Arrhythmic Complications Research Articles

Surgical ablation for atrial fibrillation: an editorial.

AF is the most common cardiac arrhythmias in background of cardiovascular structural disease as well as postoperative arrhythmic complication. Based on the international guidelines of American College of Cardiology and European Society of Cardiology, this phenomenon can be distinguished as one of the three classes including paroxysmal AF that terminates within 7 days of appearance, persistent AF that prolongs more than 7 days and can be terminated by pharmacological and non-pharmacological interventions, and permanent AF that is persisted for a long time (1). The appearance of every type of AF is strongly associated with underlying cardiac abnormalities including acute coronary syndrome, heart failure, valvular heart diseases, as well as some predisposing risk factors such as hypertension, diabetes, and obesity (2). Moreover, inflammatory and metabolic processes, hemodynamic stresses, respiratory disorders, drug and alcohol use, and endocrine abnormalities have been identified to promote AF (3). Furthermore, familial tendency of AF has been also well identified that parental AF is a trigger to increase likelihood of AF. Regardless of underlying etiological aspects and pathophysiological basis, the appearance of AF is related to increased risk for mortality and morbidity particularly due to risk for thromboembolic events (4). Some studies have revealed that people with sinus rhythm survive longer than those with AF. In fact, disruption of normal atrial conductive system may cause blood stasis leading development of thrombus and thus embolic events especially in cerebrovascular system results in brain stroke (5). Additionally, AF can predispose affected individuals to worsening heart failure and lowering functional class in these patients particularly in those patients with persistent hypertension or valvular defects. The progression of AF-induced heart failure finally leads to tachycardia-mediated cardiomyopathy if inadequate controlling arrhythmia (6). In some large cohort surveys, one-third of patients with uncontrolled AF suffered brain stroke or other thromboembolic events. These induced cerebrovascular events may also result in dementia, cognitive decline, and disabilities in daily living activities (7).

Prognostic role of isolated left ventricular diverticuli detected by cardiovascular magnetic resonance

Isolated left ventricular diverticulum, a rare cardiac malformation, can be asymptomatic or associated with systemic embolization, ventricular arrhythmias, or sudden death. MRI allows for the detection of diverticuli and the distinction between fibrous and muscular types using the delayed enhancement technique. To evaluate the prevalence of left ventricular diverticuli in nonselected consecutive patients who had undergone MRI. In a total of 3273 consecutive patients who had undergone cardiac magnetic resonance from January 2001 to December 2005, isolated ventricular diverticuli were found in 25 patients (0.76%), with no apparent cardiac disease. A delayed enhancement technique was used to distinguish fibrous and muscular types. The prevalence of complications was evaluated with a follow-up of 52 ± 8 months. The site of the left ventricular diverticuli was the septum in 10 (37%) cases, inferior wall in 6 (22%) cases, lateral wall in 4 (15%) cases, and apical in 7 (26%) cases. In two cases, multiple diverticuli were found. In delayed enhancement images, a partial or total fibrous diverticulum was found in 6 (24%) patients. At follow-up, clinical complications were recorded in 6 (24%) patients; 2 (8%) patients had arrhythmic complications and 4 (12%) patients had embolic complications of presumed cardiac origin. In addition, two patients (8%) had nonsustained ventricular tachycardia diagnosed using 24-h ECG Holter monitoring. Fibrous type diverticuli were associated with a higher incidence of arrhythmic complications than the muscular type. The prevalence of isolated ventricular diverticuli detected by MRI is higher than that previously reported with other imaging techniques. Fibrous diverticuli are associated with a higher incidence of arrhythmic complications.

Arrhythmic complications of tyrosine kinase inhibitors.

Division of Cardiovascular Medicine, University of South Florida, Morsani College of Medicine, 2 Tampa General Circle, Tampa, FL 33606, USA Department of Malignant Hematology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA *Author for correspondence: mfradley@health.usf.edu

Cardio-oncology: a new discipline in medicine to lead us into truly integrative care.

