Sustained Polymorphic Ventricular Tachycardia Research Articles

Incidence and Predictors for Recurrence of Ventricular Arrhythmia Presenting During Acute Myocarditis: A Multicenter Study

BackgroundManagement of acute myocarditis (AM) patients experiencing ventricular arrhythmia (VA) during acute illness is controversial, especially regarding early implantable cardioverter-defibrillator (ICD) implantation. ObjectivesThe purpose of this study was to evaluate the prevalence of and find predictors for long-term sustained VA recurrence and overall mortality among AM patients with VA. MethodsThis was a multicenter retrospective analysis of AM patients (verified by cardiac magnetic resonance imaging or myocardial biopsy) with documented VA during the acute illness (“initial VA”). Patients with history of myocardial infarction, heart failure, or VA were excluded. The study endpoint was a composite of sustained VA and overall mortality during follow-up. ResultsThe study included 69 AM patients with initial VA: sustained monomorphic ventricular tachycardia (MMVT) (n = 25), sustained polymorphic ventricular tachycardia (VT)/ventricular fibrillation (n = 13), and nonsustained VT (n = 31). Age was 44 ± 13 years, and 23 of 69 (33.3%) were women. During median follow-up of 5.5 years, 27 of 69 (39%) patients reached the composite endpoint including sustained VA (n = 24) and death (n = 11). Initial MMVT, predischarge left ventricular dysfunction (left ventricular ejection fraction <50%), and anteroseptal delayed enhancement on cardiac magnetic resonance imaging were significantly associated with the composite endpoint. On multivariable analysis, initial MMVT (HR: 5.17; 95% CI: 1.81-14.6; P = 0.001) and predischarge LV dysfunction (HR: 4.57; 95% CI: 1.83-11.5; P = 0.005) were independently associated with the composite endpoint. Using these 2 predictors, we could delineate subgroups with low (∼4%), medium (∼42%), and high (∼82%) 10-year incidence of composite endpoint. ConclusionsAM patients presenting with VA have high incidence of sustained VA recurrence and mortality posthospitalization. Initial MMVT and predischarge LV dysfunction are independently associated with VA recurrence and mortality. Implantable cardioverter-defibrillator implantation may be considered in such high-risk patients.

Prevalence of arrhythmia in COVID-19 patients with mild/moderate and severe illness: a prospective cohort study

ABSTRACT Objectives The type of arrhythmias, and their prevalence in mild/moderate and severe COVID-19 patients admitted to the hospital are unknown from a prospective cohort study. Methods We did continuous electrocardiograms along with multiple ECGs in 305 consecutive hospitalized COVID-19 patients. Results The incidence of arrhythmias was 6.8% (21/305) in the target population. The incidence of arrhythmias was 9.2% (17/185) in patients with severe COVID-19 illness and 3.3% (4/120) in patients with mild/moderate COVID-19 illness with no significant difference (p = 0.063). All the arrhythmias were new-onset arrhythmias in this study. 95% (20/21) of these arrhythmias were atrial arrhythmia with 71.42% (15/21) being atrial fibrillation and one episode of sustained polymorphic ventricular tachycardia. No episode of high-grade atrioventricular block, sustained monomorphic ventricular arrhythmia, or torsades de pointes arrhythmias were observed in this study. The patients with arrhythmias were admitted to the intensive care unit (80.9% vs. 50.7%; p: 0.007), were on a ventilator (47.6% vs. 21.4%; p: 0.006), and had high in-hospital mortality (57.1% vs. 21.1%; p: 0.0001) than patients without arrhythmias. Conclusion Atrial arrhythmias were the most frequent arrhythmias in hospital-admitted COVID-19 patients with atrial fibrillation being the most common arrhythmia. Trial registration Clinical Trial Registry India (CTRI) (CTRI/2021/01/030788). (https://www.ctri.nic.in/)

Valor pronóstico del intervalo Tpeak-Tend en el desarrollo de arritmias ventriculares subagudas intrahospitalarias en el síndrome de tako-tsubo

