Hemodynamic basis of mitral E transmission in the left ventricular cavity and its relation to the left ventricular relaxation process

Mitral E-wave transit time to the left ventricular outflow tract was measured as an E-Er interval in 30 subjects undergoing cardiac catheterization. The E-Er interval (range 30 to 190 ms) correlated with left ventricular peak negative dP/dt (r = -0.62, p = 0.0003) and tau (r = 0.74, p <0.0001) but not with left ventricular minimum, pre-A-wave, or end-diastolic pressures. We conclude that the E-Er interval is an easily obtainable Doppler measurement that reflects the left ventricular relaxation process.

Effect of Programmed Atrioventricular Delay on the Patterns of Mitral and Pulmonary Vein Flow Profiles and Their Durations in Patients with Dual-Chamber Pacemakers

Cardiac pacemakers are increasingly used in patients with dilated and hypertrophic cardiomyopathy. In these patients, unusually short atrioventricular (AV) delays are used. Changing the AV delay has been shown to affect the mitral E/A velocity ratio, but its effect on the duration of left ventricular (LV) isovolumic relaxation time, LV filling time, or pulmonary vein flow pattern has not been investigated. Twelve patients with dual-chamber pacemakers were studied. The pacemaker was set at a rate of 70 beats/min, and the AV delay was programmed from 25 to 250 msec in 25-msec increments. At each stage, mitral and pulmonary vein flow velocities were recorded using pulsed-wave Doppler technique. Increasing AV delay resulted in a shortened LV diastolic filling period, a change in LV isovolumic relaxation time, a reduction in the E/A velocity ratio, and an increase in A - AR wave duration. These findings have implications not only in the optimization of LV filling but also in the interpretation of mitral and pulmonary vein flow profiles in the evaluation of LV diastolic function and filling pressures.

A rare case of inferior venacaval type of atrial septal defect in an adult: echocardiographic features

We report a rare type of atrial septal defect with communication between the left atrium and the inferior vena cava. This type of defect has been referred to as a low sinus venous type of atrial septal defect because of its developmental origin, and possibly is caused by defective absorption of the left venous valve of the sinus venosus into the septum secundum. Detailed echocardiographic features are discussed.

Prognostic implications of echocardiographic measures of left and right atrial pressures on survival in patients with end stage renal disease

BACKGROUND

Volume excess is common in patients with end stage renal disease (ESRD). We examined the prognostic value of clinical and echocardiographic measures of left (LA) and right atrial (RA) hypertension in this population.

METHOD

We prospectively collected demographic, clinical, pharmacological, echocardiographic data on 575 consecutive ESRD patients on hemodialysis undergoing cardiac evaluation before renal transplantation in a dedicated cardiac clinic. Survival was analyzed as a function of clinical and echocardiographic measures of LA and (RA) hypertension.

RESULT

Elevated LA pressure was seen in 48% of the patients based on E/e' velocity ratio of ≥ 15, and 28% had elevated RA pressure based on inferior vena caval size. Physical examination grossly underestimated the prevalence of both LA and RA hypertension. Atrial pressures were normal in 46% and both atrial pressures were elevated in 20% of the patients. Elevated LA pressure in the presence of normal RA pressure was found in 30%. Over a period of 20 ± 8 months, there were 43 deaths. There was a graded increase in mortality with increases in LA and bi-atrial hypertension (p = .009). The 2-year mortality rate was 6% in those with normal atrial pressures, 13% in those with isolated LA hypertension and 28% in those with bi-atrial hypertension.

CONCLUSION

Mitral E/e' ratio and inferior vena caval size are vastly more sensitive than physical examination for recognition of elevated atrial pressures and are strong predictors of survival in ESRD patients. Limited echocardiographic examination may have a role in ESRD patients undergoing dialysis to help achieve euvolemic status.

Prognostic value of cardiac magnetic resonance imaging in patients with aortic regurgitation

