Episodes Of Polymorphic Ventricular Tachycardia Research Articles

Efficacy of Implantable Cardioverter Defibrillators in Young Patients With Catecholaminergic Polymorphic Ventricular Tachycardia

Background— The effectiveness of implantable cardioverter-defibrillator (ICD) therapy for the management of catecholaminergic polymorphic ventricular tachycardia (VT) in young patients is not known. ICD discharges are not always effective and inappropriate discharges are common, both resulting in morbidity and mortality. Methods and Results— This is a multicenter, retrospective review of young patients with catecholaminergic polymorphic VT and ICDs from 5 centers. ICD discharges were evaluated to determine arrhythmia mechanism, appropriateness, efficacy of therapy, and complications. A total of 24 patients were included. Median (interquartile range) ages at onset of catecholaminergic polymorphic VT symptoms and ICD implant were 10.6 (5.0–13.8) years and 13.7 (10.7–16.3) years, respectively. Fourteen patients received 140 shocks. Ten patients (42%) experienced 75 appropriate shocks and 11 patients (46%) received 65 inappropriate shocks. On actuarial analysis, freedom from appropriate shock at 1 year after ICD implant was 75%. Of appropriate shocks, only 43 (57%) demonstrated successful primary termination. All successful appropriate ICD discharges were for ventricular fibrillation. No episodes of polymorphic VT or bidirectional VT demonstrated successful primary termination. The adjusted mean (95% confidence interval) cycle length of successful discharges was significantly shorter than unsuccessful discharges (168 [152–184] ms versus 245 [229–262] ms; adjusted P =0.002). Electrical storm occurred in 29% (4/14) and induction of more malignant ventricular arrhythmias in 36% (5/14). There were no deaths. Conclusions— ICD efficacy in catecholaminergic polymorphic VT depends on arrhythmia mechanism. Episodes of ventricular fibrillation were uniformly successfully treated, whereas polymorphic and bidirectional VT did not demonstrate successful primary termination. Inappropriate shocks, electrical storm, and ICD complications were common.

Short-coupling premature ventricular complexes from the left ventricle triggered isoproterenol-resistant electrical storm in a patient with Brugada syndrome

Multiple episodes of polymorphic ventricular tachycardia (PVT), triggered by short-coupling (280–300ms) premature ventricular complexes (PVCs) showing a right bundle branch block (RBBB) pattern, occurred in a patient with Brugada syndrome. Isoproterenol infusion attenuated ST-segment elevation in leads V2–V3, but the triggered PVCs and PVT itself were not inhibited but rather increased. An implantable cardioverter-defibrillator (ICD) was introduced with a supplemental treatment of bepridil (150mg/d), which minimized his ST-segment elevation.

Cardiac Resynchronization Therapy and Proarrhythmia: Weathering the Storm

In patients with significant left ventricular (LV) dysfunction and congestive heart failure despite optimal medical therapy, implantation of cardiac resynchronization therapy-defibrillator (CRT-D) devices has been shown to improve symptoms and diminish ventricular tachyarrhythmia susceptibility. We describe the case of a patient with dilated cardiomyopathy who developed ventricular tachycardia storm (VTS) one month after the implantation of a CRT-D device. VTS was initially controlled with pharmacotherapy, allowing the patient to continue with biventricular pacing. Two months later the patient was readmitted due to multiple episodes of polymorphic ventricular tachycardia. VTS was refractory to various intravenous antiarrhythmic drugs and it was finally controlled only when LV pacing was turned off. In patients with heart failure treated with CRT-D, VTS can occur and is best managed by turning off LV pacing. Our report raises an important and concerning issue of biventricular pacing causing ‘proarrhythmia’ in rare instances.

Ventricular Tachycardia during Treatment with Modafinil for Narcolepsy: A Case Report

Pharmacological treatment of narcolepsy is complex. We reported a case of recurrent episodes of polymorphic ventricular tachycardia attributed to the use of modafinil, a recently approved wake-promoting agent for narcolepsy and shift work sleep disorder. Modafinil is also approved as adjunctive treatment of obstructive sleep apnea/hypopnea syndrome. While the exact mechanism of action for modafinil is not known, central dopamine receptors seem to play an essential role. Adverse influences on the electrocardiogram (ECG) or drug-related cardiac arrhythmias are rarely reported, but are considered as clinically important.

