Risks and complications of clinical cardiac electrophysiologic studies: a prospective analysis of 1,000 consecutive patients

Incidence and management of atrioventricular conduction disorders in new-onset left bundle branch block after TAVI: A prospective multicenter study

BACKGROUND

New-onset left bundle branch block (LBBB) is one of the most frequent complications after transcatheter aortic valve implantation (TAVI) and is associated with delayed high degree atrioventricular (AV) block.

OBJECTIVES

The objectives of this study were to determine the incidence of AV block in such a population and to assess the performance and safety of a risk stratification algorithm on the basis of electrophysiology study (EPS) followed by implantation of a pacemaker or implantable loop recorder (ILR).

METHODS

This was a prospective open-label study with 12-month follow-up. From June 8, 2015, to November 8, 2018, 183 TAVI recipients (mean age 82.3 ± 5.9 years) were included at 10 centers. New-onset LBBB after TAVI persisting for >24 hours was assessed by electrophysiology study during initial hospitalization. High-risk patients (His-ventricle interval ≥70 ms) were implanted with a dual-chamber pacemaker recording AV conduction disturbance episodes. Patients at lower risk were implanted with an ILR with automatic remote monitoring.

RESULTS

A high-grade AV conduction disorder was identified in 56 patients (30.6%) at 12 months. Four subjects were symptomatic, all in the ILR group. No complications were associated with the stratification procedure. Patients with His-ventricle interval ≥70 ms displayed more high-grade AV conduction disorders (53.2% [25 of 47] vs 22.8% [31 of 136]; P < .001). In a multivariate analysis, His-ventricle interval ≥70 ms was independently associated with the occurrence of a high-grade conduction disorder (subdistribution hazard ratio 2.4; 95% confidence interval 1.2-4.8; P = .010).

CONCLUSION

New-onset LBBB after TAVI was associated with high rates of high-grade AV conduction disturbances. The stratification algorithm provided safe and valuable aid to management decisions and reliable guidance on pacemaker implantation.

Brugada Syndrome

Brugada syndrome (BrS) is an "inherited" condition characterized by predisposition to syncope and cardiac arrest, predominantly during sleep. The prevalence is ∼1:2,000, and is more commonly diagnosed in young to middle-aged males, although patient sex does not appear to impact prognosis. Despite the perception of BrS being an inherited arrhythmia syndrome, most cases are not associated with a single causative gene variant. Electrocardiogram (ECG) findings support variable extent of depolarization and repolarization changes, with coved ST-segment elevation ≥2 mm and a negative T-wave in the right precordial leads. These ECG changes are often intermittent, and may be provoked by fever or sodium channel blocker challenge. Growing evidence from cardiac imaging, epicardial ablation, and pathology studies suggests the presence of an epicardial arrhythmic substrate within the right ventricular outflow tract. Risk stratification aims to identify those who are at increased risk of sudden cardiac death, with well-established factors being the presence of spontaneous ECG changes and a history of cardiac arrest or cardiogenic syncope. Current management involves conservative measures in asymptomatic patients, including fever management and drug avoidance. Symptomatic patients typically undergo implantable cardioverter defibrillator insertion, with quinidine and epicardial ablation used for patients with recurrent arrhythmia. This review summarizes our current understanding of BrS and provides clinicians with a practical approach to diagnosis and management.

Acute Cardiac Tamponade as a Complication of Pulmonary Vein Isolation Ablation

Perioperative acute cardiac tamponade associated with perforation from pulmonary vein isolation (PVI) and radiofrequency catheter ablation (RFCA) for the treatment of refractory atrial fibrillation (AF) is rare. If not identified early and managed promptly, it can lead to decreased ejection fraction, hypotension, and ultimately death. We report a case of acute tamponade that was diagnosed and successfully managed following PVI and RFCA. A 49-year-old woman with a past medical history of paroxysmal AF and sick sinus syndrome presented to our hospital with intermittent episodes of palpitations and recurrent episodes of syncope. Given the drug-refractory AF, our patient underwent PVI and RFCA. A loop recorder was implanted for recurrent episodes of syncope, which revealed that she had sick sinus syndrome. During the current visit, transthoracic ECG revealed mild tricuspid regurgitation and trace pericardial effusion. Her left ventricle (LV) ejection fraction was 60%. A CT angiography of the pulmonary vessels and the aorta showed no evidence of pulmonary embolism, aortic aneurysm, or aortic dissection. However, there was an enlarged heart size and small bilateral pleural effusions. During a second PVI and RFCA, while in the operating room, the patient became hypotensive. A transesophageal echocardiogram (TEE) showed diastolic volume reduction in the right atrium and right ventricular and pericardial effusion. Intravenous (IV) resuscitation with lactated Ringer's solution and saline solution was rapidly given to the patient while performing percutaneous pericardiocentesis. In addition, packed red blood cells were transfused into the patient, and phenylephrine was given IV. There was 400 mL of blood drained from the pericardial sac, confirming the presence of acute cardiac tamponade. Following the pericardiocentesis, the patient became normotensive. A drainage tube was inserted into the pericardial space, which drained a total of 250 mL of sanguineous fluid over the next 48 hours after the procedure, after which it was removed without signs of persistent bleeding, and the patient was discharged. We conclude that her previous PVI and RFCA, and the anatomical distortion that might have resulted from her enlarged heart size, may have predisposed her to perforation and thus acute cardiac tamponade in this PVI and RFCA. Although perforation leading cardiac tamponade is rare during PVI and RFCA, the future focus when performing this procedure should be to (i) have a high index of suspicion for acute cardiac tamponade, (ii) use TEE and intracardiac echocardiography for early detection, and (iii) promptly manage the acute cardiac tamponade with pericardiocentesis, while giving IV fluid resuscitation and positive inotropes to hemodynamically stabilize the patient.

