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Cardiovascular AND Tachycardia, ventricular, [keywords]
- Impact of Mechanical Activation, Scar, and Electrical Timing on Cardiac Resynchronization Therapy Response and Clinical Outcomes. [JOURNAL ARTICLE]
- J Am Coll Cardiol 2014 Feb 24.
Using cardiac magnetic resonance (CMR), we sought to evaluate the relative influences of mechanical, electrical, and scar properties at the left ventricular (LV) lead position (LVLP) on CRT response and clinical events.CMR cine displacement encoding with stimulated echoes (DENSE) provides high quality strain for overall dyssynchrony (circumferential uniformity ratio estimate [CURE, 0-1]) and timing of onset of circumferential contraction at the LVLP. CMR DENSE, late gadolinium enhancement, and electrical timing together could improve upon other imaging modalities for evaluating the optimal LVLP.Patients had complete CMR studies and echocardiography before CRT. CRT response was defined as a 15% reduction in LV end-systolic volume. Electrical activation was assessed as the time from QRS-onset-to-LVLP-electrogram (QLV). Patients were then followed for clinical events.In 75 patients, multivariable logistic modeling accurately identified the 40 (53%) of patients with CRT response (AUC=0.95 [p<0.0001]) based on CURE (OR 2.59/0.1 decrease), delayed circumferential contraction onset at LVLP (OR 6.55), absent LVLP scar (OR 14.9), and QLV (OR 1.31/10 ms increase). The 33% of patients with CURE<0.70, absence of LVLP scar, and delayed LVLP contraction onset had a 100% response rate, while the 31% with CURE≥0.70 had a 0% CRT response rate and a 12-fold increased risk of death, and the remaining 36% had a mixed response profile.Mechanical, electrical, and scar properties at the LVLP together with CMR mechanical dyssynchrony are strongly associated with echocardiographic CRT response and clinical events after CRT. Modeling these findings holds promise for improving CRT outcomes.
- Adenosine sensitivity of retrograde fast pathway conduction in patients with slow-fast atrioventricular nodal reentrant tachycardia: A prospective study: Fast pathway's adenosine resistance. [JOURNAL ARTICLE]
- Heart Rhythm 2014 Feb 27.
It is suggested that adenosine resistance of retrograde fast pathway in slow-fast atrioventricular nodal reentrant tachycardia (AVNRT) confirms the participation of a concealed retrograde atriohisian pathway, rather than conventional fast pathway in the arrhythmia circuit of slow-fast AVNRT.We prospectively assessed the retrograde fast pathway response to the intravenous administration of adenosine in patients with typical AVNRT and the control group.Electrophysiologic parameters and adenosine sensitivity of retrograde fast pathway were studied in 21 consecutive patients (18 women, age 57±10 years) with slow-fast AVNRT and 24 patients (11 women; age 46±16 years) as control group.Fifteen patients (71%) with AVNRT and 18 patients in control group (75%) developed transient VA block after intravenous administration of adenosine (P=0.79). Among patients with slow-fast AVNRT female gender (P=0.003), longer VA interval during right ventricular pacing (P<0.001), and longer tachycardia's cycle length (P<0.001) predicted transient VA block after intravenous administration of adenosine. Among patients in control group shorter VA interval during fixed rate right ventricular apical pacing (P=0.009) and presence of dual AV nodal physiology (P=0.002) were associated with adenosine resistance of retrograde fast pathway.The prevalence of adenosine resistance of retrograde fast pathway's conduction is comparable between patients with and without slow-fast AVNRT. This finding can be explained better by the existence of an insulated intra nodal tract with Purkinje-like properties or a superior atrionodal connection to the nodo-hisian region of the AV node, rather than presence of an atriohisian pathway.
- Channelopathies. [REVIEW]
- Korean J Pediatr 2014 Jan; 57(1):1-18.
Channelopathies are a heterogeneous group of disorders resulting from the dysfunction of ion channels located in the membranes of all cells and many cellular organelles. These include diseases of the nervous system (e.g., generalized epilepsy with febrile seizures plus, familial hemiplegic migraine, episodic ataxia, and hyperkalemic and hypokalemic periodic paralysis), the cardiovascular system (e.g., long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia), the respiratory system (e.g., cystic fibrosis), the endocrine system (e.g., neonatal diabetes mellitus, familial hyperinsulinemic hypoglycemia, thyrotoxic hypokalemic periodic paralysis, and familial hyperaldosteronism), the urinary system (e.g., Bartter syndrome, nephrogenic diabetes insipidus, autosomal-dominant polycystic kidney disease, and hypomagnesemia with secondary hypocalcemia), and the immune system (e.g., myasthenia gravis, neuromyelitis optica, Isaac syndrome, and anti-NMDA [N-methyl-D-aspartate] receptor encephalitis). The field of channelopathies is expanding rapidly, as is the utility of molecular-genetic and electrophysiological studies. This review provides a brief overview and update of channelopathies, with a focus on recent advances in the pathophysiological mechanisms that may help clinicians better understand, diagnose, and develop treatments for these diseases.
