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Concept: Premature ventricular contraction

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Premature cardiac contractions are associated with increased morbidity and mortality. Though experts associate premature atrial contractions (PACs) and premature ventricular contractions (PVCs) with caffeine, there are no data to support this relationship in the general population. As certain caffeinated products may have cardiovascular benefits, recommendations against them may be detrimental.

Concepts: Cardiac electrophysiology, Premature ventricular contraction, Premature atrial contraction

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The aim of this study was to investigate the prognostic impact of acute-phase ventricular tachycardia and fibrillation (VT/VF) on ST-segment elevation myocardial infarction (STEMI) patients in the percutaneous coronary intervention (PCI) era.Methods and Results:Using the database of the Osaka Acute Coronary Insufficiency Study (OACIS), we studied 4,283 consecutive patients with STEMI who were hospitalized within 12 h of STEMI onset and underwent emergency PCI. Acute-phase VT/VF, defined as ≥3 consecutive ventricular premature complexes and/or VF within the 1st week of hospitalization, occurred in 997 (23.3%) patients. In-hospital mortality risk was significantly higher in patients with acute-phase VT/VF than inthose without (14.6% vs. 4.3%, adjusted hazard ratio (HR) 1.83, P=0.0013). Among patients discharged alive, 5-year mortality rates were comparable between patients with and without acute-phase VT/VF. Subgroup analysis showed that acute-phase VT/VF was associated with increased 5-year mortality after discharge in high-risk patients (GRACE Risk Score ≥115; adjusted HR 1.60, P=0.043), but not in intermediate- or low-risk patients.

Concepts: Myocardial infarction, Atherosclerosis, Cardiology, Percutaneous coronary intervention, Ventricular tachycardia, Acute coronary syndrome, Ventricular fibrillation, Premature ventricular contraction

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Transendocardial stem cell injection in patients with ischemic cardiomyopathy (ICM) improves left ventricular function and structure but has ill-defined effects on ventricular arrhythmias. We hypothesized that mesenchymal stem cell (MSC) implantation is not proarrhythmic. Post hoc analyses were performed on ambulatory ECGs collected from the POSEIDON and TAC-HFT trials. Eighty-eight subjects (mean age 61 ± 10 years) with ICM (mean EF 32.2% ± 9.8%) received treatment with MSC (n = 48), Placebo (n = 21), or bone marrow mononuclear cells (BMC) (n = 19). Heart rate variability (HRV) and ventricular ectopy (VE) were evaluated over 12 months. VE did not change in any group following MSC implantation. However, in patients with ≥ 1 VE run (defined as ≥ 3 consecutive premature ventricular complexes in 24 hours) at baseline, there was a decrease in VE runs at 12 months in the MSC group (p = .01), but not in the placebo group (p = .07; intergroup comparison: p = .18). In a subset of the MSC group, HRV measures of standard deviation of normal intervals was 75 ± 30 msec at baseline and increased to 87 ± 32 msec (p =.02) at 12 months, and root mean square of intervals between successive complexes was 36 ± 30 msec and increased to 58.2 ± 50 msec (p = .01) at 12 months. In patients receiving MSCs, there was no evidence for ventricular proarrhythmia, manifested by sustained or nonsustained ventricular ectopy or worsened HRV. Signals of improvement in ventricular arrhythmias and HRV in the MSC group suggest a need for further studies of the antiarrhythmic potential of MSCs. © Stem Cells Translational Medicine 2017.

Concepts: Stem cell, Mesenchymal stem cell, Cardiology, Bone marrow, Stem cells, Standard deviation, Root mean square, Premature ventricular contraction

28

Short-coupled variant of torsade de pointes (TdP) is an uncommon variant of polymorphic ventricular tachycardia with unknown etiology. It is initiated by a closely coupled premature ventricular complex (<300 ms) in the absence of QT prolongation and structural heart disease. Verapamil seems to be the only drug able to suppress the arrhythmia but, as it does not reduce the risk of sudden death, implantation of a cardioverter-defibrillator (ICD) is recommended. We describe the case of a 46-year-old woman referred to our Emergency Department because of palpitations. The initial ECG showed a non-sustained polymorphic ventricular tachycardia with a borderline QTc interval (450 ms). After admission, the patient experienced an episode of TdP that started after short-coupling interval (280 ms) between the last sinus beat and the ventricular premature beat (VPB). DC-shock restored sinus rhythm. Physical examination, exercise testing, echocardiography and cardiac magnetic resonance were all normal, and she had no family history of sudden cardiac death. Baseline ECG showed sinus rhythm and unifocal VPBs with the same morphology of the VPB of TdP. The patient received an ICD and was treated medically with verapamil. She was discharged from the hospital on oral therapy with verapamil (240 mg/day), and she was free of recurrence 12 months later when an electrical storm occurred. The verapamil dose was therefore increased to 480 mg/day. Unifocal VPBs disappeared from her body surface ECG, and the subsequent 3-year follow-up was uneventful.

