surgery rather than a contraindication.     

Tachycardiomyopathy in patients with and without subacute cardiac pathology. Experiences at the Cardiovascular Center of Merida, Venezuela]

We report our experiences with tachycardia-induced cardiomyopathy. Nine patients (3-56 years old) had incessant supraventricular tachycardia and congestive heart failure. The cardiac eco-Doppler evidenced a significant increase of cardiac volumes and mild tricuspid and mitral regurgitation. The ejection fraction (EF) was 0.31 +/- 0.12, the end diastolic volume was 162 +/- 48 cc and the end systolic volume, 116 +/- 54 cc. Four patients had accessory pathways, 3 atrial flutter, 1 A-V nodal reentrant tachycardia, and 1 ectopic atrial tachycardia. Two patients had Chagasic myocarditis. Only in one chagasic patient a decreased number of tachycardia episodes was achieved, this patient died. The autopsy revealed cerebellar and pulmonary emboli. In the other 8 patients the arrhythmia was well controlled. In these, the ventricular volumes decreased, the EF increased to 0.51 +/- 0.14 (p = 0.00006), and the congestive heart failure remitted. We conclude that incessant tachycardia produces a symptomatic dilated cardiomyopathy in patients with and without structural heart disease. The arrhythmia control is followed by an increase in cardiac function and a remission of heart failure symptoms.     

心动过速终止后短暂心室复极异常和严重室性心律失常

目的 观察长时间心动过速终止后对心室复极和恶性室性心律失常发生的影响.方法 3例长时间心动过速(9 d～6个月)患者,两例为长时间发作室性心动过速(室速),其中1例为无休止性左心室特发性室速并诱发心动过速性心肌病;另1例为主动脉瓣换瓣术后5年发生束支折返性室速;第3例为持续性心房扑动伴心功能不良并因三度房室阻滞于10年前植入单腔起搏器.结果 3例患者在心动过速时并无晕厥和恶性室性心律失常发生,而在心动过速间隙或射频导管消融终止后均出现qr间期延长和恶性心律失常,其中1例持续心房扑动合并心力衰竭的患者最后死于多脏器功能衰竭;另两例室速射频导管消融治疗后1周QT间期逐渐恢复正常,分别随访20和39个月无室速和晕厥发作.结论 长时间心动过速后可导致短时间心室复极异常及恶性室性心律失常,应加强防范,防止发生心脏性猝死.     

Clinical characteristics of cardiomyopathy with mild dilatation

The clinical features of 20 patients with mildly dilated cardiomyopathy (MDCM) were investigated by electrocardiography and echocardiography. MDCM was defined as conditions with: 1) left ventricular end-diastolic dimension between 55 and 65 mm and 2) left ventricular fractional shortening between 10 and 25%. Nine patients (45%) had no histories of congestive heart failure. Eight patients had atrial fibrillation, and the other 12 patients were in regular sinus rhythm. Two patients had supraventricular premature contractions and five patients had ventricular premature contractions. One patient had paroxysmal atrial tachycardia. During the 40-months' span of this echocardiographic study, left ventricular end-diastolic dimension (60.8 +/- 3.8 mm to 57.3 +/- 4.6 mm) and left ventricular fractional shortening (17.2 +/- 4.6% to 22.7 +/- 7.1%) did not change significantly. One patient died suddenly. These results suggest that 1) some patients with MDCM have neither definite histories nor symptoms to suggest heart failure; 2) the hemodynamic conditions of patients with MDCM do not always deteriorate, but rather stabilize, and even improve during follow-up periods; 3) several types of arrhythmias can be observed, even in standard resting electrocardiograms; and 4) patients with MDCM may die suddenly.     