Comparative Effectiveness of Implantable Defibrillators for Asymptomatic Brugada Syndrome: A Decision-Analytic Model

Background

Optimal management of asymptomatic Brugada syndrome (BrS) with spontaneous type I electrocardiographic pattern is uncertain.

Methods and Results

We developed an individual‐level simulation comprising 2 000 000 average‐risk individuals with asymptomatic BrS and spontaneous type I electrocardiographic pattern. We compared (1) observation, (2) electrophysiologic study (EPS)‐guided implantable cardioverter‐defibrillator (ICD), and (3) upfront ICD, each using either subcutaneous or transvenous ICD, resulting in 6 strategies tested. The primary outcome was quality‐adjusted life years (QALYs), with cardiac deaths (arrest or procedural‐related) as a secondary outcome. We varied BrS diagnosis age and underlying arrest rate. We assessed cost‐effectiveness at $100 000/QALY. Compared with observation, EPS‐guided subcutaneous ICD resulted in 0.35 QALY gain/individual and 4130 cardiac deaths avoided/100 000 individuals, and EPS‐guided transvenous ICD resulted in 0.26 QALY gain and 3390 cardiac deaths avoided. Compared with observation, upfront ICD reduced cardiac deaths by a greater margin (subcutaneous ICD, 8950; transvenous ICD, 6050), but only subcutaneous ICD improved QALYs (subcutaneous ICD, 0.25 QALY gain; transvenous ICD, 0.01 QALY loss), and complications were higher. ICD‐based strategies were more effective at younger ages and higher arrest rates (eg, using subcutaneous devices, upfront ICD was the most effective strategy at ages 20–39.4 years and arrest rates >1.37%/year; EPS‐guided ICD was the most effective strategy at ages 39.5–51.3 years and arrest rates 0.47%–1.37%/year, and observation was the most effective strategy at ages >51.3 years and arrest rates <0.47%/year). EPS‐guided subcutaneous ICD was cost‐effective ($80 508/QALY).

Conclusions

Device‐based approaches (with or without EPS risk stratification) can be more effective than observation among selected patients with asymptomatic BrS. BrS management should be tailored to patient characteristics.

Venous Thrombosis After Electrophysiology Procedures: A Systematic Review

BACKGROUND

Femoral venous access for catheter introduction represents the cornerstone of electrophysiology (EP) procedures. Limited data are available regarding postprocedure VTE. The aim of this systematic review is to determine the incidence of DVT and pulmonary embolism (PE) associated with femoral vein catheterization during EP procedures.

METHODS

An electronic search was conducted for studies documenting the incidence of DVT and PE after EP procedures. Studies were classified as atrial fibrillation (AF) or non-AF ablation procedures.

RESULTS

Two thousand eight-hundred sixty-four studies were evaluated, 16 of which were included in the analysis. The incidence of DVT after AF and non-AF ablations reached as high as 0.33% and 2.38%, respectively, with a pooled incidence of 0% (95% CI, 0%-0.0003%) and 0.24% (95% CI, 0.08%-0.39%), respectively. The incidence of PE was 0.29% after AF ablation and ranged from 0% to 1.67% for non-AF procedures; the pooled incidence after non-AF ablations was 0.12% (95% CI, 0%-0.25%). Asymptomatic DVT was documented in up to 21.2% of patients. Hematomas occurred in 1.05% of AF ablations (95% CI, 0.30%-1.8%) and 0.3% of non-AF ablations (95% CI, 0.09%-0.51%).

CONCLUSIONS

A lower incidence of symptomatic DVT and PE was observed after AF ablations as opposed to non-AF ablations, likely due to the use of routine periprocedural anticoagulation. Asymptomatic DVTs appear to be common, although their significance is unclear. Future studies are required to weigh the risk of hematoma against the risk of VTE associated with the use of prophylactic anticoagulation after non-AF ablation procedures.

Evaluation and Management of Maternal Cardiac Arrhythmias

Pregnant women often complain of palpitations. The differential diagnosis for new-onset palpitations in pregnancy ranges from benign conditions to life-threatening arrhythmias. Maternal arrhythmias can occur in isolation or in the setting of underlying structural heart disease. Optimal management of maternal cardiac arrhythmias includes identification of the specific arrhythmia, diagnosis of comorbid conditions, and appropriate intervention. In general, management of maternal cardiac arrhythmias is similar to that of the general population. Special consideration must be given as to the effects of medications and procedures on both the mother and fetus to optimize outcomes. The importance of multidisciplinary care with cardiology, obstetrics, and anesthesia is emphasized.

Pulmonary embolism as a complication of an electrophysiological study: a case report

BACKGROUND

Electrophysiological studies have become an established practice in the evaluation and treatment of arrhythmias. Symptomatic pulmonary embolism as a result of deep vein thrombosis arising from multiple venous sheath femoral vein catheterization is an uncommon complication associated with it. We report the case of a 33-year-old woman who developed pulmonary embolism after an electrophysiological study, which was successfully treated at a cardiac hospital in Bangladesh.

CASE PRESENTATION

A 33-year-old Bangladeshi woman with hypertension and diabetes had initially presented with recurrent episodes of paroxysmal atrial fibrillation that manifested as palpitations for 2 years. Her atrial fibrillation was drug-refractory and could not be attributed to a treatable etiology. She had undergone an electrophysiological study at a different hospital, where right femoral venous catheterization was performed followed by the insertion of three venous sheaths. However, tachyarrhythmia could not be induced and a procedure to isolate the pulmonary vein was postponed because all the veins could not be isolated. Forty-eight hours later, she presented to our hospital with shortness of breath, chest heaviness, palpitations, and recurrent episodes of syncope. She had normal coronary arteries and no other risk factors for venous thromboembolism. She was hemodynamically stable on examination. There was echocardiographic evidence of pulmonary hypertension and right ventricular dilatation and dysfunction. A computed tomography pulmonary angiogram confirmed pulmonary embolus in the descending branch of her left pulmonary artery, extending up to the segmental arteries. Subsequently, a duplex ultrasound confirmed acute deep vein thrombosis affecting her right ilio-femoral segment. She was successfully managed with subcutaneous enoxaparin and oral warfarin (target international normalized ratio 2.5-3).