- Relation of the Unipolar Low Voltage Penumbra Surrounding the Endocardial Low Voltage Scar to Ventricular Tachycardia Circuit Sites and Ablation Outcomes in Ischemic Cardiomyopathy. [JOURNAL ARTICLE]
- J Cardiovasc Electrophysiol 2014 Feb 27.
MR-imaging has shown that infarct scars causing VT can extend deep to and beyond bipolar low voltage areas (LVA) and may be a source of ablation failure. We hypothesized that the size of the unipolar LVA 'penumbra' beyond the overlying bipolar scar may predict outcome of endocardial VT ablation.Twenty consecutive patients with ischemic cardiomyopathy who underwent endocardial VT ablation were retrospectively reviewed. Bipolar (30-500 Hz) LVA defined as <1.5 mV and unipolar (0.5-500 Hz) LVA defined as <8.3mV were reviewed on an electroanatomic mapping system. VT isthmus sites were identified from entrainment mapping, VT termination by ablation, or pace-mapping with abolition of VT inducibility by ablation.All bipolar LVAs (70.5±20cm2) had unipolar LVAs that surrounded the bipolar LVA (147±47cm2). Only 58% of the induced VTs could be mapped and ablated. During a 3-month follow-up 8/20 patients had VT recurrence. The size of the LVA penumbra was not different for those with (88±47cm2) vs without (69±35cm2) recurrences. However, all (8/8) of the group that recurred had isthmus/exits in the bipolar LVA border compared to only 3/12 that did not recur (100%vs25%;p<0.05). Furthermore, 5/8 patients who recurred harbored VT isthmuses in the unipolar LVA penumbra than 1/12 who did not recur (63%vs8%;p = 0.01).In ischemic cardiomyoapthy, unipolar LVA penumbra of varying size surrounds endocardial bipolar LVA, indicating intramural/epicardial scar. Although the size of this area did not predict early recurrence after endocardial ablation, frequent recurrences after VT ablation at scar periphery suggests deeper substrate towards the infarct border. This article is protected by copyright. All rights reserved.
- [Cardiovascular diseases during pregnancy and delivery]. [English Abstract, Journal Article]
- Med Pregl 2013 Nov-Dec; 66(11-12):507-13.
Nowadays, cardiovascular diseases are the leading cause of maternal morbidity and mortality in the current obstetric practice. PHYSIOLOGICALLY ADAPTED MECHANISMS OF THE CARDIOVASCULAR SYSTEM IN PREGNANCY: It is normal that during pregnancy some physiological adaptive changes of the cardiovascular system occur and they may contribute to the deterioration of the clinical cardiac status of a patient with preexisting or acquired cardiovascular disease. The most prominent adaptive mechanisms include the increase of circulating blood volume, decrease of peripheral vascular resistance and decrease of plasma colloid-oncotic pressure. MOST FREQUENT DISEASES OF THE CARDIOVASCULAR SYSTEM IN PREGNANCY: Due to these changes, pregnant women are prone to tachycardia, palpitations and peripheral edema. Maternal counseling is obligatory for each pregnant woman in order to decrease the maternal morbidity and mortality. The most important predictors of maternal mortality for pregnant women with cardiovascular diseases are severity of pulmonary hypertension, hemodynamic significance of valvular lesion, cyanosis and functional status in heart failure. Cardiovascular diseases in pregnant women may be congenital or acquired. The most frequent congenital cardiac diseases are atrial and ventricular septal defects as well as persistent ductus arteriosus. These diseases are mainly diagnosed and corrected before the pregnancy, or left untreated if hemodynamically insignificant. The most frequent acquired cardiovascular diseases during pregnancy include arrhythmias, ischemic heart disease, rheumatic mitral stenosis and insufficiency, arterial hypertension and aortic dissection.In all cases of pregnancy associated with cardiovascular diseases, early recognition of cardiovascular disease is crucial, as well as correct diagnosis and referral to a tertiary centre equipped for a multidisciplinary approach of specialists experienced in high-risk pregnancies and deliveries in order to prevent maternal mortality.
- Ventricular tachyarrhythmia after coronary bypass surgery: incidence and outcome. [Journal Article]
- Asian Cardiovasc Thorac Ann 2013 Oct; 21(5):551-7.
