During a median follow-up of 12 months, 112 therapies were delivered in 34 of 267 patients in the long detection arm compared with 257 therapies in 60 of 278 patients in the control arm, translating to a 48 percent reduction with intervention. The number of shocks delivered was 40 percent less in the long detection group. Anti-tachycardia pacing delivery rates of 22 per 100 patient-years in the long detection arm contrasted with 58 per 100 patient-years in the control arm. There were 55 percent fewer appropriate therapies in the long detection arm compared with standard programming. Inappropriate therapies were infrequent, with fewer inappropriate interventions reported in the long detection group. Syncope rates did not differ between groups but survival improved in the long detection arm.

“Our results have particular gravity since the ‘standard’ intervals applied in our control arm are longer than nominal ICD settings, indicating that even further prolongation of time to delivered therapy extends the advantages of this programming strategy further,” the authors write.

Gasparini M, Lunati MG, Proclemer A, et al. JACC Clin Electrophysiol 2017;May 11:[Epub ahead of print].

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High blood pressure and high cholesterol in childhood, adolescence and young adulthood, as well as smoking in adolescence and young adulthood, were associated with worse midlife cognitive performance, especially memory and learning. Study participants with all risk factors within recommended levels between ages 6 and 24 performed better on cognitive testing than those exceeding all risk factor levels at least two-fold. In all, the difference corresponded to the effect of six years of aging.

“These findings support the need for active monitoring and treatment strategies against cardiovascular risk factors from childhood,” the authors conclude. “This shouldn’t just be a matter of cognitive deficits prevention, but one of primordial prevention.”

Valentin Fuster, MD, PhD, MACC, editor-in-chief of JACC, adds that “Recent evidence has demonstrated that risk factors developed in adulthood can impact cognitive dysfunction in the elderly, if they have not been corrected. The findings in this paper are important, because they show that risk factors that develop at an even younger age can have the same adverse impact.” In an accompanying editorial, Donald M. Lloyd-Jones, MD, ScM, FACC, and Norrina B. Allen, PhD, MPH, note that, “These findings extend our prior understanding on the accumulation of cardiovascular risk and cognition back into childhood and suggest that the adverse impacts on later-life health begin accruing very early in life.”

Rovio SP, Pahkala K, Nevalainen J, et al. J Am Coll Cardiol 2017;69:2279-89.

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At an interim visit, the heart rate achieved in sinus rhythm was more strongly associated with mortality than the change in heart rate from baseline. The lowest mortality in sinus rhythm was observed in patients who attained lower heart rates after beta-blocker therapy. Neither attained nor change in heart rate was associated with survival in patients with AFib. The authors were not able to determine whether clinicians should strive to achieve a target heart rate or a target dose of beta-blocker.

“Ultimately, heart rate and prescribed beta-blocker dose are intimately related; one is a surrogate for the other although the relationship may be complicated by other factors such as genetic variations in beta-blocker response and drug metabolism,” the authors write. “Our observation of dose-related differences in mortality in patients assigned to placebo clearly demonstrates that it is unsafe to make strong inference from any analysis of a post-randomization variable such as dose. Dose achieved is itself an outcome, affected by confounding patient factors, adherence, physician preferences and bias, including the perceived risk of adverse outcomes,” they conclude.

Kotecha D, Flather MD, Altman DG, et al. J Am Coll Cardiol 2017;April 30:[Epub ahead of print].

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After the elimination of Tl-201 and before the widespread use of new camera technologies, the mean effective dose decreased from 17.9 mSv in 2009 to 12.1 mSv in 2016. Since the fall of 2012, the mean effective dose of the studies conducted on small FOV cameras with APPS was 5.6 mSv, and it was 2.8 mSv in the studies performed on CZT cameras. Over 69 percent of MPI studies were performed using low-dose, stress-only imaging. Mean body mass index (BMI) and mean effective dose were much higher for the patients imaged on large FOV cameras since 2014. Over the course of the study, the overall effective dose decreased 60 percent and the median effective dose decreased 76 percent. From 2014 to 2016, the mean dose of radiotracer rose slightly, as did mean BMI.

“This study demonstrates the compelling impact of a comprehensive radiation reduction strategy in a large nuclear cardiology laboratory network,” the authors write. “The data presented here demonstrate that adoption of widely available hardware and software options, and implementation of stress-first/stress-only protocols are practical in real-world daily practice and can result in very low radiation exposures for SPECT MPI.”

Thompson RC, O’Keefe JH, McGhie, AI, et al. JACC Cardiovasc Imaging 2017;May 6:[Epub ahead of print].

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Leadless pacemaker bradycardia pacing functionality was assessed. The mean pacing threshold, R-wave amplitude and impedance at implant were 0.53 ± 0.42 V at 0.5 msec, 19.9 ± 9.9 mV and 727 ±193 Ω, respectively. S-ICD heart rhythm discrimination was correct during intrinsic and leadless pacemaker pacing above the intrinsic rate and did not result in over-sensing. Unidirectional device-device communication from the S-ICD to the leadless pacemaker via conductive communication was successful in 306 of 309 communication attempts in the dorsal position of the animals. All ATP requests triggered by the S-ICD and received by the leadless pacemaker resulted in ATP delivery. There was a small increase in pacing threshold (p < 0.001) and decrease in R-wave amplitude (p = 0.001) and impedance (p = 0.04) between baseline and 90 days of follow-up. The chronic device-device communication success was 100 percent and all communication signals were successfully translated into ATP delivery by the leadless pacemaker.

The first-in-man trials with a validated and verified modular CRM system are planned and will combine leadless pacemaker and ICD therapy in a coordinated fashion.

Tjong FVY, Brouwer TF, Koop B, et al. JACC Clin Electrophysiol 2017;May 12:[Epub ahead of print].

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