Tachycardia-mediated cardiomyopathy and the permanent form of junctional reciprocating tachycardia

Permanent junctional reciprocating tachycardia, or atrioventricular reentrant tachycardia utilizing a slowly conducting posteroseptal accessory pathway, is a rare form of reentrant supraventricular tachycardia in children and adults. The characteristic features of this narrow complex tachycardia are a long RP interval and inverted P waves in the inferior leads. This form of accessory-pathway-mediated tachycardia, which is usually incessant, can lead to a tachycardia-induced cardiomyopathy and congestive heart failure if left untreated. Radiofrequency ablation of the accessory pathway in permanent junctional reciprocating tachycardia is the definitive treatment in these patients, and in many instances the effects of prolonged tachycardia on ventricular function are reversible after successful ablation. We present an illustrative case.     

Tachycardia-Induced Cardiomyopathy Secondary to Right Ventricular Outflow Tract Ventricular Tachycardia: Improvement of Left Ventricular Systolic Function After Radiofrequency Catheter Ablation of the Arrhythmia

Cardiomyopathy Secondary to RVOT VT. Introduction : Several reports describe development of cardiomyopathics secondary to supraventricular tachycardia. Few reports have described cardiomyopathies secondary to ventricular tachycardia.
Methods and Results : We describe a patient who presented with dilated cardiomyopathy and repetitive nonsustained monomorphic ventricular tachycardia. Cardiac cathcterization showed hemodynamically insignificant coronary artery disease. Radiofrequency ablation of a right ventricular outflow tract ventricular tachycardia resulted in improvement of the left ventricular systolic function and resolution of heart failure symptoms.
Conclusions : This report suggests that right ventricular outflow tract ventricular tachycardia may cause reversible tachycardia-induced cardiomyopathy.     

Intravenous cibenzoline in the management of acute supraventricular tachyarrhythmias

Summary Intravenous cibenzoline was evaluated in 37 patients with acute supraventricular tachyarrhytymias and a ventricular rate >120 beats/min. The presenting arrhythmia was atrial fibrillation in 15 patients, atrial flutter in 5, ectopic atrial tachycardia in 11, and paroxysmal atrioventricular (AV) junctional reentrant tachycardia in 6 patients. Intravenous cibenzoline was administered as a bolus given over 2 minutes, at a dose of 1 mg/kg in the first 26 patients and 1.2 mg/kg in the subsequent 11 patients, 15 minutes following failure of placebo (isotonic glucose). The results were evaluated 15 minutes after the intravenous injection. Restoration of sinus rhythm was obtained in 3 out of 6 patients with paroxysmal AV junctional tachycardia (50%) and in 7 out of 31 patients (23%) with atrial tachyarrhythmias (5 out of 15 patients with atrial fibrillation and 2 out of 16 patients with ectopic atrial tachycardia or atrial flutter). Five additional patients with atrial tachyarrhythmias had slowing of ventricular rate below 100 beats/min. Therefore, a satisfactory result, that is, restoration of sinus rhythm or slowing of ventricular rate, occurred in 15 patients (40.5%). Side effects were transient, including visual disturbance (one patient), asymptomatic widening of QRS complex (three patients), incessant reciprocating tachycardia (one patient), and acceleration of ventricular rate (eight patients), resulting in 1:1 flutter, with poor tolerance in two patients. In conclusion, intravenous cibenzoline may be useful in selected patients with supraventricular tachyarrhythmias. Careful monitoring is recommended during therapy in view of the possible occurrence of 1:1 atrial flutter.     

Atrial automatic ectopic tachycardia due to an atrial tumor

A dilated cardiomyopathy picture has been produced by rapid atrial and ventricular rates sustained for a long period of time in some patients. The ventricular tachycardias have in some instances been associated with ventricular tumors as the cause of the tachycardia. Once the tumor is removed, the tachycardia stops and the heart function improves. Atrial ectopic tachycardias also produce a similar picture, but have not been associated with atrial tumors. Such a case is presented with an atrial rhabdomyoma producing atrial ectopic tachycardia and a dilated, poorly contracting myocardium. The tumor was resected and the tachycardia was immediately abolished. Cardiac function quickly returned to normal.     

