Rapid Atrial Arrhythmias Research Articles

Arrhythmogenic right ventricular cardiomyopathy associated with arrhythmia-induced cardiomyopathy: A case report

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a kind of inherited cardio-myopathy, which is characterized by fibro-fatty replacement of right ventricular myocardium, leading to ventricular arrhythmia. However, rapid atrial arrhythmias are also common, including atrial fibrillation, atrial flutter and atrial tachycardia. Long term rapid atrial arrhythmia can lead to further deterioration of cardiac function. This case is a 51-year-old male. He was admitted to Department of Cardiology, Peking University Third Hospital with palpitation and fatigue after exercise. Electrocardiogram showed incessant atrial tachycardia. Echocardiography revealed dilation of all his four chambers, especially the right ventricle, with the left ventricular ejection fraction of 40% and the right ventricular hypokinesis. Cardiac magnetic resonance imaging found that the right ventricle was significantly enlarged, and the right ventricular aneurysm had formed; the right ventricular ejection fraction was as low as 8%, and the left ventricular ejection fraction was 35%. The patients met the diagnostic criteria of ARVC, and both left and right ventricles were involved. His physical activities were restricted, and metoprolol, digoxin, spironolactone and ramipril were given. Rivaroxaban was also given because atrial tachycardia could cause left atrial thrombosis and embolism. His atrial tachycardia converted spontaneously to normal sinus rhythm after these treatments. Since the patient had severe right ventricular dysfunction, frequent premature ventricular beats and non-sustained ventricular tachycardia on Holter monitoring, indicating a high risk of sudden death, implantable cardioverter defibrillator (ICD) was implanted. After discharge from hospital, physical activity restriction and the above medicines were continued. As rapid atrial arrhythmia could lead to inappropriate ICD shocks, amiodarone was added to prevent the recurrence of atrial tachycardia, and also control ventricular arrhythmia. After 6 months, echocardiography was repeated and showed that the left ventricle diameter was reduced significantly, and the left ventricular ejection fraction increased to 60%, while the size of right ventricle and right atrium decreased slightly. According to the clinical manifestations and outcomes, he was diagnosed with ARVC associated with arrhythmia induced cardiomyopathy. According to the results of his cardiac magnetic resonance imaging, the patient had left ventricular involvement caused by ARVC, and the persistent atrial tachycardia led to left ventricular systolic dysfunction.

Selective autonomic stimulation of the AV node fat pad to control rapid post-operative atrial arrhythmias.

Junctional ectopic tachycardia (JET) and atrial fibrillation (AF) occur in patients recovering from open-heart surgery (OHS). Pharmacologic treatment is used for the control of post-operative atrial arrhythmias (POAA), but is associated with side effects. There is a need for a reversible, modulated solution to rate control. We propose a non-pharmacologic technique that can modulate AV nodal conduction in a selective fashion. Ten mongrel dogs underwent OHS. Stimulation of the anterior right (AR) and inferior right (IR) fat pad (FP) was done using a 7-pole electrode. The IR was more effective in slowing the ventricular rate (VR) to AF (52 +/- 20 vs. 15 +/- 10%, p = 0.003) and JET (12 +/- 7 vs. 0 +/- 0%, p = 0.02). Selective site stimulation within a FP region could augment the effect of stimulation during AF (57 +/- 20% (maximum effect) vs. 0 +/- 0% (minimum effect), p<0.001). FP stimulation at increasing stimulation voltage (SV) demonstrated a voltage-dependent effect (8 +/- 14% (low V) vs. 63 +/- 17 (high V) %, p<0.001). In summary, AV node fat pad stimulation had a selective effect on the AV node by decreasing AV nodal conduction, with little effect on atrial activity.

GW26-e1322 Incidence and influence factors of new onset rapid atrial arrhythmias patients with permanent pacemakers

GW26-e1322 Incidence and influence factors of new onset rapid atrial arrhythmias patients with permanent pacemakers

Heart beats: not to be beaten.

Heart beats: not to be beaten.

