Proarrhythmic ECG Deterioration Caused by Myocardial Ischemia of the Conus Branch Artery in Patients with a Brugada ECG Pattern

The Brugada‐type electrocardiogram (ECG) is characterized by ST‐segment elevation in the right precordial ECG leads and has been reported to have the potential of sudden death. Right ventricular outflow tract supplied from the conus branch of the coronary artery (CB) is considered as the anatomopathologic substrate of Brugada syndrome. We experienced two asymptomatic patients with a saddleback Brugada‐type ECG who exhibited a dynamic ECG conversion to a coved type following a ventricular fibrillation/ventricular tachycardia (VT/VF) episode when myocardial ischemia occurred exclusively at the CB. Some types of Brugada syndrome might be caused VT/VF by selective myocardial ischemia at the CB. (PACE 2011; 34:e26–e29)     

Ajmaline challenge in young individuals with suspected Brugada syndrome

Background: The clinical characteristics and the results of ajmaline challenge in young individuals with suspected Brugada syndrome (BS) have not been systematically investigated. Methods: Among a larger series of patients included in the BS database of our Department, 179 patients undergoing ajmaline challenge were included in the study and categorized in two groups according to age: group 1 (<18 years old) and group 2 (≥18 years old). Clinical features and results of the ajmaline challenge of each group were compared. Results: Young individuals were more often asymptomatic compared to adult patients (P = 0.002). They showed a higher number of normal ECGs (P = 0.023), a lower percentage of Brugada type II electrocardiographic pattern compared to the adult population (P = 0.011), and a comparable amount of spontaneous Brugada type III electrocardiographic pattern (P = 0.695). Ajmaline provoked a higher degree of intraventricular conduction delay (P = 0.002) and higher degree of prolongation of the ventricular repolarization phase (P = 0.013) in young individuals but its pro‐arrhythmic risk was comparable in the two groups (P = 0.684). Furthermore, inducibility of ventricular arrhythmias in young patients with a positive ajmaline test was comparable to that of the adults with a positive ajmaline test (P = 0.694). Conclusions: The present study demonstrates the low‐risk profile of the ajmaline test in young patients when performed by experienced physicians and nurses in an appropriate environment. (PACE 2011; 736–741)     

Excellent Long‐Term Reproducibility of the Electrophysiologic Efficacy of Quinidine in Patients with Idiopathic Ventricular Fibrillation and Brugada Syndrome

Background: Quinidine is very effective in preventing the reinduction of sustained ventricular fibrillation (VF) during electrophysiologic study (EPS) in patients with idiopathic VF and Brugada syndrome. However, there are no data on the long‐term reproducibility of this EP efficacy. Methods and Results: Nine patients (seven males and two females, aged 21–72 years), who suffered from aborted cardiac arrest (n = 8) or recurrent syncope (n = 1) due to Brugada syndrome (n = 5) or idiopathic VF (n = 4), comprised the study. All patients had inducible sustained VF at baseline that was prevented by quinidine therapy and underwent another EPS on medication after 1.7–23.6 (9.8 ± 6.8) years (>5 years in eight patients). Two patients underwent two late EPS on quinidine. The goal of repeat EPS on quinidine was to ensure persistent long‐term drug efficacy (n = 6) or to elucidate the reason of syncopal episodes during therapy (n = 3). The EPS protocol significantly evolved over the years as it became more aggressive (more pacing sites and/or more ventricular extrastimuli). All nine patients tolerated the medication well and had no recurrent documented arrhythmic events during long‐term follow‐up (mean 15 ± 7 years). No sustained ventricular tachyarrhythmias could be induced in any patient during repeat late EPS. In six patients, a more aggressive stimulation protocol could be tested at repeat EPS. Conclusion: The long‐term reproducibility of the EP efficacy of quinidine in patients with idiopathic VF and Brugada syndrome is excellent. EP‐guided quinidine therapy represents a valuable long‐term alternative to ICD therapy in these patients.     