Ventricular tachyarrhythmia after coronary artery bypass graft is common and the occurrence has been described, but the incidence and risk factors are not well defined.To evaluate the incidence of arrhythmias and to detect high-risk populations.In this prospective study, 856 consecutive patients undergoing coronary artery bypass graft were monitored for new-onset ventricular tachyarrhythmias: non-sustained monomorphic ventricular tachyarrhythmia, sustained monomorphic ventricular tachyarrhythmia, sustained polymorphic ventricular tachyarrhythmia, and ventricular fibrillation. Detailed analyses of the clinical, demographic, echocardiographic, and surgical findings and arrhythmias occurrence was carried out during 6 months of follow-up.The incidence of ventricular tachyarrhythmia was 26.6% (17.6% non-sustained monomorphic ventricular tachycardia, 5.5% sustained monomorphic ventricular tachycardia, 0.8% sustained polymorphic ventricular tachycardia, and 2.7% ventricular fibrillation). The strongest degrees of statistical significance were for low ejection fraction (p = 0.01) and ischemic heart disease (p = 0.02). The incidence of ventricular fibrillation (61%) was greatest in the first 48 h after surgery. Postoperative myocardial infarction (p = 0.03) and hemodynamic instability (p = 0.05) were also predictors of arrhythmia occurrence. Recurrence of arrhythmia was highest in the ventricular fibrillation group (52%). The correlations between tachyarrhythmia, age, sex, electrolyte disorders, body mass index, and systemic or pulmonary hypertension were not significant.In view of the strong relationship between ventricular arrhythmias and low ejection fraction, ischemic heart disease, coronary artery disease severity, postoperative myocardial infection, and hemodynamic impairment, continuous monitoring is necessary, especially in the first 48 h after coronary artery bypass surgery.
- Prevention of sudden cardiac death beyond the ICD: Have we reached the boundary or are we just burning the surface? [REVIEW]
- Indian Heart J 2014 January - February.:S120-S128.
Preventing sudden cardiac death (SCD) remains a major unsolved problem in contemporary medical practice. As the most common cause of SCD, treatment for ventricular arrhythmias is the target area of interest in research field. While implantable cardioverter-defibrillator (ICD) effectively decreases death from ventricular arrhythmias in highly selected patients, risk of inappropriate shocks, mortality from frequent therapy, chance of failing in abortion of arrhythmias despite having a defibrillator, and our inability to recognize which of several hundreds of thousands of patients at risk for sudden death but do not meet current criteria for defibrillator, limit ICD effectiveness. In this article, a brief review of mechanism leading to SCD, the existing evidence for a defibrillator and the lacunae in present guidelines for patients clearly at risk for sudden death but without proven benefit from a defibrillator are presented in Section I. Following this, interventional approaches, both catheter-based and general measures that may serve as adjuncts to a defibrillator in preventing this all too common catastrophic end event, are summarized in Section II.
- Cardiac arrest and ventricular tachycardia from coronary embolism: an unusual presentation of infective endocarditis. [JOURNAL ARTICLE]
- Anadolu Kardiyol Derg 2014 Feb 4.
- Cardiac Electrophysiology and the Susceptibility to Sustained Ventricular Tachycardia in Intact, Conscious Mice. [JOURNAL ARTICLE]
- Am J Physiol Heart Circ Physiol 2014 Feb 21.
Cardiac electro-physiologic dysfunction is a major cause of death in humans. Accordingly, electrophysiological testing is routinely performed in intact, conscious, humans to evaluate arrhythmias and disorders of cardiac conduction. However, to date, in vivo electrophysiological studies in mice are limited to anesthetized, open chest or closed chest preparations. However cardiac electrophysiology in anesthetized mice or mice with surgical trauma may not adequately represent what occurs in conscious mice. Accordingly, an intact, conscious murine model of cardiac electrophysiology has the potential to be of major importance for advancing the concepts and methods that drive cardiovascular therapies. Therefore, we describe, for the first time, the use of an intact, conscious, murine model of cardiac electrophysiology. The conscious mouse model permits measurements of atrio-ventricular interval, sinus cycle length, sinus node recovery time (SNRT), SNRT corrected for spontaneous sinus cycle, Wenckebach cycle length, the ventricular effective refractory period (VERP) and the electrical stimulation threshold to induce sustained ventricular tachy-arrhythmias in an intact, complex model free of the confounding influences of anesthetics and surgical trauma. This is an important consideration because anesthesia and surgical trauma markedly reduced cardiac output and heart rate as well as altered cardiac electrophysiology parameters. Most importantly, anesthesia and surgical trauma significantly increased the VERP and virtually eliminated the ability to induce sustained ventricular tachy-arrhythmias. Accordingly, the methodology allows for the accurate documentation of cardiac electrophysiology in complex, conscious mice and may be adopted for advancing the concepts and ideas that drive cardiovascular research.