Papillary muscle perfusion pattern. A hypothesis for ischemic papillary muscle dysfunction

Papillary muscles: morphological differences and their clinical correlations

The complex architecture of the papillary muscles (PMs) of the ventricles plays a crucial role in cardiac function and pathology. This comparative study aimed to examine the differences in PMs morphology between the right and left ventricles, focusing on their number, location, and shape. A total of 38 grossly normal hearts from donated bodies were dissected, and the number, location, and shape of PMs in both ventricles were observed. In this study, the left ventricle predominantly exhibited a single PM with 71.05% on the sternocostal surface and 57.89% on the diaphragmatic surface. The right ventricle showed a higher prevalence of single PM, at 89.47% on the sternocostal surface and 63.16% on the diaphragmatic surface. Broad-based shape of the PM emerged as the predominant variant, constituting 55.26% and 44.73% on the sternocostal and diaphragmatic surfaces of the left ventricle, respectively. In contrast, conical-shaped PM predominated in the right ventricle. Unique findings included "H" and "b" shaped muscles, conjoint PMs were observed exclusively in the left ventricle, and small papillary projections with direct tendinous cord attachment in the right ventricle. A distinct webbed shaped configuration of PM was exclusively observed in the right ventricle in only one specimen. No significant difference (P=0.84) was noted in muscle bellies between ventricular surfaces. This study emphasizes the complexity and variability in PM morphology, highlighting the importance of a thorough understanding of these structures for cardiothoracic surgeons, radiologists, and cardiologists to enhance interventional techniques.

Ischemic Dual Papillary Muscle Rupture: The Causality Dilemma

Mechanical complications following acute myocardial infarction are well characterized and warrant surgical intervention. We present a rare case of a young patient with dual papillary muscle rupture after an episode of diabetic ketoacidosis in the absence of angiographic obstructive epicardial coronary artery disease.

Off-Pump Revascularization in Moderate Ischemic Mitral Regurgitation

BACKGROUND

 Ischemic mitral regurgitation (IMR) is associated with high mortality and poor outcomes. The surgical management of moderate IMR is still an object of debate.

METHODS

 Patients with moderate IMR who underwent isolated off-pump coronary bypass grafting (OPCAB) with facile stabilization between January 2015 and February 2022 were analyzed. The primary endpoint was the remaining IMR and echocardiographic findings while the secondary outcomes were defined as mortality, major adverse events, and postoperative functional status.

RESULTS

 Of 541 patients who underwent isolated OPCAB in this period, there were 62 patients with concomitant moderate IMR. The mean follow-up period was 19.4 ± 21.6 months. The median number of the coronary anastomosis was 4. In 58.06% (n = 36), the regurgitation regressed. Left atrial (LA) diameter significantly decreased postoperatively (p = 0.040). Increased LA diameter was associated with increased major adverse events (p = 0.010). Rehospitalization rates were higher in low ejection fraction (EF). The postoperative poor functional status (New York Heart Association [NYHA] III-IV) was correlated with an increased postoperative left ventricular end-systolic diameter (LVESD; 41.75 ± 6.13 vs. 34.79 ± 6.8 mm, p = 0.05). Mortality (4.8%, n = 3) was associated with older age and increased preoperative systolic pulmonary artery pressure (PAP; p = 0.050 and p = 0.046, respectively).

CONCLUSION

 LA diameter, LVESD, mean systolic PAP, left ventricular ejection fraction (LVEF), and age are important predictors for outcomes in IMR. Remaining IMR per se is not directly correlated with increased mortality and major adverse cardiac and cerebrovascular events. The facile stabilization technique we used appears to be advantageous due to the feasibility of full revascularization of all intended vessels, particularly of the inferoposterior wall by providing excellent vision without compression of the heart.

Acute Heart Valve Emergencies

Within the cardiac intensive care unit, prompt recognition of severe acute valvular lesions is essential because hemodynamic collapse can occur rapidly, especially when cardiac chambers have not had time for compensatory remodeling. Within this context, optimal medical management, considerations for temporary mechanical circulatory support and decisive treatments strategies are addressed. Fundamental concepts include an appreciation for how sudden changes in flow and pressure gradients between cardiac chambers can impact hemodynamic and echocardiographic findings differently compared to similarly severe chronic lesions, as well as understanding the main causes for decompensated heart failure and cardiogenic shock for each valvular abnormality.