A Phenotypic Combination of Idiopathic VF and Brugada Syndrome

This case study shows a young male presenting a mixture of two disease entities: (1) Brugada syndrome with a nearly‐normal baseline electrocardiogram and positive Ajmaline drug challenge as well as (2) idiopathic ventricular fibrillation including extremely short‐coupled monomorphic ventricular premature beats (VPB) triggering ventricular fibrillation (coupling interval 318 ± 21 ms). In this phenotypic patient group—more suggestive of idiopathic ventricular fibrillation due to the ultra‐short coupling interval of the VPBs—drug treatment with a class IA agent such as Quinidine might be an important option to implantable cardioverter‐defibrillator and ablation therapy. (PACE 2010; 33:e84–e87)     

Brugada syndrome associated with out-of-hospital cardiac arrest: A case report

BACKGROUNDBrugada syndrome (BrS) is an inherited disease characterized by an electrocardiogram (ECG) with a coved-type ST-segment elevation in the right precordial leads (V1-V3), which predisposes to sudden cardiac death (SCD) due to polymorphic ventricular tachycardia or ventricular fibrillation in the absence of structural heart disease. We report the case of a 29-year-old man with out-of-hospital cardiac arrest. BrS is associated with a high incidence of SCD in adults, and increasing the awareness of BrS and prompt recognition of the Brugada ECG pattern can be lifesaving.CASE SUMMARYA 29-year-old man suffered from out-of-hospital cardiac arrest, and after defibrillation, his ECG demonstrated a coved-type elevated ST segment in V1 and V2. These findings were compatible with type 1 Brugada pattern, and ECG of his brother showed a type 2 Brugada pattern. The diagnosis was BrS, NYHF IV, multiple organ dysfunction syndrome, sepsis, and hypoxic ischemic encephalopathy. The patient had no arrhythmia episodes after discharge throughout a follow-up period of 36 mo. CONCLUSIONIncreasing awareness of BrS and prompt recognition of the Brugada ECG pattern can be lifesaving.     

Procainamide and lidocaine produce dissimilar changes in ventricular repolarization and arrhythmogenicity in guinea‐pig

Procainamide is class Ia Na⁺ channel blocker that may prolong ventricular repolarization secondary to inhibition of I_Kr, the rapid component of the delayed rectifier K⁺ current. In contrast to selective I_Na blockers such as lidocaine, procainamide was shown to produce arrhythmogenic effects in the clinical setting. This study examined whether pro‐arrhythmic responses to procainamide may be accounted for by drug‐induced repolarization abnormalities including impaired electrical restitution kinetics, spatial gradients in action potential duration (APD), and activation‐to‐repolarization coupling. In perfused guinea‐pig hearts, procainamide was found to prolong the QT interval on ECG and left ventricular (LV) epicardial monophasic APD, increased the maximum slope of electrical restitution, enhanced transepicardial APD variability, and eliminated the inverse correlation between the local APD and activation time values determined at distinct epicardial recording sites prior to drug infusion. In contrast, lidocaine had no effect on electrical restitution, the degree of transepicardial repolarization heterogeneities, and activation‐to‐repolarization coupling. Spontaneous episodes of monomorphic ventricular tachycardia were observed in 57% of procainamide‐treated heart preparations. No arrhythmia was induced by lidocaine. In summary, this study suggests that abnormal changes in repolarization may contribute to pro‐arrhythmic effects of procainamide.     