Results of operative therapy in the permanent form of junctional reciprocating tachycardia

To assess the results of operative therapy for permanent junctional reciprocating tachycardia, a type of incessant tachycardia, the clinical and electrophysiologic data of 8 such patients referred for management of tachycardia were reviewed. The duration of incessant tachycardia was 14 +/- 10 years (range 2 to 30). The heart rate at rest during tachycardia ranged from 120 to 150 beats/min. Four of 8 patients had cardiomegaly or depressed ejection fraction (16 +/- 10%, range 5 to 27) at presentation and, of these, 2 had symptoms of congestive heart failure. Exertional dyspnea despite normal left ventricular function was noted in 1 patient, 2 had chronic palpitations and 3 were asymptomatic. Electrophysiologic data confirmed the presence of a posteroseptal pathway with atrioventricular node-like properties conducting slowly in the retrograde direction only. Seven patients underwent successful surgical ablation of the accessory pathway. Hypothermic cardiopulmonary bypass was used in 2 and a closed heart technique without cardiopulmonary bypass in the other 5. Three of 4 patients with reduced left ventricular function showed an improvement in ejection fraction to 34 +/- 20% (range 16 to 63) after control of dysrhythmia. Three patients had no evidence of cardiomegaly despite equivalent periods of incessant tachycardia. Another patient with normal left ventricular function despite incessant tachycardia for over 30 years underwent spontaneous remission to sinus rhythm and did not undergo surgery. These data suggest that permanent junctional reciprocating tachycardia has a variable presentation and that congestive heart failure is not an infrequent presenting symptom. The substrate is invariably an accessory atrioventricular pathway with a long conduction time and decremental properties conducting only in the retrograde direction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of chronic supraventricular tachycardia on left ventricular function and structure in newborn pigs.

OBJECTIVES. The purpose of this study was to examine the effects of supraventricular pacing tachycardia on left ventricular function and myocardial structure in newborn, immature pigs and to determine whether immature pigs respond to supraventricular tachycardia differently from adults. BACKGROUND. Previous studies have shown that supraventricular tachycardia causes dilated cardiomyopathy in adult animals; however, in humans, supraventricular tachycardia-induced congestive heart failure occurs most frequently in children and newborns. Because some clinical diseases may cause myocardial failure in adults but rarely do so in children, it was hypothesized that the effects of supraventricular tachycardia in newborns may be different from those in adults. METHODS. In two groups of newborn swine (3 weeks of age), left ventricular volume, mass and function were assessed with simultaneous echocardiography and cardiac catheterization and myocardial structure was examined with light and electron microscopy. Six piglets underwent 3 weeks of left atrial pacing tachycardia (240 beats/min) and six littermates served as a control group. Both groups were followed up for 3 weeks. RESULTS. At the end of the protocol, left ventricular dimensions increased in the piglets with supraventricular tachycardia compared with values in the control group, but there were no differences in left ventricular mass. Systolic function, assessed by fractional shortening, peak ejection rate and maximal rate of pressure development, was decreased in the group with supraventricular tachycardia. The fractional shortening-end-systolic stress relation in the piglets with supraventricular tachycardia decreased below normal values. Left ventricular diastolic function assessed by the relaxation time constant was prolonged, the peak filling rate was decreased and left ventricular stiffness was increased in the supraventricular tachycardia group. The morphologic data demonstrated that supraventricular tachycardia did not change total myocyte volume but did decrease total myofibrillar volume. CONCLUSIONS. Supraventricular tachycardia caused dilated cardiomyopathy in immature pigs. These changes in left ventricular function were associated with a decrease in cellular contractile proteins. Thus, the effects of supraventricular tachycardia on left ventricular function and structure in immature animals were comparable to previous findings in mature animals.     

