Right and left ventricular interaction in pulmonary hypertension: Insight from velocity vector imaging.

OBJECTIVE: To evaluate whether global peak systolic strain (PSS) and peak systolic strain rate (PSSR) derived from velocity vector imaging (VVI) allow early recognition of regional and global right ventricular (RV) dysfunction and the impact of this on left ventricular (LV) function in patients with pulmonary hypertension (PHT). BACKGROUND: RV function is an important determinant of prognosis in patients with heart failure, pulmonary hypertension, heart transplant, and congenital heart diseases. However, evaluation of the right ventricle is often limited by its complex geometry and inadequate visualization of RV free wall. Furthermore, the impact of RV dysfunction on the LV function is not well elucidated. METHODS: Ninety-nine participants, 35 control patients with normal RV systolic pressure (RVSP) (<30 mm Hg) and 64 patients with PHT (25 with mild-to-moderate increase in RVSP [≥36 and <60 mm Hg] and 39 with severe increase in RVSP [≥60 mm Hg]), underwent comprehensive echo-Doppler assessment and velocity vector imaging (VVI) for strain rate analysis. RV regional peak systolic and diastolic tangential velocity, strain, and strain rate were obtained from the basal, mid and apical segments of the RV free wall and interventricular septum (IVS) from apical 4-chamber view at end-expiration. Similar data were obtained from eighteen LV segments from apical 4-chamber, 2-chamber, and long-axis views. RESULTS: Peak systolic strain, strain rate, and tangential velocity at all segments in the RV free wall and IVS were decreased compared to controls in patients with PHT (P < 0.001). Significant correlation (r > 0.60; P < 0.001) was noted between RVSP and systolic and diastolic strain and strain rate at basal segment in IVS and global RV function. Peak early diastolic strain rate at all segments was also decreased in PHT patients compared with control patients (P < 0.01). Furthermore, RV systolic and diastolic strain and strain rate were lower in group 2 with mild-to-moderate hypertension while the conventional echo parameters were normal. Except for IVS segments, other LV segments had no statistical differences in systolic and diastolic velocity, strain, and strain rate compared to controls. However, they were lower than the published normal range. CONCLUSIONS: Strain and strain rate derived from VVI demonstrates early recognition of systolic and diastolic RV dysfunction in patients with PHT compared to controls. PHT is associated with global and regional RV systolic and diastolic dysfunction. Systolic and diastolic strain and strain rate from LV was lower compared to controls but were not statistically significant. This may indicate subclinical LV dysfunction in these patients, suggesting that conventional LV function parameters may not be sensitive to recognize subclinical LV dysfunction.

Impact of Left Atrial Appendage Closure During Cardiac Surgery on the Occurrence of Early Postoperative Atrial Fibrillation, Stroke, and Mortality: A Propensity Score-Matched Analysis of 10 633 Patients.

BACKGROUND: Prophylactic exclusion of the left atrial appendage (LAA) is often performed during cardiac surgery ostensibly to reduce the risk of stroke. However, the clinical impact of LAA closure in humans remains inconclusive. METHODS: Of 10 633 adults who underwent coronary artery bypass grafting and valve surgery between January 2000 and December 2005, 9792 patients with complete baseline characteristics, surgery procedure, and follow-up data were included in this analysis. A propensity score-matching analysis based on 28 pretreatment covariates was performed and 461 matching pairs were derived and analyzed to estimate the association of LAA closure with early postoperative atrial fibrillation (POAF) (atrial fibrillation ≤30 days of surgery), ischemic stroke, and mortality. RESULTS: In the propensity-matched cohort, the overall incidence of POAF was 53.9%. In this group, the rate of early POAF among the patients who underwent LAA closure was 68.6% versus 31.9% for those who did not undergo the procedure (P<0.001). LAA closure was independently associated with an increased risk of early POAF (adjusted odds ratio, 3.88; 95% confidence interval, 2.89-5.20), but did not significantly influence the risk of stroke (adjusted hazard ratio, 1.07; 95% confidence interval, 0.72-1.58) or mortality (adjusted hazard ratio, 0.92; 95% confidence interval, 0.75-1.13). CONCLUSIONS: After adjustment for treatment allocation bias, LAA closure during routine cardiac surgery was significantly associated with an increased risk of early POAF, but it did not influence the risk of stroke or mortality. It remains uncertain whether prophylactic exclusion of the LAA is warranted for stroke prevention during non-atrial fibrillation-related cardiac surgery.

