Explore the vast range of titles available.

Key Points Various cardiovascular and noncardiovascular drugs can induce proarrhythmic adverse effects Pharmacokinetic risk factors and genetic predisposition can enhance proarrhythmia Antiarrhythmic, antimicrobial, antipsychotic, and antidepressant drugs are important drug classes with an associated risk of proarrhythmia Monitoring the QT interval might not be sufficient to assess the risk of proarrhythmia Spatial and temporal dispersion of repolarization, action-potential configuration, and occurrence of early afterdepolarizations are additional predictors of proarrhythmia Various cardiovascular and noncardiovascular drugs, including so-called antiarrhythmic drugs, can induce cardiac arrhythmias. In this Review, Frommeyer and Eckardt summarize important proarrhythmic risk factors (such as age, female sex, and structural heart disease) and the underlying electrophysiological mechanisms (such as spatial or temporal dispersion of repolarization, alterations in action-potential morphology, and development of early afterdepolarizations). Drug-induced ventricular tachyarrhythmias can be caused by cardiovascular drugs, noncardiovascular drugs, and even nonprescription agents. They can result in arrhythmic emergencies and sudden cardiac death. If a new arrhythmia or aggravation of an existing arrhythmia develops during therapy with a drug at a concentration usually considered not to be toxic, the situation can be defined as proarrhythmia. Various cardiovascular and noncardiovascular drugs can increase the occurrence of polymorphic ventricular tachycardia of the 'torsade de pointes' type. Antiarrhythmic drugs, antimicrobial agents, and antipsychotic and antidepressant drugs are the most important groups. Age, female sex, and structural heart disease are important risk factors for the occurrence of torsade de pointes. Genetic predisposition and individual pharmacodynamic and pharmacokinetic sensitivity also have important roles in the generation of arrhythmias. An increase in spatial or temporal dispersion of repolarization and a triangular action-potential configuration have been identified as crucial predictors of proarrhythmia in experimental models. These studies emphasized that sole consideration of the QT interval is not sufficient to assess the proarrhythmic risk. In this Review, we focus on important triggers of proarrhythmia and the underlying electrophysiological mechanisms that can enhance or prevent the development of torsade de pointes.

Patients with an implantable cardioverter-defibrillator (ICD) often report psychological distress. Literature suggests that patients with physical disease often compare their well-being and coping to fellow patients. However, we lack knowledge on social comparison among patients with ICD. In this study, we examined psychological distress and social comparison selection in patients with (ICD+) and without experienced ICD shocks (ICD−). We theorized that relative to ICD− patients, those with ICD+ display higher levels of psychological distress and thereby compare more frequently with fellow patients with more severe disease, but better disease coping and try to identify more strongly with these standards to improve their own coping. We recruited 92 patients with (ICD+, n = 38) and without an experienced ICD shock (ICD−, n = 54), who selected one of four comparison standards varying in disease severity and coping capacity. Relative to ICD−, ICD+ patients reported higher levels of device-related distress, but there were no significant differences in anxiety, depression, or quality of life. ICD+ patients selected more often comparison standards with poor coping and, irrespective of standard choice, displayed more negative mood following comparison. Our results show that ICD+ patients tend to perform unfavorable comparisons to fellow patients, which might explain higher psychological distress and worse coping. These findings warrant further research into social comparison as a relevant coping mechanism in ICD patients.

While most sudden cardiac deaths are due to structural heart disease or cardiac ischemia, intoxications are rather rare and often unrecognized. Here we present a case of a 35-year-old patient who trickled cumulative 60 mg of the pure nicotine liquid. This led to cardiac arrest and ventricular fibrillation. After defibrillation the ECG showed pronounced early repolarization pattern with an AV block I°.