Encainide for refractory supraventricular tachycardia in children

Fifteen children, aged 5 days to 19 years (mean 4.7 years), with medically refractory supraventricular tachycardia were given oral encainide. In 10 of 15 children with "incessant" tachycardia (greater than 10% of the day), encainide alone controlled supraventricular tachycardia in 5 children; in combination with other antiarrhythmic agents, it partially controlled supraventricular tachycardia in 4 and was ineffective in 1. In 5 children with accessory atrioventricular connections, encainide eliminated supraventricular tachycardia in 3 and was ineffective in 2. Therapeutic encainide dosages ranged from 60 to 120 mg/m2/day (mean 90) (2.0 to 5.7 mg/kg/day). Encainide caused prolongation of the PR interval by 35%, RP interval by 17%, QRS interval by 44% and corrected QT interval by 10%. In 5 children with depressed left ventricular function administration of encainide, by controlling the arrhythmia, increased echocardiographic left ventricular shortening fraction from a mean of 24% to a mean of 36%. Three patients developed excessive QRS aberrancy, which was associated with wide QRS tachycardia in 2. No adverse reactions were noted in the absence of QRS aberration. Side effects were minor and noted in only 1 of 9 patients continuing to take the drug in 9 months of follow-up. Encainide was effective, or partially effective, in the control of resistant or incessant supraventricular tachycardia in 80% of children treated. Encainide allowed rapid resolution of arrhythmia-induced cardiomyopathy by controlling chronic supraventricular tachycardia.     

Recurrent rhythmic cardiomyopathy secondary to idiopathic ventricular tachycardia

Tachycardia-induced cardiomyopathy consists in severe ventricular dysfunction and heart failure secondary to incessant or prolonged supraventricular or less frequently ventricular tachycardia in the absence of any cardiac disease. We present here a case of recurrent severe cardiomyopathy secondary to idiopathic ventricular tachycardia. Complete sustained recovery in function was observed after successful radiofrequency ablation of the ventricular tachycardia focus. To the best of our knowledge, this is the first report of recurrent tachycardia-induced cardiomyopathy. The diagnosis, aetiology, physiopathology and mechanisms of tachycardia-induced cardiomyopathy are discussed. Several therapeutic implications are presented.     

Recovery of systolic and diastolic function after ablation of incessant supraventricular tachycardia

We report a case of a 26-year-old woman who presented to our hospital with arrhythmia and heart failure. She had an incessant supraventricular tachycardia, which was not reversible with electrical cardioversion. Echocardiogram showed a severe LV systolic and diastolic dysfunction. After radiofrequency catheter ablation, LV function returned to normal. This article is intended to show a case with tachycardiomyopathy, which is considered the most frequently unrecognized curable cause of heart failure, and to demonstrate that early treatment allows the recovery to a normal LV systolic and diastolic function, preventing irreversible structural cardiac damage. It is very likely that some patients with idiopathic dilated cardiomyopathy and chronic atrial fibrillation or other chronic arrhythmia actually have a curable tachycardiomyopathy.     

Indications for emergency surgical treatment of ectopic atrial tachycardia]

Recurrent automatic atrial tachycardia can induce dilated cardiomyopathy. We present clinical and therapeutic problems of 16 years old male with ectopic left atrial tachycardia refractory to pharmacological therapy. In this patient long periods of atrial tachycardia 200-240/min due to lack of effective medication caused cardiac failure. Uncontrolled taking of various antiarrhythmic drugs and persistent tachycardia led to cardiogenic shock. The electrophysiologic study revealed focus of the tachycardia localized in the area of left cardiac auricle. The rate of the tachycardia was changing from 84 to 240/min, with periods of Mobitz I block in the AV node. In periods of 1:1 AV conduction the tachycardia had sometimes LBBB QRS morphology. The atrial tachycardia provoked unsustained ventricular one. The patient was operated. Resection of left auricle and mitral valvuloplasty were performed. After the operation the patient regained undisturbed sinus rhythm and symptoms of heart failure disappeared.     