Introduction and objectivesThe clinical value of electrocardiogram (ECG) repolarization parameters associated with ventricular arrhythmias (VAs) in tako-tsubo syndrome is still under debate. We aimed to evaluate ECG predictors of subacute VAs, defined as those occurring after the first 48hours from admission. MethodsThis single-center observational study enrolled patients admitted to the cardiology department between 2012 and 2018 with a confirmed diagnosis of tako-tsubo syndrome. Data collection included a 12-lead ECG on admission and at 48hours, continuous telemetry monitoring, blood testing, transthoracic echocardiography, and coronary angiography during hospitalization. VAs events were defined as: premature ventricular contractions ≥ 2000 within a 24-hour window of telemetry monitoring, ventricular fibrillation, sustained ventricular tachycardia (VT), polymorphic VT, and non-sustained VT. ResultsA total of 87 patients (age 72±12 years) were enrolled. During a median of 8 days of hospitalization, subacute VAs were documented in 22 patients (25%) after a median of 91hours from admission. Subacute VAs were associated with an increase in mortality during hospitalization (P=.030). The corrected global (mean of the 12-lead ECG values) Tpeak-Tend interval at 48hours from admission was an independent predictor of subacute VAs and was statistically superior to the standard corrected QT interval (Z test, P=.040). A cut-off of 108 msec for the corrected global Tpeak-Tend yielded a 71% sensitivity and 72% specificity for subacute VAs. ConclusionsIn patients with tako-tsubo syndrome, subacute VAs are associated with repolarization alterations that can be identified on conventional ECG using the Tpeak-Tend interval.

352 PROGNOSTIC VALUE OF THE TPEAK-TEND INTERVAL FOR IN-HOSPITAL SUBACUTE VENTRICULAR ARRHYTHMIAS IN TAKOTSUBO SYNDROME

Abstract Introduction and objectives The clinical value of ECG repolarization parameters associated with ventricular arrhythmias (VAs) in Takotsubo syndrome is still under debate. We aimed to evaluate ECG predictors of subacute VAs, defined as those occurring after the first 48 hours from admission. Methods This is a single-center observational study enrolling patients admitted to the Cardiology Department between 2012 and 2018 with confirmed diagnosis of Takotsubo syndrome. Data collection included a 12-lead ECG on admission and at 48 hours, continuous telemetry monitoring, blood testing, transthoracic echocardiography and coronary angiography during hospitalization. VAs events were defined as: premature ventricular contractions ≥2000 within a 24-hour window of telemetry monitoring, ventricular fibrillation, sustained ventricular tachycardia (VT), polymorphic VT and non-sustained VT. Results A total of 87 patients (age 72±12 years old) were enrolled. During an average of 16±14 days of hospitalization, subacute VAs were documented in 22 patients (25%) after 127±75 hours from admission. Subacute VAs were associated with an increased in-hospital mortality (p=0.030). The corrected global (mean of the 12-lead ECG values) Tpeak-Tend interval at 48 hours from admission was an independent predictor of subacute VAs. The corrected global Tpeak-Tend was statistically superior to the standard corrected QT interval to predict subacute VAs (Z test, p=0.040). A cut-off of 108 msec for the corrected global Tpeak-Tend yielded a 71% sensitivity and 72% specificity for subacute VAs. Conclusions In patients with Takotsubo syndrome subacute VAs are associated with repolarization alterations that can be identified on the conventional ECG using the Tpeak-Tend interval.