Concomitant valve surgery is associated with worse outcomes in surgical treatments of post-infarction ventricular aneurysm

Objective

To evaluate the impact of concomitant valve surgery on the prognosis of patients who experienced coronary artery bypass graft (CABG) with/without ventricular reconstruction for the ventricular aneurysm.

Methods

In our department, 354 patients underwent CABG with/without ventricular reconstruction for a ventricular aneurysm from July 23rd, 2000 to December 23rd, 2022. A total of 77 patients received concomitant valve surgery, 37 of whom underwent replacement, and 40 of whom underwent repair. The baseline characteristics, prognostic, and follow-up information were statically analyzed. Univariate and multivariate Cox regression analyses were applied to identify the risk factors of long-term outcomes.

Results

Compared with patients who did not undergo valvular surgery, patients who experienced concomitant valve surgical treatments had a significantly lower survival rate (p = 0.00022) and a longer total mechanical ventilation time. Subgroup analysis indicated that the options of repair or replacement exhibited no statistically significant difference in postoperative mortality (p = 0.44) and prognosis. The multivariate Cox regression analysis suggested that the pre-operative cholesterol level (HR = 1.68), postoperative IABP (HR = 6.29), NYHA level (HR = 2.84), and pre-operative triglyceride level (HR = 1.09) were independent and significant predictors for overall all-cause mortality after surgery.

Conclusion

Concomitant valve surgery was considerably related to a higher risk of postoperative mortality in patients with post-infarction ventricle aneurysms who underwent surgical treatments. No significant difference in the prognosis outcomes was observed between the operating methods of repair or replacement valve surgery.

Acute partial papillary muscle rupture as a rare complication following non-ST elevation myocardial infarction

Papillary muscle rupture is a life-threatening complication of acute myocardial infarction that most commonly occurs 2-7 days after the infarct. We present a rare case of acute partial anterolateral papillary muscle rupture following non-ST elevation myocardial infarction. Our patient was an elderly male who had a detached anterolateral papillary muscle, which required emergent mitral valve replacement. Papillary muscle rupture is a rare complication of acute myocardial infarction, and anterolateral muscle rupture occurs even less commonly. When papillary muscle rupture is diagnosed, patients need to be emergently referred to cardiothoracic surgery as mortality without surgery is over 90% within a week.

Assessment of Papillary Muscle Infarction with Dark-Blood Delayed Enhancement Cardiac MRI in Canines and Humans

Background The relationship between papillary muscle infarction (papMI) and the culprit coronary lesion has not been fully investigated. Delayed enhancement cardiac MRI may detect papMI, yet its accuracy is unknown. Flow-independent dark-blood delayed enhancement (FIDDLE) cardiac MRI has been shown to improve the detection of myocardial infarction adjacent to blood pool. Purpose To assess the diagnostic performance of delayed enhancement and FIDDLE cardiac MRI for the detection of papMI, and to investigate the prevalence of papMI and its relationship to the location of the culprit coronary lesion. Materials and Methods A prospective canine study was used to determine the accuracy of conventional delayed enhancement imaging and FIDDLE imaging for detection of papMI, with pathology-based findings as the reference standard. Participants with first-time myocardial infarction with a clear culprit lesion at coronary angiography were prospectively enrolled at a single hospital from 2015 to 2018 and compared against control participants with low Framingham risk scores. In canines, diagnostic accuracy was calculated for delayed enhancement and FIDDLE imaging. Results In canines (n = 27), FIDDLE imaging was more sensitive (100% [23 of 23] vs 57% [13 of 23], P < .001) and accurate (100% [54 of 54] vs 80% [43 of 54], P = .01) than delayed enhancement imaging for detection of papMI. In 43 participants with myocardial infarction (mean age, 56 years ± 16 [SD]; 28 men), the infarct-related artery was the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and right coronary artery in 47% (20 of 43), 26% (11 of 43), and 28% (12 of 43), respectively. The prevalence of anterior papMI was lower than posterior papMI (37% [16 of 43 participants] vs 44% [19 of 43 participants]) despite more LAD culprit lesions. Culprits leading to papMI were restricted to a smaller "at-risk" portion of the coronary tree for anterior papMI (subtended first diagonal branch of the LAD or first marginal branch of the LCX) compared with posterior (subtended posterior descending artery or third obtuse marginal branch of the LCX). Culprits within these at-risk portions were predictive of papMI at a similar rate (anterior, 83% [15 of 18 participants] vs posterior, 86% [18 of 21 participants]). Conclusion Flow-independent dark-blood delayed enhancement cardiac MRI, unlike conventional delayed enhancement cardiac MRI, was highly accurate in the detection of papillary muscle infarction (papMI). Anterior papMI was less prevalent than posterior papMI, most likely due to culprit lesions being restricted to a smaller portion of the coronary tree rather than because of redundant, dual vascular supply. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Kawel-Boehm and Bremerich in this issue.