Real-time physiologic biomarker for prediction of atrial fibrillation recurrence, stroke, and mortality after electrical cardioversion: A prospective observational study.

BACKGROUND: Left atrial appendage emptying flow velocity (LAAEV) depends largely on left atrioventricular compliance and may play a role in mediating the perpetuation of atrial fibrillation (AF) and AF-related outcomes. METHODS: We identified 3,251 consecutive patients with sustained AF undergoing first-time successful transesophageal echocardiography (TEE)-guided electrical cardioversion who were enrolled in a prospective registry between May 2000 and March 2012. Left atrial appendage emptying flow velocity was stratified into quartiles: ≤20.2, 20.3-33.9, 34-49.9, and ≥50 cm/s. Multivariate Cox regression models were used to identify independent predictors of AF recurrence, ischemic stroke, and all-cause mortality. RESULTS: The mean (SD) age was 69 (12.6) years and 67% were men. Compared with the fourth quartile, patients in the first-third quartiles were significantly older, had higher CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack [TIA], vascular disease, age 65-74 years, sex category) scores, greater frequency of atrial spontaneous echo contrast, and AF of longer duration. Kaplan-Meier analysis showed a decreased probability of event-free survival with decreasing quartiles of LAAEV. Five-year cumulative event rates across first-fourth quartiles were 83%, 80%, 73%, and 73% (P < .001) for first AF recurrence; 7.5%, 7.0%, 4.1%, and 4.0%, for stroke (P = .01); and 31.3%, 26.1%, 24.1%, and 19.4%, for mortality (P < .001), respectively. Multivariate Cox regression analysis revealed an independent association of the first and second quartiles with AF recurrence (P < .001 and P < .001, respectively) and stroke (P = .03, and P = .04, respectively), and of the first quartile with mortality (P = .003). CONCLUSIONS: Patients with decreased LAAEV have an increased risk of AF recurrence, stroke, and mortality after successful electrical cardioversion. Real-time measurement of LAAEV by TEE may be a useful physiologic biomarker for individualizing treatment decisions in patients with AF.

Implications of new-onset atrial fibrillation after cardiac surgery on long-term prognosis: a community-based study.

BACKGROUND: Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery. Data are lacking on the long-term prognostic implications of POAF. We hypothesized that POAF, which reflects underlying cardiovascular pathophysiologic substrate, is a predictive marker of late AF and long-term mortality. METHODS: We identified 603 Olmsted County, Minnesota, residents without prior documented history of AF who underwent coronary artery bypass graft and/or valve surgery from 2000 to 2005. Patients were monitored for first documentation of late AF or death at >30 days postoperatively. Multivariate Cox regression models were used to assess the independent association of POAF with late AF and long-term mortality. RESULTS: After a mean follow-up of 8.3 ± 4.2 years, freedom from late AF was less with POAF than no POAF (57.4% vs 88.9%, P < .001). The risk of late AF was highest within the first year at 18%. Univariate analysis demonstrated that POAF was associated with significantly increased risk of late AF [hazard ratio (HR), 5.09; 95% CI, 3.65-7.22] and long-term mortality (HR, 1.79; 95% CI, 1.38-2.22). After adjustment for age, sex, and clinical and surgical risk factors, POAF remained independently associated with development of late AF (HR, 3.52; 95% CI, 2.42-5.13) but not long-term mortality (HR, 1.16; 95% CI, 0.87-1.55). Conversely, late AF was independently predictive of long-term mortality (HR, 3.25; 95% CI, 2.42-4.35). Diastolic dysfunction independently influenced the risk of late AF and long-term mortality. CONCLUSIONS: Postoperative atrial fibrillation was an independent predictive marker of late AF, whereas late AF, but not POAF, was independently associated with long-term mortality. Patients who develop new-onset POAF should be considered for continuous anticoagulation at least during the first year following cardiac surgery.

