Myocardial infarction secondary to coronary embolus in a patient with left ventricular non-compaction cardiomyopathy: a case report.

BACKGROUND: Coronary embolism is a rare cause of myocardial infarction (MI). We present a case report which emphasizes the importance of intracoronary imaging in these cases to identify the pathophysiological mechanism of MI. CASE SUMMARY: A 53-year-old male with no past medical history presented to the hospital with typical angina. Electrocardiogram and serum troponin I level trend confirmed non-ST-elevation myocardial infarction. Coronary angiography showed no evidence of any obstructive coronary artery disease, but two small thrombi were noted in the distal first obtuse marginal branch. Optical coherence tomography imaging confirmed this finding in absence of any underlying atherosclerotic plaque rupture or erosion. Cardiac magnetic resonance imaging revealed the diagnosis of non-compaction cardiomyopathy with severely depressed left ventricular function. Transmural MI was revealed by late gadolinium enhancement in the mid-lateral wall. Based on the pathophysiology of the MI confirmed by intracoronary imaging, antiplatelet medications were discontinued, and the patient was discharged on warfarin. Medical therapy was initiated for his cardiomyopathy. The patient recovered well and was asymptomatic at 1-year follow-up visit. DISCUSSION: Intracoronary imaging plays an important role to supplement coronary angiography to confirm the pathophysiology of MI in coronary embolism cases. This is important as it alters management in these patients.

Monitoring for Chemotherapy-Related Cardiotoxicity in the Form of Left Ventricular Systolic Dysfunction: A Review of Current Recommendations.

Cardiotoxicity is a well-established complication of multiple cancer therapeutics, and the one of the most prominent effects that limits the use of these agents is in the form of left ventricular dysfunction, otherwise known as chemotherapy-induced cardiomyopathy (CIMP). Because CIMP can worsen patient outcomes and interfere with a patient's life-saving cancer treatments, it is important to implement a monitoring strategy for patients undergoing potentially cardiotoxic treatments. Efforts have been made by multiple societies to provide recommendations for screening and monitoring for CIMP in at-risk patients, with slight variations between guideline documents and expert consensuses. Most of the recommendations for monitoring for CIMP are specific to anthracyclines and the human epidermal growth factor receptor 2-antagonist trastuzumab, with very limited guidance for other cardiotoxic agents such as Tyr kinase inhibitors and proteasome inhibitors, which we cover in this article. Echocardiography remains the mainstay for imaging surveillance because of its safety profile and widespread availability, but the accuracy of cardiac magnetic resonance imaging (CMR) makes it an important modality when there are discrepancies in left ventricular ejection fraction assessment. Subclinical cardiotoxicity may be detected using laboratory biomarkers such as cardiac troponin and brain natriuretic peptide as well as myocardial deformation (strain) imaging by echocardiography or CMR. Specific recommendations for timing and frequency of laboratory biomarker assessment remain up for debate, but myocardial deformation imaging should be performed with every echocardiogram or CMR assessment. Future studies are needed to evaluate the efficacy of established surveillance recommendations and to develop specific recommendations for novel cancer therapeutics.

Bortezomib-Induced Reversible Cardiomyopathy: Recovered With Guideline-Directed Medical Therapy.

Bortezomib (BTZ) is a proteasome inhibitor (PI) used for the treatment of several hematologic malignancies, including multiple myeloma (MM), and various lymphomas including mantle cell lymphoma (MCL). It acts via disruption of the ubiquitin-proteasome pathway which plays a major role in regulating cell cycle and inhibiting synthesis of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-KB). The ubiquitin-proteasome pathway is also important in maintaining the integral signaling in cardiac myocytes. By inhibiting this system, BTZ induces cellular apoptosis in cancer cells, and possibly the cardiomyocytes. BTZ-induced cardiotoxicity in monotherapy and combination treatments is not well described in the literature. We observed a series of three patients who developed cardiotoxicity after treatment with BTZ. All patients had echocardiograms every 3 months until recovery to assess ejection fraction (EF) and global longitudinal strain (GLS). Two of the patients had a cardiac MRI (CMR) conducted during follow-up to assess for late gadolinium enhancement (LGE).  The median age of our patients was 55 years (range 37-74). Two of them had MM, while one patient had MCL. Table 1 demonstrates patient demographics, past medical histories, and the cumulative dose and duration of BTZ therapy. Of the three patients, only one had a heart failure exacerbation at diagnosis. The other two patients were diagnosed with asymptomatic left ventricular systolic dysfunction on routine pre-transplant echocardiograms. Most importantly, all three patients had improvement or normalization of cardiac function with discontinuation of BTZ and initiation of guideline-directed medical therapy (GDMT) for heart failure. The median duration to recovery was 5 months (range 3-13). One patient had underlying non-compaction cardiomyopathy, and although EF did not normalize, it recovered to his previous baseline. All 3 patients had improvement in GLS. Two patients underwent CMRI at the time of cardiomyopathy diagnosis and neither of them had any late gadolinium enhancement. Since there was no routine pre-treatment echocardiogram, using the GLS trend to detect subclinical cardiac dysfunction was not possible. This case series demonstrates that BTZ-induced cardiomyopathy is potentially reversible with discontinuation of the drug and early initiation of GDMT. Further studies are needed to determine the ideal surveillance strategy for BTZ-induced cardiomyopathy.

High Prevalence of Clinically Important Echocardiographic Abnormalities in Patients with a Normal Electrocardiogram Referred for Transthoracic Echocardiography.

BACKGROUND: Normal electrocardiographic (ECG) results have been reported to be associated with a low prevalence of structural heart disease and thus may preclude the need for transthoracic echocardiographic (TTE) imaging. The goal of this study was to determine the prevalence of important TTE abnormalities in patients with a normal ECG referred for TTE imaging. METHODS: Consecutive electrocardiograms over 6 months were reviewed. Patients with a normal ECG who underwent TTE imaging within 30 days formed the study group. TTE indication and appropriateness designation were determined. TTE findings were noted, including a composite, "major TTE abnormalities" (Maj TTE ABNs). RESULTS: Of 26,254 electrocardiograms reviewed, 3,955 (15%) were normal, 522 with qualifying TTE studies. Maj TTE ABNs were common (27%). The most common TTE indication was signs or symptoms of congestive heart failure (17%), 35% of which had Maj TTE ABNs. Two echocardiographic indications were found to have significantly fewer of Maj TTE ABNs: palpitations (4%, P < .01) and preoperative evaluation before noncardiac surgery (6%, P < .01). A majority of TTE studies were appropriate (76%), with only 14% rarely appropriate. Maj TTE ABNs were less common in rarely appropriate compared with appropriate TTE studies (13% vs 30%, P < .01), with a very low prevalence of Maj TTE ABNs in outpatient rarely appropriate TTE studies (4%). CONCLUSIONS: Clinically important TTE abnormalities in patients with a normal ECG are common, suggesting that normal ECG results should not routinely preclude TTE imaging to identify structural heart disease. However, recognition of common clinical indications and application of the appropriate use criteria may identify patients with a normal ECG in whom TTE imaging is of very low yield.