Influence of obstructive sleep apnea and treatment with continuous positive airway pressure on fractional flow reserve measurements for coronary lesion assessment.

Obstructive sleep apnea (OSA) and sleep-disordered breathing have been implicated in the progression of cardiovascular disease and with increased risk of coronary artery disease, congestive heart failure, and stroke. Fractional flow reserve (FFR) is used to evaluate the physiological significance of coronary artery stenosis, and this technique is largely thought to be independent of systemic hemodynamic changes. Herein, we describe a case of OSA and sleep-disordered breathing cyclically altering FFR measurements from normal to abnormal in a patient with coronary artery disease. More specifically, we show that the abnormal FFR across a coronary lesion in a patient with sleep disordered apnea improves (to a normal threshold) with the initiation of continuous positive airway pressure (CPAP). This finding may have implications for the mechanisms of cardiac dysfunction in patients with OSA.

Variations in Thebesian valve anatomy and coronary sinus ostium: implications for invasive electrophysiology procedures.

AIMS: The coronary sinus (CS) is a commonly cannulated structure in patients undergoing electrophysiology studies, catheter ablation of arrhythmias, implantation of resynchronization therapy devices and, more recently, percutaneous mitral valve repair. The advent of these procedures has led to a renewed interest in the anatomy of the coronary venous system including its various components. To improve our understanding of this structure, we studied the anatomy of the human CS, including the valve that guards its ostium, the Thebesian valve. METHODS AND RESULTS: In 75 randomly selected autopsied human hearts, we measured the transverse and craniocaudal dimensions of the CS ostium and characterized the shape, composition, per cent coverage, and attachment points of the Thebesian valve when present. Of the 75 hearts examined, 54 had organic heart disease including atherosclerotic coronary artery disease, left ventricular hypertrophy, dilated cardiomyopathy, rheumatic heart disease, infective endocarditis, and non-rheumatic valvular heart disease. A wide variety of Thebesian valve morphologies were seen, ranging from the absence of any valve to those where the valve was completely occluding the CS ostium. A Thebesian valve was present in the majority of the hearts examined (55/75 hearts-73%). The average transverse dimension of the CS ostium in hearts with Thebesian valves (7.3+/-2.8 mm) was significantly shorter than those without Thebesian valves (9.4+/-2.9 mm, P=0.005). Similarly, the average craniocaudal dimension of the CS ostium in hearts with Thebesian valves (7.9+/-2.7 mm) was also significantly shorter than those without Thebesian valves (9.3+/-2.9 mm, P=0.045). CONCLUSION: Our study shows that some form of Thebesian valve is present in the majority of hearts (>70%). Of these, a significant minority (16%) had a valve morphology (covering >75% of the ostium, a fibrous, fibromuscular, or muscular composition, and devoid of fenestrations) that makes them a 'potentially complicating' structure interfering with the cannulation of the CS.

Utility of B-natriuretic peptide in the evaluation of left ventricular diastolic function: comparison with tissue Doppler imaging recordings.

BACKGROUND: Although Doppler echocardiography provides assessment of abnormal left ventricular (LV) diastolic filling dynamics, its inherent limitations suggest the need for additional measures of diastolic dysfunction. The ratio of mitral velocity to early diastolic velocity of the mitral annulus (E/E') derived from tissue Doppler imaging is associated with the mean LV end diastolic pressure (LVEDP). Because data suggest that B-natriuretic peptide (BNP) reflects ventricular pressure, we hypothesized that BNP levels correlate with indices of LV diastolic function by tissue Doppler imaging. METHODS AND RESULTS: Doppler recordings of the mitral inflow and tissue Doppler imaging of the mitral annulus were obtained in 108 patients referred for echocardiography. BNP levels were measured by a rapid immunoassay and blinded to cardiologists making the assessment of LV function. BNP levels were higher when elevated E/E' ratios derived from tissue Doppler imaging were identified. Patients identified with elevated LVEDP, defined as E/E' >15 (n = 16), had the highest BNP levels (463 +/- 80 pg/mL). Those with normal LVEDP, as predicted by E/E' <8 (n = 36), had a mean BNP concentration of 97 +/- 27 pg/mL. Those with E/E' of 8 to 15 (n = 48) had a mean BNP level of 122 +/- 24 pg/mL. The area under the receiver-operating curve for BNP to detect E/E' >15 was 0.89 (95% CI, 0.82 to 0.96; P < .001). A BNP value of 173 pg/mL had a sensitivity of 88%, a specificity of 82%, and an accuracy of 83% for predicting E/E' >15. CONCLUSIONS: BNP levels correlate with the E/E' ratios from tissue Doppler imaging (r = 0.48) and can reliably provide estimation of LV filling pressures. Although BNP levels do not correlate well with E/E' ratios across the full spectrum of values, the combination of BNP levels along with E/E' ratios from tissue Doppler imaging may be a better predictor of elevated LV filling pressures in patients with suspected diastolic dysfunction.