Future Science Group, Unitec House, 2 Albert Place, London, N3 1QB, UK Vanderbilt University, 1215 21st Ave South, Suite 5209, Nashville, TN 37232, USA *Author for correspondence: Tel.: +1 615 9360335; daniel.lenihan@vanderbilt.edu This themed issue of Future Cardiology, guest edited by Daniel Lenihan and Steven Lipshultz, fully introduces the myriad of important clinical practice issues and emerging science that encompasses the newly identif ied discipline of cardiooncology, primarily from a cardiovascular perspective. Many existing and emerging cancer therapies have been linked with adverse cardiovascular events, and with an astonishing improvement in cancer survival rates over the past two decades the cardiovascular effects of cancer therapies are becoming increasingly relevant [1]. In the interview in this issue, Parashar discusses the emerging field of cardiooncology, highlighting both advances and challenges within the field. She focuses on the need for collaboration between cardiologists and oncologists to improve the cardiac health of cancer survivors [2]. Jahangir et al. explore the idea that as data on the relationships between lipids, statins and cancer continue to accumulate, the role of cardiovascular specialists may expand from prevention and treatment of cardiovascular disease to interventions aimed at reducing cancer incidence and mortality [3]. It is increasingly being recognized that cancer therapeutics have unintended cardio vascular toxicity [1]. Codon, Rodriguez and Lopez-Fernandez provide insight into cardiotoxicity focusing on the known mechanisms related to cardiac dysfunction and the techniques utilized in the cardiac evaluation of cancer patients [4]. More than 25 different chemotherapeutic agents that have been linked with cardiac adverse events and a number of articles within the issue focus on this topic. Storozynsky overviews the current and emerging strategies for assessment and treatment of chemotherapy-induced cardiotoxicity [5], while Piper reviews chemotherapy-related heart failure and chemotherapeutic agents [6], Fradley and Pinilla-Ibarz look at the arrhythmic complications of tyrosine kinase inhibitors [7] while Salvatorelli, Menna and Minotti focus on the management of anthracycline-induced cardiotoxicity [8]. Patients with cancer who are treated with radiation therapy clearly experience higher rates of “...with an astonishing improvement in cancer survival rates over the past two decades the cardiovascular effects of cancer therapies are becoming increasingly relevant.”

The importance of electrocardiographic findings in the diagnosis of atrial septal defect.

Atrial septal defect (ASD) is the most frequent heart defect observed in adulthood. Although it is usually non-symptomatic, it may result in heart failure, arrhythmic complications, and paradoxical embolism-related morbidity or mortality if the diagnosis is late. This study was planned in order to investigate the importance of electrocardiographic findings in the diagnosis of ASD. Sixty-one patients with a diagnosis of ASD and 66 healthy volunteers without cardiac disease were enrolled in the study. Electrocardiographs (ECG) were performed on all patients to investigate the presence of right bundle branch block (RBBB), incomplete RBBB, defective T wave (DTW), and notch finding in the R wave of inferior derivations (crochetage R wave). ASD types and diameters were determined via transthoracic and transoesophageal echocardiography. It was determined that incomplete RBBB (56% vs. 5%), DTW (48% vs. 3%), and R wave crochetage (57% vs. 8%) in inferior derivations were more frequent in ASD patients compared to the control group patients. The specificity of the defined ECG findings in the diagnosis of ASD were 95%, 97%, and 92%, respectively. No correlation was detected between the ASD diameter and incomplete RBBB, whereas significant correlation was observed between the ASD diameter and the presence of crochetage R wave (17.5 ± 4.0 mm in patients with crochetage R wave, and 20.9 ± 8.2 mm in patients without crochetage R wave, p = 0.057). Detection of RBBB, DTW, and crochetage R wave in superficial ECG may contribute to early detection in patients with ASD.

Genotype-dependent differences in age of manifestation and arrhythmia complications in short QT syndrome