449 HYPERTROPHIC CARDIOMYOPATHY: A CASE OF CHALLENGING ARRHYTHMIC RISK STRATIFICATION

Abstract Hypertrophic cardiomyopathy (HCM) is a common disease, mostly inherited, with a prevalence of 1:500. Cornerstone of the clinical management of HCM patients is stratifying the risk of sudden cardiac death (SCD) which is the most frightening complication despite its relatively low incidence (0,9% per year). Although mathematical risk scores, as proposed by ESC, are the most used to assess the probability of arrhythmic complications leading to SCD, they have been associated with low sensitivity, precluding some high-risk patients from prophylactic ICD implantation. Among the tools at clinicians’ disposal for risk stratification in HCM patients, the latest AHA/ACC guidelines propose an “individual risk markers strategy”, based on the presence of ≥1 clinical feature such as a family history of SCD, extreme left ventricular hypertrophy (LVH), unexplained recent syncope, NSVT, late gadolinium enhancement (LGE) at CMR, systolic dysfunction and LV apical aneurysm. We present a case that lets us reflect on arrhythmic risk stratification. P.C. is a 58 y.o. male with a history of septal hypertrophy (19 mm) and T wave inversion but without an established diagnosis of HCM. He did not have any familiar history of syncope or SCD. He came to the emergency department for epistaxis and was admitted to the cardiology unit due to the previously mentioned findings, where he underwent cardiac-CTA and CMR showing myocardial bridge of left anterior descending artery, LVH with apical aneurysm and LGE areas localized on the apex (transmural) and on the interventricular septum (subendocardial). No signs of dynamic LVOT obstruction or atrial enlargement emerged from echocardiography. During the observation, asymptomatic NSVT were recorded on continuous ECG monitoring. According to the ESC risk prediction score (3.7%) ICD was not strictly indicated but considering the CMR high-risk profile (according to the suggestions of AHA/ACC) we proposed an ICD implantation anyways. The patient refused any invasive procedure and was implanted with a loop recorder. At 12 months remote monitoring showed a single episode of self-terminated sustained polymorphic ventricular tachycardia (02:23 mm: ss) symptomatic of pre-syncope. The patient was then immediately reached and admitted for ICD implantation in secondary prevention. According to the patient's will, and the no need for bradycardia therapy, an S-ICD was implanted. Figure 1LV apical aneurysm at CMRFigure 2Remote Monitoring

Prognostic value of the Tpeak-Tend interval for in-hospital subacute ventricular arrhythmias in tako-tsubo syndrome

Introduction and objectivesThe clinical value of electrocardiogram (ECG) repolarization parameters associated with ventricular arrhythmias (VAs) in tako-tsubo syndrome is still under debate. We aimed to evaluate ECG predictors of subacute VAs, defined as those occurring after the first 48hours from admission. MethodsThis single-center observational study enrolled patients admitted to the cardiology department between 2012 and 2018 with a confirmed diagnosis of tako-tsubo syndrome. Data collection included a 12-lead ECG on admission and at 48hours, continuous telemetry monitoring, blood testing, transthoracic echocardiography, and coronary angiography during hospitalization. VAs events were defined as: premature ventricular contractions ≥ 2000 within a 24-hour window of telemetry monitoring, ventricular fibrillation, sustained ventricular tachycardia (VT), polymorphic VT, and non-sustained VT. ResultsA total of 87 patients (age 72±12 years) were enrolled. During a median of 8 days of hospitalization, subacute VAs were documented in 22 patients (25%) after a median of 91hours from admission. Subacute VAs were associated with an increase in mortality during hospitalization (P=.030). The corrected global (mean of the 12-lead ECG values) Tpeak-Tend interval at 48hours from admission was an independent predictor of subacute VAs and was statistically superior to the standard corrected QT interval (Z test, P=.040). A cut-off of 108 msec for the corrected global Tpeak-Tend yielded a 71% sensitivity and 72% specificity for subacute VAs. ConclusionsIn patients with tako-tsubo syndrome, subacute VAs are associated with repolarization alterations that can be identified on conventional ECG using the Tpeak-Tend interval.