Overview of mitral valve replacement versus mitral valve repair due to ischemic papillary muscle rupture: A meta-analysis inspired by a case report

BACKGROUND

Papillary muscle rupture (PMR) is an infrequent but catastrophic complication after myocardial infarction (MI). Surgical procedure is considered the optimal treatment, despite high risk. However, the gold standard technique is still a major dilemma. Therefore, a meta-analysis was carried out to assess and provide an overview comparing mitral valve replacement (MVR) and mitral valve repair (MVr) for PMR post-MI.

METHODS

A systematic literature search was performed. Data were extracted and verified using a standardized data extraction form. Meta-analysis was realized mainly using RevMan 5.4 software.

RESULTS

From four observational studies 1640 patients were identified; 81% underwent MVR and 19% MVr. Operative mortality results were significantly higher in MVR group than the MVr group. MVR was performed under emergency conditions and patients admitted in cardiogenic shock or who required the use of mechanical cardiac support underwent MVR. MVr had shorter time of hospitalization and similar incidence of postoperative complications than MVR. No significant differences existed between the two procedures regarding cardiopulmonary bypass time.

CONCLUSIONS

Mitral valve repair appears to be a viable alternative to MVR for post-MI PMR, given that it has lower operative mortality, shorter time of hospitalization and similar incidence of short-term postoperative complications than MVR. However, it needs to be pointed out that MVR was associated with the most critical clinical condition following PMR. There is uncertainty regarding the overall survival and improvement of the quality of life between the procedures. Nevertheless, further completed investigation is required.

Biomechanical engineering analysis of an acute papillary muscle rupture disease model using an innovative 3D-printed left heart simulator

OBJECTIVES

The severity of acute papillary muscle (PM) rupture varies according to the extent and site of the rupture. However, the haemodynamic effects of different rupture variations are still poorly understood. Using a novel ex vivo model, we sought to study acute PM rupture to improve clinical management.

METHODS

Using porcine mitral valves (n = 32) mounted within an ex vivo left heart simulator, PM rupture was simulated. The mitral valve was divided into quadrants for analysis according to the PM heads. Acute PM rupture was simulated by incrementally cutting from 1/3 to the total number of chordae arising from 1 PM head of interest. Haemodynamic parameters were measured.

RESULTS

Rupture >2/3 of the chordae from 1 given PM head or regurgitation fraction >60% led to markedly deteriorated haemodynamics. Rupture at the anterolateral PM had a stronger negative effect on haemodynamics than rupture at the posteromedial PM. Rupture occurring at the anterior head of the anterolateral PM led to more marked haemodynamic instability than rupture occurring at the other PM heads.

CONCLUSIONS

The haemodynamic effects of acute PM rupture vary considerably according to the site and extent of the rupture. Rupture of ≤2/3 of chordae from 1 PM head or rupture at the posteromedial PM lead to less marked haemodynamics effects, suggesting a higher likelihood of tolerating surgery. Rupture at the anterolateral PM, specifically the anterior head, rupture of >2/3 of chordae from 1 PM head or regurgitation fraction >60% led to marked haemodynamic instability, suggesting the potential benefit from bridging strategies prior to surgery.

Acute coronary syndrome on non-electrocardiogram-gated contrast-enhanced computed tomography

It is not rare for acute coronary syndrome (ACS) patients to present with symptoms that are atypical, rather than chest pain. It is sometimes difficult to achieve a definitive diagnosis of ACS for such patients who present with atypical symptoms, normal initial biomarkers of myocardial necrosis, and normal or nondiagnostic electrocardiograms (ECGs). Although cardiac CT allows for assessments of coronary artery stenosis as well as myocardial perfusion defect in patients with suspected ACS, it requires ECG gating and is usually performed with high-performance multislice CT for highly probable ACS patients. However, several recent reports have stated that ACS is detectable by myocardial perfusion defects even on routine non-ECG-gated contrast-enhanced CT. A growing number of contrast-enhanced CT scans are now being performed in emergency departments in search of pathologies responsible for a patient’s presenting symptoms. In order to avoid inappropriate management for this life-threatening event, clinicians should be aware that myocardial perfusion defect is more commonly detectable even on routine non-ECG-gated contrast-enhanced CT performed in search of other pathologies.

