Tongue infarction in suspected lingual artery thromboembolism in a cat with hypertrophic cardiomyopathy.

Case Presentation: A 38-year-old man with hypertrophic cardiomyopathy (HCM) was referred for management of intermittent palpitations and exertional dyspnea with routine activities despite escalated β-blocker therapy. His initial examination was notable for a regular pulse at 72 bpm and harsh systolic murmur that increased with the Valsalva maneuver. A 12-lead electrocardiography revealed sinus rhythm with increased QRS voltage, repolarization abnormalities, and a QTc of 430 milliseconds. Echocardiography was notable for severe asymmetrical hypertrophy (septal thickness, 22 mm), normal systolic function, severe outflow tract obstruction (70 mm Hg), and left atrial (LA) enlargement. A 24-hour Holter monitor detected 6 minutes of rapid atrial fibrillation (AF) that coincided with his palpitations. Therapy was recommended with warfarin to prevent stroke and with disopyramide to minimize outflow tract obstruction and frequency of AF. HCM, which affects 0.2% of the population, is an important cause of heart failure and is the leading cause of nonviolent sudden death in the young. Traditionally defined as left ventricular hypertrophy that develops in the absence of abnormal hemodynamics, it is caused by dominant mutations in sarcomere genes.1 Prevention of sudden death and management of left ventricular outflow tract obstruction (LVOTO) have been the primary focus of HCM clinical research and management since its original descriptions. However, AF is more prevalent than either sudden death or medically refractory obstruction and is the most common sustained arrhythmia in HCM.2 The combination of HCM and AF is associated with a markedly increased risk of stroke, overall mortality, and heart failure. This Clinician Update focuses on the epidemiology, pathophysiology, and clinical management of AF in patients with HCM. AF represents the most common sustained arrhythmia in both the general and HCM populations. In the general population, AF prevalence increases progressively with age and occurs predominantly in patients >60 years of age.3 …

Atrial Fibrillation and Thromboembolism

Introduction: The presence of spontaneous echo contrast (SEC) on transesophageal echocardiography (TEE) is associated with increased thrombogenecity and a risk factor of thromboembolism. The increased thrombogenecity in SEC may produce larger intracardiac thrombi, which result in larger cerebral infarctions and severe stroke. Hypothesis: We hypothesized that infarction volume will be larger in stroke patients with SEC than in those without SEC. Methods: This was a post-hoc analysis using a prospective cohort of acute ischemic stroke. This study included patients with nonvalvular atrial fibrillation (NVAF) who underwent TEE and diffusion weighted imaging (DWI) from Jan. 2008 to Dec. 2014. The volume of cerebral infarction on DWI was measured semi-automatically using 3-dimensional software by an investigator who was blinded to clinical information. The infarction volume was compared between patients with SEC and those without. Results: Of 4252 considered patients, 889 patients had NVAF. After excluding 449 patients without TEE and 39 patients without DWI, 401 patients were included for analysis. Of them, SEC was found in 181 patients (45.1%, 82 mild, 35 moderate, and 64 severe SEC). Infarction volume was larger for the patients with SEC than those without SEC (median [interquartile range], 7226.8 mm 3 [1218.1-28804.6] vs. 4756.8 mm 3 [672.8-14887.8], p=0.015). Infarction volume also increased with SEC severity (p=0.006). Initial National Institute of Health Stroke Scale scores were higher for the patients with SEC than those without SEC (median [interquartile range], 5.0 [2.0-12.0] vs. 3.0 [1.0-8.0]. p=0.008). On multivariate analysis, infarction volume was independently associated with the presence of SEC (p=0.014). Conclusion: Among stroke patients with NVAF, those with co-existing SEC had larger cerebral infarction, which may account for severe stroke. This may be related with increased thrombogenecity in patients with SEC.

ObjectivesThe purpose of this article is to describe the key cardiac magnetic resonance imaging (MRI) features to differentiate hypertrophic cardiomyopathy (HCM) phenotypes from other causes of myocardial thickening that may mimic them.ConclusionsMany causes of myocardial thickening may mimic different HCM phenotypes. The unique ability of cardiac MRI to facilitate tissue characterisation may help to establish the aetiology of myocardial thickening, which is essential to differentiate it from HCM phenotypes and for appropriate management.Teaching points• Many causes of myocardial thickening may mimic different HCM phenotypes.• Differential diagnosis between myocardial thickening aetiology and HCM phenotypes may be challenging.• Cardiac MRI is essential to differentiate the aetiology of myocardial thickening from HCM phenotypes.