Effects of subacute dietary salt intake and acute volume expansion on diastolic function in young normotensive individuals.

AIMS: Chronic excess salt intake may have blood pressure-independent adverse effects on the heart such as myocardial hypertrophy and fibrosis. Effects of subacute sodium loading with excess dietary salt on diastolic function in normotensive individuals have been conflicting and the mechanisms are poorly understood. METHODS AND RESULTS: Thirteen healthy normotensive subjects (age 24 ± 4 years) entered a 2-week crossover study with 1 week of a low-salt diet <10 mEq/day and 1 week of a high-salt diet >200 mEq/day. At the end of each study week, left ventricular dimensions, systolic, and diastolic function were assessed with echocardiography before and after 2 L of normal saline infusion. One week of high-salt and low-salt diets did not lead to differences in echocardiographic parameters of systolic or diastolic function, even after rapid volume expansion with saline infusion. The peak early diastolic strain rate (SR) increased after volume loading both after completion of low-salt (1.62 ± 0.23/s vs. 1.82 ± 0.14/s, P < 0.05) and high-salt diets (1.67 ± 0.16/s vs. 1.86 ± 0.22/s, P < 0.05). There was a positive correlation between the peak early diastolic SR and the cardiac index (r = 0.52, P = 0.017). CONCLUSION: In healthy normotensive individuals, subacute excess dietary sodium intake does not affect diastolic function. The peak early diastolic SR, similar to other mitral Doppler and tissue Doppler parameters of diastolic function, appears to be strongly dependent on pre-load.

Cardiac CT: Imaging of and Through Cardiac Devices.

For patients with cardiac devices, cardiac computed tomography (CT) remains the mainstay for imaging due to its superior resolution as compared with echocardiography and nuclear studies and no contraindication to metal as with cardiac magnetic resonance imaging. This review focuses on the evaluation and pitfalls of coronary arterial imaging in patients with devices, such as pacemakers, implantable defibrillators, cardiac resynchronization therapy (CRT), as well as complications such as lead perforation and safety concerns of CT interference. We discuss both pre- and post-procedural CRT assessment for coronary venous imaging and pre-procedural myocardial scar assessment to localize regions of scar and peri-infarct zone to facilitate ventricular tachycardia ablation in patients with devices. We describe potential new research on dyssynchrony and integration with myocardial scar and site of latest activation for patients with or being considered for CRT. We detail the utility of CT for the assessment of proper function and complications in patients with left ventricular assist device implantation.

Pericardial diseases.

The pericardium provides an enclosed lubricated space for the beating heart and functions to fix the heart in the chest cavity relative to adjacent organs. Pericardial pathophysiology is often manifested in a spectrum of distinct cardiac and systemic disease states. The pericardial response to injury typically involves a spectrum of inflammation with both acute and chronic features and/or fluid accumulation. Recent advances in imaging methods have refined the diagnosis and therapy of pericardial disease. This article presents the anatomy and physiology of pericardial disease and the clinical approach for diagnosis and treatment.