Guidelines on valve replacement recommend aortic valve replacement for patients with severe aortic regurgitation (AR) with symptoms or left ventricular (LV) dysfunction. However, the optimal timing of surgery for asymptomatic AR patients without LV dilation or dysfunction is not known. There are data to suggest that excess volume load imposed by AR may not only produce subclinical LV dysfunction, but produce neurohormonal activation similar to the heart failure syndrome resulting in reduced survival. The study by Myerson et al. is the first to investigate the predictive ability of cardiac MRI (CMR) for the outcome of asymptomatic patients with AR. They studied 113 asymptomatic patients with moderate-to-severe AR on echocardiography in four centers. A total of 39 (35%) patients developed symptoms or an indication for surgery over a mean follow-up period of 2.6 years. AR volume, AR regurgitant fraction, LV end-diastolic and end-systolic volumes had high discriminatory powers (area under curve of 0.96, 0.93, 0.88 and 0.78, respectively) to predict these events. Higher association with the outcome was observed when LV end-diastolic volume and regurgitant fraction were combined. A significantly higher number of patients with regurgitant fraction >33% were likely to progress to surgery compared with patients with a regurgitant fraction of <33% (85 vs 8%; p < 0.001). These results demonstrate a potential role for CMR for risk stratification of patients with asymptomatic moderate or severe AR, given the ability of CMR to accurately quantify AR and LV volumes. Based on the data presented, it is possible that we may be waiting too long to offer surgery in patients with severe AR.

Noninvasive Assessment With Transthoracic Echocardiography in End-Stage Heart Failure

Heart failure is a common cardiac condition that carries a substantial risk of morbidity and mortality despite advances in management. Echocardiography plays a central role in its diagnosis, elucidation of mechanisms, and detailed hemodynamic analysis. In this E-Challenge, the authors review a few transthoracic echocardiographic findings that yield insights into the hemodynamics.

Synthetic Fibroblasts: Terra Incognita in Cardiac Regeneration

Ischemic heart disease, a major risk factor for myocardial infarction (MI), occurs when the blood vessels supplying oxygen-rich blood to the heart become partially or fully occluded by lipid-rich plaques, resulting in myocardial cell death, remodeling, and scarring. In addition, MI occurs as result of lipid-rich plaque rupture, resulting in thrombosis and vessel occlusion. Cardiac fibroblasts (CFs) and CF-derived growth factors are crucial post-MI in myocardial remodeling. Information regarding the regenerative phenotypes of CFs is scarce; however, regenerative CFs are translationally relevant in myocardial regeneration following MI. The emerging technologies in regenerative cardiology offer cutting-edge translational opportunities, including synthetic cells. In this review, we critically reviewed the current knowledge and the ongoing research efforts on application of synthetic cells for improving cardiac regeneration post-MI. Impact statement Synthetic cells offer tremendous regenerative potential in otherwise deleterious cardiac remodeling postmyocardial infarction. Understanding the role of fibroblasts in cardiac healing and the therapeutic applications of synthetic cells would open a multitude of novel cardiac regenerative approaches. The novel concept of synthetic fibroblasts that emulate native cardiac fibroblasts can provide an effective solution in cardiac healing.

Prevalence and Clinical Significance of an E-Reversal Wave in the Left Ventricular Outflow Tract

Diastolic waves are commonly seen in the left ventricular outflow tract on echocardiography. This work focuses on the E-reversal wave (Er) that occurs early in diastole, shortly after the mitral E wave. Factors associated with Er presence and velocity were investigated in a broad patient sample: 100 subjects with normal ejection fraction (EF >55%) and 100 subjects with reduced EF (<45%). Er presence was noted in 58% of the total cohort and correlated inversely with age. It was more common with normal EF (70% vs 45%, p = 0.0005) and was associated with higher mitral E velocity (78.3 ± 23.3 vs 68.4 ± 19.0 cm/s; p = 0.002) and septal e' velocity (6.7 ± 2.5 vs 5.3 ± 2.3 cm/s; p <0.0001). Er velocity was higher in the normal EF group (50 ± 18 vs 34 ± 13 cm/s, p <0.0001) and showed moderate correlation with septal e' velocity (r = 0.43; p <0.0001); 56 subjects experienced major adverse cardiovascular events (MACE) over 1.7 ± 0.3 years of follow-up. Those with an Er had less MACE (particularly heart failure), even after adjustment for multiple clinical and echocardiographic variables (OR 0.28, 95% CI 0.11 to 0.65; p = 0.003). When stratified by EF, the association between Er presence and MACE was significant only in the low EF group. Thus, Er occurs more commonly in younger subjects and those with preserved EF. It is associated with less MACE although this effect appears to be limited to patients with reduced EF.

Impact of mitral insufficiency on reoperative coronary artery surgery in ischemic cardiomyopathy patients

OBJECTIVE

To determine the impact of mitral insufficiency on survival after reoperative coronary artery bypass grafting (CABG) in ischemic cardiomyopathy patients.

METHODS

We retrospectively studied 891 (Initial 708, Redo 183) consecutive CABG patients (1993-2002) with ejection fraction (EF) 35% or less.