Sustained Ventricular Fibrillation in a Conscious Pediatric LVAD Patient

<h3>Introduction</h3> Non-sustained ventricular tachycardia (NSVT), defined by ventricular tachycardia lasting less than 30 seconds, is common in patients with left ventricular assist devices (LVADs)​. Ventricular tachy-arrhythmias (VAs) such as sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) are uncommon but carry a significant risk of morbidity and death. <h3>Case Report</h3> A 16-year-old male underwent continuous flow LVAD implantation after presenting with end stage heart failure due to dilated cardiomyopathy. Prior to LVAD, he had an increasing burden of NSVT, which improved post-LVAD insertion. On post-op day 11, he developed palpitations related to sinus tachycardia and monomorphic NSVT. He remained conscious with clinical signs of adequate peripheral perfusion. The VAD flows fell from 5.2 L/min to 1.9 L/min secondary to the effects of the VA on the right ventricle (RV). The VAs then deteriorated into sustained polymorphic VT followed by VF (<i>Image 1</i>). He continued to answer questions appropriately but complained of dizziness and visual changes. Medical management included lidocaine, calcium, magnesium, amiodarone, and epinephrine for RV support. In addition, he received 4 defibrillations, the last of which successfully converted him to sinus rhythm. He did not require chest compressions and maintained adequate cardiac output throughout. He underwent cardiac catheterization which confirmed normal coronary arteries and enabled optimization of LVAD settings. He was discharged home 15 days later on LVAD support, with amiodarone, metoprolol and a home automated external defibrillator. He remains well 10 months later with no further events. <h3>Summary</h3> VF, a potentially life-threatening arrhythmia, was remarkably well tolerated in a teenager on LVAD support despite some evidence of RV compromise. This case highlights the importance of improved risk stratification of NSVTs in the LVAD population to establish the need for anti-arrhythmic medication or implantable cardioverter-defibrillator.

Sinus Standstill in a Patient after Intracoronary Papaverine Administration for a Coronary Fractional Flow Reserve

A 78-year-old woman had paroxysmal atrial fibrillation and effort angina. Two months before she was admitted for a coronary angiography, she had been feeling dizzy. A Holter 24-hour electrocardiography monitor exhibited an asymptomatic episode of 2.9 seconds of RR interval. She underwent a coronary angiography, which showed intermediate stenosis in the left descending artery. Fractional flow reserve (FFR) measurement using intracoronary papaverine administration was performed. After intracoronary papaverine (12 mg) administration, pause of 4 seconds led to polymorphic ventricular tachycardia (VT), although the VT terminated spontaneously. Premature ventricular beat occurred and led to sustained polymorphic VT. In cardiac electrophysiology study, pacing from the right atrium showed that the maximum sinus node recovery time (SRT) was 910 ms. After procainamide (10 mg/kg) administration, the maximum SRT was 16.3 seconds with some junctional escapes. After intravenous papaverine administration, there was a slight change. Intracoronary papaverine administration induced about 9-seconds pause with some junctional escapes. We conclude that intracoronary papaverine administration reveals potential sinus node dysfunction. The patient has been asymptomatic since the implantation of the pacemaker. Patients with suspicious sinus dysfunction should be careful.

Asymptomatic Sustained Polymorphic Ventricular Tachycardia in a Patient with a Left Ventricular Assist Device: Case Report and what the Emergency Physician Should Know

BackgroundLeft ventricular assist devices (LVADs) are a viable treatment option for patients with end-stage heart failure. LVADs can improve survival, quality of life, and functional status. The indications for LVAD placement to support left ventricular function are temporary support, a bridge to transplantation, or destination therapy. Case ReportA 61-year-old man with past medical history significant for advanced congestive heart failure from ischemic cardiomyopathy, status post LVAD (HeartMate II; Thoratec Corporation, Pleasanton, CA) placement 2009 as destination therapy, presented to the Emergency Department (ED) with implantable cardiac defibrillators firing four times that morning. While in the care of Emergency Medical Services, he was in ventricular tachycardia, and they gave him a bolus of amiodarone 150 mg intravenously prior to arrival in the ED. He was reportedly alert and oriented without any chest pain on arrival to the ED, where an electrocardiogram was obtained showing polymorphic ventricular tachycardia. Why Should an Emergency Physician Be Aware of This?Emergency physicians must be familiar with the atypical presentations of potentially lethal dysrhythmias in this patient population. They must also be familiar with the major adverse events after LVAD implantation. These include device malfunction, cardiac dysrhythmias, bleeding, thromboembolism, neurological events, and infection. The causes of device malfunction can include thrombus formation with hemolysis, mechanical failure of the impeller, and driveline lead fractures with electric failure. Although time is critical in the heart failure patient with an LVAD failure or complication, expert consultation with cardiology or the LVAD specialist should occur when possible.