In patients with ventricular tachycardia (VT) and a history of myocardial infarction, intervention with an implantable cardioverter defibrillator (ICD) can prevent sudden cardiac death and thereby reduce total mortality. However, ICD shocks are painful and do not provide complete protection against sudden cardiac death. We assessed the potential benefit of catheter ablation before implantation of a cardioverter defibrillator. The Ventricular Tachycardia Ablation in Coronary Heart Disease (VTACH) study was a prospective, open, randomised controlled trial, undertaken in 16 centres in four European countries. Patients aged 18–80 years were eligible for enrolment if they had stable VT, previous myocardial infarction, and reduced left-ventricular ejection fraction (LVEF; ≤50%). 110 patients were randomly allocated in a 1:1 ratio to receive catheter ablation and an ICD (ablation group, n=54) or ICD alone (control group, n=56). Randomisation was done by computer-generated randomly permuted blocks and stratified by centre and LVEF (≤30% or >30%). Patients were followed up for at least 1 year. The primary endpoint was the time to first recurrence of VT or ventricular fibrillation (VF). Analysis was by intention to treat (ITT). This study is registered with ClinicalTrials.gov, number NCT00919373. 107 patients were included in the ITT population (ablation group, n=52; control group, n=55). Two patients (one in each group) withdrew consent immediately after randomisation without any follow-up data and one patient (ablation group) was excluded because of a protocol violaton. Mean follow-up was 22·5 months (SD 9·0). Time to recurrence of VT or VF was longer in the ablation group (median 18·6 months [lower quartile 2·4, upper quartile not determinable]) than in the control group (5·9 months [IQR 0·8–26·7]). At 2 years, estimates for survival free from VT or VF were 47% in the ablation group and 29% in the control group (hazard ratio 0·61; 95% CI 0·37–0·99; p=0·045). Complications related to the ablation procedure occurred in two patients; no deaths occurred within 30 days after ablation. 15 device-related complications requiring surgical intervention occurred in 13 patients (ablation group, four; control group, nine). Nine patients died during the study (ablation group, five; control group, four). Prophylactic VT ablation before defibrillator implantation seemed to prolong time to recurrence of VT in patients with stable VT, previous myocardial infarction, and reduced LVEF. Prophylactic catheter ablation should therefore be considered before implantation of a cardioverter defibrillator in such patients. St Jude Medical.

Lidocaine is classified as a class Ib anti‐arrhythmic that blocks voltage‐ and pH‐dependent sodium channels. It exhibits well investigated anti‐arrhythmic effects and has been the anti‐arrhythmic of choice for the treatment of ventricular arrhythmias for several decades. Lidocaine binds primarily to inactivated sodium channels, decreases the action potential duration, and increases the refractory period. It increases the ventricular fibrillatory threshold and can interrupt life‐threatening tachycardias caused by re‐entrant mechanisms, especially in ischemic tissue. Its use was pushed into the background in the era of amiodarone and modern electric device therapy. Recently, lidocaine has come back into focus for the treatment of acute sustained ventricular tachyarrhythmias. In this brief overview, we review the clinical pharmacology including possible side effects, the historical course, possible indications, and current Guideline recommendations for the use of lidocaine.

Guidelines recommend transesophageal echocardiography (TEE) before cardioversion in thrombogenic arrhythmias when the requirement of ≥ 3 weeks of anticoagulation is not met. Current data to support this approach, especially with direct oral anticoagulants (DOAC), are scarce. We analyzed consecutive elective pre-cardioversion TEE in a high-volume electrophysiology center for the occurrence of left atrial appendage (LAA) thrombi or reduced LAA flow velocity. Possible predictors were recorded and compared in a multivariate logistic regression analysis. Consecutive pre-cardioversion TEE in 512 patients (148 female, median age 69 years) were included. In all patients, indication for TEE was either intake of anticoagulation < 3 weeks before cardioversion or uncertain adherence to the prescribed anticoagulation regimen. Of the 512 TEE, 19 (3.7%) depicted a LAA thrombus. An additional 41 patients (8.0%) showed either a reduced LAA flow velocity (≤ 20 cm/s), LAA sludge, or both. In a multivariate logistic regression analysis, QRS width on admission 12-lead ECG emerged as a possible predictor of LAA thrombus and reduced LAA flow (p = 0.008). Noteworthy, a high CHA 2 DS 2 -VASc score was not associated with an increased risk of reduced LAA emptying velocity and LAA thrombi were even found in patients with a CHA 2 DS 2 -VASc score of 0 (n = 1) and 1 (n = 1). The presence of LAA thrombus before an elective cardioversion is a rare event in the age of direct oral anticoagulants. However, LAA thrombi occurred even in supposed low-risk individuals according to the CHA 2 DS 2 -VASc score. QRS width may aid in identifying patients at risk of reduced LAA flow velocity.

