Dangerous Ventricular Arrhythmias Research Articles

Novel NKX2.5 variant associated with congenital heart disease and increased risk of malignant arrhythmia and sudden cardiac death.

The NKX2.5 gene is an important cardiac developmental transcription factor, and variants in this gene are most commonly associated with CHD. However, there is an increased need to recognise associations with conduction disease and potentially dangerous ventricular arrhythmias. There is an increased risk of arrhythmia and sudden cardiac death in patients with NKX2.5 variants, an association with relatively less attention in the literature. We created a family pedigree and reconstructed familial relationships involving numerous relatives with CHD, conduction disease, and ventricular non-compaction following the sudden death of one family member. Two informative but distantly related family members had genetic testing to determine the cause of arrhythmias via arrhythmia/cardiomyopathy gene testing, and we identified obligate genetic-positive relatives based on family relationships and Mendelian inheritance pattern. We identified a novel pathogenic variant in the NKX2.5 gene (c.437C > A; p. Ser146*), and segregation analysis allowed us to link family cardiac phenotypes including CHD, conduction disease, left ventricular non-compaction, and ventricular arrhythmias/sudden cardiac death. We report a novel NKX2.5 gene variant linking a spectrum of familial heart disease, and we also encourage recognition of the association between NKX2.5 gene and potentially dangerous ventricular arrhythmias, which will inform clinical risk stratification, screening, and management.

Fibroblast growth factor 21 is associated with widening QRS complex and prolonged corrected QT interval in patients with stable angina

BackgroundFibroblast growth factor 21 (FGF21) is produced by cardiac cells, may acts in an autocrine manner, and was suggested to has a cardioprotective role in atherosclerosis. Wide QRS complex and heart rate-corrected QT interval (QTc interval) prolongation are associated to dangerous ventricular arrhythmias and cardiovascular disease mortality. Yet, the role of FGF21 in cardiac arrhythmia has never been studied. The aim of the study was to investigate the relationship between plasma FGF21 and the QRS duration and QTc interval in patients with stable angina.MethodsThree hundred twenty-one consecutive stable angina patients were investigated. Plasma FGF21 was measured through ELISA, and each subject underwent 12-lead electrocardiography.ResultsFGF21 plasma levels were positively associated with the QRS duration (β = 0.190, P = 0.001) and QTc interval (β = 0.277, P < 0.0001). With increasing FGF21 tertiles, the patients had higher frequencies of wide QRS complex and prolonged QTc interval. After adjusting for patients’ anthropometric parameters, the corresponding odd ratios (ORs) for wide QRS complex of the medium and high of FGF21 versus the low of FGF21 were 1.39 (95% CI 0.51–3.90) and 4.41 (95% CI 1.84–11.59), respectively, and p for trend was 0.001. Furthermore, multiple logistic regression analysis also showed the corresponding odd ratios (ORs) for prolonged QTc interval of the medium and high of FGF21 versus the low of FGF21 were 1.02 (95% CI 0.53–1.78) and 1.93 (95% CI 1.04–3.60) respectively with the p for trend of 0.037. In addition, age- and sex-adjusted FGF21 levels were positively associated with fasting glucose, HbA1c, creatinine, and adiponectin, but negatively associated with albumin, and the estimated glomerular filtration rate.ConclusionsThis study indicates that plasma FGF21 is associated with wide QRS complex and prolonged corrected QT interval in stable angina patients, further study is required to investigate the role of plasma FGF21 for the underlying pathogenesis.

Relationship between heart rhythm turbulence and ventricular arrhythmia in patients with multivessel lesion of coronary arteries