CONCLUSIONS

Pulmonary embolism is a rare but serious complication that may occur in patients who undergo electrophysiological studies. Multiple venous sheaths inserted into the femoral vein and catheter-induced endothelial injury, further compounded by prolonged procedural time, may be responsible for the increased thrombogenicity leading to deep vein thrombosis and subsequent pulmonary embolism. An adequate observation time after the procedure and clinical alertness are necessary for rapid diagnosis and treatment.

Clinical Features of Acute Massive Pulmonary Embolism Complicated by Radiofrequency Ablation: An Observational Study

Although pulmonary embolism (PE) complicated by radiofrequency catheter ablation (RFCA) is rare, it can be life-threatening. Our goal was to elucidate the clinical features of acute massive PE after RFCA. Of 2386 patients who underwent RFCA for supraventricular tachycardia or idiopathic ventricular arrhythmia, 4 patients (0.16%) whose cases were complicated by acute massive PE were examined. These 4 patients were female and middle-aged (range 43-52 years), and 2 of the 4 patients had iron-deficiency anemia and reactive thrombocytosis. Ablation in all patients was performed in the left heart via the right femoral arterial approach. All of the patients had a long-duration hemostasis procedure and bed rest following femoral arterial sheath removal after RFCA. All of the patients collapsed and lost consciousness during their &filig;rst attempt at walking after RFCA. The emergent electrocardiogram in 2 of the 4 patients revealed an S1Q3T3 pattern, 1 patient demonstrated new onset of right bundle-branch block (RBBB) and S1Q3 pattern and Qr pattern in V1, and the remaining patient had negative T waves in leads V1, V2, and III. The emergent echocardiogram revealed right ventricular hypokinesis and pulmonary hypertension in the 4 patients with acute PE after ablation. Although all of the patients initially experienced sinus tachycardia when they recovered consciousness, 2 of the 4 patients suddenly developed intense bradycardia and lost consciousness again, and these patients finally died (50% fatality rate). All of the patients were identi&filig;ed by CT pulmonary angiography or pulmonary angiography. Our report suggests that although acute massive PE is highly rare, there is a real and fatal risk in patients who experienced acute massive PE after RFCA. Particular attention should be paid to the first ambulation after RFCA. Acute PE should be strongly suspected when sudden loss of consciousness occurs upon mobilization after RFCA. The new onset of S1Q3T3 pattern, RBBB or T wave inversion in the right precordial leads, and early detection of echocardiographic right ventricular dysfunction may be useful for making an early diagnosis of acute PE after RFCA. Early ambulation after left-sided RFCA might be helpful to prevent the formation of deep venous thrombosis and subsequent PE.

Value of EP Study and Other Cardiac Investigations

With the advent of implantable loop recorders capable of prolonged electrocardiographic monitoring, and following studies demonstrating the benefit of implantable cardioverter-defibrillator therapy in subgroups of patients with structural heart disease and depressed left ventricular function, the role of invasive cardiac electrophysiologic (EP) studies in patients with unexplained syncope has been substantially reduced. Nonetheless, in select high-risk patients presenting with unexplained syncope, EP studies still play an important role in identifying a diagnosis in these patients and assessing long-term risk of mortality.

Electrogram guidance: a method to increase the precision and diagnostic yield of endomyocardial biopsy for suspected cardiac sarcoidosis and myocarditis

OBJECTIVES

The aim of this study was to describe the method used to perform electrogram-guided EMB and correlate electrogram characteristics with pathological and clinical outcomes.

BACKGROUND

Endomyocardial biopsy (EMB) is valuable in determining the underlying etiology of a cardiomyopathy. The sensitivity, however, for focal disorders, such as lymphocytic myocarditis and cardiac sarcoidosis (CS), is low. The sensitivity of routine fluoroscopically guided EMB is low. Abnormal intracardiac electrograms are seen at sites of myocardial disease. However, the exact value of electrogram-guided EMB is unknown.

METHODS

We report 11 patients who underwent electrogram-guided EMB for evaluation of myocarditis and CS.

RESULTS

Of 40 total biopsy specimens taken from 11 patients, 19 had electrogram voltage <5 mV, all of which resulted in histopathologic abnormality (100% specificity and positive predictive value). A voltage amplitude cutoff value of 5 mV had substantially higher sensitivity (70% vs. 26%) and negative predictive value (62%) than 1.5 mV. Abnormal electrogram appearance at biopsy site had good sensitivity (67%) and specificity (92%) in predicting abnormal myocardium. Normal signals with voltage >5 mV signified normal myocardium with no significant diagnostic yield. Biopsy results guided therapy in all patients, including 5 with active myocarditis or CS, all of whom subsequently received immunosuppressive therapy. There were no procedural complications.

CONCLUSIONS

In patients with suspected myocarditis or CS, electrogram-guided EMB targeting sites with abnormal or low-amplitude electrograms may increase the diagnostic yield for detecting abnormal pathological findings.

Evaluation and management of wolff-Parkinson-white in athletes

CONTEXT

Wolff-Parkinson-White (WPW) is a cardiac conduction system disorder characterized by abnormal accessory conduction pathways between the atria and the ventricles. Symptomatic patients classically present with palpitations, presyncope, or syncope that results from supraventricular tachycardia. While rare, sudden cardiac death may be the first manifestation of underlying disease and occurs more frequently in exercising individuals.