Left atrial anatomy and physiology: echo/Doppler assessment.

PURPOSE OF REVIEW: This article provides a state-of-the-art perspective of left atrial anatomy and physiology. RECENT FINDINGS: Left atrial structure and function can be used to reflect and quantify the physiologic state of complex disease processes. No single left atrial anatomic, functional, or clinical feature will adequately define a complex system. The state of combined left atrial structural and functional features (i.e., systems biology) defines disease clustering (i.e., commonality of underlying left atrial pathophysiology), cause and effect (i.e., left atrial dynamics impute disease events as consequences), disease classification (e.g., primary vs. secondary atrial fibrillation), and intensity of a pathophysiologic state (i.e., quantifiably infer the magnitude of a pathophysiologic perturbation), and helps explain complex pathophysiology (e.g., myocyte death vs. hibernation). SUMMARY: Individual left atrial structural and functional features do not define the state of complex systems. Systems biology and multifeature profiles of left atrial anatomy and physiology should be used to assist the prediction, management, and, ultimately, prevention of preclinical and overt complex disease processes.

Cardiac evaluation of collegiate student athletes: a medical and legal perspective.

Physicians participate in the screening, routine medical supervision, and disqualification process of collegiate student athletes today. Physicians and universities evaluating collegiate student athletes for athletic participation should understand the meticulous medical process necessary to make eligibility/disqualification decisions and the associated liability issues. It is the responsibility of a team physician to take the lead role in the college sports medical evaluation process. The first duty of a team physician and institution is to protect the health and well-being of their collegiate student athletes. The potential liability associated with the evaluation process requires institutions of higher education and physicians to develop sound and reasonable administrative strategies regarding college athletes and their participation in intercollegiate athletics. Reducing this liability risk requires an understanding of the evolving judicial framework and compliance with standard case law and available guidelines. As medical professional standards evolve, so will responsibilities under legal standards.

The ABCs of left ventricular assist device echocardiography: a systematic approach.

Echocardiography is an important imaging modality used to determine the indication of left ventricular assist device (LVAD) implantation for patients with advanced heart failure (HF) and for serial follow-up to make management decisions in patient care post-implant. Continuous axial-flow LVAD therapy provides effective haemodynamic support for the failing left ventricle, improving both the clinical functional status and quality of life. Echocardiographers must develop a systematic approach to echocardiographic assessment of LVAD implantation and post-LVAD implant cardiac morphology and physiology. This approach must include the evaluation of left and right heart chamber morphology and physiology and the anatomy and physiology of the inflow and outflow cannulas and the rotor pump, and the determination of the degree of tricuspid regurgitation and the presence of interatrial shunts and aortic regurgitation. Collaboration among the echocardiography and HF/transplant teams is essential to obtain this comprehensive evaluation. We outline a systematic approach to evaluating patients with HF who have failed conventional therapy and require LVAD therapy as a bridge to cardiac transplantation or destination therapy.

March Madness 2011: for whom the bell tolls?

The American Heart Association has developed 12 recommendations for preparticipation screening of high school and college athletes, but the application of these recommendations across the US is inconsistent. A recent clinical study suggests that the incidence and prevalence of sudden athletic death (SAD) is greater than previously believed. Currently, diagnostic screening is considered too expensive and is delivered sporadically. Logic dictates that the medical community must become more involved in reducing the incidence and prevalence of SAD through an improved preparticipation screening process. An effective screening process must be able to reproducibly predict and prevent potential risk using the most effective resources and keeping the cost-benefit ratio at a minimum. The most effective use of our resources will limit the potential of liability for institutions and physicians and, hopefully, eliminate episodes of SAD.

