Raphael Rosso

The Response of the QT Interval to the Brief Tachycardia Provoked by Standing: A Bedside Test for Diagnosing Long QT Syndrome

OBJECTIVES This study was undertaken to determine whether the short-lived sinus tachycardia that occurs during standing will expose changes in the QT interval that are of diagnostic value. BACKGROUND The QT interval shortens during heart rate acceleration, but this response is not instantaneous. We tested whether the transient, sudden sinus tachycardia that occurs during standing would expose abnormal QT interval prolongation in patients with long QT syndrome (LQTS). METHODS Patients (68 with LQTS [LQT1 46%, LQT2 41%, LQT3 4%, not genotyped 9%] and 82 control subjects) underwent a baseline electrocardiogram (ECG) while resting in the supine position and were then asked to get up quickly and stand still during continuous ECG recording. The QT interval was studied at baseline and during maximal sinus tachycardia, maximal QT interval prolongation, and maximal QT interval stretching. RESULTS In response to brisk standing, patients and control subjects responded with similar heart rate acceleration of 28 +/- 10 beats/min (p = 0.261). However, the response of the QT interval to this tachycardia differed: on average, the QT interval of controls shortened by 21 +/- 19 ms whereas the QT interval of LQTS patients increased by 4 +/- 34 ms (p < 0.001). Since the RR interval shortened more than the QT interval, during maximal tachycardia the corrected QT interval increased by 50 +/- 30 ms in the control group and by 89 +/- 47 ms in the LQTS group (p < 0.001). Receiver-operating characteristic curves showed that the test adds diagnostic value. The response of the QT interval to brisk standing was particularly impaired in patients with LQT2. CONCLUSIONS Evaluation of the response of the QT interval to the brisk tachycardia induced by standing provides important information that aids in the diagnosis of LQTS.

Pulmonary Vein Antral Isolation for Paroxysmal Atrial Fibrillation: Results from Long-Term Follow-Up

Long‐Term Follow‐Up After Atrial Fibrillation Ablation. Introduction: Pulmonary veins play an important role in triggering atrial fibrillation (AF). Pulmonary vein isolation (PVI) is an effective treatment for patients with paroxysmal AF. However, the late AF recurrence rate in long‐term follow‐up of circumferential PV antral isolation (PVAI) is not well documented. We sought to determine the time to recurrence of arrhythmia after PVAI, and long‐term rates of sinus rhythm after circumferential PVAI.

The "Short-Coupled" Variant of Right Ventricular Outflow Ventricular Tachycardia: A Not-So-Benign Form of Benign Ventricular Tachycardia?

Idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT‐VT) and idiopathic RVOT‐extrasystoles are generally considered benign arrhythmias. We described three cases who originally presented with typical “benign looking” RVOT‐extrasystoles or RVOT‐VT but developed malignant polymorphic VT during follow‐up. The unusual aspect of their RVOT‐extrasystoles was their coupling interval, which appears to be intermediate between the ultra‐short coupling interval of idiopathic VF and the long coupling interval seen in the truly benign RVOT‐VT.

Low risk of major complications associated with pulmonary vein antral isolation for atrial fibrillation: results of 500 consecutive ablation procedures in patients with low prevalence of structural heart disease from a single center.

Complications Associated With Pulmonary Vein Antral Isolation for Atrial Fibrillation. Objectives: To report the major complication rate associated with pulmonary vein antral isolation (PVAI) in a consecutive series of 500 patients from a single center.

Fundamental Differences in Electrophysiologic and Electroanatomic Substrate Between Ischemic Cardiomyopathy Patients With and Without Clinical Ventricular Tachycardia

OBJECTIVES The aim of this study was to compare the electrophysiologic substrate in ischemic cardiomyopathy (ICM) patients with and without sustained monomorphic ventricular tachycardia (SMVT). BACKGROUND Despite the universal presence of potentially arrhythmogenic left ventricular (LV) scarring, it is not clear why the majority of ICM patients never develop SMVT. METHODS Detailed electroanatomic mapping of the LV endocardium was performed in 17 stable control ICM patients (16 males) without clinical SMVT. They were compared with 17 ICM patients (15 males) with spontaneous SMVT. Standard definitions of low-voltage zones and fractionated, isolated, and very late potentials were used. RESULTS There were no significant baseline differences between the groups in terms of LV diameter, ejection fraction (27% vs. 28%), infarct territory, or time from infarction. However, control patients had smaller total low-voltage area < or =1.5 mv (30% of surface area vs. 55%, p < 0.001); smaller very low-voltage area <0.5 mv (7.3% vs. 29%, p < 0.001); higher mean voltage of low-voltage zones; fewer fractionated, isolated, and very late potentials with lower density of these scar-related electrograms per unit low-voltage area; and less SMVT inducibility. Potential conducting channels within dense scar and adjacent to the mitral annulus were more frequent in SMVT patients. CONCLUSIONS Compared with ICM patients with SMVT, an otherwise similar control group demonstrated markedly smaller endocardial low-voltage zones, lower scar-related electrogram density, and fewer conducting channels with faster conduction velocity. These findings may explain why some ICM patients develop SMVT and others do not.

Preventing Sudden Death of Athletes With Electrocardiographic Screening: What Is the Absolute Benefit and How Much Will it Cost?

OBJECTIVES This study sought to estimate the costs of a national electrocardiographic (ECG) screening of athletes in the United States and the number of lives that would be saved by that program. BACKGROUND A single study from Italy suggests that mandatory ECG screening of athletes reduces their risk of sudden cardiac death. Based on that study, ECG screening of athletes is endorsed by the European Society of Cardiology, though not by the American Heart Association. The widespread application of ECG screening remains controversial because the absolute reduction of sudden cardiac death risk provided, and its economic ramifications, have not been studied in detail. METHODS A cost-projection model was based on the Italian study, replicating its data in terms of athlete characteristics and physician performance. The size of the screening-eligible population was estimated from data provided by the National Collegiate Athletic Association and the National Federation of State High School Associations. The costs of diagnostic tests were obtained from Medicare reimbursement rates. RESULTS A 20-year program of ECG screening of young competitive athletes in the United States would cost between

Quinidine, A Life-Saving Medication for Brugada Syndrome, Is Inaccessible in Many Countries

51 and

Viewpoint and CommentaryPreventing Sudden Death of Athletes With Electrocardiographic Screening: What Is the Absolute Benefit and How Much Will it Cost?

69 billion and could be expected to save 4,813 lives. Accordingly, the cost per life saved is likely to range between

Effects of flecainide on exercise-induced ventricular arrhythmias and recurrences in genotype-negative patients with catecholaminergic polymorphic ventricular tachycardia

10.6 and

Risk stratification in Brugada syndrome: Clinical characteristics, electrocardiographic parameters, and auxiliary testing

14.4 million. CONCLUSIONS Our cost-projection model suggests that replicating the Italian strategy of ECG screening in the United States would result in enormous costs per life saved.