Cardiac arrest due to long QT syndrome associated with excessive consumption of energy drinks

Amphetamines 1000 Negative Barbiturates 300 Negative Benzodiazepines 300 Negative Cannabinoids 50 Negative Cocaine 300 Negative MDMA 500 Negative Metamphetamine 1000 Negative Methadone 300 Negative The congenital form of long QT syndrome is characterized by a prolonged QT interval in the electrocardiogram (ECG) and is complicated by episodes of polymorphic ventricular tachycardia known as torsades de pointes (TdP). Patients with long QT syndrome 1 (LQTS-1) typically may suffer cardiac arrest during exercise. Based on these observations beta-blocker therapy is recommended in these patients to reduce the maximal heart rate and blunt the effects of adrenaline. Energy drinks contain high doses of taurine (an amino acid), caffeine and glucuronolactone (a glucose metabolite), neither of which is considered to have significant toxicity. We report a case of a 22 year old female with out of hospital cardiac arrest (OHCA) due to initial torsades de pointes tachycardia secondary degenerating to ventricular fibrillation. Sudden cardiac death occurred without prodrome in a discotheque. Basic life support was performed immediately. After 15 minutes of resuscitation with fractionated administration of 3 mg adrenaline return of spontaneous circulation (ROSC) could be achieved after the patient received five 360 Joule shocks by the emergency medical services personnel. Initial ECG showed torsades de pointes tachycardia, which degenerated during resuscitation to ventricular fibrillation. After ROSC the patient was admitted to our intensive care unit. Acute cardiac catheterization excluded coronary macroangiopathy or coronary anomalies. Cardiac ventriculography revealed a normal ejection fraction of 69. Echocardiography showed normal cardiac function without any pathologic pattern. Furthermore, no pericardial effusion was found. Results of a urinary screen for drug or alcohol misuse were negative (Table 1). Potassium level at admission was normal (4.4 mmol/l). Abnormal

Renal sympathetic denervation for treatment of electrical storm: first-in-man experience

Sympathetic activity plays an important role in the pathogenesis of ventricular tachyarrhythmia. Catheter-based renal sympathetic denervation (RDN) is a novel treatment option for patients with resistant hypertension, proved to reduce local and whole-body sympathetic activity. Two patients with chronic heart failure (CHF) (non-obstructive hypertrophic and dilated cardiomyopathy, NYHA III) suffering from therapy resistant electrical storm underwent therapeutic renal denervation. In both patients, RDN was conducted with agreement of the local ethics committee and after obtaining informed consent. The patient with hypertrophic cardiomyopathy had recurrent monomorphic ventricular tachycardia despite extensive antiarrhythmic therapy, following repeated endocardial and epicardial electrophysiological ablation attempts to destroy an arrhythmogenic intramural focus in the left ventricle. The second patient, with dilated nonischemic cardiomyopathy, suffered from recurrent episodes of polymorphic ventricular tachycardia and ventricular fibrillation. The patient declined catheter ablation of these tachycardias. In both patients, RDN was performed without procedure-related complications. Following RDN, ventricular tachyarrhythmias were significantly reduced in both patients. Blood pressure and clinical status remained stable during the procedure and follow-up in these patients with CHF. Our findings suggest that RDN is feasible even in cardiac unstable patients. Randomized controlled trials are urgently needed to study the effects of RD in patients with electrical storm and CHF.

Anesthetic management of patients with Brugada syndrome: a case series and literature review

To review the anesthetic management and perioperative outcomes of patients diagnosed with Brugada syndrome (BrS) who were treated at a single centre and to compare those results with a comprehensive review of the existing literature. A retrospective chart review of anesthesia records from patients diagnosed with BrS at the Mayo Clinic was undertaken with the emphasis on administered drugs, ST segment changes, and occurrence of complications, including death, hemodynamic instability, and dysrhythmias. Eight patients were identified who underwent a total of 17 operative procedures from 2000 through 2010. A total of 20 significant ST segment elevations were recorded in four patients, several of which occurred in close temporal relation to anesthetic drug administration. These elevations resolved uneventfully. There were no recorded dysrhythmias, and recovery from anesthesia proceeded uneventfully. A literature review of patients with BrS yielded 52 anesthetics in 43 patients. The only recorded complications included unmasking of a Brugada ECG pattern, one episode of polymorphic ventricular tachycardia, which converted spontaneously to sinus rhythm, and one episode of postoperative ventricular fibrillation in the setting of epidural anesthesia. In this series and in the literature, BrS patients tolerated anesthesia without untoward disease-related complications. Propofol and local anesthetics carry a theoretical risk of arrhythmogenic potential in BrS patients, but clear evidence is lacking. However, awareness of their potential to induce arrhythmias warrants caution, especially with propofol infusions. Factors that might exacerbate ST segment elevations and subsequently lead to dysrhythmias (e.g., hyperthermia, bradycardia, and electrolyte imbalances, such as hyper- and hypokalemia and hypercalcemia) should be avoided or corrected.