Differential diagnosis of tachycardia with a broad QRS-complex

The electrocardiographic (ECG) differential diagnosis of tachycardia with a broad QRS complex (BCT) represents a challenge for physicians but is important for adequate treatment and risk evaluation. Differentiated algorithms have been established and can increase the specificity of the diagnosis in individual patients but are often hampered by complexity and yield a pragmatic ECG approach. Irregular BCTs (irregular R-R distances) despite the patient being hemodynamically stable are almost always due to atrial fibrillation with bundle branch block (pre-existing or functional) or conduction via accessory pathways. In contrast, sustained polymorphic ventricular tachycardia (VT) is always associated with hemodynamic collapse. In regular BCT the following mechanisms must be differentiated: (1) VT, (2) supraventricular tachycardia (SVT) with bundle branch block or (3) SVT with pre-excitation via accessory pathways, e.g. Wolff-Parkinson-White (WPW) syndrome. The presence of an underlying structural heart disease, specifically a history of myocardial infarction is suggestive of VT. For a differentiated analysis in hemodynamically stable patients a 12-lead ECG is essential. Identification of signs of atrioventricular (AV) dissociation or a negative precordial concordance of QRS are indicative of VT. In V1 positive BCTs a positive precordial concordance, QRS width > 140ms, superiorly directed QRS axis, monophasic or biphasic QRS complexes in V1 and deep S wave in V6 are indications of a VT. In V1 negative BCTs, QRS width > 160ms, right-sided QRS axis, broad R peak (> 40ms) in V1/V2, slurred S downstroke in V1/V2 and any Q peak in V6 are all indications of VT as the mechanism.

An Uncommon Presentation for Cardiac Melanoma

A 66-year-old man with locally advanced malignant melanoma, which was surgically resected, presented with a 3-week history of dizziness, recurrent near-syncopal episodes and generalized weakness. He was found to have sustained polymorphic ventricular tachycardia in the setting of cardiac melanoma. We draw attention to an unusual presentation of malignant melanoma with cardiac metastasis and discuss both its etiology and treatment options.

Underdetection of ventricular tachycardia by an implantable cardioverter–defibrillator due to a locally prolonged arrhythmia cycle length