Prevalence of electrocardiographic findings suggestive of sudden cardiac death risk in 10,867 apparently healthy young Korean men

Background: The objective of this study was to determine the prevalence of electrocardiographic (ECG) findings suggestive of sudden cardiac death risk in apparently healthy young Korean men. Methods: We administered questionnaires that elicited personal and family histories and performed ECGs on 10,867 male subjects (mean age, 20.9 years). The subjects with abnormal ECG findings underwent echocardiography, a treadmill test, Holter monitoring, a flecainide provocation test, or an electrophysiologic study (EPS) according to the ECG findings and histories. Results: Of the subjects, 5.95% had left ventricular hypertrophy on ECG, but no subjects had hypertrophic cardiomyopathy by echocardiography. The percentage of subjects with a Brugada ECG pattern was 0.90%. We identified one subject with a positive result on the flecainide provocation test. The percentage of subjects with a preexcitation ECG was 0.17%. In two of the subjects, supraventricular tachycardia was induced in the EPS. Of the subjects, 0.05% had epsilon waves, but there were no subjects with arrhythmogenic right ventricular dysplasia/cardiomyopathy by echocardiography. The percentage of subjects with long QT intervals was 0.02%, but there were no arrhythmias on the treadmill test or Holter monitoring. Conclusions: The prevalence of a Brugada ECG pattern in apparently healthy young men is higher in Korea than other countries. (PACE 2011; 717–723)     

Incidence and initial characteristics of pilsicainide-induced ventricular arrhythmias in patients with Brugada syndrome

BACKGROUND: In patients with Brugada syndrome, class I antiarrhythmic drugs can trigger ventricular arrhythmias (VA). The incidence and initial characteristics of VA that developed after pilsicainide was examined in 28 patients with Brugada-type electrocardiographic (ECG) abnormalities and with a positive response in the pilsicainide test. The clinical outcome was also compared between patients with and without pilsicainide-induced VA. METHODS AND RESULTS: In all patients, pilsicainide increased ST segment elevation and accentuated type 1 ECG changes. Ventricular tachycardia (VT) developed in 3 patients and premature ventricular complexes (PVC) in 2 other patients. These 5 patients (group I) had higher ST segment elevation in lead V2 on the ECG at baseline and after pilsicainide and showed a longer QTc interval after pilsicainide than the other 23 patients (group II). However, there was no difference between the 2 groups regarding incidence of prior cardiac events, results of signal-averaged ECG, HV interval, inducibility of ventricular fibrillation by programmed electrical stimulation, or QRS duration. In 1 patient, PVC originated from 3 sites, 2 of which triggered polymorphic VT. The right ventricular (RV) outflow tract was the origin of 2 types of PVC, and other RV sites of 5 other types. During a 45 +/- 37 months follow-up, polymorphic VT recurred in 2 patients in group II. CONCLUSIONS: Pilsicainide induced VA in some patients with Brugada syndrome, but this result may not be used as a parameter of the risk stratification of Brugada syndrome. Multiple PVC induced by pilsicainide and triggering polymorphic VT originated from several RV sites is an important factor when considering patients for treatment with catheter ablation.     

Increased intraatrial conduction abnormality assessed by P-wave signal-averaged electrocardiogram in patients with Brugada syndrome

Background: Atrial fibrillation (AF) is observed in patients with Brugada syndrome (BS), especially those showing coved‐type electrocardiogram (ECG) pattern. Using P‐wave signal‐averaged ECG (P‐SAE), we investigated whether increased intraatrial conduction abnormality contributed to AF generation in BS patients. Methods: Twenty BS patients and 20 age‐ and gender‐matched healthy controls were enrolled. At the P‐SAE recording, 12 of the 20 BS patients showed coved‐type (C‐BS) and eight showed saddleback‐type (S‐BS). The total duration (Ad) and root mean square voltage for the terminal 20 ms (LP₂₀) of the filtered P wave were measured. P‐wave dispersion (P‐disp) was defined as the difference between the maximum and minimum, measured from 16 precordial recording sites. Results: BS patients had a significantly longer Ad (128.2 ± 7.6 vs 116.3 ± 8.2 ms, P < 0.0001), lower LP₂₀ (2.6 ± 0.9 vs 3.4 ± 0.8 μV, P < 0.01), and greater P‐disp (15.5 ± 7.0 vs 7.4 ± 3.2 ms, P < 0.0001) than the controls. C‐BS patients had significantly longer Ad (131.0 ± 7.2 vs 124.1 ± 6.8 ms, P < 0.05) and lower LP₂₀ (2.2 ± 0.6 vs 3.2 ± 1.0 μV, P < 0.05) than S‐BS patients. All C‐BS patients and only three S‐BS patients had atrial late potential (100% vs 38%, P < 0.01). Conclusion: Intraatrial conduction delay and its heterogeneity may exist in BS patients, especially those showing coved‐type ECG patterns. These atrial electrical abnormalities could be a substrate for atrial reentrant tachycardia such as AF. (PACE 2011; 34:1138–1146)     