Prolongation of the Corrected QT Complex – A Cause of Sudden Cardiac Death in the Mountain Environment?

In the mountain environment sudden cardiac death (SCD) has been shown to be responsible for the deaths of up to 52% of downhill skiers and 30% of hikers. The majority...

Degeneration of atrioventricular nodal reentrant tachycardia into polymorphic ventricular tachycardia: a case report

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of paroxysmal supraventricular tachycardia and is usually treated successfully by radiofrequency catheter ablation. We report on a 38-year-old woman whose AVNRT attacks occasionally degenerated into polymorphic ventricular tachycardia (VT). The patient presented with a complaint of palpitations. The electrocardiogram was in sinus rhythm with a normal corrected QT interval. During Holter monitoring, narrow QRS complex tachycardia with a heart rate of 220 beats/min was noted at nighttime, that lasted for 90 minutes, during which two episodes of polymorphic VT were also seen. The diagnosis of AVNRT was confirmed on an electrophysiologic study and AVNRT was successfully treated by radiofrequency catheter ablation. The patient had no complaint during a follow-up of eight months, with no signs of arrhythmia on repeat Holter monitoring.

Homozygous mutation in SCN5A associated with atrial quiescence, recalcitrant arrhythmias, and poor capture thresholds

Case report A 6-year-old Hispanic girl was referred to cardiology for irregular heartbeats. On electrocardiogram (ECG), she was noted to have sinus bradycardia with nonspecific intraventricular conduction delay, as well as frequent sinus pauses with junctional escape on Holter monitoring. Despite multiple attempts to contact her, she did not follow up, and at 11 years of age collapsed while running at school. She was unresponsive, and an automated external defibrillator determined her rhythm to be “shockable” ventricular tachycardia. After defibrillation, perfusion was re-established, and she was taken to a local emergency room, where a lidocaine infusion was initiated with temporary stabilization in her rhythm. While in the emergency room, she had recurrent episodes of unstable, sustained ventricular tachycardia, requiring 6 separate cardioversions and ongoing cardiopulmonary resuscitation. A chest radiograph showed moderate cardiomegaly. Electrocardiography revealed no discernible atrial activity, with a slow junctional escape and frequent premature ventricular contractions (Fig. 1). It also revealed low-voltage QRS complexes and a prolonged QT interval, although this was after cardiac arrest. Subsequent telemetry revealed frequent episodes of polymorphic ventricular tachycardia. An echocardiogram was performed, which revealed severely depressed biventricular function (ejection fraction 19%), with normal anatomy and coronary origins. Because of recurrent episodes of ventricular tachycardia/ventricular fibrillation, she was transitioned to an amiodarone infusion. She was transferred to our institution and was ultimately placed on extracorporeal membrane oxygenation for recalcitrant arrhythmias and progressive metabolic acidosis. In the operating room, it was noted that her atria were dilated and not contracting.

Löffler Endocarditis Presenting With Recurrent Polymorphic Ventricular Tachycardia Diagnosed by Cardiac Magnetic Resonance Imaging

A 56-year-old white man was admitted with palpitations, chest pressure, and dyspnea on exertion. He had an embolic stroke 2 months before admission without a defined embolic source. He had history of well-controlled hypertension and allergic asthma treated with theophylline. On admission, the resting ECG revealed sinus rhythm, right axis deviation, anterolateral ST-segment depression, and a normal QT interval (Figure 1). His cardiac biomarkers were elevated to indicate myocardial injury (troponin I, 2.66 ng/mL; creatine kinase-MB, 5.8 ng/mL). While in hospital, he developed episodes of polymorphic ventricular tachycardia (Figure 2) requiring multiple cardioversions and eventually temporary pacing. The initial peripheral blood count revealed a marked leukocytosis (22 000/μL) with a severe hypereosinophilia (47%, 10 000/μL). A transthoracic echocardiogram showed a normal-size left ventricle (LV) with normal global systolic function. The right ventricle (RV) was mildly enlarged with a mildly decreased systolic function. The LV and RV apexes appeared thickened and hypokinetic (Movie I in the online-only Data Supplement). Subsequent left and right cardiac catheterization demonstrated normal coronary arteries and elevated right and left heart filling pressures (right atrial pressure, 20 mm Hg; capillary wedge pressure, 23 mm Hg) with signs of restrictive physiology (Figure 3). An extensive workup for conditions associated with hypereosinophilia was negative. The patient had no rash or other evidence of vasculitis. Parasitosis was ruled out with serial …