We report the case of a 69-year-old man with idiopathic dilated cardiomyopathy, biventricular implanted cardioverter–defibrillator (ICD) and a spontaneous ventricular tachycardia during device follow-up that was not automatically treated by the ICD. Four years before a dilated left ventricle (end-diastolic diameter, 92 mm) with a severely reduced ejection fraction (EF 20 %), congestive heart failure (NYHA class III), left bundle branch block (QRS duration 200 ms) and syncope during sustained ventricular tachycardia (VT) were noted. Subsequently, a biventricular ICD (Sorin Ovatio CRT-D, leads: RA: Medtronic 4076; RV: Guidant 0185; LV: Medtronic 4194) had been implanted for secondary prevention of sudden cardiac death (SCD) and for cardiac resynchronization. On the day after implantation an electrical storm had occurred and six effective shocks had been delivered. Amiodarone therapy was initiated and no further sustained ventricular arrhythmias occurred. However, due to skeletal muscle myopotential oversensing ventricular episodes were inadequately diagnosed by the ICD. Therefore, two further defibrillation testings were performed to ensure proper sensing of VF after stepwise increasing of the sensing threshold. The last test was performed with a sensing of 2.2 mV, and permanent ICD sensitivity was set to 1.6 mV. Sensing (RA: 4 mV; RV: 15 mV) and pacing thresholds (RA: 0.75 mV/0.35 ms; RV: 0.75 mV/0.35 ms; LV: 0.75 mV/0.35 ms) remained stable during the following years and no further noise signals were detected. At device follow-up 4 years after implantation, a sustained polymorphic VT (*200 bpm) occurred spontaneously (Fig. 1) during determination of ventricular sensing. The tachycardia was hemodynamically relevant with fainting of the patient, but ICD therapy was not delivered. The ICD even performed ventricular backup-pacing during the VT. ICD detection settings were: slow VT—120/bpm, 12 cycles; VT—150/bpm, 12 cycles; FVT—200/bpm, 10 cycles; VF—240/bpm. Intracardiac electrogram (IEGM) showed undersensing of the ventricular tachycardia due to the previously programmed low sensitivity. An internal manual shock was delivered that terminated the VT. Revision of the ICD was performed on the next day. Assuming that the combination of an integrated bipolar lead with the sensing algorithm and/or signal processing of the ICD manufacturer was responsible for the previous oversensing of myopotentials, only generator exchange (Boston Scientific Cognis 100-D CRT-D) was targeted at first. For intraoperative testing, ventricular sensing was set to 1.2 mV and a polymorphic fast VT was induced by T-wave shock. Now, there was no undersensing but underdetection of the induced arrhythmia, i.e. the local V–V interval detected by the ICD was clearly longer than the apparent cycle length in the ECG resulting in failure to diagnose VT (see Fig. 2). A manually applied ICD shock with 41 J terminated the arrhythmia. Programmed ventricular stimulation using the implanted RV electrode (apical position) revealed a locally long effective refractory period (ERP) of 400 ms (basic cycle length 500 ms, 3 times threshold). A new pace-sense electrode (Medtronic 5076) was placed in septal position and an ERP of 300 ms could be measured there. During ICD testing, the induced ventricular arrhythmia was appropriately detected using a I.-O. Lee (&) C. Ukena M. Bohm A. Buob H.-R. Neuberger Klinik fur Innere Medizin III (Kardiologie, Angiologie, Internistische Intensivmedizin), Universitatsklinikum des Saarlandes, 66421 Homburg/Saar, Germany e-mail: illkyu@hotmail.com

Cardiac characteristics and long-term outcome in Andersen-Tawil syndrome patients related to KCNJ2 mutation

Andersen-Tawil syndrome (ATS) is an uncommon form of channelopathy linked to mutations in the KCNJ2 gene. Currently, little is known about the long-term arrhythmic prognosis of this disease. We conducted a retrospective multicentre study in nine French hospitals. Patients were recruited only if they were KCNJ2 mutation carriers. Thirty-six patients (female n = 22, 61%) from 20 unrelated kindred were included with a mean follow-up of 9.5 ± 8.2 years. We found 12 distinct KCNJ2 mutations in the 20 probands. Three of them were novel. Thirteen patients (36%) experienced syncope and one patient was resuscitated from cardiac arrest before diagnosis. The mean QTc interval was 439 ± 57 ms and QUc was 642 ± 64 ms. All patients had normal ejection fraction. Holter recordings in 33 patients found 11 272 premature ventricular complexes (PVCs) per day on average, 25 patients had episodes of bigeminy, and 25 patients had polymorphic PVCs. Twenty-three patients (70%) had non-sustained polymorphic ventricular tachycardia (VT), and six sustained polymorphic VT. Only one patient presented with torsades de pointes. Patients were treated with beta-blocker (n = 20), beta-blocker and amiodarone (n = 2), beta-blocker and flecainide (n = 6), or acetazolamide (n = 6). Radiofrequency ablation was attempted in five patients without clinical success. An implantable cardiac defibrillator was implanted in three patients. During follow-up, none of the patients died, four patients experienced syncope under treatment, and one patient had non-fatal cardiac arrest. Despite a severe clinical presentation with a very high rate of ventricular arrhythmias, the arrhythmic prognosis of the ATS patients is relatively good under treatment.