PATIENT CHARACTERISTICS

mean age=67.0+/-10.5 yrs, men=77.1%, EF=26.4+/-7.4%, mean CCS=3.47+/-0.73, mean NYHA=3.50+/-0.68. There were 180 (Initial 141, Redo 39) patients with 3/4+mitral regurgitation (MR). Late survival statistics of cohorts were compiled using National Death Index.

RESULTS

At a mean follow-up period of 3 years, reoperative CABG with MR (Redo/MR+) survival was 41.7+/-9.2% (n=39), which was worse than reoperative CABG without MR (Redo/MR-) survival of 71.8+/-4.1% (n=144, P=0.0003), initial CABG with MR (Initial/MR+) survival of 68.5+/-4.2% (n=141, P=0.014) and initial CABG without MR (Initial/MR-) survival of 76.2+/-2.0% (n=567, P<0.0001). By multivariate analysis, congestive heart failure (P=0.029), 3/4+MR (P=0.044) were independent predictors of Redo late mortality. In contrast, renal failure on dialysis, stroke, no angina, age >65 yrs, absence of hypercholesterolemia, EF<26% but not 3/4+MR were independent predictors of Initial late mortality. In subset analysis, adverse impact of 3/4+MR on late survival was greatest in Redo with EF<26%. The 3- and 5-yr late survival were only 44.4 and 26.8% (P=0.041). Concomitant mitral valve repair (MVrep) was performed in 100 (Initial 75, Redo 25) patients. MVrep in Initial/MR+patients achieved similar late survival as Initial/MR- patients. MVrep did not produce the same late survival benefit in Redo/MR+ patients.

CONCLUSIONS

(1) Mitral insufficiency has a greater survival impact on redo than initial CABG patients with ischemic cardiomyopathy. (2) Mitral insufficiency and congestive heart failure are the primary independent predictors of late survival following redo CABG. (3) Mitral repair has less neutralizing effect on late survival in redo than initial CABG patients.

Use of Unique Doppler Flow‐Pattern for the Diagnosis of Left Ventricular Diverticulum

Isolated congenital left ventricular diverticulum (LV) is reportedly a rare finding. It is frequently associated with other congenital defects involving heart, pericardium, sternum, diaphragm, and abdominal wall. It is an outpouching from the ventricle and has all three layers of left ventricular free walls. We present the case of a 53‐year‐old woman who was discovered to have an outpouching of the LV apex on a nongated chest CT scan raising possibility of a pseudoaneurysm. A transesophageal echocardiogram (TEE) showed systolic diminution of this outpouching with unique Doppler flow‐patterns suggesting a diagnosis of a muscular type of LV diverticulum instead of a postinfarct LV pseudoaneurysm. The patient was reassured and treated conservatively.

Noncatheter-associated vegetative phlebitis of the superior vena cava presenting with multiple lung abscesses

We present a patient with a large vegetation in the superior vena cava (SVC) presenting with multiple staphylococcal lung abscesses. We believe that this is the first reported case of vegetative phlebitis of the SVC without a history of central venous catheter line. Our case emphasizes the need for careful imaging SVC using transesophageal echocardiography in bacteremic patients even in the absence of a central catheter.

Dabigatran use in mechanical heart valve patients

Current guidelines have no recommendations on the utilization of novel oral anticoagulants, such as dabigatran, for the prevention of thromboembolic events in patients with mechanical heart valves. However, recent studies on the use of dabigatran in patients with atrial fibrillation and animal studies have suggested a new potential role for dabigatran in patients with mechanical heart valves. The study by Eikelboom et al. investigates this important clinical question in a prospective, randomized controlled Phase II clinical trial. The authors randomly assigned 252 patients from 39 centers in ten countries to receive dabigatran or warfarin in a 2:1 ratio. The objective of the study was to validate a dosing regimen for use of dabigatran in patients with mechanical heart valves. The trial was prematurely terminated after a recommendation by the data and safety monitoring board. The composite of stroke, systemic embolism, myocardial infarction and death was 8% in the dabigatran group and 2% in the warfarin group (hazard ratio: 3.37; 95% CI: 0.76–14.95; p = 0.11). There were significantly higher bleeding rates of any type in the dabigatran group (27%) compared with the warfarin group (12%; hazard ratio: 2.45; 95% CI: 1.23–4.86; p = 0.01). These results demonstrated a higher risk and no additional benefits in using dabigatran compared with warfarin in patients with mechanical heart valves.