Ablation of Incessant Left Atrial Tachycardia Without Fluoroscopy in a Pregnant Woman

Ablation Without Fluoroscopy in Pregnancy. Background: Management of symptomatic atrial arrhythmia in pregnancy remains a challenge. In this case report, a pregnant woman with incessant tachycardia underwent successful left atrial ablation. The entire procedure was performed without fluoroscopy. Methods and Results: A 20‐year‐old woman, 27 weeks pregnant, was admitted with congestive cardiac failure and incessant atrial tachycardia. She had an elevated brain natriuretic peptide (BNP) and chest X‐ray demonstrating heart failure. The 12‐lead electrocardiogram (ECG) showed atrial tachycardia with a cycle length of 310 ms, inverted P waves in lead I and the inferior leads, and a ventricular rate of 84 bpm during 2:1 block. Echocardiogram showed a global reduction in left ventricular function with a left ventricular ejection fraction (LVEF) of 0.40. Electrical cardioversion failed. Rate control could not be achieved with beta‐blockers and calcium antagonists. Amiodarone with repeat cardioversion was also unsuccessful. The patient then underwent catheter ablation. The entire procedure was performed using intracardiac echocardiography (ICE) and electroanatomical mapping with no fluoroscopy. Electrophysiology (EP) study and an activation map of the left atrium confirmed a focal left atrial tachycardia which was successfully ablated. Six weeks postablation, the left ventricular function had normalized and the patient delivered a healthy child at term, without complication. Conclusion: Ablation of left atrial tachycardia using ICE and electroanatomical guidance is feasible in pregnant women. (J Cardiovasc Electrophysiol, Vol. 22, pp. 346‐349, March 2011)     

Sustained intraatrial reentrant tachycardia: clinical, electrocardiographic and electrophysiologic characteristics and long-term follow-up

Although intraatrial reentry has been traditionally listed as a mechanism for supraventricular tachycardia, few reports describing the clinical features of this arrhythmia exist. Nineteen patients with a clinical history of sustained supraventricular tachycardia were diagnosed as having intraatrial reentrant tachycardia. Seventeen (89%) patients of the 19 had underlying structural heart disease and 17 had echocardiographic evidence of atrial enlargement; the mean left ventricular ejection fraction was 51 +/- 16%. A history of concomitant atrial fibrillation or flutter was present in 13 patients (68%). The mean atrial cycle length during tachycardia was 326 +/- 57 ms (range 260 to 460). Fourteen patients had 1:1 atrioventricular (AV) conduction during tachycardia, of whom 50% had an RP'/RR' ratio greater than 0.5. Intravenous adenosine (dose range 37.5 to 150 micrograms/kg) and verapamil (dose range 5 to 10 mg) had no effect on atrial tachycardia cycle length in 13 of 14 and 9 of 9 patients, respectively, despite induction of second degree AV block. Type 1a antiarrhythmic drugs achieved long-term suppression of intraatrial reentrant tachycardia in only 6 patients, whereas amiodarone (326 +/- 145 mg/day) was successful in 11 patients during a 32 +/- 20 month follow-up period. The remaining two patients and one patient who later developed amiodarone toxicity either progressed to (n = 1) or had (n = 2) catheter-induced high grade AV block and were treated with long-term ventricular pacing. It is concluded that intraatrial reentrant tachycardia is often associated with structural heart disease, particularly of types that cause atrial abnormalities, but left ventricular dysfunction is not a requisite finding. Other arrhythmias are frequently observed in these patients. This arrhythmia responds poorly to type 1a antiarrhythmic drugs, but is effectively treated with amiodarone. Catheter ablation of the AV junction offers a therapeutic option for patients who are refractory to medical therapy.     