Papillary muscle ischemia on high-resolution cine imaging of nitrogen-13 ammonia positron emission tomography: Association with myocardial flow reserve and prognosis in coronary artery disease

BACKGROUND

The evaluation of papillary muscle (PM) perfusion through existing perfusion imaging, including single-photon emission computed tomography and magnetic resonance imaging, is not possible. Therefore, this study sought to investigate the detection of PM ischemia in coronary artery disease (CAD) using nitrogen-13 (N-13) ammonia positron emission tomography (NH3 PET) and its association with global myocardial flow reserve (MFR) and major adverse cardiac events (MACE).

METHODS

Data of adenosine-stress NH3 PET for 263 consecutive patients with known or suspected CAD were retrospectively analyzed. PM ischemia was defined as the absence of PM accumulation under stress conditions and PM presence at rest on high-resolution cine imaging derived from PET-computed tomography scanner with time-of-flight technology. The primary outcome was MACE.

RESULTS

Of 263 patients, 30 experienced mean follow-up period of 910 days (MACE), while 31 (11.8%) presented PM ischemia. Compared to patients without PM ischemia, those with PM ischemia reported a significantly lower global MFR and a significantly higher rate of MACE (P < .0001).

CONCLUSION

NH3 PET enables the detection of PM ischemia in approximately 10% of patients with known or suspected CAD. PM ischemia is associated with reduced global MFR and is an important sign in predicting prognosis.

Mitral valve surgery for ischemic papillary muscle rupture: outcomes from the Japan cardiovascular surgery database

Background

Ischemic papillary muscle rupture (PMR) is a catastrophic complication following acute myocardial infarction (AMI). We evaluated early outcomes of PMR by using data from the Japan Cardiovascular Surgery Database, a nationwide Japanese registry.

Methods

We retrospectively analyzed data from 196 patients diagnosed with PMR following AMI in Japan between January 2014 and December 2017. Risk factors for operative mortality and severe complications following mitral valve surgery were analyzed.

Results

The 30-day and hospital mortality rates were 20% and 26%, respectively. Chronic hemodialysis, abrupt rupture after AMI, resuscitation before surgery, and preoperative venoarterial extracorporeal membrane oxygenation were associated with mortality. Mitral valve replacement was chosen mainly (90%) for surgical correction of mitral regurgitation in these patients. There was no significant difference in short-term outcomes between mitral valve replacement versus mitral valve repair, despite non-matched characteristics in background between the treatment groups. Concomitant coronary artery bypass grafting had no impact on short-term outcomes.

Conclusions

Information derived from the nationwide database of patients with AMI-associated PMR show that PMR is a rare condition in the modern era. However, PMR is a severe disease with a mortality rate as high as 26%. The severity of the condition is associated with the risk for poor outcomes.

Electronic supplementary material

The online version of this article (10.1007/s11748-020-01418-y) contains supplementary material, which is available to authorized users.

Magnetic resonance imaging of the papillary muscles of the left ventricle: normal anatomy, variants, and abnormalities

Left ventricular papillary muscles are small myocardial structures that play an important role in the functioning of mitral valve and left ventricle. Typically, there are two groups of papillary muscles, namely the anterolateral and the posteromedial groups. Cardiovascular magnetic resonance (CMR) is a valuable imaging modality in the evaluation of papillary muscles, providing both morphological and functional information. There is a remarkably wide variation in the morphology of papillary muscles. These variations can be asymptomatic or associated with symptoms related to LV outflow tract obstruction, often associated with hypertrophic cardiomyopathy. Abnormalities of the papillary muscles range from congenital disorders to neoplasms. Parachute mitral valve is the most common congenital abnormality of papillary muscles, in which all the chordae insert into a single papillary muscle. Papillary muscles can become dysfunctional, most commonly due to ischemia. Papillary muscle rupture is a major complication of acute myocardial infarction that results in mitral regurgitation and associated with high mortality rates. The most common papillary neoplasm is metastasis, but primary benign and malignant neoplasms can also be seen. In this article, we discuss the role of CMR in the evaluation of papillary muscle anatomy, function, and abnormalities.