EVIDENCE ACQUISITION

Medline and PubMed databases were evaluated through 2012, with the following keywords: WPW, Wolff-Parkinson-White, pre-excitation, sudden cardiac death, risk stratification, and athletes. Selected articles identified through the primary search, along with relevant references from those articles, were reviewed for pertinent clinical information regarding the identification, evaluation, risk stratification, and management of WPW as they pertained to the care of athletes.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 1.

RESULTS

Diagnosis of WPW is confirmed by characteristic electrocardiogram changes, which include a delta wave, short PR interval, and widened QRS complex. Utilization of the electrocardiogram as part of the preparticipation physical evaluation may allow for early identification of asymptomatic individuals with a WPW pattern. Risk stratification techniques identify individuals at risk for malignant arrhythmias who may be candidates for curative therapy through transcatheter ablation.

CONCLUSION

WPW accounts for at least 1% of sudden death in athletes and has a prevalence of at least 1 to 4.5 per 1000 children and adults. The risk of lethal arrhythmia appears to be higher in asymptomatic children than in adults, and sudden cardiac death is often the sentinel event. The athlete with WPW should be evaluated for symptoms and the presence of intermittent or persistent pre-excitation, which dictates further consultation, treatment, and monitoring strategies as well as return to play.

Survey of reoperation indications in tetralogy of fallot in Japan

BACKGROUND

Although the survival rate for repaired Tetralogy of Fallot (TOF) is dramatically improving, anatomical and functional residua and sequelae followed by arrhythmias and sudden death are still challenging issues to be resolved. Reoperation can reduce the incidence of arrhythmias and sudden death, but there is no consensus on the indications of reoperation for patients with TOF, especially in Japan.

METHODS AND RESULTS

A cross-sectional questionnaire survey of reoperation indications in patients with TOF was performed through a Japanese multicenter study. The questionnaire, which focused on the number of repaired TOF patients aged >15 years old, reoperation indications and management, was sent to the institutions belonging to Japanese Society for Adult Congenital Heart Disease. In total, 41.5% (78/188) of the institutions replied. The total number of repaired TOF patients was 4,010, and sudden cardiac death was observed in 45.236/4,010 (5.9%) experienced reoperation. Pulmonary stenosis (32%) and pulmonary regurgitation (29%) were the most common reasons for reoperation. There were only 2 implantable cardioverter defibrillator or resynchronization therapy defibrillator implantations. The physiological/anatomical indications of reoperation differed among the hospitals.

CONCLUSIONS

Approximately 1.1% of patients suffered sudden death and 6% of repaired TOF patients had reoperation. The indications of reoperation, however, varied among the institutions. Therefore, detailed information for each case of sudden death or reoperation should be collected and analyzed in order to establish guidelines for reoperation.

Inadvertently Developed Ventricular Fibrillation during Electrophysiologic Study and Catheter Ablation: Incidence, Cause, and Prognosis

Background and Objectives

Ventricular fibrillation (VF) can inadvertently occur during electrophysiologic study (EPS) or catheter ablation. We investigated the incidence, cause, and progress of inadvertently developed VF during EPS and catheter ablation.

Subjects and Methods

We reviewed patients who had developed inadvertent VF during EPS or catheter ablation. Patients who developed VF during programmed ventricular stimulation to induce ventricular tachycardia or VF were excluded.

Results

Inadvertent VF developed in 11 patients (46.7±9.3 years old) among 2624 patients (0.42%); during catheter ablation for atrial fibrillation (AF) in nine patients, frequent ventricular premature beats (VPBs) in one, and Wolff-Parkinson-White (WPW) syndrome were observed in one. VF was induced after internal cardioversion in six AF patients due to incorrect R-wave synchronization of a direct current shock. Two AF patients showed spontaneous VF induction during isoproterenol infusion while looking for AF triggering foci. The remaining AF patient developed VF after rapid atrial pacing to induce AF, but the catheter was accidentally moved to the right ventricular (RV) apex. A patient with VPB ablation spontaneously developed VF during isoproterenol infusion. The focus of VPB was in the RV outflow tract and successfully ablated. A patient with WPW syndrome developed VF after rapid RV pacing with a cycle length of 240 ms. Single high energy (biphasic 150-200 J) external defibrillation was successful in all patients, except in two, who spontaneously terminated VF. The procedure was uneventfully completed in all patients. At a mean follow-up period of 17.4±15.5 months, no patient presented with ventricular arrhythmia.

Conclusion

Although rare, inadvertent VF can develop during EPS or catheter ablation. Special caution is required to avoid incidental VF during internal cardioversion, especially under isoproterenol infusion.

Prevalence of inducible paroxysmal supraventricular tachycardia during esophageal electrophysiologic study in patients with unexplained stroke

BACKGROUND

The relationships between stroke and atrial tachycardia or atrial fibrillation were previously reported. Electrophysiological study is one of the means, used to detect and evaluate these atrial tachyarrhythmias. But, some other arrhythmias as paroxysmal supraventricular tachycardia, can be induced during electrophysiologic study and their significance in stroke is unknown. The aim of the study was to assess the significance of inducible paroxysmal supraventricular tachycardia (PSVT) in stroke.

METHODS

One hundred thirty seven patients, aged 61+/-12 years had unexplained stroke (group I) and were compared to 60 subjects aged 45+/-18.5 years without stroke and history of tachycardia (group II); Holter monitoring (HM), echocardiogram and esophageal electrophysiologic study (EPS) in basal state and after isoproterenol were performed.