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): MoH Research Grant "Development of methods for differentiated prevention and treatment of potentially dangerous heart rhythm disorders" Prediction of adverse outcomes in patients after myocardial infarction (MI) remains a serious and not completely resolved problem, which pushes researchers to search for new technologies. One of the relatively promising new non-invasive methods for predicting sudden coronary death in patients with coronary heart disease and ventricular arrhythmias (VA) may be an assessment of heart rate turbulence (HRT). Given its important prognostic role, primarily in patients after MI, the aim of this work was to study the relationship between HRT and cardiovascular remodeling in patients with VA with history of MI and multivessel nature of coronary lesions. Materials and research methods 123 patients with history of MI, aged 38 to 76 years (average age 61.0 ± 7.6 years), were included into the study. The multivessel nature of coronary lesions was established based on the results of diagnostic selective coronary angiography. All patients underwent Holter monitoring of the electrocardiogram (HMECG). HRT was determined using two indicators, in accordance with the guidelines: Turbulence Onset (To, %) and Turbulence Slope (Ts, ms/RRi). Results Potentially dangerous ventricular arrhythmias (PDVA) were noted in more than half of the examined patients (n = 67; 54.5%). In analyze of the structure of PDVA, II class of VA, as the highest class, was not observed in any of the examined patients, class III was detected in 35% of cases, IVA – in 37.5%, and IVB – in 27.5%. In assessing the frequency of VAs, according to the Bigger classification, frequent PVC &amp;gt;10 VA/hour was detected in 41.5% of patients. The analysis of the HRT indicators did not reveal a decrease in the mean values both To (-1.2 ± 1.5%) and Ts (3.9 ± 3.1 ms/RRi) indicators in the main group of patients. However, after appropriate separation of the main group, 21.1% of them had disorders of only one (category 1; 15.4%) or both of the HRT indicators (category 2; 5.7%). Category 0 included patients without any disorder of HRT indicators. In analysis of the relationship between the PDVA and the category of HRT reduction, a significant interrelation between them was revealed (Table 1). Result Our study demonstrates presence of strong interrelation between HRT parameters disorder and severity of PDVA. Thus, study of HRT in patients after MI could be a strong and independent predictor of cardiovascular events including sudden cardiac death. Abstract Figure. Tab. 1. Interrelation between HRT and VA

RECURRENT SYNCOPE AS A SYMPTOM OF ELECTRICAL STORM – CASE PRESENTATION

Dangerous ventricular arrhythmias leading to sudden cardiac death (SCD) are some of the most diffi-cult diagnostic challenges. They are often mildly symptomatic. Their often self-limiting nature means that they are difficult to capture on ECG. A 75-year old woman with chronic heart failure due to nonis-chemic cardiomyopathy reported to the cardiology clinic for a scheduled routine follow-up of the ICD, implanted three years prior as primary prevention of SCD. The patient reported recent episodes of sud-den weakness and described the episodes as hypotension. The patient associated it with too aggressive treatment of arterial hypertension. During the visit the patient experienced one of these episodes that she had previously described. The monitoring equipment in the clinic revealed ventricular tachycardia (VT). The history of the implanted ICD revealed many similar previous episodes including 5 episodes in the last 24 hours which led to a diagnosis of electrical storm. Dangerous ventricular arrhythmias may be mildly symptomatic and they are often underestimated by the patient. Fainting, especially in situa-tions unusual for the vasovagal reflex or orthostatic hypotension, should always arouse vigilance to-wards life-threatening ventricular arrhythmia.

Influence of Omega-3 PUFA on Non-invasive factors determining the risk of arrhYthmias eXcess and sudden cardiac death in patients with HFpEF with ischemic etiology (ONYX)

Aim Patients with heart failure with reduced left ventricular (LV) ejection fraction (HFrEF) who have had acute myocardial infarction have an unfavorable prognosis, largely due to ventricular arrhythmias (VA) and risk of sudden cardiac death (SCD). The optimal treatment (triple neurohormonal blockade plus implantable cardioverter defibrillator and cardiac resynchronization therapy) reduced the risk of SCD primarily due to reverse cardiac remodeling, but has not solved this problem completely. Efficacy of purified ω-3 polyunsaturated fatty acid esters (PUFA) in low doses (1 g/day) in reducing VA and risk of SCD in HFrEF patients was demonstrated in two large randomized clinical trials. The PUFA effects was suggested to be related also with increased heart rhythm variability (HRV) and chronotropic action, which might depend on the drug dose. The present open, prospective, randomized, comparative study in parallel groups evaluated the effect of Omacor in different doses on noninvasive markers of SCD risk in patients with ischemic HFrEF receiving the optimal drug therapy.Methods Patients (n=40) were randomized at a 1:1:2 ratio to the control group (n=10), the Omacor 1 g/day treatment group (n=10), and the Omacor 2 g/day treatment group (n=20) and were followed up for 12 months. Clinical evaluation included changes in the CHF functional class (FC) and Clinical Condition Scale (CCS) score; concentration of N-terminal pro-hormone brain natriuretic peptide (NT-proBNP); and peak oxygen consumption during exercise (peak VO2). The LV function was evaluated by LVEF. Holter ECG monitoring was used for evaluation of HRV (SDNN), average 24-h heart rate (HR), number of ventricular extrasystoles (VE) per hour and severity of VA, and presence of paired VE and VT runs.Results Improvement of CHF FC became significant only with the high-dose Omacor treatment (2 g/day). The CCS score showed a tendency towards decrease also with a lower dose (1 g/day) whereas the level of NT-proBNP significantly decreased with both Omacor doses. The increase in LV EF was significant only with the use of Omacor 2 g/day (+3 %, р=0.002). A negative chronotropic effect of ω-3 PUFA was observed. Average 24-h HR decreased by 8 bpm (р=0.05) and 11 bpm (р&lt;0.001) with Omacor 1 g/day and 2 g/day, respectively. Either dose of ω-3 PUFA significantly improved VO2, which directly correlated with LV EF and inversely correlated with HR. The decrease in number of VE was associated not only with improved HRV (SDNN) but also with the decrease in 24-h HR, and thus Omacor 2 g/day significantly decreased the number of VE (by 16 per hour) and dangerous VA (paired VE and VT runs ceased to be detected in 40 % of patients).Conclusion Since HR, HRV, and VA are closely interrelated, the effect of ω-3 PUFA specifically on these noninvasive markers apparently determines its ability to decrease the risk of SCD in patients with ischemic HFrEF. The antiarrhythmic effect of Omacor was greater with higher doses of this drug.