Microbubble Formulations: Synthesis, Stability, Modeling and Biomedical Applications

Microbubbles are increasingly being used in biomedical applications such as ultrasonic imaging and targeted drug delivery. Microbubbles typically range from 0.1 to 10 µm in size and consist of a protective shell made of lipids or proteins. The shell encapsulates a gaseous core containing gases such as oxygen, sulfur hexafluoride or perfluorocarbons. This review is a consolidated account of information available in the literature on research related to microbubbles. Efforts have been made to present an overview of microbubble synthesis techniques; microbubble stability; microbubbles as contrast agents in ultrasonic imaging and drug delivery vehicles; and side effects related to microbubble administration in humans. Developments related to the modeling of microbubble dissolution and stability are also discussed.

Individual variability of vascularization of the anterior papillary muscle within the right ventricle of human heart

Background

To date there is scarce published evidence reporting the dual blood supply reaching anterior papillary muscle (APM), which descends from both major coronary arteries. Such a vascular configuration can prevent the dysfunction of right ventricular entire valvular system in case of the occlusion of proximal part of either right coronary artery (RCA) or left coronary artery (LCA). The aim of our study was to determine the vascular pattern of APM blood supply which originates from two main coronary arteries, in the context of the APM and septomarginal trabecula (SMT) topography.

Methods

The study was carried out using tissue obtained from 36 human hearts. The material was divided into four morphological types of SMT/APM arrangement. Vascularization and blood supply pattern of papillary muscle was investigated following the analysis of multiple tissue cross sections. The origin of APM arterial supply was traced back to both main coronary arteries. Cross-sectional area of the arteries was estimated at the base of APM and compared within mixed male-female population, aged 18–76.

Results

We noted that as much as 78% of entire APM material had a blood supply vasculature originating from both LCA and RCA branches. In contrast, 22% of cases APM was supplied by a single coronary artery, while in each case it proved to be LCA. We have never found APM arterial supply provided exclusively by RCA. In case of double AMP blood supply an average of total cross-section area of the arteries branching from LCA, was noted to be in excess of two and a half times bigger in type III and more than two times bigger in type IV, as compared with the arteries originating from RCA.

Conclusions

Our research confirm the possibility of double blood supply which vascularizes APM, but the finding does not necessarily apply in all cases. However, APM seems to be predominantly vascularized by arteries deriving from LCA, regardless of their morphological type.

Acute torrential mitral regurgitation during transcatheter aortic valve replacement: a case report

Background

Transcatheter aortic valve replacement (TAVR) is a minimally invasive approach to aortic valve replacement. However, critical cardiovascular collapse can occur during the procedure for various reasons.

Case presentation

A 90-year-old man with severe aortic stenosis and left circumflex artery stenosis developed acute torrential mitral regurgitation (MR) during TAVR. The valve deployment process induced left ventricular dyssynchrony due to left bundle-branch block and myocardial ischemia in the left circumflex artery region with torrential MR. Transesophageal echocardiography clearly demonstrated the mechanisms of MR, which was successfully bailed out by left ventricular pacing and intra-aortic balloon pumping.

Conclusions

MR can be seriously exaggerated by various and complicated mechanisms during TAVR and should be rapidly assessed and appropriately managed depending on its mechanisms.

Electronic supplementary material

The online version of this article (10.1186/s40792-018-0446-z) contains supplementary material, which is available to authorized users.

Ruptured Papillary Muscles After Chordae-Preserving Bioprosthetic Mitral Valve Replacement

Bioprosthetic valve-associated masses in the perioperative period are rare. This report describes the case of a 68-year-old man with perivalvular masses that were initially discovered on a routine postoperative transthoracic echocardiogram 7 days after chordae-preserving mitral valve replacement and coronary artery bypass grafting. An intraoperative transesophageal echocardiogram demonstrated ruptured papillary muscles. This case report describes the differential diagnosis and surgical management of this rare finding.

Contrast-Enhanced Ultrasound Imaging in Detection of Changes in Cerebral Perfusion

Contrast-enhanced ultrasonography (CEU) is a non-invasive imaging technique that provides real-time, bedside information on changes in global and segmental organ perfusion. Currently, there is a lack of data concerning changes in the distribution of segmental brain perfusion in acute ischemic stroke treated by decompressive craniectomy. The aim of our case series was to assess the role of CEU after decompressive craniectomy in patients with acute ischemic stroke. CEU was performed in 12 patients at baseline and after any one of the following interventions was performed as dictated by the patient's clinical condition: vasoactive drug administration (in order to achieve cerebral perfusion pressure ≥70 mm Hg and mean arterial pressure <100 mm Hg for management of arterial blood pressure) and mild hyperventilation (carbon dioxide arterial pressure = 30-35 mm Hg). CEU was able to detect a significant variation in cerebral contrast distribution in both normal and pathologic hemispheres after induced hyperventilation (difference in time to peak [dTTP] = -38.4%), vasodilation (dTTP = -6.6%) and vasoconstriction (dTTP = +31.2%) (p < 0.05). CEU can be useful in assessing real-time cerebral perfusion changes in neurocritical care patients.