RESULTS

Heart disease was noted in 19 group I patients (14%) and 10 group II patients (17%). In group I, atrial fibrillation or tachycardia (AF-AT) was induced in 20 patients (15%) and PSVT was induced in 19 patients (14%) aged 66+/-12 years. In group II, AF/AT was induced in 3 patients (5%); no group II patient had induced PSVT. After 3+/-1 years, in group I, one of 98 patients without induced arrhythmias had new strokes and 2 had AF; 5 patients with induced AT/AF developed AF; 5 patients with induced PSVT had PSVT's, requiring ablation in 4 of them; 1 died from a new stroke; one had a second non-fatal stroke and 3 patients developed AF (16%). In group II, there were no events.

CONCLUSION

In 14% of patients with unexplained stroke, PSVT was inducible during esophageal electrophysiologic study. Further studies are warranted to assess the significance of this finding in patients with unexplained stroke.

Massive pulmonary embolism with cardiac arrest after an intracardiac electrophysiological study: a strong case for venous thromboprophylaxis

A 47-year-old woman was referred to our hospital for an intracardiac electrophysiological study. The procedure was complicated by cardiac arrest due to massive pulmonary embolism, which only successfully resolved after the administration of a thrombolytic agent. This case suggests that there is a real risk of venous thromboembolism in certain patients during electrophysiological studies. Therefore, a consensus should be reached concerning the prevention of venous thromboembolism during these procedures.

Syncope and burns

Syncope is a common condition that may lead to serious injuries including burns and head injury. To date, here has been no specific discussion of syncope and burns in the literature. A retrospective case-note review of consecutive patients admitted to a Tertiary Burns Centre over a 3.5-year-period was conducted. Five hundred and fifty nine patients were admitted during the study period. Six of these had burns related to alterations of consciousness that excluded alcohol/drug ingestion and epilepsy. The mean percentage body surface area burnt was 9.7%, the mean length of hospital stay was 28.5 days and the mean length of stay per percentage surface area burnt was 4.0 days per percent body surface burnt. The mean size of the injury in syncopal patients is slightly larger than the general burns patients (8.4%) but the length of stay is doubled. This is partly related to surgery being delayed due to investigation of the syncope episode. Focused investigations should reduce both the overall length of hospital stay and the number of investigations.

Prognostic value of baseline electrophysiology studies in patients with sustained ventricular tachyarrhythmia: the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial

OBJECTIVES

We sought to determine the value of electrophysiology (EP) testing in patients with ventricular fibrillation (VF), ventricular tachycardia (VT) with syncope, or sustained VT in the setting of left ventricular dysfunction.

BACKGROUND

Traditionally, EP testing is part of the workup of patients with sustained VT or VF. Recently, some have suggested that EP testing is unnecessary in these patients, many of whom are likely to receive an implantable cardioverter-defibrillator (ICD).

METHODS

Within a multicenter trial (Antiarrhythmics Versus Implantable Defibrillators) designed to evaluate whether drugs or ICD resulted in a better outcome, data were analyzed regarding EP testing. Although this testing was not required, it was performed in >50% of patients. Information regarding the results of EP testing was correlated to baseline clinical characteristics and outcome.

RESULTS

Of 572 patients subjected to an EP test, 384 (67%) had inducible sustained VT or VF. Inducible patients were more likely to have coronary artery disease, previous infarction, and VT as their index arrhythmic event. Inducibility of VT or VF did not predict death or recurrent VT or VF.

CONCLUSIONS

Information derived from EP testing in this patient population, particularly those with VF, is of limited value and may not be worth the risks and costs of the procedure, particularly in those patients likely to receive an ICD.

Intrinsic sinus and atrioventricular node electrophysiologic adaptations in endurance athletes

OBJECTIVES

In the present study, we evaluated sinus and atrioventricular (AV) node electrophysiology of endurance athletes and untrained individuals before and after autonomic pharmacologic blockade.

BACKGROUND

Endurance athletes present a higher prevalence of sinus bradycardia and AV conduction abnormalities, as compared with untrained individuals. Previous data from our laboratory suggest that nonautonomic factors may be responsible for the longer AV node refractory period found in well-trained athletes.

METHODS

Six aerobically trained male athletes and six healthy male individuals with similar ages and normal rest electrocardiograms were studied. Maximal oxygen uptake (O(2)max) was measured by cardiopulmonary testing. The sinus cycle length (SCL), AV conduction intervals, sinus node recovery time (SNRT), Wenckebach cycle (WC) and anterograde effective refractory period (ERP) of the AV node were evaluated by invasive electrophysiologic studies at baseline, after intravenous atropine (0.04 mg/kg) and after addition of intravenous propranolol (0.2 mg/kg).

RESULTS

Athletes had a significantly higher O(2)max as compared with untrained individuals. The SCL was longer in athletes at baseline, after atropine and after the addition of propranolol for double-autonomic blockade. The mean maximal SNRT/SCL was longer in athletes after atropine and after propranolol. The WC and anterograde ERP of the AV node were longer in athletes at baseline, after atropine and after propranolol.

CONCLUSIONS

Under double-pharmacologic blockade, we demonstrated that sinus automaticity and AV node conduction changes of endurance athletes are related to intrinsic physiology and not to autonomic influences.

Diagnostic evaluation and management of patients with syncope

This article focuses on the evaluation of patients with syncope, a symptom not a disease. Syncope is a transient loss of consciousness associated with loss of postural tone with spontaneous recovery. The authors discuss the utility of an indications for different diagnostic tests, the indications for hospital admission, and the management of patients with certain known causes of syncope, including vasovagal and arrhythmic.

Feasibility and safety of two French electrode catheters in the performance of electrophysiological studies

The aim of this study was to analyze prospectively the feasibility and safety of using 2 Fr versus 6 Fr standard electrode catheters for diagnostic electrophysiological study.