A New Algorithm to Diagnose Atrial Ectopic Origin from Multi Lead ECG Systems - Insights from 3D Virtual Human Atria and Torso

Rapid atrial arrhythmias such as atrial fibrillation (AF) predispose to ventricular arrhythmias, sudden cardiac death and stroke. Identifying the origin of atrial ectopic activity from the electrocardiogram (ECG) can help to diagnose the early onset of AF in a cost-effective manner. The complex and rapid atrial electrical activity during AF makes it difficult to obtain detailed information on atrial activation using the standard 12-lead ECG alone. Compared to conventional 12-lead ECG, more detailed ECG lead configurations may provide further information about spatio-temporal dynamics of the body surface potential (BSP) during atrial excitation. We apply a recently developed 3D human atrial model to simulate electrical activity during normal sinus rhythm and ectopic pacing. The atrial model is placed into a newly developed torso model which considers the presence of the lungs, liver and spinal cord. A boundary element method is used to compute the BSP resulting from atrial excitation. Elements of the torso mesh corresponding to the locations of the placement of the electrodes in the standard 12-lead and a more detailed 64-lead ECG configuration were selected. The ectopic focal activity was simulated at various origins across all the different regions of the atria. Simulated BSP maps during normal atrial excitation (i.e. sinoatrial node excitation) were compared to those observed experimentally (obtained from the 64-lead ECG system), showing a strong agreement between the evolution in time of the simulated and experimental data in the P-wave morphology of the ECG and dipole evolution. An algorithm to obtain the location of the stimulus from a 64-lead ECG system was developed. The algorithm presented had a success rate of 93%, meaning that it correctly identified the origin of atrial focus in 75/80 simulations, and involved a general approach relevant to any multi-lead ECG system. This represents a significant improvement over previously developed algorithms.

Hemangioma as a rare cause of a neonatal cardiac tumor resulting in inflow obstruction of the tricuspid valve

Sirs: Cardiac tumors are rare in children. Prevalence varies between 0.0017 and 0.027% in autopsy studies [1]. Approximately, 90% of the pediatric primary cardiac tumors are benign. Rhabdomyomas are the most common subtype accounting for about 60% while hemangiomas are rare with about 5% [2]. Diagnosis in the neonatal age group may be difficult because of nonspecific symptoms such as murmur, dysrhythmia, hypoxia, or congestive heart failure. Transthoracic echocardiography is the most important diagnostic tool allowing rapid diagnosis and assessment for the need for surgical intervention. A male infant was born at 36 + 6 weeks of gestation after an uneventful pregnancy by caesarean section because of pathologic cardiotokography. He was noted to have cyanosis, tachypnea, and signs of poor perfusion in the first hour of life. On chest radiograph, an enlarged heart with a prominent right atrium was evident (Fig. 1). Echocardiography revealed a large mass in the right atrium adhering in large parts to the atrial wall causing severe inflow obstruction to the tricuspid valve (Fig. 2). Low cardiac output and metabolic acidosis were resistant to fluid supplementation. Emergent cardiac surgery was performed using cardiopulmonary bypass. The tumor could be removed in toto by peeling it off the atrial wall. Surgical reconstruction of the dilated atrium was performed. The tumor had an extension of 4.5 × 3.5 × 2.8 cm. Histologically, it consisted mostly of blood, lined by a thin strip of tissue that was diagnosed as benign cavernous hemangioma. Fig. 1 Initial radiograph demonstrating an enlarged heart with a prominent right atrium without signs of pulmonary congestion Fig. 2 2-D echocardiogram, subxiphoidal view, showing a large tumor in the dilated right atrium attached to the atrial-free-wall with inflow obstruction to the tricuspid valve. LA left atrium, LV left ventricle, RV right ventricle, T tumor The postoperative course was complicated by a multifocal atrial tachycardia resulting in a ventricular heart rate of 270–290/min refractory to medical treatment and cardioversion. Because of severe hemodynamic compromise extracorporal membrane oxygenation support was required for 5 days, until sufficient heart rate control could be achieved by amiodarone and overdrive pacing. Cardiac function and rhythm normalised in the following weeks. The patient was discharged home without residual arrhythmias and normal cardiac function. Until now, there are no signs of relapse or hemangiomas in other locations. Hemangiomas are a known but rare entity of primary cardiac tumors in childhood [1]. There are reports of tumors diagnosed prenatally in screening ultrasound examinations [3]. Pregnancy in our patient had been unremarkable. Retrospectively, the pathologic cardiotokography just before birth may have been the first sign of hemodynamic compromise in this patient. It is likely that an initially rather small hemangioma ruptured just before birth resulting in a rapid expansion of the tumor, as it was filled with blood, that subsequently caused the significant inflow obstruction to the tricuspid valve. Immediate surgical intervention was necessary due to imminent low output failure of the right heart. The tumor was peeled off the atrial wall causing a large area of endothelial and myocardial trauma. The intractable atrial arrhythmia that developed postoperatively was probably caused by this necessary procedure. Arrhythmias due to right atrial surgery are a known but often unavoidable complication. This tachycardia required initial extracorporal membrane oxygenation support [4]. Subsequently, it could be controlled by amiodarone and overdrive pacing, and finally it resolved completely after 2 months. As in all patient described so far, there are no signs of recurrence of the hemangioma in our patient up to date. This case report describes a hemangioma as a rare cause of a neonatal intracardiac tumor. In this patient, the large atrial mass resulted in severe inflow obstruction to the tricuspid valve requiring emergent surgical relief. The postoperative course was complicated by rapid atrial arrhythmias probably due to large atrial endothelial and myocardial trauma.