Importance of papillary muscle infarction detected by cardiac magnetic resonance imaging in predicting cardiovascular events

BACKGROUND

Recent studies suggest that papillary muscle infarction (PMI) following recent myocardial infarction (MI) correlates with adverse cardiovascular outcomes. The purpose of this study is to determine the prevalence and prognostic significance of PMI by cardiac magnetic resonance (CMR) in a large cohort of patients.

METHODS

Retrospective study of patients who underwent CMR between January 2007 and December 2009 were evaluated for the presence of PMI in one or both of the left ventricle papillary muscles. The primary outcome was a time to a combined endpoint of all-cause mortality and worsening heart failure. Secondary outcomes were time to individual components of the combined outcome.

RESULTS

419 patients were included in our analysis, 232 patients (55%) had ischemic cardiomyopathy. Patients were followed at six-month intervals for a median follow-up time of 3.7 (interquartile range (IQR): 1.6; 6.3) years after initial imaging. During this period 196 patients (46.8%) had a primary outcome and 92 patients (22%) died. PM infarct was identified in 204 (48.7%) patients with twice as many posteromedial (PRM) (27%) than anterolateral (ARL) lesions (11%) and a similar number with infarct in both (11%). There was no association between studied outcomes and the presence of PMI in either PRM or ARL PM. The presence of infarct in both PM was a predictor of both the primary outcome (HR 1.69, CI[1.01-2.86], p<0.049.) and mortality (HR 1.69, CI[1.01-4.2], p<0.046).

CONCLUSION

The presence of infarct in either papillary muscle was not associated with outcomes. However, infarct involving both papillary muscles was associated with worse outcomes.

Myocardial perfusion pattern for stratification of ischemic mitral regurgitation response to percutaneous coronary intervention

OBJECTIVE

Ischemic mitral regurgitation (MR) is common, but its response to percutaneous coronary intervention (PCI) is poorly understood. This study tested the utility of myocardial perfusion imaging (MPI) for the stratification of MR response to PCI.

METHODS

MPI and transthoracic echocardiography (echo) were performed among patients undergoing PCI. MPI was used to assess stress/rest myocardial perfusion. MR was assessed via echo (performed before and after PCI).

RESULTS

A total of 317 patients with abnormal myocardial perfusion on MPI underwent echo 25±39 days before PCI. MR was present in 52%, among whom 24% had advanced (≥moderate) MR. MR was found to be associated with left ventricular (LV) chamber dilation on MPI and echo (both P<0.001). The magnitude of global LV perfusion deficits increased in relation to MR severity (P<0.01). Perfusion differences were greatest for global summed rest scores, which were 1.6-fold higher among patients with advanced MR versus those with mild MR (P=0.004), and 2.4-fold higher versus those without MR (P<0.001). In multivariate analysis, advanced MR was found to be associated with a fixed perfusion defect size on MPI [odds ratio 1.16 per segment (confidence interval 1.002-1.34), P=0.046], independent of LV volume [odds ratio 1.10 per 10 ml (confidence interval 1.04-1.17), P=0.002]. Follow-up via echo (1.0±0.6 years) demonstrated MR to decrease (≥1 grade) in 31% of patients and increase in 12% of patients. Patients with increased MR after PCI had more severe inferior perfusion defects on baseline MPI (P=0.028), whereas defects in other distributions and LV volumes were similar (P=NS).

CONCLUSION

The extent and distribution of single-photon emission computed tomography-evidenced myocardial perfusion defects impact MR response to revascularization. An increased magnitude of inferior fixed perfusion defects predicts post-PCI progression of MR.

Chronic ischemic mitral regurgitation and papillary muscle infarction detected by late gadolinium-enhanced cardiac magnetic resonance imaging in patients with ST-segment elevation myocardial infarction

BACKGROUND

Both papillary muscle infarction (PMI) and chronic ischemic mitral regurgitation (CIMR) are associated with reduced survival after myocardial infarction. The influence of PMI on CIMR and factors influencing both entities are incompletely understood.

