Assessment of biventricular remodeling by magnetic resonance imaging after successful primary stenting for acute myocardial infarction

Determinants of right ventricular remodeling following ST-segment elevation myocardial infarction

Right ventricular (RV) function after ST-segment elevation myocardial infarction (STEMI) has important prognostic implications. However, the changes in RV function over time after STEMI and the incidence of RV remodeling remain unknown. The present study evaluated changes in RV dimensions and function in contemporary patients with first STEMI and assessed the independent determinants of RV dysfunction at follow-up. Patients with first STEMI (n = 940, 60 ± 11 years, 77% men) treated with primary percutaneous coronary intervention underwent echocardiography at baseline and 6- and 12-month follow-up. The prevalence of RV dysfunction (tricuspid annular plane systolic excursion [TAPSE] ≤15 mm) decreased significantly at 6 months follow-up (from 15% to 8%, p <0.001) and the incidence of RV remodeling (increase in RV end-diastolic area [RVEDA] ≥20%) was observed in 200 patients (25%). Absolute changes in RVEDA were independently associated with absolute changes in wall motion score index and left ventricular (LV) remodeling (p <0.001 for both parameters), whereas absolute changes in TAPSE were independently related with absolute changes in wall motion score index and mitral regurgitation grade (p <0.001 for both parameters). Independent correlates of RV dysfunction at 6 months follow-up were multivessel coronary disease (odds ratio [OR] 2.13), peak cardiac troponin T (OR 1.05), angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers use (OR 0.27), baseline LV ejection fraction (OR 0.96) and baseline TAPSE (OR 0.88). In conclusion, despite the non-negligible incidence of RV remodeling in patients with first STEMI, RV function improves early after STEMI. Multivessel coronary disease, infarct size, baseline LV ejection fraction and TAPSE and the nonuse of angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers are independent determinants of RV dysfunction.

[Current indications for cardiac MR imaging]

MRI has acquired over the years a role in the evaluation of cardiovascular pathology especially with regards to its ability to assess right and left ventricular function and delayed postcontrast "viability" sequences. Current class I clinical indications include: viability for patients with ischemic cardiomyopathy and acute coronary syndrome, etiology and prognostic evaluation of non-ischemic cardiomyopathies including myocarditis and arrhytmogenic right ventricular cardiomyopathy, chronic pericarditis and cardiac masses, non-urgent aortic aneurysm and dissection, congenital cardiopathies: vascular malformations and follow-up after curative or palliative surgery. MRI provides a complete non operator dependent evaluation, and is particularly useful for follow-up since it may be repeated due to its absence of ionizing radiation

Pathophysiological basis of right ventricular remodeling

The pathophysiology of right ventricular (RV) remodeling is a complex process and may include unique elements not observed in left ventricular (LV) remodeling. The RV also has a relatively irregular geometry not accounted for in LV analyses. RV remodeling includes basic changes in geometry, wall thickness, and ventricular pressure-volume relationships. Also, myocyte dimensions and number increase, and myocardial extracellular matrix and biochemical milieu are modified. Remodeling has been associated with such diseases as pulmonary hypertension, lung transplant, LV pathology, Chagas' disease, and arrhythmogenic right ventricular cardiomyopathy. Disease progression may lead to further RV changes, including hypertrophy, dilatation, and subsequently to variable alterations in RV hemodynamic status. The multiple methods to assess RV hypertrophy include cine magnetic resonance imaging and 3-D echocardiography. Each technique offers different precision in evaluating RV dimensions and functional performance characteristics. Strategies to prevent RV remodeling include pharmacological agents, such as vasodilators and angiotensin-converting enzyme inhibitors, as well as more invasive interventions, such as ventricular assist devices.

Reverse right ventricular remodeling after pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension: Utility of magnetic resonance imaging to demonstrate restoration of the right ventricle

OBJECTIVES

Pulmonary arterial hypertension causes right ventricular remodeling; that is, right ventricular dilatation, hypertrophy, and leftward ventricular septal bowing. We studied the effect of pulmonary endarterectomy on the restoration of right ventricular remodeling in patients with chronic thromboembolic pulmonary hypertension by magnetic resonance imaging.

METHODS

In 17 patients with chronic thromboembolic pulmonary hypertension, before and at least 4 months after pulmonary endarterectomy, and in 12 healthy controls, right ventricular and left ventricular end-diastolic and end-systolic volumes (milliliters) and mass (grams per meter squared) and leftward ventricular septal bowing (1 divided by the radius of curvature in centimeters) were determined by magnetic resonance imaging.

RESULTS

Before pulmonary endarterectomy, right ventricular volumes, left ventricular end-diastolic volume, right ventricular mass, and leftward ventricular septal bowing differed significantly between patients with chronic thromboembolic pulmonary hypertension and healthy control subjects. After pulmonary endarterectomy, pulmonary hemodynamics improved, and right and left ventricular volumes and leftward ventricular septal bowing normalized; right ventricular mass decreased significantly (46 +/- 14 to 31 +/- 9 g x m(-2), P< .0005), but did not completely normalize. The change in total pulmonary resistance correlated with the change in right ventricular ejection fraction (r = 0.50, P < .05), right ventricular mass (r = 0.63, P < .01), and leftward ventricular septal bowing (r = 0.50, P < .05).

CONCLUSIONS

Right ventricular remodeling was observed in patients with chronic thromboembolic pulmonary hypertension and restored almost completely after a hemodynamically successful pulmonary endarterectomy. Magnetic resonance imaging is a valuable tool to evaluate cardiac remodeling and function in patients with chronic thromboembolic pulmonary hypertension, both before and after pulmonary endarterectomy.

Effects of cardiac resynchronization therapy on disease progression in chronic heart failure

Despite the alleviation of symptoms and longer survival conferred by pharmacological management of chronic congestive heart failure (CHF), this progressive syndrome remains associated with high morbidity and premature death. A new treatment of CHF should ideally alleviate symptoms, improve functional capacity, decrease mortality, and slow or reverse its progression without adding risks for the patient that outweighs the benefits. Growing evidence indicates that devices implanted to resynchronize ventricular contraction are a beneficial adjunct in the treatment of CHF. This review discusses the remodelling process, and its clinical and prognostic significance. We also discuss the impact of CRT, on remodelling and disease progression with a particular focus on patients with asymptomatic or mild heart failure (NYHA Class I-II).