The role of 3D imaging in the follow-up of patients with repaired tetralogy of Fallot.

The patients with repaired Tetralogy of Fallot (rToF) are a growing population due to the improvement of surgical management in neonatal age. However, the significant pulmonary regurgitation, consequent to the repair, is the most frequent sequelae and leads to a progressive right ventricle dilation over time. The latter, in turn, is responsible for the possible dysfunction of right and/or left ventricle and an increased risk of dangerous ventricular arrhythmias. Therefore, right ventricle monitoring is necessary for rToF patients and a 3D method is required due to its three anatomical and functional subunits. Magnetic resonance imaging (MRI) has become the 3D modality of choice in the evaluation of both cardiac anatomy and ventricular volumes in rToF patients since it is able to evaluate both the pathophysiology and anatomy, it is free of radiation and, when strictly necessary, it uses a non-iodinated contrast agent. Cardiac CT should be considered in the evaluation of the sequelae in rToF only in selected cases, given that it implies a radiation dose and iodinated contrast, in addition to not evaluating the pathophysiology as MRI.

AKT and ERK1/2 activation via remote ischemic preconditioning prevents Kcne2-dependent sudden cardiac death.

Sudden cardiac death (SCD) is the leading global cause of mortality. SCD often arises from cardiac ischemia reperfusion (IR) injury, pathologic sequence variants within ion channel genes, or a combination of the two. Alternative approaches are needed to prevent or ameliorate ventricular arrhythmias linked to SCD. Here, we investigated the efficacy of remote ischemic preconditioning (RIPC) of the limb versus the liver in reducing ventricular arrhythmias in a mouse model of SCD. Mice lacking the Kcne2 gene, which encodes a potassium channel β subunit associated with acquired Long QT syndrome were exposed to IR injury via coronary ligation. This resulted in ventricular arrhythmias in all mice (15/15) and SCD in 5/15 mice during reperfusion. Strikingly, prior RIPC (limb or liver) greatly reduced the incidence and severity of all ventricular arrhythmias and completely prevented SCD. Biochemical and pharmacological analysis demonstrated that RIPC cardioprotection required ERK1/2 and/or AKT phosphorylation. A lack of alteration in GSK‐3β phosphorylation suggested against conventional reperfusion injury salvage kinase (RISK) signaling pathway protection. If replicated in human studies, limb RIPC could represent a noninvasive, nonpharmacological approach to limit dangerous ventricular arrhythmias associated with ischemia and/or channelopathy‐linked SCD.

Theoretical overview of clinical and pharmacological aspects of the use of etelcalcetide in diabetic patients undergoing hemodialysis.