Newer antiarrhythmic drugs in children

Our experience with the use of five new antiarrhythmic drugs for treating life-threatening arrhythmias in children will be briefly reviewed. Prevention of recurrent episodes of atrial flutter with digoxin and local anesthetic antiarrhythmic drugs often is only moderately successful, benefiting 65% of patients. Amiodarone is particularly useful for those patients who cannot be controlled on this regimen. We caution that the heart rate be monitored carefully when therapy with amiodarone is initiated in patients likely to have sick sinus syndrome. We have found mexiletine useful for controlling significant ventricular arrhythmias in patients with congenital heart disease. Likewise, 79% (11 of 14) of patients with ventricular tachycardia treated with amiodarone were well controlled. However, the range of disease categories (congenital heart disease, myocarditis, cardiomyopathy) in which amiodarone is effective is much broader than for mexiletine. Although other investigators have used amiodarone successfully for controlling supraventricular tachycardia in the Wolff-Parkinson-White syndrome or secondary to concealed accessory AV connections, we recommend surgical ablation. Propafenone has significantly improved our ability to control postoperative JET. Although JET is self-limited in duration and spontaneously remits, it frequently produces life-threatening hemodynamic compromise in the postoperative setting. Propafenone slows the ventricular rate into a range in which AV sequential pacing may be instituted. Generally, after 24 to 72 hours, the patient may be quickly weaned from propafenone. Chronic incessant supraventricular tachycardia (SVT) is frequently associated with a dilated cardiomyopathy. The two most common mechanisms of incessant SVT are PJRT and AET. We have found encainide and ethmozine extremely effective in suppressing tachycardia episodes in PJRT and AET, respectively. Medical therapy has been associated with few side effects.     

Transcatheter ablation of incessant ectopic left atrial tachycardia using radiofrequency current

Catheter ablation of ectopic atrial tachycardia has been previously reported in a small number of patients in whom the ectopic focus was predominantly located in the right atrium. We report on a 51-year-old patient with atrial automatic tachycardia originating in the left atrium, in whom successful radiofrequency catheter ablation was performed via a transseptal puncture. The patient had suffered incessant atrial tachycardia for several years, refractory to antiarrhythmic drug treatment and DC-cardioversion. Radiofrequency ablation terminated left ectopic atrial tachycardia and, therefore, should have been attempted before resorting to open heart surgical ablation.     

Incessant ventricular tachycardia in infants: myocardial hamartomas and surgical cure

Infants with incessant ventricular tachycardia (occurring greater than 10% of the day) have generally been described in pathologic studies. This report describes 21 patients with incessant ventricular tachycardia present greater than 90% of the day and night; the age at diagnosis ranged from birth to 30 months (mean 10.5 months). The most common clinical presentation was cardiac arrest (11 patients, in 5 after digitalis for presumed supraventricular tachycardia); another 6 patients had congestive heart failure and 4 were asymptomatic. Three patients had coexisting Wolff-Parkinson-White syndrome. The rate of incessant ventricular tachycardia ranged from 167 to 440 (mean 260 beats/min) and the QRS duration from 0.06 to 0.11 second. The most common electrocardiographic (ECG) pattern (10 of 21) was right bundle branch block with left axis deviation, but other right and left bundle branch block patterns were observed. Conventional and investigational antiarrhythmic agents (nine patients received amiodarone) failed to eliminate incessant ventricular tachycardia in all. Electrophysiologic studies localized incessant ventricular tachycardia to the left ventricle in 17 (to the apex in 2, the free wall in 9 and the septum in 6) and to the right ventricular septum in 4. No structural abnormalities were found on the echocardiogram or angiocardiogram. All 21 patients had surgery at an age of 3.5 to 31 months (mean 16). In 15 a tumor was found: 13 myocardial hamartomas (9 discrete, 4 diffuse throughout both ventricles) and 2 rhabdomyomas (1 multiple). Myocarditis was found in one patient (the oldest). In four, only myocardial fibrosis was found; results of one biopsy were normal.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electrical storm of monomorphic ventricular tachycardia after a cardiac-resynchronization-therapy-defibrillator upgrade.

In patients with significant left ventricular dysfunction and congestive heart failure despite optimal medical therapy, implantation of cardiac resynchronization therapy-defibrillation (CRT-D) devices has been shown to improve symptoms and mortality. In this report, we describe a case of a patient with ischaemic cardiomyopathy who developed incessant ventricular tachycardia (VT) after undergoing an upgrade from an implantable cardioverter defibrillator to a CRT-D device. The patient required multiple anti-arrhythmic agents, removal of the coronary sinus lead, and radiofrequency ablation to control VT. Thus, in rare patients, the CRT devices may potentially cause 'proarrhythmia' with serious consequences.