BackgroundShort QT syndrome (SQTS) is a rare inheritable arrhythmia, associated with atrial and ventricular fibrillations, caused by mutations in six cardiac ion channel genes with high penetrance. However, genotype-specific clinical differences between SQTS patients remain to be elucidated. Methods and resultsWe screened five unrelated Japanese SQTS families, and identified three mutations in KCNH2 and KCNQ1. A novel mutation KCNH2-I560T, when expressed in COS-7 cells, showed a 2.5-fold increase in peak current density, and a positive shift (+14mV) of the inactivation curve compared with wild type. Computer simulations recapitulated the action potential shortening and created an arrhythmogenic substrate for ventricular fibrillation. In another family carrying the mutation KCNQ1-V141M, affected members showed earlier onset of manifestation and frequent complications of bradyarrhythmia. To determine genotype-specific phenotypes in SQT1 (KCNH2), SQT2 (KCNQ1), and other subtypes SQT3–6, we analyzed clinical variables in 65 mutation-positive patients among all the 132 SQTS cases previously reported. The age of manifestation was significantly later in SQT1 (SQT1: 35±19years, n=30; SQT2: 17±25years, n=8, SQT3–6: 19±15years, n=15; p=0.011). SQT2 exhibited a higher prevalence of bradyarrhythmia (SQT2: 6/8, 75%; non-SQT2: 5/57, 9%; p<0.001) and atrial fibrillation (SQT2: 5/8, 63%; non-SQT2: 12/57, 21%; p=0.012). Of 51 mutation-positive individuals from 16 SQTS families, nine did not manifest short QT, but exhibited other ECG abnormalities such as atrial fibrillation. The resulting penetrance, 82%, was lower than previously recognized. ConclusionWe propose that SQTS patients may exhibit different clinical manifestations depending upon their genotype.

Arrhythmias in takotsubo cardiomyopathy.

Acute emotional or physical stress can trigger a catecholamine-mediated myocardial stunning known as takotstubo cardiomyopathy (TCM). Although TCM is generally reversible, it can be associated with significant morbidity, including secondarily to cardiac arrhythmia. Lethal arrhythmias such as heart block, ventricular tachycardia, and ventricular fibrillation have been described. Repolarization abnormalities associated with TCM can lead to characteristic T-wave abnormalities and QT prolongation that place patients at increased risk for ventricular arrhythmia, including torsades de pointes. This article focuses on the arrhythmic complications associated with TCM and explores the underlying etiology of these arrhythmias.

Weighing the risks: Thrombotic and bleeding events in adults with atrial arrhythmias and congenital heart disease

IntroductionAtrial arrhythmias are associated to thromboembolism and anticoagulant treatment is installed according to risk profile. This study aimed to assess the rate of thrombotic events and major bleedings in adults with congenital heart disease (CHD) and atrial arrhythmias, as well as to determine the predictive value of specific clinical features and two risk scores for thromboembolism and bleeding. Methods and resultsIn this retrospective study, a total of 229 adult CHD patients with atrial arrhythmias, were included. Incidence and risk factors of thromboembolism were assessed in patients without a mechanical valve (n=191), whereas bleeding incidence and risk factors were studied in patients receiving vitamin K antagonists (n=164). In 13 patients without a mechanical valve thrombotic events occurred, the first thrombotic event rate per year being 1.4%. A total of 29 patients on vitamin K antagonists suffered from major bleedings, at an annual first event rate of 4.4%. CHA2DS2-VASc score and HAS-BLED score predicted thromboembolic and bleeding risk best in a dichotomized form. At a cut-off of ≥2 for high risk the rate of thrombotic events was 3.0% per year compared to 0.7% for a score of <2 (HR 3.7; 95%-CI 1.2–11.5; p=0.021). A major bleeding rate of 10.8% per year was found in patients on vitamin K antagonists for HAS-BLED≥2 as opposed to 3.5% with a score of <2 (HR 2.6; 95%-CI: 1.1–6.6; 0.017). ConclusionIn adult CHD patients, thrombotic events and major bleedings are important complications of atrial arrhythmias and anticoagulant treatment. Assessment of thromboembolic and bleeding risk in this patients group can be performed with dichotomized CHA2DS2-VASc and HAS-BLED scores respectively.

Cardiac magnetic resonance evidence of diffuse myocardial fibrosis in patients with mitral valve prolapse

Background Diffuse myocardial fibrosis can be assessed by cardiac magnetic resonance (CMR) using the myocardial longitudinal relaxation time constant (T1). Mitral valve prolapse (MVP) is a common valvulopathy with known arrhythmic complications and in-vitro evidence of overexpression of pro-fibrotic TGF-beta. Papillary muscle fibrosis has been described in MVP, but the potential association of MVP with diffuse myocardial fibrosis is unknown. This association is important as it may increase our future understanding of ventricular arrhythmias in MVP.