OBJECTIVES

We sought to determine the influence of PMI on CIMR after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) and to define independent predictors of PMI and CIMR.

METHODS

Between January 2011 and May 2013, 263 patients (mean age 57.8 ± 11.5 years) underwent late gadolinium-enhanced cardiac magnetic resonance imaging and transthoracic echocardiography 4 months after PCI for STEMI. Infarct size, PMI, and mitral valve and left ventricular geometric and functional parameters were assessed. Univariate and multivariate analyses were performed to identify predictors of PMI and CIMR (≥grade 2+).

RESULTS

PMI was present in 61 patients (23 %) and CIMR was present in 86 patients (33 %). In patients with PMI, 52 % had CIMR, and in patients without PMI, 27 % had CIMR (P < 0.001). In multivariate analyses, infarct size [odds ratio (OR) 1.09 (95 % confidence interval 1.04-1.13), P < 0.001], inferior MI [OR 4.64 (1.04-20.62), P = 0.044], and circumflex infarct-related artery [OR 8.21 (3.80-17.74), P < 0.001] were independent predictors of PMI. Age [OR 1.08 (1.04-1.11), P < 0.001], infarct size [OR 1.09 (1.03-1.16), P = 0.003], tethering height [OR 19.30 (3.28-113.61), P = 0.001], and interpapillary muscle distance [OR 3.32 (1.31-8.42), P = 0.011] were independent predictors of CIMR.

CONCLUSIONS

The risk of PMI is mainly associated with inferior infarction and infarction in the circumflex coronary artery. Although the prevalence of CIMR is almost doubled in the presence of PMI, PMI is not an independent predictor of CIMR. Tethering height and interpapillary muscle distance are the strongest independent predictors of CIMR.

Chronic Papillary Muscle Rupture: 14-Year Survival without Surgical Treatment

Papillary muscle rupture is a life-threatening complication of myocardial infarction which is usually refractory to medical treatment. We present a very rare case of a 65-year-old woman who had a myocardial infarction and posteromedial papillary muscle rupture which was only treated with medical therapy, including her corresponding 14-year follow-up. However, surgical intervention is still strongly recommended because the prognosis of acute papillary muscle rupture associated with myocardial infarction remains poor.

KEY WORDS

Complication; Myocardial infarction; Papillary muscle rupture; Survival.

Complete rupture of the anterolateral papillary muscle caused by coronary spasm

Papillary muscle rupture usually occurs as a catastrophic complication of acute myocardial infarction in patients with coronary artery stenosis; it is therefore less common in patients without coronary artery stenosis. We report the case of a 67-year old woman without coronary artery stenosis who suffered an acute anterolateral papillary muscle rupture and was successfully treated with mitral valve replacement. Evidence of coronary spasm was found on a coronary vasomotion test, suggesting that a high sensitivity to coronary spasm may explain a mechanism of isolated papillary muscle infarction.

Echocardiographic assessment of ischemic mitral regurgitation

Ischemic mitral regurgitation is an important consequence of LV remodeling after myocardial infarction. Echocardiographic diagnosis and assessment of ischemic mitral regurgitation are critical to gauge its adverse effects on prognosis and to attempt to tailor rational treatment strategy. There is no single approach to the echocardiographic assessment of ischemic mitral regurgitation: standard echocardiographic measures of mitral regurgitation severity and of LV dysfunction are complemented by assessments of displacement of the papillary muscles and quantitative indices of mitral valve deformation. Development of novel approaches to understand mitral valve geometry by echocardiography may improve understanding of the mechanism, clinical trajectory, and reparability of ischemic mitral regurgitation.

Three patients with signs of acute flail mitral leaflet seen on emergency department echo: a critical constellation within the focused cardiac exam

Acute flail mitral leaflet is a time-sensitive, reversible cause of cardiogenic shock. Transthoracic echocardiography (echo) is increasingly becoming a vital tool for non-cardiologist physicians who treat patients with undifferentiated chest pain and dyspnoea. The sonographic abnormalities seen in acute flail mitral leaflet are within the boundaries of a focused echo. Individually, these findings are non-specific. As a constellation, however, they are highly suggestive of this disease process. We present a case series of three patients with acute flail mitral leaflet seen on emergency department echo along with a discussion of the findings and the disease itself.