Left ventricular noncompaction: a 25-year odyssey.

Left ventricular noncompaction (LVNC) is a cardiomyopathy associated with sporadic or familial disease, the latter having an autosomal dominant mode of transmission. The clinical features associated with LVNC vary from asymptomatic to symptomatic patients, with the potential for heart failure, supraventricular and ventricular arrhythmias, thromboembolic events, and sudden cardiac death. Echocardiography is the diagnostic modality of choice, revealing the pathognomonic features of a thick, bilayered myocardium; prominent ventricular trabeculations; and deep intertrabecular recesses. Widespread use and advances in the technology of echocardiography and cardiac magnetic resonance imaging are increasing awareness of LVNC, and cardiac magnetic resonance imaging is improving the ability to stage the severity of the disease and potential for adverse clinical consequences. Study of LVNC through research in embryology, imaging, and genetics has allowed enormous strides in the understanding of this heterogeneous disease over the past 25 years.

Diastolic dysfunction in patients undergoing cardiac surgery: a pathophysiological mechanism underlying the initiation of new-onset post-operative atrial fibrillation.

OBJECTIVES: Our goal was to investigate whether left ventricular (LV) diastolic dysfunction was an important pathophysiological mechanism underlying the initiation of new-onset post-operative atrial fibrillation (POAF). BACKGROUND: Atrial fibrillation is a common complication after cardiac surgery. However, the precise mechanism underlying its development remains poorly understood. Pre-existing alterations of myocardial diastolic function may predispose patients to the development of POAF. METHODS: Patients were residents of Olmsted County, Minnesota, who underwent complete LV diastolic function assessment before coronary artery bypass grafting and/or valve surgery between January 1, 2000, and December 31, 2005. All were in sinus rhythm and had no history of atrial fibrillation, a pacemaker, mitral stenosis, or congenital heart disease. POAF was defined as any episode of atrial fibrillation within 30 days after surgery. RESULTS: POAF occurred in 135 of 351 patients (38.5%). Patients with POAF were older (mean age 72.5 ± 10.3 years vs. 63.1 ± 14.1 years; p < 0.001) and more likely to have abnormal diastolic function. The rate of POAF increased exponentially with diastolic function grade (DFG) severity (p < 0.001). By multivariate analysis, after adjusting for clinical and surgical risk factors, independent predictors of POAF were older age (odds ratio [OR]: 1.05; p < 0.001), higher body mass index (OR: 1.06; p = 0.03), and abnormal LV DFG (DFG 1, OR: 5.12 [p = 0.006]; DFG 2, OR: 9.87 [p < 0.001]; and DFG 3, OR: 28.52 [p < 0.001]). CONCLUSIONS: LV diastolic dysfunction is a powerful, independent predisposing substrate for the initiation of POAF. Evaluation may be useful during risk stratification of patients undergoing cardiac surgery.

Left atrial function: physiology, assessment, and clinical implications.

The interest in the left atrium (LA) has resurged over the recent years. In the early 1980s, multiple studies were conducted to determine the normal values of LA size. Over the past decade, LA size as an imaging biomarker has been consistently shown to be a powerful predictor of outcomes, including major public health problems such as atrial fibrillation, heart failure, stroke, and death. More recently, functional assessment of the LA has been shown to be, at least as, if not more robust, a marker of cardiovascular outcomes. Current available data suggest that the combined evaluation of LA size and LA function will augment prognostication. The aim of this review is to provide a critical appraisal of current echocardiographic techniques for the assessment of LA function and the implications of such assessment for prediction and disease prevention.

Left atrial volume in children without heart disease and in those with ventricular septal defect or patent ductus arteriosus or hypertrophic cardiomyopathy.