Resting heart rate (RHR) has prognostic implications in heart failure with reduced ejection fraction, where ≤ 70 bpm is targeted. Whether a RHR > 70 bpm assessed within clinical practice goes along with elevated cardiovascular risk in implantable cardioverter-defibrillator (ICD) / cardiac resynchronization therapy-defibrillator (CRT-D) recipients remains incompletely understood. A total of 1589 patients (ICD n  = 1172 / CRT-D n  = 417, median age 65 years, 22.6% female) undergoing ICD/CRT-D implantation or revision in the prospective German DEVICE multicenter registry were analyzed. RHR was assessed via a 12-channel electrocardiogram at enrollment. 1-year outcomes (all-cause mortality, major cardio- and cerebrovascular events (MACCE), all-cause hospital admission) were compared between patients with a RHR ≤ 70 bpm and > 70 bpm. 733 patients (46.1%) showed a RHR > 70 bpm. Median RHR was 63 (interquartile range 59; 68) bpm (≤ 70 bpm group) and 80 (75; 89) bpm (> 70 bpm group). Heart failure with reduced ejection fraction was present in 76.3%, a prior myocardial infarction in 32.4% and non-ischemic heart disease in 44.9%. One-year all-cause mortality was similar between RHR groups (≤ 70 bpm 5.4% vs. > 70 bpm 5.4%, p  = 0.96), and subgroup analysis regarding patient characteristics and comorbidities revealed only a significantly higher rate of patients with dual chamber ICD in the > 70 bpm group (0.8% vs. 9.2%, p  = 0.003). MACCE (5.9% vs. 6.1%, p  = 0.87) and defibrillator shock rates (9.9% vs. 9.8%, p  = 1.0) were similar. Higher all-cause hospital admission rates were observed in patients with > 70 bpm RHR (23.1% vs. 29.0%, p  = 0.027) driven by non-cardiovascular events (6.0% vs. 11.7%, p  = 0.001). In conclusion, in ICD and CRT-D recipients a RHR at admission > 70 bpm may indicate patients at increased risk of all-cause hospital admission but not of other adverse cardiovascular events or death at 1-year follow-up.

Previous studies suggest an impact of dexmedetomidine on cardiac electrophysiology. However, experimental data is sparse. Therefore, purpose of this study was to investigate the influence of dexmedetomidine on different experimental models of proarrhythmia. 50 rabbit hearts were explanted and retrogradely perfused. The first group (n = 12) was treated with dexmedetomidine in ascending concentrations (3, 5 and 10 µM). Dexmedetomidine did not substantially alter action potential duration (APD) but reduced spatial dispersion of repolarization (SDR) and rendered the action potentials rectangular, resulting in no proarrhythmia. In further 12 hearts, erythromycin (300 µM) was administered to simulate long-QT-syndrome-2 (LQT2). Additional treatment with dexmedetomidine reduced SDR, thereby suppressing torsade de pointes. In the third group (n = 14), 0.5 µM veratridine was added to reduce the repolarization reserve. Further administration of dexmedetomidine did not influence APD, SDR or the occurrence of arrhythmias. In the last group (n = 12), a combination of acetylcholine (1 µM) and isoproterenol (1 µM) was used to facilitate atrial fibrillation. Additional treatment with dexmedetomidine prolonged the atrial APD but did not reduce AF episodes. In this study, dexmedetomidine did not significantly alter cardiac repolarization duration and was not proarrhythmic in different models of ventricular and atrial arrhythmias. Of note, dexmedetomidine might be antiarrhythmic in acquired LQT2 by reducing SDR.

