Sinus pause in association with Lyme carditis.

Lyme disease is the most prevalent tick-borne disease in the United States. It is caused by the spirochete Borrelia burgdorferi. Cardiac involvement is seen in 4% to 10% of patients with Lyme disease. The principal manifestation of Lyme carditis is self-limited conduction system disease, with predominant involvement of the atrioventricular node. On rare occasions, Lyme carditis patients present with other conduction system disorders such as bundle branch block, intraventricular conduction delay, and supraventricular or ventricular tachycardia. We report the unusual case of a 59-year-old man who presented with new-onset symptomatic sinus pauses one month after hiking in upstate New York. To our knowledge, this is the first case report from North America that describes the relationship between symptomatic sinus pause and Lyme carditis.

Diagnosis and management of heart failure with preserved ejection fraction: 10 key lessons.

Heart failure with preserved ejection fraction (HFpEF) is a common clinical syndrome associated with high rates of morbidity and mortality. Due to the lack of evidence-based therapies and increasing prevalence of HFpEF, clinicians are often confronted with these patients and yet have little guidance on how to effectively diagnose and manage them. Here we offer 10 key lessons to assist with the care of patients with HFpEF: (1) Know the difference between diastolic dysfunction, diastolic heart failure, and HFpEF; (2) diagnosing HFpEF is challenging, so be thorough and consider invasive hemodynamic testing to confirm the diagnosis; (3) a normal B-type natriuretic peptide does not exclude the diagnosis of HFpEF; (4) elevated pulmonary artery systolic pressure on echocardiography in the presence of a normal ejection fraction should prompt consideration of HFpEF; (5) use dynamic testing in evaluating the possibility of HFpEF in patients with unexplained dyspnea or exercise tolerance; (6) all patients with HFpEF should be systematically evaluated for the presence of coronary artery disease; (7) use targeted treatment for HFpEF patients based on their phenotypic classification; (8) treat HFpEF patients now by treating their comorbidities; (9) understand the importance of heart rate in HFpEF- lower is not always better; and (10) do not forget to consider rare diseases ("zebras") as causes for HFpEF when evaluating and treating patients. Taken together, these 10 key lessons can help clinicians care for challenging patients with HFpEF while we eagerly await the results of ongoing HFpEF clinical trials and observational studies.

Current perspectives on systemic hypertension in heart failure with preserved ejection fraction.

Hypertension is a major contributor to the development of heart failure with preserved ejection fraction (HFpEF). Our understanding of the epidemiology and pathophysiology of HFpEF in relation to hypertension has increased considerably in recent years. We now know that the pathophysiologic relationship between hypertension and HFpEF is more complex than simply the development of left ventricular hypertrophy and diastolic dysfunction and that there are multiple ways in which hypertension interacts with other comorbidities, the vasculature, and the heart to predispose to HFpEF. Although the treatment of HFpEF has been challenging, there is widespread agreement that control of systemic blood pressure is important in the management of these patients. Here we review the relationship between hypertension and HFpEF, focusing on (1) epidemiology and (2) pathophysiology of HFpEF in relation to hypertension; (3) prevention of HFpEF by controlling hypertension; and (4) established and novel therapeutics for hypertension in the setting of HFpEF.

Extreme externalisation of a Riata defibrillator lead conductor cable with prolapse into the left pulmonary artery.

The Riata family of defibrillator leads (St. Jude Medical, Sylmar, CA) has been recalled because of externalisation of conductor cables and increased electrical failure. We describe the case of a man with an incidental finding of extreme externalisation of a conductor from the right ventricular defibrillator lead (Riata family) with prolapse into the left pulmonary artery.

The emerging epidemic of heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF), which currently represents approximately 50 % of heart failure (HF) cases, is common and associated with high morbidity and mortality. Understanding the epidemiology of HFpEF has been difficult due to the challenges in HFpEF diagnosis and the heterogeneous etiologies and pathophysiologies that underlie HFpEF. Nevertheless, several high-quality epidemiology and observational registry studies of HFpEF demonstrate that an increasing prevalence of HFpEF in both the outpatient and inpatient settings, coupled with a lack of evidence-based effective treatments for HFpEF, is resulting in an emerging epidemic of HFpEF. In this review, we discuss the emerging HFpEF epidemic, focusing on: (1) reasons for the rising prevalence of HFpEF; (2) the abnormalities in cardiac structure and function that dictate the transition from risk factors to HFpEF; (3) novel HFpEF mechanisms that may underlie the increase in HFpEF prevalence; (4) prognosis of HFpEF; and (5) risk prediction in HFpEF. We conclude with 10 unanswered questions onHFpEF epidemiology thatwill be important areas for future investigation.

A common spinal muscular atrophy deletion mutation is present on a single founder haplotype in the US Hutterites.

Spinal muscular atrophy (SMA) is an autosomal recessive (AR) neuromuscular disease that is one of the most common lethal genetic disorders in children, with carrier frequencies as high as ∼1 in 35 in US Whites. As part of our genetic studies in the Hutterites from South Dakota, we identified a large 22 Mb run of homozygosity, spanning the SMA locus in an affected child, of which 10 Mb was also homozygous in three affected Hutterites from Montana, supporting a single founder origin for the mutation. We developed a haplotype-based method for identifying carriers of the SMN1 deletion that leveraged existing genome-wide SNP genotype data for ∼1400 Hutterites. In combination with two direct PCR-based assays, we identified 176 carriers of the SMN1 deletion, one asymptomatic homozygous adult and three carriers of a de novo deletion. This corresponds to a carrier frequency of one in eight (12.5%) in the South Dakota Hutterites, representing the highest carrier frequency reported to date for SMA and for an AR disease in the Hutterite population. Lastly, we show that 26 SNPs can be used to predict SMA carrier status in the Hutterites, with 99.86% specificity and 99.71% sensitivity.