Abnormal global longitudinal strain (GLS) has been independently associated with adverse cardiac outcomes in both obstructive and nonobstructive hypertrophic cardiomyopathy.
The goal of this study ...was to understand predictors of abnormal GLS from baseline data from the National Heart, Lung, and Blood Institute (NHLBI) Hypertrophic Cardiomyopathy Registry (HCMR).
The study evaluated comprehensive 3-dimensional left ventricular myocardial strain from cine cardiac magnetic resonance in 2,311 patients from HCMR using in-house validated feature-tracking software. These data were correlated with other imaging markers, serum biomarkers, and demographic variables.
Abnormal median GLS (> –11.0%) was associated with higher left ventricular (LV) mass index (93.8 ± 29.2 g/m2 vs 75.1 ± 19.7 g/m2; P < 0.0001) and maximal wall thickness (21.7 ± 5.2 mm vs 19.3 ± 4.1 mm; P < 0.0001), lower left (62% ± 9% vs 66% ± 7%; P < 0.0001) and right (68% ± 11% vs 69% ± 10%; P < 0.01) ventricular ejection fractions, lower left atrial emptying functions (P < 0.0001 for all), and higher presence and myocardial extent of late gadolinium enhancement (6 SD and visual quantification; P < 0.0001 for both). Elastic net regression showed that adjusted predictors of GLS included female sex, Black race, history of syncope, presence of systolic anterior motion of the mitral valve, reverse curvature and apical morphologies, LV ejection fraction, LV mass index, and both presence/extent of late gadolinium enhancement and baseline N-terminal pro–B-type natriuretic peptide and troponin levels.
Abnormal strain in hypertrophic cardiomyopathy is associated with other imaging and serum biomarkers of increased risk. Further follow-up of the HCMR cohort is needed to understand the independent relationship between LV strain and adverse cardiac outcomes in hypertrophic cardiomyopathy.
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Objectives We studied associations of magnetic resonance imaging measurements of plaque area and relative percent lumen reduction in the proximal superficial femoral artery with functional ...performance among participants with peripheral arterial disease. Background The clinical significance of directly imaged plaque characteristics in lower extremity arteries is not well established. Methods A total of 454 participants with an ankle brachial index <1.00 underwent magnetic resonance cross-sectional imaging of the proximal superficial femoral artery and completed a 6-min walk test, measurement of 4-m walking velocity at usual and fastest pace, and measurement of physical activity with a vertical accelerometer. Results Adjusting for age, sex, race, body mass index, smoking, statin use, comorbidities, and other covariates, higher mean plaque area (1st quintile least plaque: 394 m, 2nd quintile: 360 m, 3rd quintile: 359 m, 4th quintile: 329 m, 5th quintile greatest plaque: 311 m; p trend <0.001) and smaller mean percent lumen area (1st quintile greatest plaque: 319 m, 2nd quintile: 330 m, 3rd quintile: 364 m, 4th quintile: 350 m, 5th quintile: 390 m; p trend <0.001) were associated with shorter distance achieved in the 6-min walk test. Greater mean plaque area was also associated with slower usual-paced walking velocity (p trend = 0.006) and slower fastest-paced 4-m walking velocity (p trend = 0.003). Associations of mean plaque area and mean lumen area with 6-min walk distance remained statistically significant even after additional adjustment for the ankle brachial index and leg symptoms. Conclusions Among participants with peripheral arterial disease, greater plaque burden and smaller lumen area in the proximal superficial femoral artery are associated independently with poorer functional performance, even after adjusting for the ankle brachial index and leg symptoms.
Optogenetics has become an emerging technique for neuroscience investigations owing to the great spatiotemporal precision and the target selectivity it provides. Here we extend the optogenetic ...strategy to GABA(A) receptors (GABA(A)Rs), the major mediators of inhibitory neurotransmission in the brain. We generated a light-regulated GABA(A) receptor (LiGABAR) by conjugating a photoswitchable tethered ligand (PTL) onto a mutant receptor containing the cysteine-substituted alpha 1-subunit. The installed PTL can be advanced to or retracted from the GABA-binding pocket with 500 and 380 rim light, respectively, resulting in photoswitchable receptor antagonism. In hippocampal neurons, this LiGABAR enabled a robust photoregulation of inhibitory postsynaptic currents. Moreover, it allowed reversible photocontrol over neuron excitation in response to presynaptic stimulation. LiGABAR thus provides a powerful means for functional and mechanistic investigations of GABA(A)R-mediated neural inhibition.