Postthoracotomy atrial fibrillation

Rapid atrial arrhythmias affect the elderly who undergo cardiac or noncardiac operations annually and have been associated with prolonged hospital stays. This article focuses on new issues leading to the improved understanding of the pathophysiology and mechanisms of postoperative atrial arrhythmias. New risk factors and a prediction rule for postthoracotomy atrial fibrillation are discussed. Settings in which amiodarone prophylaxis against atrial fibrillation after cardiac surgery is appropriate are contrasted with evidence for postthoracotomy atrial fibrillation. Once atrial fibrillation develops, rate versus rhythm control strategies are reviewed. The most recent recommendations of the American Heart Association Task Force on the management of patients with atrial fibrillation are highlighted. Recent approaches directed at prophylaxis and acute therapy of atrial arrhythmias are discussed as are recommendations to prevent thromboembolic events.

Strategies for perioperative arrhythmias

Rapid atrial arrhythmias affect close to one million elderly Americans who undergo cardiac or non-cardiac operations annually and have been associated with prolonged hospital stays. In contrast, bradyarrhythmias or ventricular arrhythmias severe enough to require treatment occur in less than 1% of patients who undergo all types of surgery, including cardiac. This article focuses on new issues leading to the improved understanding of the pathophysiology and mechanisms of post-operative atrial arrhythmias. New approaches directed at prophylaxis and acute therapy of atrial arrhythmias are discussed, as are recommendations to prevent thromboembolic events. Practice and research agenda are proposed.

Association of angiotensin converting enzyme gene polymorphism with tachycardia cardiomyopathy

Despite incessant tachycardia, not all patients develop tachycardia-mediated cardiomyopathy. The cardiac renin-angiotensin system may be involved in cardiac remodelling and fibrosis. The level of angiotension-converting enzyme (ACE) in the serum is associated with a 287 bp insertion (I)/deletion (D) polymorphism in intron 16 of the ACE gene. The DD genotype is associated with increased serum ACE levels and a higher incidence of idiopathic dilated and ischemic cardiomyopathy. The objective of this study was to assess whether the ACE gene I/D polymorphism is responsible for development of tachycardia-mediated cardiomyopathy. We identified 20 consecutive patients with persistent tachycardia and cardiomyopathy who showed significant improvement in ejection fraction after rate control (group A, tachycardia cardiomyopathy group). We compared the I/D genotype frequency of group A with the gene frequency of a separate group of 20 patents who, despite rapid atrial arrhythmias had preserved left ventricular ejection fraction (group B, tachycardia without cardiomyopathy group). These two groups were then compared with 24 healthy normal volunteers (group C). After a mean follow-up of 30 months, group A patients showed improvement in ejection fraction from 20+/-7 to 43+/-9% (p<0.001). Group A had a significantly higher frequency of the DD genotype than groups B and C (p-value <0.035 and <0.009 respectively). The profile of group B patients was intermediate between normal and patients with tachycardia-mediated cardiomyopathy. I/D polymorphism of the ACE gene may account for cardiomyopathy secondary to tachycardia.

Perioperative atrial tachyarrhythmias.

Perioperative atrial tachyarrhythmias.

Is Telemetry Monitoring Necessary in Low-Risk Suspected Acute Chest Pain Syndromes?