Recovery Following Propofol‐Associated Brugada Electrocardiogram

Brugada syndrome is a genetic disorder associated with an increased risk of sudden cardiac death that has typical electrocardiographic (ECG) patterns. Recently, there have been reports of Brugada ECG patterns seen in critically ill patients who received propofol, 1 and this pattern was associated with a very high imminent mortality. We report a case in which a critically ill patient developed a Brugada ECG pattern following high‐dose propofol infusion. Once the ECG pattern was recognized, the propofol was discontinued and the ECG pattern resolved, and the patient was discharged home with no arrhythmic sequelae.     

Epinephrine Administered for Anaphylaxis Unmasking a Type 1 Brugada Pattern on Electrocardiogram

Background

Brugada pattern on electrocardiography (ECG) can manifest as type 1 (coved pattern) and type 2 (saddleback pattern). Brugada syndrome represents an ECG with Brugada pattern in a patient with symptoms or clinical factors, including syncope, cardiac arrest, ventricular dysrhythmias, and family history. Brugada syndrome is caused by a genetic channelopathy, but the Brugada pattern may be drug-induced. Epinephrine-induced Brugada pattern has not been reported previously.

Quinidine Induced Electrocardiographic Normalization in Two Patients with Brugada Syndrome

ALINGS, M., et al. : Quinidine Induced Electrocardiographic Normalization in Two Patients with Bru-gada Syndrome. Two patients with Brugada syndrome are presented. The ECGs showed right precordial J waves and ST-segment elevation. Patient 1 was resuscitated from nocturnal ventricular fibrillation, patient 2 was asymptomatic. In only patient 1, flecainide was infused causing monomorphic "malignant" ventricular extrasystoles (R on T), demonstrating the deleterious effect of Class IC antiarrhythmic drugs in Brugada syndrome. However, administration of the Class Ia antiarrhythmic drug quinidine caused normalization of the ECG in both patients. Based on in vitro experiments, agents that reduce the magnitude of I_to-mediated phase 1 have been suggested to normalize ST-segment elevation in Brugada syndrome. This is the first clinical report of such a quinidine induced ECG normalization.     

Asymptomatic Brugada Syndrome Associated with Postural Orthostatic Tachycardia Syndrome:

Autonomic imbalance may work as a modifying factor for initiating lethal arrhythmia in patients with Brugada syndrome. A 26-year-old man with episodes of near syncope was given a diagnosis of an autonomic disorder, postural orthostatic tachycardia syndrome (POTS). The patient spontaneously showed typical Brugada-type ECG, and ventricular fibrillation was induced by programmed electrical stimulation, which allowed the further diagnosis of Brugada syndrome. Although it seems that Brugada syndrome is asymptomatic, its uncommon association of POTS may increase the risk for future arrhythmic events in this patient.     

Pericarditis mimicking Brugada syndrome

Introduction

Brugada syndrome (BrS) is a genetic heart disorder due to alteration of the ion channels function that causes an impaired in the cardiac conduction system. It is characterized by an abnormal electrocardiogram pattern and may be complicated by malignant ventricular arrhythmias.Pericarditis is an inflammation of the pericardium and 90% of isolated cases of acute pericarditis are idiopathic or viral. Acute pericarditis may appears with chest pain, fever, pericardial friction rub, and cardiac tamponade. Moreover, widespread ST segment changes occur due to involvement of the underlying epicardium.