Pregnancy and Delivery in Women With Congenital Heart Disease

Because of the growing population of patients with congenital heart disease (CHD), most maternal cardiac disease is now congenital in origin. For women with complex CHD, pregnancy poses an increased risk for both the mother, with complications of arrhythmias and heart failure being the most common, and the baby, with a higher chance of miscarriage, intrauterine growth retardation, and the need for early delivery. Pre-pregnancy counseling must be performed by cardiologists who have expertise in both CHD and pregnancy, with a detailed clinical assessment of the patient and the current hemodynamic situation, including echocardiography and an exercise test. In each case the approach must be individualized with consideration of the risks in each case. In some cases, such as Eisenmenger syndrome, pregnancy is contraindicated. Optimum outcomes in these complex patients are achieved when a multidisciplinary approach is used, involving maternal-fetal medicine specialists, cardiologists with expertise in CHD and obstetric anesthesia.

Development of ST Elevation Myocardial Infarction and Atrial Fibrillation after an Electrical Injury.

Electrical energy is a type of energy that is commonly used in daily life. Ventricular premature beats, ventricular tachycardia, ventricular fibrillation, atrial tachycardia, atrial fibrillation, bundle branch blocks, and AV block are arrhythmic complications that are encountered in case of electric shocks. Myocardial infarction is one of the rarely seen complications of electric shocks yet it has fatal outcomes. Coronary arteries were detected to be normal in most of the patients who had myocardial infarction following an electric shock. So, etiology of myocardial infarction is thought to be unrelated to coronary atherosclerosis in these cases. Coronary artery vasospasm is thought to be the primary etiological cause. In our case report, we presented a patient who developed ST elevation MI with atrial fibrillation after an electric shock.

Fertility and pregnancy in the Fontan population

Abstract Background Women with a Fontan circulation are deemed at significantly increased risk of maternal morbidity and mortality during pregnancy. Publications describe a small number of pregnancies worldwide and a high rate of miscarriage. We compiled the experience of women enrolled in the Australia and New Zealand Fontan (ANZ) Registry with regard to menarche, contraceptive use, pregnancy advice and pregnancy outcomes. Methods Women within the ANZ Fontan Registry were contacted and asked to consent to receiving sequential questionnaires. Results 156 women ≥18years of age (including 4 deceased individuals) were identified, 101 women consented and 97 completed the initial questionnaire. Women were aged (median) 25years (23–32); menarche occurred at a median 14years (13–16). A wide variety of contraceptive methods was reported. 81% of women reported having received advice that pregnancy carried an increased risk or was inadvisable. Pregnancy was reported in a minority (n=27). Miscarriage (42.5%) and termination (7.5%) accounted for half the pregnancy outcomes and the babies were born early (median 31.5weeks) and small (median 1350g). Maternal complications of bleeding, arrhythmia and heart failure were reported with no early maternal mortality. Conclusions In women with a Fontan circulation the fertility onset is delayed and pregnancy has a higher rate of miscarriage. Successful pregnancy resulted in small and premature babies. Significant maternal morbidity occurred. Whether pregnancy with its volume loading has an adverse effect on the long-term outcome of women with a single ventricle remains to be elucidated.

Noncompaction Cardiomyopathy with Charcot-Marie-Tooth Disease.

We report a case of a 53-year-old female presenting with a new-onset heart failure that was contributed secondary to noncompaction cardiomyopathy. The diagnosis was made by echocardiogram and confirmed by cardiac MRI. Noncompaction cardiomyopathy (also known as ventricular hypertrabeculation) is a newly discovered disease. It is considered to be congenital (genetic) cardiomyopathy. It is usually associated with genetic disorders and that could explain the genetic pathogenesis of the non-compaction cardiomyopathy. Our case had a history of Charcot-Marie-Tooth disease. There is a high incidence of arrhythmia and embolic complications. The treatment usually consists of the medical management, defibrillator placement, and lifelong anticoagulation. Heart transplantation will be the last resort.

Electrical Injury-Induced Complete Atrioventricular Block: Is Permanent Pacemaker Required?

