Renee M. Sullivan

Inappropriate Sinus Tachycardia

Inappropriate sinus tachycardia (IST) is a syndrome in which the sinus heart rate is inexplicably faster than expected and associated symptoms are present. The heart rate at rest, even in a supine position, can exceed 100 beats/min; minimal activity accelerates the rate rapidly and substantially. Patients with IST may require restriction from physical activity. Mechanisms responsible for IST are understood incompletely. It is important to distinguish IST from so-called appropriate sinus tachycardia and from postural orthostatic tachycardia syndrome, with which overlap may occur. Because the long-term outcome seems to be benign, treatment may be unnecessary or may be as simple as physical training. However, for patients with intolerable symptoms, therapeutic measures are warranted. Even at high doses, β-adrenergic blockers, the first-line therapy, often are ineffective; the same is true for most other medical therapies. In rare instances, catheter- or surgically- based right atrial or sinus node modification may be helpful, but even this is fraught with limited efficacy and potential complications. Overtreatment, in an attempt to reduce symptoms, can be difficult to avoid, but is discouraged.

Sports and exercise cardiology in the United States: cardiovascular specialists as members of the athlete healthcare team.

In recent years, athletic participation has more than doubled in all major demographic groups, while simultaneously, children and adults with established heart disease desire participation in sports and exercise. Despite conferring favorable long-term effects on well-being and survival, exercise can be associated with risk of adverse events in the short term. Complex individual cardiovascular (CV) demands and adaptations imposed by exercise present distinct challenges to the cardiologist asked to evaluate athletes. Here, we describe the evolution of sports and exercise cardiology as a unique discipline within the continuum of CV specialties, provide the rationale for tailoring of CV care to athletes and exercising individuals, define the role of the CV specialist within the athlete care team, and lay the foundation for the development of Sports and Exercise Cardiology in the United States. In 2011, the American College of Cardiology launched the Section of Sports and Exercise Cardiology. Membership has grown from 150 to over 4,000 members in just 2 short years, indicating marked interest from the CV community to advance the integration of sports and exercise cardiology into mainstream CV care. Although the current athlete CV care model has distinct limitations, here, we have outlined a new paradigm of care for the American athlete and exercising individual. By practicing and promoting this new paradigm, we believe we will enhance the CV care of athletes of all ages, and serve the greater athletic community and our nation as a whole, by allowing safest participation in sports and physical activity for all individuals who seek this lifestyle.

Protecting the heart of the American Athlete: Proceedings of the American college of cardiology sports and exercise cardiology think tank October 18, 2012, Washington, DC

Yvette L. Rooks, MD, CAQ, FAAFP[1][1]nnG. Paul Matherne, MD, FACC[2][2]nnJim Whitehead[3][3]nnDan Henkel[3][3]nnIrfan M. Asif, MD[4][4]nnJames C. Dreese, MD[5][5]nnRory B. Weiner, MD[6][6]nnBarbara A. Hutchinson, MD, PhD, FACC[7][7]nnLinda Tavares, MS, RN, AACC[8][8]nnSteven Krueger, MD, FACC[9][9

Sudden death risk in syncope: the role of the implantable cardioverter defibrillator.

Syncope is generally benign but when it is due to an underlying cardiovascular condition, the prognosis can be guarded. Patients with syncope may be at risk of dying suddenly from a ventricular arrhythmia especially if the collapse is caused by a poorly-tolerated, self-terminating, ventricular tachycardia (VT). If a similar VT recurs, and persists, it could initiate cardiac arrest, leading to sudden cardiac death. However, distinguishing which patient with syncope may benefit most from implantable cardioverter defibrillator (ICD) therapy, which can stop life-threatening and poorly tolerated VT, thereby preventing sudden cardiac death, remains an ongoing challenge. Careful assessment of the patients underlying cardiovascular conditions, scrupulous attention to historical detail to assess potential causes for syncope, and risk stratification based upon clinical characteristics and short and long-term risks can help. This review focuses on the sudden death risk in patients with syncope and explores the role of the ICD to treat ventricular arrhythmias, prevent symptoms, and prevent death.

