Sammy Khatib

Atrial Fibrillation in the 21st Century: A Current Understanding of Risk Factors and Primary Prevention Strategies

Atrial fibrillation (AF) is the most common arrhythmia worldwide, and it has a significant effect on morbidity and mortality. It is a significant risk factor for stroke and peripheral embolization, and it has an effect on cardiac function. Despite widespread interest and extensive research on this topic, our understanding of the etiology and pathogenesis of this disease process is still incomplete. As a result, there are no set primary preventive strategies in place apart from general cardiology risk factor prevention goals. It seems intuitive that a better understanding of the risk factors for AF would better prepare medical professionals to initially prevent or subsequently treat these patients. In this article, we discuss widely established risk factors for AF and explore newer risk factors currently being investigated that may have implications in the primary prevention of AF. For this review, we conducted a search of PubMed and used the following search terms (or a combination of terms): atrial fibrillation, metabolic syndrome, obesity, dyslipidemia, hypertension, type 2 diabetes mellitus, omega-3 fatty acids, vitamin D, exercise toxicity, alcohol abuse, and treatment. We also used additional articles that were identified from the bibliographies of the retrieved articles to examine the published evidence for the risk factors of AF.

Relationships between the T-peak to T-end interval, ventricular tachyarrhythmia, and death in left ventricular systolic dysfunction

AIMS The interval between the T-waves peak and end (Tpe), an electrocardiographic (ECG) index of ventricular repolarization, has been proposed as an indicator of arrhythmic risk. We aimed to clarify the clinical usefulness of Tpe for risk stratification. METHODS AND RESULTS We evaluated 327 patients with left ventricular ejection fraction (LVEF) ≤ 35% (75% male, LVEF 23 ± 7%). All patients had an implanted implantable cardioverter-defibrillator (ICD). Clinical data and ECGs were analysed at baseline. Prospective follow-up for the endpoints of appropriate ICD therapy and mortality was conducted via periodic device interrogation, chart review, and the Social Security Death Index. During device clinic follow-up of 17 ± 12 months, 59 (18%) patients had appropriate ICD therapy, and during mortality follow-up of 30 ± 13 months, 67 (21%) patients died. A longer Tpe(c) predicted appropriate ICD therapy, death, and the combination of appropriate ICD therapy or death (P< 0.01 for each endpoint). On multivariable analysis correcting for other univariable predictors, Tpe(c) remained predictive of ICD therapy [hazard ratio (HR) per 10 ms increase: 1.16, P= 0.02], all-cause mortality (HR per 10 ms: 1.14, P= 0.03), and the composite endpoint of ICD therapy or death (HR per 10 ms: 1.16, P< 0.01). CONCLUSIONS In patients with left ventricular systolic dysfunction and an implanted ICD, Tpe(c) independently predicts both ventricular tachyarrhythmia and overall mortality.

T-peak to T-end interval for prediction of ventricular tachyarrhythmia and mortality in a primary prevention population with systolic cardiomyopathy

BACKGROUND The electrocardiographic T-wave peak to T-wave end interval (Tpe) correlates with dispersion of ventricular repolarization (DVR). Increased DVR increases propensity toward electrical reentry that can cause ventricular tachyarrhythmia. The baseline rate-corrected Tpe (Tpec) has been shown to predict ventricular tachyarrhythmia and death in multiple patient populations but not among cardiomyopathic patients undergoing insertion of an implantable cardioverter-defibrillator (ICD) for primary prevention. OBJECTIVE The purpose of this study was to assess the risk stratification ability of the Tpec in patients with systolic cardiomyopathy without prior ventricular tachyarrhythmia (ie, the primary prevention population). METHODS We performed prospective follow-up of 305 patients (73% men; left ventricular ejection fraction [LVEF] 23 ± 7%) with LVEF ≤35% and an ICD implanted for primary prevention. Baseline ECGs were analyzed with automated algorithms. Endpoints were ventricular tachycardia (VT)/ventricular fibrillation (VF), death, and a combined endpoint of VT/VF or death, assessed by device follow-up and Social Security Death Index query. RESULTS The average Tpec was 107 ± 22 ms. During device clinic follow-up of 31 ± 23 months, 82 patients (27%) had appropriate ICD therapy for VT/VF, and during mortality follow-up of 49 ± 21 months, 91 patients (30%) died. On univariable analysis, Tpec predicted VT/VF, death, and the combined endpoint of VT/VF or death (P < .05 for each endpoint). Multivariable analysis included univariable predictors among demographics, clinical data, laboratory data, medications used, and electrocardiography parameters. After correction, Tpec remained predictive of VT/VF (hazard ratio [HR] per 10-ms increase 1.16, P = .009), all-cause mortality (HR per 10 ms 1.13, P = .05), and the combined endpoint (HR per 10 ms 1.17, P = .001). CONCLUSION Tpec independently predicts both VT/VF and overall mortality in patients with systolic dysfunction and ICDs implanted for primary prevention.

Computed tomography of a coronary sinus diverticulum associated with Wolff-Parkinson-White syndrome

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Induction of Left Ventricular Fascicular Tachycardia with Transesophageal Pacing in a Toddler

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USE OF AMIODARONE TO CONTROL ATRIAL FIBRILLATION CAUSED BY MECHANICAL COMPRESSION OF THE LEFT ATRIUM

J.V. is a 3(1/2)-year-old patient with left ventricular fascicular ventricular tachycardia that had been well controlled on verapamil for 3 years. He was taken for a transesophageal electrophysiology study prior to discontinuing medication in an attempt to induce his tachycardia. We report the use of transesophageal electrophysiology study as a noninvasive method to induce left ventricular fascicular ventricular tachycardia in a toddler.

CORRELATION BETWEEN POSITRON EMISSION TOMOGRAPHY STRESS MYOCARDIAL BLOOD FLOW AND VENTRICULAR TACHYARRHYTHMIA OR DEATH IN PATIENTS WITH CARDIOMYOPATHY

Atrial Fibrillation is the most common cardiac arrhythmia, with a prevalence of 3-6 million in the United States. Arising from the pulmonary veins of the left atrium, mechanical compression of the left atrium may precipitate this rhythm. A 67-year-old lady presented for biopsy of a lung mass and

Cardiometabolic Risk Factors and Atrial Fibrillation

In patients with cardiomyopathy (CM) and an implantable cardioverter-defibrillator (ICD), the relationship between positron emission tomography (PET) stress myocardial blood flow (sMBF) and adverse cardiac events including ventricular arrhythmia (VT/VF) is unknown. Patients with CM with an ICD in