METHODS

Two hundred and five consecutive patients were randomized to receive the 6 Fr approach (3 quadripolar, 6 Fr, electrode catheters inserted through the left or right femoral vein and placed in the high right atrium, right ventricular apex, and His bundle area) or the 2 Fr approach (3 quadripolar, 2 Fr, electrode catheters inserted through a single, 7 Fr, triple lumen, guiding catheter and positioned at the same sites as the 6 Fr approach).

RESULTS

Introduction time was shorter in the 2 Fr group (133.3 +/- 65 s, range 87-669 s) than in the 6 Fr group (242.8 +/- 91.8 s, range 168-1024 s, P < 0.001). The overall fluoroscopy time was longer in the 2 Fr group (141.2 +/- 40.1 s, range 78-312 s) than in the 6 Fr group (126.4 +/- 39.7 s, range 58-341 s, P = 0.009). However in the last 100 patients there was no more difference between the two groups (137.6 +/- 28.2 s vs 128.4 +/- 23.2 s, P = 0.07). There was no significant difference between 2 Fr and 6 Fr groups in the mean atrial (5.9 +/- 2.2 mV, range 2.2-11.3 mV, vs 6.1 +/- 2.3 mV, range 2.4-12.4 mV, P = 0.57) and ventricular (5.6 +/- 2.1 mV, range 1.9-9.7 mV, vs 5.7 +/- 2.2 mV, range 2.3-10.5 mV, P = 0.66) activation potential amplitudes recorded during sinus rhythm, or in the rate of stable His bundle potential recording (P = 0.3), and catheter dislodgment (P = 0.54). The overall number of complications was significantly higher in the 6 Fr group than in the 2 Fr group (29 vs 5, P = 0.001), as well as the number of entry site related complications (3 vs 12, P = 0.02) and catheter manipulation related complications (2 vs 17, P < 0.001).

CONCLUSIONS

The results of this study show that the use of 2 Fr electrode catheters reduces the rates of entry site and catheter manipulation related complications during EPS. Despite their small size, these catheters allow quick and precise positioning of the electrode.

[Ambulatory catheter ablation. Indications, results and risks]

The purpose of this study was to test the efficacy, feasibility, and safety of outpatient radiofrequency catheter ablation in 162 consecutive patients. There were 83 men and 79 women at a mean age of 47 + 15 years; 13 patients underwent 2 and 1 patient 3 ablation procedures. In 167 cases patients suffered from highly symptomatic paroxysmal tachycardia associated with presyncope or syncope in 74. Severe palpitations were present in 7 cases and recurrent syncope in 1 case. One patient had an asymptomatic Wolff-Parkinson-White syndrome with a shortest RR-interval during atrial fibrillation of 150 ms. The mechanism of tachycardia was found to be atrioventricular nodal reentry in 78 cases, atrioventricular reentry involving an accessory atrioventricular pathway in 56, atrial fibrillation in 16, atrial flutter of the common type in 15, ectopic atrial tachycardia in 8, and idiopathic ventricular tachycardia in 3. Catheter ablation was performed in these 176 cases at an overall success rate of 86%. In 148 cases patients could be treated on an outpatient basis and were discharged after a maximal observation time of 3 hours in 28, and 24 hours in another 120 cases. Short-term follow-up was uneventful in these patients. After 28 ablation procedures patients had to be admitted to the hospital, because of pain at the puncture sites or after pacemaker implantation in 15 cases, because of minor complications in 12, and because of pericardial tamponade in 1 case. Another severe complication occurred in 1 patient after successful ablation of right atrial tachycardia. Three days after discharge the patient suffered from pulmonary embolism originating from a thrombus at the ablation site. After hospital admission the patient recovered completely. In general, complication rate was 2.27%. This study shows that catheter ablation can be performed effectively and safety on an outpatient basis.

Radiofrequency ablation for cardiac arrhythmias causing postcardiac injury syndrome

We report 2 cases of exudative left pleural effusion following radiofrequency catheter ablation of cardiac arrhythmias complicated by cardiac perforation. We suggest that radiofrequency ablation may be a previously unsuspected cause of postcardiac injury syndrome.

Is a baseline electrophysiologic study mandatory for the management of patients with spontaneous, sustained, ventricular tachyarrhythmias?

Should the patient being treated for spontaneous, sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) routinely undergo a baseline, diagnostic, catheter electrophysiologic (EP) study? The potential patient advantages of such a policy include identification of the tachyarrhythmia-initiating episodes of presumed VT or VF, prediction of the subsequent risk of VT/VF recurrences, identification of VT mechanisms amenable to cure by catheter ablation, assessment of the response of a patient's VT to attempts at pace termination, evaluation of the patient's candidacy for some of the approaches to VT/VF therapy selection, and enhancement of our understanding of the mechanisms and therapeutics of VT/VF. Disadvantages of such a policy include patient discomfort, patient risks, and cost. Recognizing that the decision to perform a baseline catheter EP study in a patient with VT/VF must be based on an individualized, patient-based, risk-benefit analysis; this review details each of the advantages and disadvantages of doing so to identify patient populations for whom a baseline catheter EP study is or is not usually indicated.

Complications of diagnostic electrophysiologic studies and radiofrequency catheter ablation in patients with tachyarrhythmias: an eight-year survey of 3,966 consecutive procedures in a tertiary referral center

Predictors and comparisons of complications in patients with electrophysiologic study or radiofrequency ablation have not been assessed in previous published reports. The purpose of this study was to prospectively evaluate the procedure-specific complications and investigate the possible causes and predictors of complications in electrophysiologic study and radiofrequency ablation. Data of diagnostic electrophysiologic studies and radiofrequency ablation were prospective, and represented a consecutive series of 2,593 patients with 3,966 procedures. The present study showed that a significantly higher complication rate occurred in radiofrequency ablation than in electrophysiologic study (3.1% vs. 1.1%, respectively, p = 0.00002) and a significantly higher complication rate occurred in elderly than in young patients with electrophysiologic study (2.2% vs 0.5%, p = 0.0002) or radiofrequency ablation (6.1% vs 2.0%, p = 0.00015). Multiple logistic analysis found that older age (p < 0.01) and systemic disease in elderly patients (p < 0.01) were the independent predictors of complications in both procedures. Furthermore, there was no temporal trend in the incidence of complication. We conclude that the incidence of complication was higher in radiofrequency ablation, and elderly patients had a higher incidence of complications in both electrophysiologic study and radiofrequency ablation; these procedures, when performed by experienced personnel in an appropriately staffed and equipped laboratory, can be undertaken with an acceptable risk.