In adults, the left atrial (LA) volume has been shown to reflect diastolic function and is a powerful predictor of cardiac morbidity and mortality. Normative LA volume values in children and the effect of loading conditions on the LA volume in those with congenital heart disease are lacking. The purposes of the present study were to (1) establish normal LA volume values for children, (2) assess the effect of left ventricular volume loading conditions on LA volume, and (3) describe the effect of abnormal myocardial relaxation on the LA volume. We retrospectively reviewed the echocardiograms from 3 pediatric cohorts: group N (n = 522), children with normal echocardiographic findings; group VSD/PDA (n = 71), children with ventricular septal defect (VSD; n = 50) or patent ductus arteriosus (PDA; n = 21); and group HC (n = 63), children with hypertrophic cardiomyopathy (HC). In group N, we identified the LA volume indexed to the body surface area (LA volume index) as a consistent measure of the LA volume in children 3 to 23 months old (mean 16 ± 3 ml/m(2)) and 2 to 17 years old (mean 22 ± 4 ml/m(2)). LA dilation was more common in group VSD/PDA than in group N (27% vs 2%, p <0.0001) and in children with moderate or large shunts than in those with smaller shunts (61% vs 5%, p <0.0001). In group HC, the LA volume index correlated with the mitral valve E/e' ratio (p <0.0001). In conclusion, this is the first study to establish normal pediatric LA volume values. The LA volume index is a reproducible measure of LA size in children ≥ 3 months old. The LA volume index reflects a chronically increased left ventricular volume load in children with VSD or PDA and chronically elevated left ventricular filling pressures in children with HC.

Infiltrative cardiovascular diseases: cardiomyopathies that look alike.

Infiltrative cardiomyopathies are characterized by the deposition of abnormal substances that cause the ventricular walls to become progressively rigid, thereby impeding ventricular filling. Some infiltrative cardiac diseases increase ventricular wall thickness, while others cause chamber enlargement with secondary wall thinning. Increased wall thickness, small ventricular volume, and occasional dynamic left ventricular outflow obstruction (e.g., amyloidosis) can outwardly appear similar to conditions with true myocyte hypertrophy (e.g., hypertrophic cardiomyopathy, hypertensive heart disease). Likewise, infiltrative disease that presents with a dilated left ventricle with global or regional wall motion abnormalities and aneurysm formation (e.g., sarcoidosis) may mimic ischemic cardiomyopathy. Low-voltage QRS complex was the sine qua non of infiltrative cardiomyopathy (i.e., cardiac amyloid). However, low-voltage QRS complex is not a uniform finding with the infiltrative cardiomyopathies. The clinical presentation, along with functional and morphologic features, often provides enough insight to establish a working diagnosis. In most circumstances, however, tissue or serologic evaluation is needed to validate or clarify the cardiac diagnosis and institute appropriate therapy.

C-reactive protein, left atrial volume, and atrial fibrillation: a prospective study in high-risk elderly.

BACKGROUND: The data regarding the interrelationships of high-sensitive C-reactive protein (CRP), left atrial (LA) volume, and atrial fibrillation (AF) are sparse. Additionally, while LA volume has been shown to be useful for prediction of AF in low-to-moderate risk populations, its predictive value in clinically high-risk populations is unknown. METHODS: SAFHIRE (Study of Atrial Fibrillation in High Risk Elderly) is an ongoing prospective study of the pathophysiology of first AF in persons aged > or = 65 years with > or = 2 other AF risk factors [systemic hypertension, proven coronary artery disease, heart failure (HF), diabetes]. Participants are followed annually, and undergo an interview, physical examination, blood work, electrocardiogram, and echocardiogram assessment. RESULTS: Of 800 participants, mean age of 74 +/- 6 years, 34 developed first AF over 1.7+/- 0.9 years. A history of systemic hypertension and proven coronary artery disease was present in 97% and 78%, respectively. CRP was unrelated to LA volume on univariable or multivariable analyses (P > 0.10), and not predictive of first AF on univariable or multivariable models (all P > 0.10). Indexed LA volume was an independent predictor of first AF (unadjusted P< 0.0001; age and sex adjusted P = 0.0006; adjusted for multiple factors, HR 1.3/5 ml per m(2), 95% CI, 1.09 to 1.48, P = 0.001). CONCLUSION: In this elderly population at high clinical risk for the development of first AF, CRP was unrelated to LA volume and nonpredictive of first AF, while indexed LA volume was incremental to clinical risk factors for the prediction of first AF.