Etelcalcetide is the first intravenous calcimimetic agent authorized for the treatment of secondary hyperparathyroidism (sHPT) in patients undergoing hemodialysis in Europe, the US, and Japan. The relationship between sHPT and diabetes resides on complex, bidirectional effects and largely unknown homeostatic mechanisms. Although 30% or more patients with end-stage renal disease are diabetics and about the same percentage of those patients suffer from sHPT associated with hemodialysis, no data on the specificities of the use of etelcalcetide in such patients are available yet. Regarding pharmacokinetic interactions, etelcalcetide may compete with oral hypoglycemics recommended for use in patients undergoing hemodialysis and insulins detemir and degludec, causing unexpected hypocalcemia or hypoglycemia. More importantly, hypocalcemia, a common side effect of etelcalcetide, may cause decompensation of preexisting cardiac insufficiency in diabetic patients or worsen dialysis-related hypotension and lead to hypotension-related cardiac events, such as myocardial ischemia. In diabetic patients, hypocalcemia may lead to dangerous ventricular arrhythmias, as both insulin-related hypoglycemia and hemodialysis prolong QT interval. Patients with diabetes, therefore, should be strictly monitored for hypocalcemia and associated effects. Due to an altered parathormone activity in this patient group, plasma calcium should be the preferred indicator of etelcalcetide effects. Until more clinical experience with etelcalcetide is available, the clinicians should be cautious when using this calcimimetic in patients with diabetes.

Fragmented QRS complex – an important prognostic risk factor?

Fragmentation of the QRS complex is caused by the presence of myocardial scarring and prolonged, non-homogenous conduction. These areas are the source of dangerous ventricular arrhythmias. The potential role of fragmented QRS as a non-invasive marker of increased risk of sudden cardiac death is under investigation. The present article summarises the current knowledge on this topic.

Ventricular arrhythmias associated with long QT interval as a predictor of sudden cardiac death in patients with coronary heart disease and type 2 diabetes mellitus

Aim. To determine the prognostic value of blood glucose level changes in patients with coronary heart disease and type 2 diabetes from the perspective of their impact on the duration of QT interval and type of cardiac arrhythmias.Methods. The study involved 101 patients of 50 years or older with a diagnosis of ischemic heart disease (stable angina, II-III functional class) and healthy volunteers. Synchronous monitoring of ECG and blood glucose measuring were performed in all surveyed patients.Results. The average duration of QT interval in patients with coronary heart disease and type 2 diabetes was significantly higher than in patients with coronary heart disease without diabetes and in the control group. Glycaemia less than 4 mmol/L and more than 12 mmol/L and high glycemic variability (mean amplitude of glycemic excursion more than 5 mmol/L) increase the risk of QT prolongation and dangerous ventricular arrhythmias. In patients with ischemic heart disease and type 2 diabetes premature ventricular contractions (PVCs) of high grade are detected more often compared to patients without diabetes mellitus and healthy individuals. In patients with coronary heart disease and type 2 diabetes with episodes of glycaemia below 4 mmol/L prevalence of PVCs of high grade is higher than that of patients with glycaemia 4,1 to 11,9 mmol/L.Conclusion. Patients with coronary heart disease and type 2 diabetes with blood glucose levels below 4 mmol/L and above 12 mmol/L and high glycemic variability have an increased risk of arrhythmogenic sudden cardiac death.

Proarrhythmic Effects Of Antiarrhythmic Drugs: Case Study Of Flecainide Induced Ventricular Arrhythmias During Treatment Of Atrial Fibrillation.

Flecainide is a class 1C antiarrhythmic drug especially used for the management of supraventricular arrhythmia. Flecainide also has a recognized proarrhythmic effect in patients treated for ventricular tachycardia. It is used to treat a variety of cardiac arrhythmias including paroxysmal atrial fibrillation, paroxysmal supraventricular tachycardia and ventricular tachycardia. Flecainide has local anesthetic effects and belongs to the class 1C AADs that block sodium channels, thereby slowing conduction through the heart. It selectively increases anterograde and retrograde accessory pathway refractoriness. The action of flecainide in the heart prolongs the PR interval and widens the QRS complex. The proarrhythmic effects however noted are not widely reported. We report a case of paroxysmal atrial fibrillation with structurally normal heart who was treated with oral Flecainide. There were no adverse events and no QTc prolongation was noted on ECG. Despite subjective improvement a repeat Holter detected him to have multiple short non sustained ventricular arrhythmias. Development of ventricular arrhythmias, salvos and non-sustained ventricular tachycardia after a month of initiation of oral flecainide detected by 24 hours ECG Holter lead to discontinuation of flecainide and subsequent early electrophysiological studies and successful ablation. Initiation of oral Flecainide in a case of atrial fibrillation with subjective improvement and regular ECG monitoring, no QTc prolongation can still lead to development of dangerous ventricular arrhythmias. A cautious approach and thorough investigations and follow up are recommended.