Safety and diagnostic yield of noninvasive ventricular stimulation performed via tiered therapy implantable defibrillators

Extensive electrophysiological testing is critical for the effective utilization of sophisticated tachycardia detection and termination algorithms available in tiered therapy ICDs. To evaluate the safety and diagnostic yield of electrophysiological testing via noninvasive ventricular stimulation, we performed 294 electrophysiological studies in 154 patients (age 65 +/- 10; left ventricular ejection fraction 0.36 +/- 0.15) with tiered therapy ICDs. Stimulation was performed under methohexital anesthesia. A total of 918 sustained ventricular tachyarrhythmias were induced (3.1 +/- 2.5 per procedure): monomorphic VT, 550; ventricular flutter, 74; and VF, 246. The results of invasive and noninvasive programmed stimulation were compared for 79 patients who had both studies under similar treatment. Overall concordance was 83%, and did not differ significantly between patients who had the noninvasive stimulation via epicardial or endocardial pacing leads. VF could be induced in 206 of 257 studies (82%), and it was less likely to be induced in patients on amiodarone (74% vs 85%; P = 0.02), or beta blockers (55% vs 83%; P = 0.017). No patient presented a serious complication. Minor complications occurred during 39 studies: transient laryngospasm in 1, unintended delivery of an ICD shock to a conscious patient in 4; induction of sustained atrial fibrillation in 8; need for external rescue defibrillation shocks in 13; and delivery of inappropriate shocks for supraventricular rhythms in 14 studies. Noninvasive ventricular stimulation performed under methohexital anesthesia is safe. Its diagnostic yield compares favorably with that of conventional electrophysiological studies. VF can be induced in a majority of patients. There is good correlation between invasive and noninvasive programmed stimulation for induction of VT. Noninvasive ventricular stimulation may emerge as standard procedure for the initial programming and follow-up of ICDs.

Mildly symptomatic pulmonary emboli associated with electrophysiologic procedures. Indications for anticoagulant use

Symptomatic pulmonary emboli complicating electrophysiologic procedures are uncommon. Asymptomatic or mildly symptomatic embolic are likely much more common. This case report highlights the problem of extensive, but mildly symptomatic, pulmonary emboli occurring as a complication of electrophysiologic procedures, including catheter ablation. The role of anticoagulation during and following electrophysiologic procedures in preventing pulmonary emboli (which can have long-term sequelae) is unknown. Currently, there appears to be no consensus regarding the use of anticoagulants either during or following electrophysiologic procedures, including those involving catheter ablation. Based on the presumed frequency and potential long-term complications of pulmonary emboli, anticoagulation during electrophysiologic procedures should be recommended.

Myocardial perforation in the cardiac catheterization laboratory: incidence, presentation, diagnosis, and management

The introduction of balloon valvuloplasty and new devices for coronary intervention has increased the incidence and changed the site and clinical presentation of cardiac perforation. We reviewed all cases of cardiac perforation that occurred during 11,845 consecutive catheterization procedures during a 6-yr period (1986-91). Fourteen cardiac perforations (overall incidence 0.12%) occurred as a result of the following procedures: mitral valvuloplasty 7 of 150 (4.7%), aortic valvuloplasty 4 of 260 (1.5%), pericardiocentesis 1 of 90 (1.1%), temporary pacer 1 of 1,660 (0.06%), and diagnostic left heart catheterization 1 of 6,965 (0.01%). Perforation was recognized in the catheterization laboratory in 11 patients, within 1 hr of leaving the laboratory in two patients, and 15 hr later in one patient. Hemodynamic evidence of tamponade developed in 13 patients and was confirmed by fluoroscopy (immobile heart borders) or echocardiography. Pericardiocentesis is definitive therapy in nearly half of the cases; the remaining patients require pericardiocentesis plus surgical repair of the perforation.

Accessory pathway and atrioventricular node reentrant tachycardia in elderly patients: clinical features, electrophysiologic characteristics and results of radiofrequency ablation

OBJECTIVES

This study was designed to evaluate the clinical features, electrophysiologic characteristics and results of radiofrequency ablation in elderly patients with accessory atrioventricular (AV) pathways or AV node reentrant tachycardia.

BACKGROUND

Radiofrequency ablation in elderly patients with paroxysmal supraventricular tachycardia has not been well described, and comparative study between elderly and younger patients is limited.

METHODS

Electrophysiologic studies and radiofrequency ablation were performed in 92 elderly patients (45 with an accessory pathway, 47 with AV node reentrant tachycardia).

RESULTS

The elderly patients had poorer electrophysiologic properties in accessory pathways and dual AV node pathways than those of younger patients. The success rate of radiofrequency ablation was similar in elderly and younger patients. However, elderly patients had more complications (14%) in left-sided accessory pathways.

CONCLUSIONS

Radiofrequency ablation in elderly patients with supraventricular tachycardia was effective. However, it must be performed cautiously in those patients with left-sided accessory pathways.

Femoral vein delivery of contrast medium enhances transthoracic echocardiographic detection of patent foramen ovale

OBJECTIVES

We postulated that femoral vein delivery of contrast medium because of streaming, might enhance precordial echocardiographic detection of patent foramen ovale.