A considerable percentage of electrical injuries occur as a result of work activities. Electrical injury can lead to various cardiovascular disorders: acute myocardial necrosis, myocardial ischemia, heart failure, arrhythmias, hemorrhagic pericarditis, acute hypertension with peripheral vasospasm, and anomalous, nonspecific ECG alterations. Ventricular fibrillation is the most common arrhythmia resulting from electrical injury and is the leading cause of death in electrical (especially low voltage alternating current) injury cases. Asystole, premature ventricular contractions, ventricular tachycardia, conduction disorders (various degrees of heart blocks, bundle-brunch blocks), supraventricular tachycardia, and atrial fibrillation are the other arrhythmic complications of electrical injury. Complete atrioventricular block has rarely been reported and permanent pacemaker was required for the treatment in some of these cases. Herein, we present a case of reversible complete atrioventricular block due to low voltage electrical injury in a young electrical technician.

Mechanisms of new-onset atrial fibrillation complicating acute coronary syndrome.

Atrial fibrillation (AF) is one of the most common arrhythmia complications of acute coronary syndrome (ACS). The incidence of new-onset AF is 2.3-37 %, and it is an important predictor of a patient's morbidity, mortality, and prolonged hospitalization. Various risk factors for the development of new-onset AF after ACS have been identified, including: old age, higher Killip class, relevant history (e.g., hypertension), and enlarged left atrium. Insights into the pathophysiological mechanisms of new-onset AF have been provided by both experimental and clinical investigations and show that new-onset AF is multifactorial, involving atrial ischemia and atrial stretch, inflammation, autonomic nervous system activity, and hormone activation. An understanding of the mechanisms underlying new-onset AF complicating ACS can provide new insight of therapeutic importance.

Beverages Of Daily Life: Impact Of Caffeine On Atrial Fibrillation.

In recent years, clinical and observational studies reported that caffeine consumption was associated with cardiac arrhythmias, affected heart rate variability, and subsequently increased cardiovascular risk. The analysis of these paper shows that data are controversial and strongly depends on methodology. Moderate intake of caffeine seems to have protective effects on arrhythmias, on contrary high intake of caffeine seems to be associated with increased risk of atrial fibrillation. There is a deep difference when we analysed intake of caffeine from coffee compared to other sources. In very recent time an increase in caffeinated beverages, namely energy drinks, has been reported in young people and several arrhythmic complications has been observed. A review of literature is presented.

Early repolarization is associated with atrial and ventricular tachyarrhythmias in patients with acute ST elevation myocardial infarction undergoing primary percutaneous coronary intervention

BackgroundRecent studies found that early repolarization (ER) is significantly more common in survivors of aborted sudden cardiac death. We hypothesized that ER might be more common in patients with ST elevation myocardial infarction (STEMI) who have complications of atrial and ventricular arrhythmias. MethodsThis study included 266 patients with acute STEMI undergoing primary percutaneous coronary intervention. Twelve-lead electrocardiograms were analyzed for ER, defined as J-point elevation≥0.1mV and “notching” and “slurring” of the terminal part of the QRS complex in at least 2 lateral or inferior leads. Acute and late atrial and ventricular arrhythmic events were evaluated. ResultsThe ER pattern was observed in 76 patients (28.6%). Atrial arrhythmia [21/76 (27.6%) vs. 22/190 (11.6%), p=0.001] and ventricular arrhythmia [16/76 (21.1%) vs. 16/190 (8.4%), p=0.004] were more frequently complicated in patients with ER than those without during hospitalization. ER was a significant independent predictor of developing atrial (HR=2.682, 95% CI=1.355–5.310, p=0.005) and ventricular arrhythmia (HR=2.936, 95% CI=1.360–6.335, p=0.006). Three patients with ER and ventricular fibrillation expired during hospitalization [3.9% (3/76) vs. 0% (0/190), p=0.023]. However, the presence of ER did not affect the late recurrence of atrial and ventricular arrhythmia. ConclusionsThe ER pattern is commonly observed in patients with STEMI and associated with atrial and ventricular tachyarrhythmia during acute setting.

Human embryonic-stem-cell-derived cardiomyocytes regenerate non-human primate hearts.