Ventricular ectopic beats in structurally normal heart: When to stop investigations

Background and objective: Ventricular ectopic beats (extra systoles, premature beats) are frequently found in healthy people. Ectopic beats in patients without apparent heart disease are more prominent at rest and disappear with exercise. Treatment is not necessary unless the patient is highly symptomatic. Methods: Patients having ventricular ectopic beats were assessed clinically, by ECG and by echocardiography. Those with normal structure hearts underwent exercise ECG and among those we selected 50 patients whose ectopics were suppressed by exercise then followed them for 5 years. The study started from 2000 to 2010. Results: During 5-year follow-up of the above mentioned patients, relevant complications such as dangerous ventricular arrhythmias, ischemic heart diseases or heart failure were not recorded. Conclusion: In patients having ventricular ectopic beats and structurally normal heart, the suppressibilty of the ectopic by exercise indicated their benign origin and may preclude further invasive investigations and even specific treatment.

Pheochromocytoma, a diagnostic challenge

Objective: To study frequency and peculiarities of cardiovascular disorders in hypertensive pheochromocytoma (pheo) patients (pts). Design and methods: 250 hypertensive pheo pts (112 males and 138 females, mean age 41.7 11.8 y) were retrospectively studied. Tumors were located in adrenals in 232 (right 120, left 92, both 20) and were extraadrenal in 18 pts. 38 pts had recurrent pheo. All pts were operated and pheo was verified as benign (n1⁄4108), malignant (n1⁄4139) and borderline (n1⁄43) by histology. Tumor’s weight varied from 15 to 900 g and size from 1.5 to 12 cm. Results: In 41 of 250 pts (16.4%) hypertension was malignant (M), in 141 pts including 3M (56.4%, 2.1 %M) paroxysmal, in 70 pts including 31M (28.0%, 44.3 %M) sustain with crises, in 39 pts including 7M (15.6%, 17.9 %M) sustain without crises. Pulmonary edema was diagnosed in 8 of 250 pts (3.2%). Renal arteriography (n1⁄440) revealed renal artery stenosis (RAS) in 3 cases (7.5%), in 2 of them RAS was reversible. According to ECHOCG (n1⁄440) cardiac valve prolapse was registered in 19 pts (47.%), left ventricular hypertrophy 16 pts (40.0%). Myocardial infarction (MI) like changes were seen in 12 of 250 pts (4.8%), and postinfarction cardiosclerosis in 2 pts with recurrent pheo (0.8%). ECG 12 was normal in 20 pts (8%); different arrhythmias, conduction disorders were registered in 66 pts (26.4%). Holter ECG-monitoring (n1⁄440) revealed different arrhythmias in 19 pts (47.5%), dangerous ventricular arrhythmias (VA) in 7 pts (17.5%) and life-threatening VA in 2 pts (5%). Transient stroke was diagnosed in 14 (5.6%), both severe stroke and retinal detachment in 4 (1.6% each) of 250 pts. Conclusions: MI-like changes and reversible RAS were most likely caused by coronary or renal artery spasm, and were resolved after therapy with alpha-blockers and pheo removal. MI related to coronary atherosclerosis was observed in patients with recurrent pheo. Stroke, pulmonary edema and retinal detachment were related to high BP during hypertensive crises. Various arrhythmias were registered with Holter ECG-monitoring in 47.5% pheo pts, but dangerous and life-threatening ventricular arrhythmias in 17.5% and 5% respectively. Cardiac valve prolapse was revealed in nearly half of the pheo pts, most frequently mitral valve prolapse was seen. Most complications of high BP took place in pheo pts with malignant hypertension. In most cases (44.3%) malignant hypertension was observed in patients with sustain hypertension with crises.