Ventricular tachyarrhythmia after coronary bypass surgery: incidence and outcome

Ventricular tachyarrhythmia after coronary artery bypass graft is common and the occurrence has been described, but the incidence and risk factors are not well defined. To evaluate the incidence of arrhythmias and to detect high-risk populations. In this prospective study, 856 consecutive patients undergoing coronary artery bypass graft were monitored for new-onset ventricular tachyarrhythmias: non-sustained monomorphic ventricular tachyarrhythmia, sustained monomorphic ventricular tachyarrhythmia, sustained polymorphic ventricular tachyarrhythmia, and ventricular fibrillation. Detailed analyses of the clinical, demographic, echocardiographic, and surgical findings and arrhythmias occurrence was carried out during 6 months of follow-up. The incidence of ventricular tachyarrhythmia was 26.6% (17.6% non-sustained monomorphic ventricular tachycardia, 5.5% sustained monomorphic ventricular tachycardia, 0.8% sustained polymorphic ventricular tachycardia, and 2.7% ventricular fibrillation). The strongest degrees of statistical significance were for low ejection fraction (p = 0.01) and ischemic heart disease (p = 0.02). The incidence of ventricular fibrillation (61%) was greatest in the first 48 h after surgery. Postoperative myocardial infarction (p = 0.03) and hemodynamic instability (p = 0.05) were also predictors of arrhythmia occurrence. Recurrence of arrhythmia was highest in the ventricular fibrillation group (52%). The correlations between tachyarrhythmia, age, sex, electrolyte disorders, body mass index, and systemic or pulmonary hypertension were not significant. In view of the strong relationship between ventricular arrhythmias and low ejection fraction, ischemic heart disease, coronary artery disease severity, postoperative myocardial infection, and hemodynamic impairment, continuous monitoring is necessary, especially in the first 48 h after coronary artery bypass surgery.

Stress Cardiomyopathy (Tako‐Tsubo) Associated with Sustained Polymorphic Ventricular Tachycardia

We present a case of 38-year-old woman with stress cardiomyopathy presenting to the emergency department with a 1-week history of recurrent syncope due to sustained polymorphic ventricular tachycardia.

Abstract P229: Ibutilide Therapy for Atrial Fibrillation - Five-Year Experience in a Community Hospital

Body: Background Ibutilide fumarate is a class III antiarrhythmic agent whose sole indication is the acute conversion of atrial fibrillation or atrial flutter to sinus rhythm. Ibutilide blocks potassium channels and activates slow inward sodium channels, which delays repolarization. These actions prolong the action potential in atrial and ventricular refractory periods, leading to arrhythmia termination. Many institutions restrict the use of ibutilide because of the potential risk of polymorphic ventricular tachycardia (PMVT). Limitations include administration only in the presence of a physician, use only in certain monitored units, or an Intensive Care Unit. Methods Over a five-year period, 238 patients, 151 male/87 female, mean age 67.1 years, received intravenous ibutilide at our institution. Ibutilide was administered in four clinical settings: Emergency Department (n=80), Intensive Care Unit (n=11), Telemetry (n=107), and the Cardiac Catheterization /Electrophysiology Laboratory (n=40). Ibutilide was administered by infusion of one milligram over 15 minutes followed by a 15 minute waiting period, the infusion was repeated. The infusion was discontinued if the patient converted to sinus rhythm. Results Conversion to sinus rhythm occurred in 59% of patients outside the cath/EP lab. The incidence of PMVT was 1.7%. Three patients had brief, non-sustained polymorphic ventricular tachycardia and one patient had a sustained PMVT. Our data suggest that ibutilide is safe and efficacious drug when ordered by experienced physicians in properly selected patients in a variety of monitored settings. Ibutilide is ordered at our institution almost exclusively by cardiac electrophysiologists and emergency physicians who routinely consult with the electrophysiologists prior to administration. No deaths occurred in our five-year series. As a result of this study, the policy at our institution is that ibutilide may be administered by nurses on telemetry units. Close Window