BACKGROUND

Although precordial contrast echocardiography is widely used to diagnose patent foramen ovale, this method is limited by poor sensitivity. Previous investigators have demonstrated enhanced detection of atrial defects by the dye-dilution technique after delivery of contrast medium into the inferior rather than the superior vena cava.

METHODS

Transthoracic contrast examinations were performed in a randomly selected group of 70 patients (without previous history of cerebral or systemic embolus) undergoing cardiac catheterization. Paired contrast agent injections (10 ml dextrose in water/0.25 ml air) were administered from an upper extremity vein and femoral vein in each patient during spontaneous respiration, cough and Valsalva maneuvers. Studies were interpreted by an experienced echocardiographer unaware of the sequence and site of injections. Positive studies were semiquantitatively graded from +1 (minimal left ventricular opacification) to +4 (intense left ventricular opacification). Catheterization and echocardiographic assessment of patent foramen ovale were compared in 21 subjects.

RESULTS

Patent foramen ovale was detected significantly more often during femoral vein versus upper extremity contrast delivery (23 of 70 patients [prevalence 33%] vs. 9 of 70 patients [prevalence 13%], p < 0.001). The intensity of left ventricular opacification was also greater during femoral vein contrast injection. Precordial echocardiography combined with femoral contrast delivery was significantly more sensitive than cardiac catheterization for assessment of patent foramen ovale (8 of 21 patients vs. 2 of 21 patients, p < 0.05).

CONCLUSIONS

Femoral vein contrast delivery significantly enhances the ability of precordial contrast echocardiography to diagnose patent foramen ovale. Physiologic patency of the foramen ovale is more common (prevalence 33%) than previously documented.

Invasive electrophysiologic evaluation in octogenarians: is age a limiting factor?

To assess the indications, diagnostic yield, and incidence of complications of electrophysiologic testing in the elderly we reviewed our experience with 60 procedures in 45 patients aged > or = 80 years (range 80 to 92 years, mean age 83) undergoing full electrophysiologic evaluation in our laboratory over the past 7 years. The yield of inducible ventricular tachycardia (31%), supraventricular tachycardia (4%), and previously unsuspected conduction abnormalities significant enough to warrant permanent pacemaker implantation (9%), together with the low incidence of complications (1 patient had a deep venous thrombosis and femoral artery pseudoaneurysm, representing an incidence of 2.2% of patients undergoing studies or 3.3% incidence of complications per procedure), suggest that invasive electrophysiologic procedures in the elderly can provide useful information at a complication rate comparable with that of younger patients.

Comparison of epicardial and endocardial programmed stimulation in patients at risk for ventricular arrhythmias after cardiac surgery

Programmed ventricular stimulation was performed on 36 patients after recent cardiac surgery using implanted right ventricular epicardial temporary wires and with catheters positioned percutaneously at two right ventricular endocardial sites. Patients were followed for a mean of 18.5 months (range 3 to 36 months). Epicardial wires were nonfunctional in 10 patients (28%) due to excessively high pacing thresholds. Overall, 22 patients (61%) had inducible sustained ventricular tachycardia; epicardial wires were functional in 15 (68%) of these patients. Six patients without inducible ventricular tachycardia with epicardial stimulation were inducible using endocardial stimulation. Of the 24 patients in whom epicardial and endocardial ventricular stimulation could be performed, concordant results were obtained in only 17 (71%), despite similar epicardial and endocardial ventricular effective and functional refractory periods. A total of 14 arrhythmic events occurred during the follow-up period. Of the 22 patients with an inducible sustained ventricular tachycardia, 12 (64%) had subsequent arrhythmic events. Only 2 of the 14 noninducible patients had follow-up arrhythmic events, one of which was caused by medication proarrhythmia. Endocardial ventricular stimulation had a superior sensitivity (83% versus 30%, P < 0.0001) and an improved negative predictive value (86% versus 61%, P < 0.05) compared with epicardial ventricular stimulation. These results indicate that noninducibility using epicardial programmed ventricular stimulation does not reliably portend a low risk for recurrent ventricular tachyarrhythmias. Epicardial programmed stimulation, used alone, may be inadequate for postoperative electrophysiological evaluation of patients at risk for ventricular arrhythmias.

Infarct artery patency predicts outcome of serial electropharmacological studies in patients with malignant ventricular tachyarrhythmias

BACKGROUND

Surviving myocardial cells near the infarct border zone form the arrhythmogenic substrate for sustained ventricular tachycardia (VT) in humans. Infarct-related artery (IRA) patency may modulate the electrophysiological function of this arrhythmogenic substrate and its response to antiarrhythmic drug therapy. We postulated that effective antiarrhythmic drug therapy selected during serial electrophysiological studies in patients with VT after a myocardial infarction would be identified more frequently when the IRA is patent than when chronically occluded.

METHODS AND RESULTS

Consecutive patients (n = 64) with documented coronary artery disease and remote myocardial infarction presenting with spontaneous sustained VT or ventricular fibrillation (VF) were studied. These patients underwent 4 +/- 2 electropharmacological studies identifying effective antiarrhythmic drug therapy in 16 (25%) patients. Drug responders did not differ significantly from nonresponders in demographic, electrocardiographic, angiographic, or hemodynamic measurements. A patent IRA was associated with antiarrhythmic drug response significantly more frequently than was an occluded IRA (45% versus 9%, p = 0.001). Patency of the IRA was the only independent predictor of response to antiarrhythmic drug therapy in this study population. The sensitivity and specificity of using a patent IRA to predict successful drug testing were 81% and 67%, respectively.

CONCLUSIONS

The outcome of electropharmacological studies was predicted by the patency of the IRA. A patent IRA was associated with a greater probability of finding effective drug therapy.