Pluripotent stem cells provide a potential solution to current epidemic rates of heart failure 1 by providing human cardiomyocytes to support heart regeneration 2. Studies of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) in small animal models have shown favorable effects of this treatment 3–7. It remains unknown, however, whether clinical scale hESC-CMs transplantation is feasible, safe or can provide large-scale myocardial regeneration. Here we show that hESC-CMs can be produced at a clinical scale (>1 billion cells/batch) and cryopreserved with good viability. Using a non-human primate (NHP) model of myocardial ischemia-reperfusion, we show that that cryopreservation and intra-myocardial delivery of 1 billion hESC-CMs generates significant remuscularization of the infarcted heart. The hESC-CMs showed progressive but incomplete maturation over a three-month period. Grafts were perfused by host vasculature, and electromechanical junctions between graft and host myocytes were present within 2 weeks of engraftment. Importantly, grafts showed regular calcium transients that were synchronized to the host electrocardiogram, indicating electromechanical coupling. In contrast to small animal models 7, non-fatal ventricular arrhythmias were observed in hESC-CM engrafted primates. Thus, hESC-CMs can remuscularize substantial amounts of the infarcted monkey heart. Comparable remuscularization of a human heart should be possible, but potential arrhythmic complications need to be overcome.

0194: Flecainide and ajmaline challenge in Brugada syndrome patients under the age of 15 years

Brugada syndrome (BrS) is an inherited arrhythmia syndrome with increased risk of syncope and sudden death. The typical ECG pattern of ST-segment elevation in the right precordial leads can fluctuate. Sodium channel blockers, such as ajmaline or flecainide, are used to unmask the diagnostic ECG pattern of BrS in case of non-diagnostic basal ECG. There is no direct comparison of the electrocardiographic modification induced by these drugs in patients under the age of 15 years. The aim of this study is to relate our experience in our reference centre. Injections are performed by continuous infusion over a period of 10 minutes at 1mg/kg dose for ajmaline and 2 mg/kg for flecainide. Tests were performed in case of absence of type 1 aspect on the resting ECG and in absence of major conduction defects. The flecainide test (group F) was performed in 36 patients and ajmaline test (group A) in 11 patients. Mean age was 12±4 years in group F and 14±2 years in A (p=0.04). There was 14 girls in group F (39%) vs 4 in group A (36%), NS. All patients were in sinus rhythm in both groups. There was no difference between the two groups for heart rate 78±21 vs 72±15 bpm (p=0.35), PR 148±28 ms vs 138±22 ms (p=0.32), QRS 87±11 ms vs 91+/−10 ms (p=0.29) and QTc 412±40 vs 425±30 ms (p =0.31). During the test, HR increase in both groups 9±12 vs 6±7 bpm (p=0.52). There was no difference for PR 31±27 ms vs 32±22 ms (p=0.89). The QRS and QTc were slightly higher in F group (QRS 25±23 ms vs 13±12 ms, p=0.11 and QTc 32±40 vs 18±15 ms, p=0.25) even if the difference was not significant. The number of positive tests F 11/36 (31%) vs 3/11 (27%) were similar in both groups. During pharmacological test no arrhythmic complications has been observed. In patients under the age of 15 years and suspected of BrS, the results of Flecainide and Ajmaline challenge are similar for conduction parameters and positive results. The risk of ventricular arrhythmias appears very low.

Landiolol Hydrochloride for Prevention of Atrial Fibrillation after Cardiac Surgery: A Meta‐Analysis

Atrial fibrillation (AF) is the most common arrhythmic complication after cardiac surgery. Several studies have compared the efficacy of landiolol and placebo or other agents in preventing new-onset AF in patients after cardiac surgery. In this study, we conducted a meta-analysis to determine whether landiolol is effective in preventing new-onset AF after cardiac surgery. Five randomized controlled trials and two retrospective analyses were included in this study. The clinical outcomes of interest were the occurrence of AF after cardiac surgery and major complications. Meta-analysis was performed using RevMan 5.0.18 software, and pooled estimates of the effect were reported as risk ratios (RR) with 95% confidence intervals (CI). The results of this meta-analysis indicate that landiolol is significantly associated with a decreased risk of occurrence of AF after cardiac surgery (RR = 0.33; 95% CI: 0.23-0.48; P < 0.00001) and is not associated with an increased risk of major complications (RR = 0.79; 95% CI: 0.43-1.45; P = 0.45) compared with the control group. Landiolol administration in the perioperative period can reduce the occurrence of AF after cardiac surgery without increasing the risk of major complications. It can be used to prevent new-onset AF safely after cardiac surgery.