The diagnosis and management of ventricular arrhythmias

The term 'ventricular arrhythmias' incorporates a wide spectrum of abnormal cardiac rhythms, from single premature ventricular complexes to sustained monomorphic ventricular tachycardia (VT), polymorphic VT, and ventricular fibrillation. Sustained ventricular arrhythmias are the most common cause of sudden cardiac death. These arrhythmias occur predominantly in patients with structural heart disease, but are also seen in patients with no demonstrable cardiac disease. The diagnosis of VT can be made reliably using electrocardiographic criteria, and a number of algorithms have been proposed. Among patients with VT and a structurally normal heart, the prognosis is usually benign and treatment is predominantly focused on the elimination of symptoms. Patients who have VT in the presence of structural heart disease are often managed with implantable cardioverter-defibrillators. These devices are effective for both primary and secondary prevention of VT and sudden cardiac death. Pharmacological therapy for VT has limited efficacy and is associated with a high incidence of adverse effects. Radiofrequency catheter ablation is useful for controlling recurrent episodes of monomorphic VT; however, research is needed to define the role of catheter ablation in the treatment of other ventricular arrhythmias.

Pneumomediastinum after implantable cardiac defibrillator implantation

A 66-year-old male with prior tuberculosis pleuritis and anterior myocardial infarction was admitted to our hospital for sustained polymorphic ventricular tachycardia. The patient was already on oral amiodarone, sotalol, and perindopril. Invasive external overdrive pacing terminated the arrhythmia. Acute ischaemia was ruled out and an implantable cardiac defibrillator (ICD) implantation was decided. A …

Hypokalemia during the cooling phase of therapeutic hypothermia and its impact on arrhythmogenesis

Background Mild to moderate therapeutic hypothermia (TH) has been shown to improve survival and neurological outcome in patients resuscitated from out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation (VF) as the presenting rhythm. This approach entails the management of physiological variables which fall outside the realm of conventional critical cardiac care. Management of serum potassium fluxes remains pivotal in the avoidance of lethal ventricular arrhythmia. Methods We retrospectively analyzed potassium variability with TH and performed correlative analysis of QT intervals and the incidence of ventricular arrhythmia. Results We enrolled 94 sequential patients with OHCA, and serum potassium was followed intensively. The average initial potassium value was 3.9 ± 0.7 mmol l −1 and decreased to a nadir of 3.2 ± 0.7 mmol l −1 at 10 h after initiation of cooling ( p < 0.001). Eleven patients developed sustained polymorphic ventricular tachycardia (PVT) with eight of these occurring during the cooling phase. The corrected QT interval prolonged in relation to the development of hypothermia ( p < 0.001). Hypokalemia was significantly associated with the development of PVT ( p = 0.002), with this arrhythmia being most likely to develop in patients with serum potassium values of less than 2.5 mmol l −1 ( p = 0.002). Rebound hyperkalemia did not reach concerning levels (maximum 4.26 ± 0.8 mmol l −1 at 40 h) and was not associated with the occurrence of ventricular arrhythmia. Furthermore, repletion of serum potassium did not correlate with the development of ventricular arrhythmia. Conclusions Therapeutic hypothermia is associated with a significant decline in serum potassium during cooling. Hypothermic core temperatures do not appear to protect against ventricular arrhythmia in the context of severe hypokalemia and cautious supplementation to maintain potassium at 3.0 mmol l −1 appears to be both safe and effective.

Increase in Internal Defibrillation Threshold During Acute Myocardial Infarction

A 67-year-old man suffered an acute anteroseptal myocardial infarction complicated by multiple episodes of ventricular fibrillation, which were not systematically defibrillated by maximum, internal 35-J shocks delivered by an implanted cardioverter defibrillator (ICD). He had suffered from acute inferior myocardial infarction 6 years earlier, complicated with sustained polymorphic ventricular tachycardia (VT). Due to inducibility of sustained VT on an electrophysiologic study, an ICD was implanted. Defibrillation testing performed after healing of anteroseptal infarction was successful with a 10-J safety margin, suggesting that acute myocardial ischemia transiently elevated the internal defibrillation threshold.