Repetitive polymorphic ventricular tachycardia initiated by phase 4 block in the His-Purkinje system

We report a case of a patient who developed repetitive episodes of polymorphic ventricular tachycardia with a stereotypical pattern of initiation. A premature atrial complex would result in a brief pause followed by left bundle branch block aberrancy. Ventricular bigeminy would ensue followed by episodes of polymorphic ventricular tachycardia, some requiring cardioversion. We postulate that delay within the His-Purkinje system initiated by phase 4 block was proarrhythmic in this patient.

Frequent Recurrent Polymorphic Ventricular Tachycardia during Sleep Due to Managed Ventricular Pacing

We report a case of a patient with an implantable cardioverter defibrillator and no prior history of heart block with managed ventricular pacing (MVP) programmed who had frequent recurrent episodes of polymorphic ventricular tachycardia. All of the episodes were initiated by transient atrioventricular block which resulted in short-long-short sequences permitted by MVP. This case illustrates that MVP should be used with caution not only in patients with complete heart block, but also in patients at risk for brief heart block due to such states as hypervagatonia due to sleep apnea.

Paroxysmal β-adrenergic Receptor-mediated Alterations in Ventricular Repolarization at Rapid Heart Rates During Inhibition of Delayed Rectifier Currents

The contribution of the slow component of the delayed rectifier current (IKs) to ventricular repolarization is increased during rapid heart rates and prolonged repolarization. The objective was to characterize physiologically relevant paroxysmal beta-adrenergic receptor-mediated alterations on ventricular repolarization under these conditions. Paced guinea pig hearts were perfused with (1) control, (2) sparfloxacin (IKr inhibitor), or (3) sparfloxacin and HMR 1556 (IKs inhibitor). The mean +/- standard error of the mean epicardial action potential duration at 90% repolarization (APD90) increased from baseline with IKr inhibition (12.9% +/- 4.7%) and dual IKr/IKs inhibition (25.1% +/- 5.3). Paroxysmal isoproterenol (0.01 and 1.0 nM) significantly decreased APD90 in the presence of IKr inhibition but was attenuated with the addition of IKs inhibition. Spontaneous episodes of polymorphic ventricular tachycardia were observed with isoproterenol during dual IKr and IKs inhibition. The endocardial expression of KCNQ1 increased greater than 2-fold after exposure to IKr and dual IKr/IKs inhibition relative to control but was not altered in epicardial tissue. The beta-adrenergic receptor-mediated decrease in APD90 during IKr inhibition is reversed in the presence of IKs inhibition at rapid heart rates. IKs may serve as an important compensatory mechanism to protect against adrenergically induced arrhythmias when the repolarization reserve is depleted.

Clinical Effects of Cesium Intake

The knowledge about cesium metabolism and toxicity is sparse. Oral intake of cesium chloride has been widely promoted on the basis of the hypothesis referred to as "high pH cancer therapy", a complimentary alternative medicine method for cancer treatment. However, no properly confirmed tumor regression was reported so far in all probability because of neither theoretical nor experimental grounds for this proposal. The aim of the present review was to resume and discuss the material currently available on cesium salts and their applications in medicine. The presence of cesium in the cell does not guarantee high pH of its content, and there is no clinical evidence to support the claims that cancer cells are vulnerable to cesium. Cesium is relatively safe; signs of its mild toxicity are gastrointestinal distress, hypotension, syncope, numbness, or tingling of the lips. Nevertheless, total cesium intakes of 6 g/day have been found to produce severe hypokalemia, hypomagnesemia, prolonged QTc interval, episodes of polymorphic ventricular tachycardia, with or without torsade de pointes, and even acute heart arrest. However, full information on its acute and chronic toxicity is not sufficiently known. Health care providers should be aware of the cardiac complications, as a result of careless cesium usage as alternative medicine.