Background: The two antiepileptic drugs lacosamide and lamotrigine exert their antiepileptic effect by inhibiting sodium channels. Lacosamide enhances the inactivation of sodium channels, while lamotrigine inhibits the activation of the channel. Interactions with sodium channels also play an interesting role in cardiac pro- and antiarrhythmia, with inhibition of inactivation, in particular, being regarded as potentially proarrhythmic. Therefore, the ventricular electrophysiologic effects of lacosamide and lamotrigine were investigated in an established experimental whole-heart model. Methods: A total of 67 rabbit hearts were allocated to four groups. Retrograde aortic perfusion was performed using the Langendorff setup. The action potential duration at 90% repolarization (APD90), QT intervals, spatial dispersion of repolarization, effective refractory period, post-repolarization refractoriness, and VT incidence were determined. The electrophysiological effects of lacosamide and lamotrigine were investigated in increasing concentrations on the natively perfused heart. On the other hand, perfusion with the IKr-blocker sotalol was performed to increase arrhythmia susceptibility, followed by perfusion with lacosamide or lamotrigine to investigate the effects of both in a setting of increased arrhythmia susceptibility. Perfusion with lacosamide and lamotrigine tended to decrease APD90 and QT-interval. As expected, perfusion with sotalol led to a significant increase in APD90, QT interval, and arrhythmia incidence. Additive perfusion with lacosamide led to a further increase in arrhythmia incidence, while additive perfusion with lamotrigine led to a decrease in VT incidence. Conclusions: In this model, lacosamide showed proarrhythmic effects, especially in the setting of an additive prolonged QT interval. Lamotrigine showed no significant proarrhythmia under baseline conditions and rather antiarrhythmic effects with additive QT prolongation.

Background: Previous studies suggest a direct effect of sacubitril on cardiac electrophysiology and indicate potential arrhythmic interactions between sacubitril and antiarrhythmic drugs. Therefore, the aim of this study was to explore the electrophysiologic effects of combining sacubitril with the antiarrhythmic drugs d,l-sotalol and mexiletine in isolated hearts. Methods and results: A total of 25 rabbit hearts were perfused using a Langendorff setup. Following baseline data collection, hearts were treated with mexiletine (25 µM, 13 hearts) or d,l-sotalol (100 µM, 12 hearts). Monophasic action potential demonstrated an abbreviation of action potential duration (APD90) after administration of mexiletine. Spatial dispersion of repolarization remained unchanged after mexiletine treatment, whereas effective refractory periods (ERP) were significantly prolonged. D,l-sotalol prolonged cardiac repolarization and amplified spatial dispersion. Further infusion of sacubitril (5 µM) led to a significant reduction in APD90 and ERP in the mexiletine group. In the d,l-sotalol group, additional administration of sacubitril shortened cardiac repolarization duration without affecting spatial dispersion. No proarrhythmic effect was observed after mexiletine treatment as assessed by a predefined pacing protocol. Additional sacubitril treatment did not increase ventricular vulnerability. When potassium concentration was reduced, 30 episodes of torsade de pointes tachycardia occurred after d,l-sotalol treatment. Additional sacubitril treatment significantly suppressed torsade de pointes tachycardia (eight episodes) in the d,l-sotalol-group. Conclusions: In class IB- and class III-pretreated hearts, sacubitril shortened refractory periods and cardiac repolarization duration. The combination of sacubitril with the antiarrhythmic drugs d,l-sotalol and mexiletine demonstrates a safe electrophysiologic profile and sacubitril reduces the occurrence of class III-related proarrhythmia, i.e., torsade de pointes tachycardia.