New left ventricular systolic dysfunction affects 500,000 Americans and coronary artery disease (CAD) is responsible for two-thirds of cases. Identifying CAD has both prognostic and therapeutic ...implications. We evaluated the ability of late gadolinium enhancement (LGE) by cardiovascular magnetic resonance imaging (CMR) to detect CAD as the etiology of recent onset congestive heart failure (CHF).
CMR and LGE were performed in 26 patients with new onset left ventricular systolic dysfunction. All patients received an x-ray angiography for identification of CAD. Patients with an acute coronary syndrome with troponin I > 1.0 ng/ml or a history of CAD were excluded. The presence and distribution of LGE was evaluated.
Significant coronary stenoses were present in 5 of 26 patients (19%). LGE in an infarct pattern was found in 2 of the 5 patients with CAD. Of the 21 patients without CAD, 2 had midwall enhancement but none had evidence of LGE in an infarct pattern.
When present, LGE in an infarct pattern suggests CAD as the etiology of new onset CHF. However, the absence of LGE does not exclude CAD as the underlying etiology. A small proportion of patients with a nonischemic cause of new onset CHF have LGE limited to the midwall.
The current accepted risk factors for primary prevention therapy with implantable cardioverter-defibrillators (ICDs) include: 1) family history of HCM-related SCD; 2) unexplained recent syncope; 3) ...massive left ventricular (LV) hypertrophy (thickness >30 mm); 4) nonsustained ventricular tachycardia on 24-h Holter monitor; and 5) hypotensive or attenuated blood pressure response to exercise (1). (16) followed 424 patients with HCM (mean age 55 years) over 3.6 years and demonstrated a strong association of LGE with SCD and appropriate ICD discharges even after controlling for other variables. ...the studies in this issue of the Journal add to the growing body of literature suggesting that LGE should be considered as an independent predictor of adverse cardiac outcomes.
The American College of Cardiology Foundation (ACCF), Society for Cardiovascular Angiography and Interventions, Society of Thoracic Surgeons, and the American Association for Thoracic Surgery, along ...with key specialty and subspecialty societies, conducted an update of the appropriate use criteria (AUC) for coronary revascularization frequently considered. In the initial document, 180 clinical scenarios were developed to mimic patient presentations encountered in everyday practice and included information on symptom status, extent of medical therapy, risk level as assessed by noninvasive testing, and coronary anatomy. This update provides a reassessment of clinical scenarios the writing group felt to be affected by significant changes in the medical literature or gaps from prior criteria. The methodology used in this update is similar to the initial document, and the definition of appropriateness was unchanged. The technical panel scored the clinical scenarios on a scale of 1 to 9. Scores of 7 to 9 indicate that revascularization is considered appropriate and likely to improve patients' health outcomes or survival. Scores of 1 to 3 indicate revascularization is considered inappropriate and unlikely to improve health outcomes or survival. Scores in the mid-range (4 to 6) indicate a clinical scenario for which the likelihood that coronary revascularization will improve health outcomes or survival is uncertain. In general, as seen with the prior AUC, the use of coronary revascularization for patients with acute coronary syndromes and combinations of significant symptoms and/or ischemia is appropriate. In contrast, revascularization of asymptomatic patients or patients with low-risk findings on noninvasive testing and minimal medical therapy are viewed less favorably. The technical panel felt that based on recent studies, coronary artery bypass grafting remains an appropriate method of revascularization for patients with high burden of coronary artery disease (CAD). Additionally, percutaneous coronary intervention may have a role in revascularization of patients with high burden of CAD. The primary objective of the appropriate use criteria is to improve physician decision making and patient education regarding expected benefits from revascularization and to guide future research.
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