Echo Doppler guidance for atrial fibrillation ablation: recognition of primary electropathy.

Atrial fibrillation (AF) is a multivariable disease. Young patients with paroxysmal AF without structural cardiac abnormality ("lone AF") likely have a primary electropathy with excellent results from radiofrequency ablation. However, with persistent AF with cardiac abnormalities, including left atrial enlargement and systolic ventricular dysfunction (ejection fraction percent), the electropathy is considered secondary and ablation results poor. We describe a case with persistent AF, depressed systolic function, and marked left atrial enlargement but without echo Doppler evidence of diastolic dysfunction. At electrophysiology study, findings were consistent with a primary electropathy, and the patient did well following ablation.

Acute weight gain and diastolic dysfunction as a potent risk complex for post stem cell transplant atrial fibrillation.

The management of atrial fibrillation (AF) following stem cell transplant (SCTX) is often challenging because of the universal presence of profound bone marrow suppression. The incidence of and risk factors for AF/flutter following SCTX are not well known. A total of 395 multiple myeloma (MM) patients consecutively underwent SCTX between 2002 and 2005 at the Mayo Clinic, and 383 of whom, mean age 57 +/- 9 years, had no history of evidence of AF/flutter constituted the study population. During 1,002 person-years of follow up, 39 (10%) patients developed first AF/flutter (incidence of 39 per 1,000 person years), and 28 of these (72%) occurred within 21 days of SCTX. In multivariable-adjusted analyses, weight gain of > or = 7% in the 1st week post-SCTX (HR 3.68; P = 0.0120) and presence of diastolic dysfunction at MM diagnosis (HR 2.294; P = 0.0082) were independent predictors of AF/flutter. The risk of AF/flutter post-SCTX increased by about ninefold when both factors were present. Compared to age and sex-matched MM patients without SCTX, the risk of AF/flutter differed significantly only over the 1st year after MM diagnosis, during which SCTX was performed for the majority. Beyond the 1st year, there was no significant difference in risk of AF/flutter between the two groups. The data suggested that SCTX was associated with significantly increased risk of first AF/flutter, which typically occurred within the first 21 days of the transplant. Weight gain of > or = 7% was strongly predictive of first AF/flutter, and the risk was augmented by the presence of diastolic dysfunction at baseline.

Minimum vs. maximum left atrial volume for prediction of first atrial fibrillation or flutter in an elderly cohort: a prospective study.

AIMS: We sought to compare the predictive power and reproducibility between minimum and maximum left atrial (LA) volume for the development of first atrial fibrillation (AF)/flutter. METHODS AND RESULTS: This prospective study included 574 adults, mean age 74+/-6 years, in sinus rhythm, and had no history or evidence of prior atrial arrhythmias. During a mean follow-up of 1.9+/-1.2 years, 30 (5.2%) developed first AF/flutter. The 3-year risk estimates of freedom from AF/flutter by tertiles of minimum and maximum LA volumes were, respectively, 97, 87, and 74% (P<0.0006) and 94, 85, and 78% (P=0.03). Minimum LA volume was incremental to clinical and other echocardiographic parameters of AF/flutter prediction [per tertile, hazard ratio (HR) 2.4], as was maximum LA volume (per tertile, HR 1.8) in a separate model. When both volumes were entered into the same model and adjusting for covariates, minimum but not maximum LA volume retained significance. However, in terms of interobserver reproducibility, maximum LA volume compared more favourably (mean difference 3.1+/-7.1 vs. 7.4+/-7.3 mL/m(2)). CONCLUSION: Minimal LA volume was an independent predictor of first AF/flutter. Although it was marginally superior to maximal LA volume in terms of predictive ability, the interobserver variability was greater.