Clinical predictors of conduction disease progression in type I myotonic muscular dystrophy

Background: Patients with type I myotonic muscular dystrophy (DM1) are at risk for sudden death due to atrioventricular conduction block. We sought to characterize the trends and predictors of time‐dependent electrocardiographic (ECG) variations in patients with DM1. Methods: Seventy patients with DM1 underwent standard electrocardiography at first evaluation and routine and symptom prompted follow‐up. Individual variations in ECG conduction intervals were assessed using spaghetti plots. Clinical predictors of conduction disease progression were assessed using multivariate random effects regression models of panel data clustered by patient and adjusted for heart rate. Results: Substantial individual variability was noted in time‐dependent changes in PR, QRS, and QTc intervals of patients with DM1 . Changes in the QTc interval were closely associated with prolongation of the QRS interval. Age, the presence of paroxysmal atrial flutter or fibrillation, and the number of cytosine‐thymine‐guanine (CTG) repeats were independent positive predictors of time‐dependent PR and QRS prolongation during long‐term follow‐up. Female sex was negatively associated with PR prolongation but positively associated with QTc prolongation. Lower left ventricular ejection fraction was associated with greater QRS interval progression during long‐term follow‐up but was not predictive of PR interval progression. Conclusions: Patients with DM1 can develop rapid changes in cardiac conduction intervals. Paroxysmal atrial flutter or fibrillation, older age, and larger CTG expansions predict greater time‐dependent PR and QRS interval prolongation and warrant particular attention in the arrhythmic evaluation of this high risk patient subset. (PACE 2011; 34:171–176)     

Ventricular Fibrillation and Ventricular Tachycardia Triggered by Late‐Coupled Ventricular Extrasystoles in a Brugada Syndrome Patient

Premature ventricular complexes (PVC) falling after the end of the T wave triggered ventricular fibrillation (VF) at night and monomorphic ventricular tachycardia (MVT) during daytime, in a recipient of implantable cardioverter defibrillator with Brugada syndrome. Treatment with bepridil (1) decreased the height of ST segment elevation in leads V1‐V3, (2) completely eliminated VF, and (3) markedly decreased the incidence of PVC and MVT. Albeit rare, VF can be triggered by late‐coupled PVC, due to a mechanism other than phase 2 reentry in some patients with Brugada syndrome. (PACE 2011; e1–e5)     

Brugada electrocardiographic pattern in a postoperative patient

OBJECTIVE: To report the development of the Brugada electrocardiographic (ECG) pattern in the immediate postoperative setting. DESIGN: Case report. SETTING: Postanesthesia care unit at Memorial Sloan-Kettering Cancer Center. PATIENT: A 51-yr-old white male who developed new ST-segment elevation in leads V(1)-V(3) typical of the ECG changes of the Brugada syndrome immediately after undergoing head and neck surgery for cancer. The patient was asymptomatic, and the cardiac enzymes and echocardiogram were normal; therefore, electrophysiologic study was not performed. CONCLUSIONS: We postulated that the Brugada ECG abnormalities were induced primarily by an increase in parasympathetic tone resulting from vagal nerve manipulation during deep neck dissection and partially by the fever he developed during the postoperative period. In addition to the more common causes of ST-segment elevation, the Brugada ECG pattern or syndrome should be considered in patients undergoing deep neck dissection who develop characteristic ECG changes in association with normal cardiac enzymes and echocardiogram.     