A novel SCN5A mutation V1340I in Brugada syndrome augmenting arrhythmias during febrile illness

Mutations in the SCN5A gene, which encodes the cardiac sodium channel, have been implicated in the pathogenesis of Brugada syndrome (BrS). Febrile illnesses have been recognized to unmask and/or trigger the BrS phenotype. However, the pathophysiological mechanism has not been fully elucidated. A novel SCN5A missense mutation, V1340I, was identified in a patient with BrS suffering from frequent episodes of polymorphic ventricular tachycardia (VT) and syncope associated with fever. The biophysical modifications of hNa(v)1.5 by V1340I were studied. The effects of the V1340I mutation were studied in the 2 splice variants, SCN5A and SCN5A-Q1077del (delQ), using patch-clamp techniques at various temperatures between 22 degrees C and 40 degrees C. At 22 degrees C, V1340I-SCN5A generated markedly diminished sodium currents compared to the wild-type (WT) SCN5A. On the contrary, V1340I-delQ generated almost identical current density compared to the WT-delQ. However, V1340I-delQ significantly attenuated the peak current density compared to the WT-delQ at 32 degrees C, 37 degrees C and 40 degrees C. The voltage dependency of steady-state activation was leftward shifted both in WT-delQ and V1340I-delQ at 40 degrees C. In addition, the V1340I-delQ accelerated the recovery time course from fast inactivation compared to the WT-delQ at 40 degrees C. Immunohistochemical staining showed that both V1340I-SCN5A and V1340I-dQ were expressed in the plasma membrane. Our study supports the concept that febrile illness predisposes individuals who carry a loss of function SCN5A mutation, such as V1340I, to fever-induced ventricular arrhythmias in BrS by significantly reducing the sodium currents in the hyperthermic state.

Recurrence of cardiac arrest after 14 years without ICD interventions: a VF cluster immediately after delivery.

One day after childbirth, a 29-year-old woman had several episodes of polymorphic ventricular tachycardia and ventricular fibrillation. She was rescued by an internal cardioverter defibrillator (ICD) which she had received 14 years ago, after out-of-hospital cardiac arrest, without recurrences until now. The electrocardiogram showed a normal QT interval, and ventricular premature beats, which seemed to arise from the same site. This case report illustrates that, even after years with freedom of ICD therapy, depleted devices still have to be replaced. (Neth Heart J 2008;16:242-5.).

Coronary spasm: a case of transient ST elevation and syncopal ventricular tachycardia without angina

We report the case of a 60-year-old male with recurrent pre-syncope, referred with a provisional diagnosis of carotid sinus syndrome on the basis of a 4 s asystolic pause following carotid sinus massage. On repeat Holter monitoring there was ST-segment elevation followed by episodes of polymorphic ventricular tachycardia during a mild episode of pre-syncope. Coronary angiography showed mild right coronary artery irregularity without significant stenosis. An automatic cardioverter defibrillator was implanted and high dose combined vasodilator therapy was commenced. At follow-up 18 months after implantation, the device has recorded no episode of tachycardia and the patient reports no recurrence of symptoms.

A case of short-coupled variant of torsade de pointes characterized by spatial heterogeneity of action potential duration and its restitution kinetics

A 21-year-old male experienced frequent episodes of polymorphic ventricular tachycardia (PVT) initiated by a closely coupled premature ventricular complex (PVC) in the absence of QT prolongation and structural heart disease. Programmed stimulation at right ventricular apex (RVA), but not at the outflow tract (RVOT), provoked PVT degenerating into ventricular fibrillation (VF). Monophasic action potential duration (MAPD) was significantly shorter at RVA than RVOT. The maximum slope of MAPD restitution was much steeper at RVA than RVOT (1.91 versus 0.50). Such spatial heterogeneities of MAPD and its restitution may facilitate wavebreak and functional reentry predisposing to PVT and VF.

Short QT syndrome: A case report and review of literature

The short QT syndrome has been recently recognised as a genetic ion channel dysfunction. This new clinical entity is associated with an incidence of sudden cardiac death, syncope, and atrial fibrillation in otherwise healthy individuals. The distinctive ECG pattern consists of an abnormally short QT interval, a short or even absent ST segment and narrow T waves. A 30-year-old resuscitated woman with short QT syndrome is described together with an example of the classic ECG characteristics. A short-coupled variant of torsade de pointes was reveal on Holter recordings. The implantable cardioveter defibrillator seems to be the therapy of choice to prevent from sudden cardiac death. Quinidine proved to be efficient in prolonging the QT interval and rendering ventricular tachyarrhythmias non-inducible in patients with a mutation in KCNH2 (HERG). Our preliminary data suggest amiodarone combined with beta-blocker may be helpful in treating episodes of polymorphic ventricular tachycardia for patients with an unknown genotype. Because the short QT syndrome often involves young patients with an apparently normal heart, it is imperative for physicians to recognize the clinical features of the short QT syndrome in making a timely correct diagnosis.