Supraventricular tachycardia-Part II: History, presentation, mechanism, and treatment.

Supraventricular tachycardias (SVTs) affect all age groups and are a source of significant morbidity. They are frequently encountered in otherwise healthy individuals without structural heart disease. Advances in the understanding of their mechanisms and anatomical locations have led to highly effective pharmacologic and nonpharmacologic treatment strategies.

Supraventricular tachycardia--part I.

Supraventricular tachycardias (SVTs) affect all age groups and are a source of significant morbidity. They are frequently encountered in otherwise healthy individuals without structural heart disease. Advances in the understanding of their mechanisms and anatomical locations have led to highly effective pharmacologic and nonpharmacologic treatment strategies.

[A Novel mutation of F189L in CASQ2 in families with catecholaminergic polymorphic ventricular tachycardia].

Objective: To identify mutations and variants in CASQ2 gene in 27 CPVT patients/family members.

Methods: Mutational analysis was performed with direct DNA sequence analysis. The frequency of an identified CASQ2 variant was determined using the Taqman genotyping assay.

A first-degree family history in lone atrial fibrillation patients.

Background: Atrial fibrillation (AF) may be due to an inherited trait, particularly in lone AF patients. A family history of AF in lone AF patients has not previously been compared with a family history of patients with AF and established risk factors (non-lone AF).

Objective: The purpose of this study was to compare the frequency of having a first-degree relative with AF in lone and non-lone AF patients.

Exercise-induced polymorphic ventricular tachycardia in adults without structural heart disease.

Patients with catecholaminergic polymorphic ventricular tachycardia present at a young age with exercise-induced ventricular arrhythmias (VAs) and may have a positive family history. We describe 8 patients who presented with exercise-induced symptoms as adults, have a negative family history, and responded to beta-blocker therapy. The study evaluated exercise treadmill electrocardiographic data from patients referred for exercise-induced VA.

Alcohol intake is significantly associated with atrial flutter in patients under 60 years of age and a shorter right atrial effective refractory period.

Background: Although evidence suggests that alcohol is associated with atrial fibrillation (AF), the association between alcohol and atrial flutter (AFL) has not been examined. The mechanism connecting alcohol and atrial arrhythmias is unknown.

Methods: Alcohol intake was determined in 195 consecutive patients with AF and AFL.

Markers of inflammation before and after curative ablation of atrial flutter.

Background: Atrial arrhythmias are associated with inflammation. The cause and effect of the association are unknown.

Objective: The purpose of this study was to test the hypothesis that atrial tachyarrhythmias contribute to inflammation.

Role of magnetic resonance imaging in arrhythmogenic right ventricular dysplasia: insights from the North American arrhythmogenic right ventricular dysplasia (ARVD/C) study.

Background: Prior reports describing magnetic resonance (MR) imaging abnormalities in arrhythmogenic right ventricular dysplasia (ARVD/C) were limited by nonuniform inclusion criteria. The aim of our study was to define the prevalence, sensitivity, and specificity of quantitative MR imaging findings in the probands of multidisciplinary study of right ventricular dysplasia.

Methods: Individuals with ventricular arrhythmias of left bundle-branch block morphology meeting the Task Force criteria for ARVD/C underwent MR imaging.

Using the initial vector from surface electrocardiogram to distinguish the site of outflow tract tachycardia.

Background: The purpose of this study is to determine whether initial vector force might best distinguish tachycardias arising from the right ventricular (RV) outflow tract (OT) versus aortic sinus cusps (ASCs).

Methods: Among 45 patients with OT tachycardia, we measured the time from the earliest QRS onset in any lead to local onset and to the first QRS peak/nadir in each surface leads during VT. We compared the earliest phase differences among patients with foci in RVOT (n = 32) and in ASCs (n = 13) (determined by ablation), using unpaired t-tests.

Impact of renal function on survival in patients with implantable cardioverter-defibrillators.

Background: Although chronic renal insufficiency (CRI) is associated with increased cardiac and noncardiac mortality, there is limited data on the relationship between CRI and survival in patients with implantable cardioverter-defibrillators (ICDs), particularly across a wide range of renal function.

Methods: We studied 507 consecutive patients receiving first-time ICDs from 1993-2003 at a single center. Preimplant serum creatinine measurements were used to determine glomerular filtration rate (GFR) and stage of chronic kidney disease (CKD).

Regional left atrial voltage in patients with atrial fibrillation.

Background: Regional differences in fibrosis, particularly related to the posterior wall and septum, may be important in atrial fibrillation (AF). Using electroanatomic mapping, voltage can be used as a measure of fibrosis.

Objectives: The purpose of this study was to determine if patients with AF have disproportionately lower voltage in the septal and posterior walls of the left atrium.

Idiopathic ventricular tachycardia: Diagnosis and management.

Idiopathic ventricular tachycardia (VT) is an uncommon form of VT that is seen in patients without structural heart disease. It is commonly seen in young patients and usually has a benign course. Recent studies have delineated the mechanisms and anatomical locations of this form of VT.

The 12-lead electrocardiogram in supraventricular tachycardia.

The 12-lead electrocardiogram (ECG) is an invaluable tool for the diagnosis of supraventricular tachycardia (SVT). Most forms of SVT can be distinguished with a high degree of certainty based on specific ECG characteristics by using a systematic, stepwise approach. This article provides a general framework with which to approach an ECG during SVT by describing the salient characteristics, ECG findings, and underlying electroanatomical relationships of each specific type of SVT encountered in adults.

Exercise-induced ventricular arrhythmias in patients with no structural cardiac disease.

We review the clinical and genetic disorders associated with exercise-induced ventricular arrhythmias in patients with normal hearts. Foremost are those with catecholaminergic polymorphic ventricular tachycardia due to abnormalities in either the ryanodine receptor 2 genes (RyR2) or the calsequestrin genes (CASQ). These patients manifest ventricular premature beats and polymorphic ventricular tachycardia in response to exercise or on exposure to catecholamines.

Ratio of late to early T-wave peak amplitude in 24-h electrocardiographic recordings as indicator of symptom history in patients with long-QT Syndrome types 1 and 2.

Unlabelled: We reviewed 24-h electrocardiographic recordings from 214 genotyped subjects--97 with long-QT syndrome type 1 (LQT1), 62 with LQT2, and 55 unaffected--to record maximal diurnal amplitude ratios between late and early T-wave peaks. Maximal amplitude ratios between late and early T-wave peaks were higher in symptomatic than in asymptomatic patients both in LQT1 (3.2 +/- 1.