Switching from NPH insulin to once‐daily insulin detemir in basal–bolus‐treated patients with diabetes mellitus: data from the European cohort of the PREDICTIVE™ study

Background: The PREDICTIVE? study is a multinational observational study designed to follow up patients with diabetes who started insulin detemir (IDet) in routine care. Recruitment started in June 2004 and is ongoing in some countries. Methods: We report 12‐week follow‐up data for patients with type 1 (T1D) or type 2 diabetes (T2D) in the European cohort who, as part of basal–bolus therapy, switched from once‐ (qd) or twice‐daily (bid) neutral protamine Hagedorn insulin (NPH) to qd IDet. End‐points – evaluated from patients’ records and diaries – were incidence of serious adverse drug reactions, glycaemic parameters, hypoglycaemia and weight change. Results: A total of 3637 patients were included, n = 1500 T1D [mean age 40.9 years, body mass index (BMI) 25.0 kg/m², glycosylated haemoglobin (HbA_1c) 7.9%] and n = 2137 T2D (mean age 60.5 years, BMI 31.9 kg/m², HbA_1c 8.0%). IDet was well tolerated. Lower overall, major and nocturnal rates of hypoglycaemia were observed in T1D and T2D patients switching from NPH to IDet (overall, T1D: 38.2–18.56 episodes/patient year, p < 0.001; T2D: 13.8–3.2 episodes/patient year, p < 0.001). Switching from bid NPH to qd IDet resulted in significant 12‐week reductions in HbA_1c (T1D: ?0.40%; T2D: ?0.56%; both p < 0.001). Switching from qd NPH to qd IDet, resulted in HbA_1c reductions of: T1D ?0.52%; T2D ?0.56%; both p < 0.001. Fasting blood glucose levels were also significantly reduced in patients with T1D or T2D. Overall mean weight changes were: T1D: 0.0 kg, T2D: ?0.2 kg after 12 weeks. Conclusion: In routine care, patients with T1D or T2D may be switched from NPH to IDet qd as part of a basal–bolus regimen.     

Brugada Pattern Caused by a Flecainide Overdose

Background

Brugada pattern can be found on the electrocardiogram (ECG) of patients with altered mental status, usually with fever or drug intoxication. Diagnosis remains challenging, because the ECG changes are dynamic and variable. In addition, triggers are not always clearly identified. In patients with atrial fibrillation (AF), the use of class IC antidysrhythmic drugs can unmask a Brugada pattern on the ECG, especially if combined with other medications acting on sodium channels.

Effects of Bepridil Versus E‐4031 on Transmural Ventricular Repolarization and Inducibility of Ventricular Tachyarrhythmias in the Dog

Background: Bepridil (a multiple channel blocker) may markedly prolong the QT interval and induce polymorphic ventricular tachyarrhythmias (VTA). We compared the transmural ventricular repolarization characteristics and inducibility of polymorphic VTA after administration of bepridil versus the pure I_Kr blocker, E‐4031, each administered to five open‐chest dogs. Methods: We used plunge needle electrode to record transmural left ventricular (LV) repolarization and activation‐recovery interval (ARI) to estimate local repolarization. The correlation between paced cycle length and ARI was separately examined in the LV endocardium, mid‐myocardium (Mid), and epicardium. Attempts to induce VTA were made during bradycardia and sympathetic stimulation. Results: Bepridil and E‐4031 prolonged QT interval and ARI in all LV layers, though the magnitude of prolongation was greatest in Mid, increasing the transmural ARI dispersion, particularly during bradycardia. Compared with E‐4031, bepridil caused mild, reverse use‐dependent changes in ventricular repolarization, and less ARI dispersion than E‐4031 during slow ventricular pacing. Both drugs increased ARI_max and cycle length at 50% of ARI_max, though the changes were smaller after bepridil than after E‐4031 administration. Bradycardia after the administration of each drug induced no VTA; however, sympathetic stimulation induced sustained polymorphic VTA in two of five dogs treated with E‐4031 versus no dog treated with bepridil. Conclusions: Unlike the pure I_kr blocker, E‐4031, bepridil exhibited weak properties of reverse use‐dependency and protected against sympathetic stimulation‐induced VTA. It may be an effective supplemental treatment for recipients of implantable cardioverter defibrillator. (PACE 2010; 950–959)