Cardiovascular disorders in hypertensive pheochromocytoma patients

Objective: To study frequency and peculiarities of cardiovascular disorders in hypertensive pheochromocytoma (pheo) patients (pts). Design and methods: 250 hypertensive pheo pts (112 males and 138 females, mean age 41.7 11.8 y) were retrospectively studied. Tumors were located in adrenals in 232 (right 120, left 92, both 20) and were extraadrenal in 18 pts. 38 pts had recurrent pheo. All pts were operated and pheo was verified as benign (n1⁄4108), malignant (n1⁄4139) and borderline (n1⁄43) by histology. Tumor’s weight varied from 15 to 900 g and size from 1.5 to 12 cm. Results: In 41 of 250 pts (16.4%) hypertension was malignant (M), in 141 pts including 3M (56.4%, 2.1 %M) paroxysmal, in 70 pts including 31M (28.0%, 44.3 %M) sustain with crises, in 39 pts including 7M (15.6%, 17.9 %M) sustain without crises. Pulmonary edema was diagnosed in 8 of 250 pts (3.2%). Renal arteriography (n1⁄440) revealed renal artery stenosis (RAS) in 3 cases (7.5%), in 2 of them RAS was reversible. According to ECHOCG (n1⁄440) cardiac valve prolapse was registered in 19 pts (47.%), left ventricular hypertrophy 16 pts (40.0%). Myocardial infarction (MI) like changes were seen in 12 of 250 pts (4.8%), and postinfarction cardiosclerosis in 2 pts with recurrent pheo (0.8%). ECG 12 was normal in 20 pts (8%); different arrhythmias, conduction disorders were registered in 66 pts (26.4%). Holter ECG-monitoring (n1⁄440) revealed different arrhythmias in 19 pts (47.5%), dangerous ventricular arrhythmias (VA) in 7 pts (17.5%) and life-threatening VA in 2 pts (5%). Transient stroke was diagnosed in 14 (5.6%), both severe stroke and retinal detachment in 4 (1.6% each) of 250 pts. Conclusions: MI-like changes and reversible RAS were most likely caused by coronary or renal artery spasm, and were resolved after therapy with alpha-blockers and pheo removal. MI related to coronary atherosclerosis was observed in patients with recurrent pheo. Stroke, pulmonary edema and retinal detachment were related to high BP during hypertensive crises. Various arrhythmias were registered with Holter ECG-monitoring in 47.5% pheo pts, but dangerous and life-threatening ventricular arrhythmias in 17.5% and 5% respectively. Cardiac valve prolapse was revealed in nearly half of the pheo pts, most frequently mitral valve prolapse was seen. Most complications of high BP took place in pheo pts with malignant hypertension. In most cases (44.3%) malignant hypertension was observed in patients with sustain hypertension with crises.

Ventricular arrhythmias in patients of atrial fibrillation treated with flecainide: A case report

Purpose: Flecainide is a class 1C antiarrhythmic drug, especially used for the management of supraventricular arrhythmia. Flecainide also has a recognized proarrhythmic effect in all age groups of adult patients treated for ventricular tachycardia. It is used to treat a variety of cardiac arrhythmias including paroxysmal fibrillation, Paroxysmal Supraventricular tachycardia and ventricular tachycardia. Flecainide works by regulating the flow of sodium in the heart, causing prolongation of the cardiac action potential. The proarrhythmic effects however noted are not widely reported. Case report: We report a case of paroxysmal atrial fibrillation with structurally normal heart who was treated with oral Flecainide. Despite subjective improvement and no adverse events [QTc prolongation] a repeat holter detected him to have multiple short non sustained ventricular arrhythmias. Results: Development of ventricular arrhythmias, salvos &non sustained ventricular tachycardia after a month of initiation of oral Flecainide detected by 24 hours ECG holter lead to discontinuation of Flecainide and subsequent early electro physiological studies and successful ablation. Conclusion: Initiation of oral Flecainide in a case of atrial fibrillation with subjective improvement and regular ECG monitoring, no QTc prolongation can still lead to development of dangerous ventricular arrhythmias. A cautious approach and thorough investigations and follow up are recommended.

Flecainide Induced Ventricular Arrhythmias in Atrial Fibrillation

Purpose: Flecainide is a class 1C antiarrhythmic drug especially used for the management of supraventricular arrhythmia. Flecainide also has a recognized proarrhythmic effect in patients treated for ventricular tachycardia. It is used to treat a variety of cardiac arrhythmias including paroxysmal fibrillation, Paroxysmal Supraventricular tachycardia and ventricular tachycardia. Flecainide works by regulating the flow of sodium in the heart, causing prolongation of the cardiac action potential. The proarrhythmic effects however noted are not widely reported. Method: We report a case of paroxysmal atrial fibrillation with structurally normal heart who was treated with oral Flecainide. Despite subjective improvement and no adverse events [QTc prolongation] a repeat holter detected him to have multiple short non sustained ventricular arrhythmias. Results: Development of ventricular arrhythmias, salvos & non sustained ventricular tachycardia after a month of initiation of oral Flecainide detected by 24 hours ECG holter lead to discontinuation of Flecainide and subsequent early electro physiological studies and successful ablation. Conclusion: Initiation of oral Flecainide in a case of atrial fibrillation with subjective improvement and regular ECG monitoring, no QTc prolongation can still lead to development of dangerous ventricular arrhythmias. A cautious approach and thorough investigations and follow up are recommended.