Concepts: Myocardial infarction, Cardiology, Cardiac electrophysiology, Long QT syndrome, QT interval, Ventricular tachycardia, Ventricular fibrillation, Premature ventricular contraction

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Catheter ablation of premature ventricular complexes (PVC) improves left ventricular (LV) systolic performance in certain patients; however, the effect on diastolic function and left atrial (LA) remodeling is unclear. We assessed the effects of catheter ablation of PVCs on parameters of LV diastolic function and LA remodeling.

Concepts: Improve, Effect, Blood pressure, Effectiveness, Ventricle, Effects unit, Premature ventricular contraction

14

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disease caused by defective prelamin A processing, leading to nuclear lamina alterations, severe cardiovascular pathology, and premature death. Prelamin A alterations also occur in physiological aging. It remains unknown how defective prelamin A processing affects the cardiac rhythm. We show age-dependent cardiac repolarization abnormalities in HGPS patients that are also present in the Zmpste24(-/-) mouse model of HGPS. Challenge of Zmpste24(-/-) mice with the β-adrenergic agonist isoproterenol did not trigger ventricular arrhythmia but caused bradycardia-related premature ventricular complexes and slow-rate polymorphic ventricular rhythms during recovery. Patch-clamping in Zmpste24(-/-) cardiomyocytes revealed prolonged calcium-transient duration and reduced sarcoplasmic reticulum calcium loading and release, consistent with the absence of isoproterenol-induced ventricular arrhythmia. Zmpste24(-/-) progeroid mice also developed severe fibrosis-unrelated bradycardia and PQ interval and QRS complex prolongation. These conduction defects were accompanied by overt mislocalization of the gap junction protein connexin43 (Cx43). Remarkably, Cx43 mislocalization was also evident in autopsied left ventricle tissue from HGPS patients, suggesting intercellular connectivity alterations at late stages of the disease. The similarities between HGPS patients and progeroid mice reported here strongly suggest that defective cardiac repolarization and cardiomyocyte connectivity are important abnormalities in the HGPS pathogenesis that increase the risk of arrhythmia and premature death.

Concepts: Cell nucleus, Blood, Senescence, Heart, Gerontology, Premature ventricular contraction, Progeria, Werner syndrome

12

A 68-year-old woman presented with palpitations and was found to have frequent premature ventricular contractions and nonsustained ventricular tachycardia. A left ventriculogram showed hypertrophic cardiomyopathy with an apical variant; a video is available at NEJM.org.

Concepts: Myocardial infarction, Cardiology, Ventricular tachycardia, Supraventricular tachycardia, Hypertrophic cardiomyopathy, Premature ventricular contraction

6

-Catheter ablation for ventricular tachycardia (VT) and premature ventricular complexes (PVCs) is common. Catheter ablation of atrial fibrillation is associated with a risk of cerebral emboli attributed to cardioversions and numerous ablation lesions in the low-flow left atrium, but cerebral embolic risk in ventricular ablation has not been evaluated.

Concepts: Heart, Atrial fibrillation, Cardiac anatomy, Tachycardia, Embolism, Premature ventricular contraction

2

The origin and clinical relevance of exercise-induced premature ventricular beats (PVBs) in patients without coronary heart disease or cardiomyopathies is unknown. Cardiovascular magnetic resonance enables us to non-invasively assess myocardial scarring and oedema. The purpose of our study was to discover any evidence of myocardial anomalies in patients with exercise-induced ventricular premature beats.

Concepts: Myocardial infarction, Cardiology, Heart, Cardiac muscle, Avicenna, Heart disease, Circulatory system, Premature ventricular contraction