Syncope in Patients with Organic Heart Disease.

Patients with syncope and organic heart disease remain a small but important subset of those patients who experience transient loss of consciousness. These patients require thoughtful and complete evaluation in an attempt to better understand the mechanism of syncope and its relationship to the underlying disease, and to diagnose and treat both properly. The goal is to reduce the risk of further syncope, to improve long-term outcomes with respect to arrhythmic and total mortality, and to improve patients quality of life.

Does change in device detected frequency of non-sustained or diverted episodes serve as a marker for inappropriate shock therapy? Analyses from the INTRINSIC RV and ALTITUDE-REDUCES Trials

AIMSnImplantable cardioverter-defibrillators (ICDs) treat ventricular tachycardia or fibrillation but may also deliver unnecessary shocks. We sought to determine if the frequency of ICD-detected non-sustained or diverted (NSD) episodes increases before appropriate or inappropriate ICD shocks.nnnMETHODS AND RESULTSnWe evaluated NSD episodes in the INTRINSIC RV Trial and their relationship to ICD shocks (appropriate and inappropriate). Time from NSD to shock was analysed. Results were validated by utilizing 1495 adjudicated ICD and cardiac resynchronization therapy-defibrillator shocks following NSD episodes collected through the LATITUDE remote monitoring system as part of the ALTITUDE-REDUCES Study. In INTRINSIC RV, 185 participants received 373 shocks; 148 had at least 1 NSD episode. Non-sustained or diverted frequency increased 24 h before the first shock for those receiving an inappropriate (P < 0.01) but not an appropriate shock (P = 0.17). Patients with NSD episodes within 24 h of a shock were significantly more likely to receive inappropriate therapy [odds ratio (OR) = 3.12, P < 0.01]. At the receiver operator curve determined optimal cutoff, an NSD episode within 14 min before shock strongly predicted inappropriate therapy (sensitivity 48%, specificity 91%; OR = 8.8, and P < 0.001). The 14 min cut-off evaluated on an independent dataset of 1495 shock episodes preceded by an NSD in the ALTITUDE-REDUCES Study confirmed these results (sensitivity = 47%, specificity = 85%, OR = 5.0, and P < 0.001).nnnCONCLUSIONnDevice-detected NSD episodes increase before inappropriate but not appropriate shocks. Novel alerts or automated algorithms based on NSD episodes may reduce inappropriate shocks.

The Parasympathetic Nervous System and Heart Failure: Pathophysiology and Potential Therapeutic Modalities for Heart Failure

Congestive heart failure is associated with essential perturbations in the autonomic nervous system. Early in the development of heart failure, there may be defective parasympathetic cardiac control. This may occur before, or in parallel with, elevation in sympathetic tone. Here, we consider alterations that occur in the parasympathetic nervous system during the initiation and development of congestive heart failure. We also consider targets in the parasympathetic nervous system at various levels that may affect and improve clinical outcomes (survival, measures of progressive heart failure and debilitation, and cardiac remodeling, to name a few) by unique mechanistic effects that the parasympathetic nervous system exerts on heart rate, inflammation, remodeling, endothelial nitric oxide synthase activity, inhibition of the sympathetic nervous system, and other potential mechanisms. We consider approaches to vagus nerve stimulation, the designs and early outcomes of trials, and some of the drug interventions that have been attempted. In this rapidly emerging field, with little clinical data, we discuss issues regarding study designs and outcome measures of importance.

IMPORTANCE OF REDUCTION IN QRS DURATION IN CARDIAC RESYNCHRONIZATION

Following cardiac resynchronization therapy (CRT), the postoperative paced QRS duration may be more prolonged than the preoperative QRS (+QRS). The outcome of +QRS patients is unclear.nnAnalysis of 100 consecutive patients with successful CRT implantation.nnThirty seven patients had a +QRS. These