Determination of Adequate Defibrillation of Ventricular Tachycardia Using Computer Simulation of Electroporation Aftershock Effects on Human Cardiomyocytes

Electric defibrillation is a life-saving therapy for clinically dangerous ventricular arrhythmias. Unfortunately, direct-current (DC) shock treatment often induces or worsens other tachyarrhythmias. The adverse effects of electric shock delivered to human ventricular cardiomyocytes are not fully understood. This study thus uses computer simulation to investigate the pathogenesis of the electrophoresis in epicardial and endocardial human tissue. The O'Hara-Rudy dynamic human ventricular cell model incorporated with Ohuchi's mathematical DC shock model is used. The effect of electroporation is described as a transmembrane pore, mimicking the reversible breakdown of the cell membrane. The aftershock effects on epiardial and endocardial ventricular cardiomyocytes are evaluated. The effects of delivering shock from the endocardium and epicardium using a multicellular one-dimensional strand model are also investigated. Ventricular tachycardia can be terminated by a low-strength shock to endocardial cardiomyocytes. However, an excessively strong shock to epicardial cardiomyocytes induces early afterdepolarization and is arrhythmogenic. The aftershock effect of the electroporation is serious for epicardial ventricular myocytes. The optimization of defibrillation energy delivery to the maximum membrane potential and the pathogenesis of the aftershock effect during ventricular tachycardia are also investigated. The aftershock effect of electroporation is more serious in epicardial cells than it is in endocardial cells. It is suggested that the DC shock be delivered to endocardium cells before the maximum membrane potential of the epicardial cell in a multicellular one-dimensional strand model is reached, which is before the electrocardiogram R wave spike.

PREVALENCE AND RELATED FACTORS OF ARRHYTHMIAS IN PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY

ObjectivesWe aim to explore the incidence and risk factors of AF, dangerous ventricular arrhythmias and bradyarrhythmia in patients with HCM, and improve the awareness of clinicians on hypertrophic cardiomyopathy (HCM)...

Arteriogenesis ? Therapeutic Stimulation of the Coronary Collateral Circulation

The coronary arteries have been regarded as end-arteries for a long time. Functionally, they are end-arteries in most cases indeed. However, there are interconnecting collateral channels between the large epicardial arteries which are sufficient to prevent myocardial ischemia during an acute vessel occlusion in about 1/4 to 1/3 of patients [1]. There are even very impressive rare examples of patients with left main artery occlusions who never had a myocardial infarction and who have very mild symptoms [2]. Despite such anecdotes which clearly illustrate the importance of the collateral circulation in human in some extreme situations, the overall relevance of collaterals is still not very clear. Even a very recent large study failed to show a clear clinical benefit of collaterals [3]. However, this study had some limitations and pooling the results of all currently available data on this topic clearly shows an association between the degree of collateralization and survival [4]. This meta-analysis included a total of 12 studies enrolling 6529 patients. Patients with a well developed collateral network had a 36% reduced mortality risk. One potential mechanism is the protective effect of the collateral circulation on the repolarization during an acute occlusion of a main coronary artery which usually puts the patient at risk for dangerous ventricular arrhythmias [5].

Wolff-Parkinson-White Syndrome Presenting After a Motorcycle Accident

Wolff-Parkinson-White (WPW) syndrome is uncommon in emergency services, but clinicians come across patients with pre-excitation syndrome. WPW is characterized by the presence of an accessory pathway that predisposes patients to tachyarrhythmias and sudden death. Patients with WPW syndrome are potentially at an increased risk of dangerous ventricular arrhythmias. Most of the patients are young and do not have underlying structural heart disease. Management of asymptomatic patients with WPW syndrome has always remained controversial. Here, we present a rare case of a 29-year-old man with WPW syndrome after a motorcycle accident. doi:10.4021/jmc331w