Mitral apparatus assessment by delayed enhancement CMR: relative impact of infarct distribution on mitral regurgitation

OBJECTIVES

This study sought to assess patterns and functional consequences of mitral apparatus infarction after acute myocardial infarction (AMI).

BACKGROUND

The mitral apparatus contains 2 myocardial components: papillary muscles and the adjacent left ventricular (LV) wall. Delayed-enhancement cardiac magnetic resonance (DE-CMR) enables in vivo study of inter-relationships and potential contributions of LV wall and papillary muscle infarction (PMI) to mitral regurgitation (MR).

METHODS

Multimodality imaging was performed: CMR was used to assess mitral geometry and infarct pattern, including 3D DE-CMR for PMI. Echocardiography was used to measure MR. Imaging occurred 27 ± 8 days after AMI (CMR, echocardiography within 1 day).

RESULTS

A total of 153 patients with first AMI were studied; PMI was present in 30% (n = 46 [72% posteromedial, 39% anterolateral]). When stratified by angiographic culprit vessel, PMI occurred in 65% of patients with left circumflex, 48% with right coronary, and only 14% of patients with left anterior descending infarctions (p <0.001). Patients with PMI had more advanced remodeling as measured by LV size and mitral annular diameter (p <0.05). Increased extent of PMI was accompanied by a stepwise increase in mean infarct transmurality within regional LV segments underlying each papillary muscle (p <0.001). Prevalence of lateral wall infarction was 3-fold higher among patients with PMI compared to patients without PMI (65% vs. 22%, p <0.001). Infarct distribution also impacted MR, with greater MR among patients with lateral wall infarction (p = 0.002). Conversely, MR severity did not differ on the basis of presence (p = 0.19) or extent (p = 0.12) of PMI, or by angiographic culprit vessel. In multivariable analysis, lateral wall infarct size (odds ratio 1.20/% LV myocardium [95% confidence interval: 1.05 to 1.39], p = 0.01) was independently associated with substantial (moderate or greater) MR even after controlling for mitral annular (odds ratio 1.22/mm [1.04 to 1.43], p = 0.01), and LV end-diastolic diameter (odds ratio 1.11/mm [0.99 to 1.23], p = 0.056).

CONCLUSIONS

Papillary muscle infarction is common after AMI, affecting nearly one-third of patients. Extent of PMI parallels adjacent LV wall injury, with lateral infarction-rather than PMI-associated with increased severity of post-AMI MR.

Unusual case of acute posteromedial papillary muscle rupture after acute anterior myocardial infarction

Papillary muscle rupture is now a rare complication of acute myocardial infarction. Posteromedial papillary muscle rupture is more common than anterolateral papillary muscle rupture. The posteromedial papillary muscle is usually supplied from a branch of the right coronary artery. We present a case of posteromedial papillary muscle rupture due to an isolated left anterior descending artery lesion. This was diagnosed on the fifth day post infarction. The patient progressed to mitral valve replacement and coronary artery bypass grafting to the left anterior descending artery. We believe this unusual arterial supply to the posteromedial papillary muscle is due to an apex forming left anterior descending artery coupled with an apically located posteromedial papillary muscle.

Isolated right coronary lesion and anterolateral papillary muscle rupture--case report and review of the literature

Ischemic rupture of the anterolateral papillary muscle is uncommon due to its dual blood supply. It usually follows an ischemic event involving branches of the left circumflex or left anterior descending arteries. We present a case of a patient admitted with an acute inferior wall myocardial infarction and an isolated distal right coronary artery occlusion. Acute mitral regurgitation with rupture of the anterolateral papillary muscle was diagnosed on the fifth post-infarction day. The patient underwent mitral valve replacement and coronary artery bypass grafting to the posterior descending artery. We conclude that anterolateral papillary muscle rupture may also result from an isolated right coronary lesion.

Complete rupture of the anterolateral papillary muscle complicated with acute myocardial infarction due to diagonal branch occlusion

It is well known that post-infarction papillary muscle rupture of the anterolateral papillary muscle is less frequent than that of the posteromedial papillary muscle. This is thought to be due to a difference in blood supply (single vs dual) of the papillary muscles. Recently, we had two cases in which occlusion of the diagonal branch of the left anterior descending artery was found to be the culprit lesion of acute myocardial infarction leading to complete rupture of the anterolateral papillary muscle. Herein, we report on these two rare successful surgical cases with some review of the literature.