Non-ICU telemetry monitoring has proven to be a valuable resource for patients suspected of having an acute myocardial infarction. While a significant number of patients are admitted to these units, the actual incidence of events or interventions is low. To identify a subset of patients in whom telemetry monitoring does not alter management. Prospective observational study. Large tertiary care facility. A total of 414 patients consecutively admitted from the emergency department for suspected acute coronary syndromes were studied. Patients were excluded if they presented with ST-segment elevations, were revascularized on hospital admission, were admitted to a surgical service, were transferred from another floor or unit, or remained in the emergency department for the course of the stay. Events were defined as development of myocardial infarction, episodes of chest pain, new or rapid atrial arrhythmias, ventricular arrhythmias, any form of AV nodal block, and asystole. Intervention or change in management was any increase, decrease, or change in medication, cardioversion, electrophysiology study, or transfer to the ICU. Patients who had atypical chest pain and normal ECG findings were significantly less likely to have both intervention and events (4 interventions vs 23 interventions [p < 0.0001], 12 events vs 45 events [p < 0.0001]), compared to those with typical chest pain and abnormal ECG findings. When normal laboratory values were added, only four telemetry events were observed. Patients with atypical chest pain and normal ECG findings represent a subset of patients with low risk for life-threatening arrhythmia. Use of telemetry monitoring in this subset of patients should be reevaluated.

Electrophysiologic consequences of the mustard repair of d-transposition of the great arteries

This study describes the electrophysiologic effects of the Mustard repair of d-transposition of the great arteries on the sinus node and on conduction and refractoriness in the atrium, atrioventricular (AV) node and ventricle. Seventy-two electrophysiologic studies were performed on 64 patients after the Mustard operation. Standard rest and 24 hour ambulatory electrocardiograms were evaluated. Catheter endocardial atrial mapping, available in 67 of the 72 studies, revealed that sinus rhythm was present in the atria in 33 patients, ectopic atrial rhythm in 26 and junctional rhythm in 8. Intraatrial conduction delays with very late activation of the low medial, low lateral or low right atrium at the AV junction were present in 53 of 59 patients with atrial or sinus rhythm. Sinus node function was normal in only nine patients. Prolonged refractory periods were found in the right atrial portion of the new right atrium when compared with the left atrial portion of the new right atrium. Forty-one percent of the patients had prolongation of atrial refractoriness with shortening of the paced cycle lengths. Fifty-one percent developed sustained intraatrial reentry with programmed atrial stimulation. Forty-eight percent of these patients with inducible atrial tachycardia have since developed clinical episodes of atrial flutter. In summary, electrophysiologic studies revealed significant abnormalities of sinus node function and atrial conduction and refractoriness. Alone or in combination, these abnormalities, which result in severe bradycardia or rapid atrial arrhythmias, may lead to sudden death. The Jatene or arterial switch procedure may provide an appropriate alternative operation in this group of patients.

Unexplained Atrial Flutter: A Frequent Herald of Pulmonary Embolism

Of 5,396 consecutive new patients studied in our electrocardiographic laboratory between September 1967 and April 1970, 45 were found to have atrial flutter. In 19 of the 45, esophageal leads were used to confirm the diagnosis of the arrhythmia and 25 of the 45 patients with atrial flutter were thought to have definite evidence of pulmonary embolism. Two facts are of clinical significance: First, the judicious use of esophageal or intraatrial electrograms may enhance the frequency with which rapid atrial arrhythmias with block are clearly identified rather than superficially dismissed as “sinus” or “supraventricular” tachycardia; second, and more important, the occurrence of atrial flutter with no clear etiologic basis should precipitate a careful search for the presence of covert pulmonary embolism.

Unexplained atrial flutter: A frequent herald of pulmonary embolism

Abstract Of 5,396 consecutive new patients studied in our electrocardiographic laboratory between September 1967 and April 1970, 45 were found to have atrial flutter. In 19 of the 45, esophageal leads were used to confirm the diagnosis of the arrhythmia and 25 of the 45 patients with atrial flutter were thought to have definite evidence of pulmonary embolism. Two facts are of clinical significance: First, the judicious use of esophageal or intraatrial electrograms may enhance the frequency with which rapid atrial arrhythmias with block are clearly identified rather than superficially dismissed as “sinus” or “supraventricular” tachycardia; second, and more important, the occurrence of atrial flutter with no clear etiologic basis should precipitate a careful search for the presence of covert pulmonary embolism.