Aims To evaluate the prevalence of subclinical cardiomyopathy and cardiac mortality in a research colony of non-purebred cats, established as a model of the wider cat population in New Zealand. Methods All apparently healthy, compliant, non-pregnant, non-neonatal cats in the colony at the Centre for Feline Nutrition (Massey University, Palmerston North, NZ) underwent physical examination and echocardiography using a 4.4–6.2-MHz probe by a board-certified veterinary cardiologist. Cardiac phenotype was classified following current guidelines. Hypertrophic cardiomyopathy (HCM) phenotype was defined as an end-diastolic left ventricular wall thickness ≥ 6 mm. Colony mortality data from February 2012 to February 2022 was reviewed to determine cardiac mortality. Results Cats (n = 132; 65 females and 67 males) included in the study had a median age of 4.1 (IQR 3.0–8.0) years. Thirty-two (24%) cats had a heart murmur, and three (2%) cats had an arrhythmia. Echocardiography revealed heart disease in 24 (18.2%) cats, including 23 with an HCM phenotype and one with a restrictive cardiomyopathy phenotype. Of the cats with the HCM phenotype, 3/23 had systemic hypertension or hyperthyroidism or both, and these cats were excluded from the final diagnosis of HCM (20/132; 15.2 (95% CI = 9.5–22.4)%). Between 2012 and 2022, 168 colony cats died, with 132 undergoing post-mortem examination. Heart disease was considered the cause of death in 7/132 (5.3%; 95% CI = 2.2–10.6%) cats; five had HCM, one a congenital heart defect, and one myocarditis. The overall prevalence of death related to HCM in the colony during this period was 3.8% (95% CI = 1.2–8.6%). Three cats with HCM and the cat with a congenital heart defect died unexpectedly without prior clinical signs, while congestive heart failure was observed prior to death in two cats with HCM and the cat with myocarditis. Additionally, 30/132 (22.7%) cats had cardiac abnormalities but died for non-cardiac reasons. Conclusions Subclinical cardiomyopathy, specifically HCM, was common in cats in the colony. Given that the colony originated as a convenience selection of non-purebred cats in New Zealand, the true prevalence of HCM in the wider New Zealand population is likely to fall within the 95% CI (9.5–22%). The proportion of deaths of colony cats due to HCM was lower (3.8%) supporting the conclusion that subclinical cardiomyopathy may not progress to clinical disease causing death. Clinical relevance Veterinarians should be aware of the high prevalence of subclinical HCM when treating cats. Abbreviations CAM: Systolic anterior motion of the chordae tendineae; CFN: Centre for Feline Nutrition; HCM: Hypertrophic cardiomyopathy; LA/Ao: Left atrial to aortic ratio; LV FS: Left ventricular fractional shortening; LVIDd: Left ventricular internal diameters in end-diastole; LVIDs: Left ventricular internal diameter in end-systole; LVWT: Max Maximum left ventricular wall thickness; SAM: Systolic anterior motion of the mitral valve; 2D: Two-dimensional

The number of cats requiring treatment for hypertrophic cardiomyopathy (HCM) and arterial thromboembolism (ATE) continues to increase, and the knowledge regarding its management is constantly evolving. The pathological lesions of HCM include hypertrophy of the left ventricle, which causes abnormalities in the relaxation function of the heart. This phenomenon increases the stiffness of the ventricular muscle, thereby reducing the ability of the left ventricle to fill with blood during diastole. This is accompanied by an increase in ventricular filling pressure and left atrial pressure. HCM in cats is characterized by concentric hypertrophy and atrial enlargement. Hypertrophic obstructive cardiomyopathy (HOCM) also involves a narrowed left ventricular outflow tract, and in humans, it is generally perceived to be a more serious disease. However, unlike in humans, HCM and HOCM in cats do not result in significantly different survival times. Heart murmurs, gallop rhythms, arrhythmias, cardiac hypertrophy, congestive heart failure (CHF), ATE, and cardiac sudden death (CSD) have all been associated with HCM. Although the presence of a heart murmur is a characteristic feature of heart disease, it may be a functional one, which is defined as “dynamic right ventricular outflow track obstruction” (DRVOTO) in cats. Therefore, it is difficult to evaluate the presence of HCM based on the existence of a heart murmur alone. ATE typically affects one or both hind limbs, resulting in acute paralysis and severe pain, consistent with lower motor neuron disease. The clot, which is formed in the left atrium of the heart, travels to an artery and becomes an ATE, which then blocks the blood flow and impairs circulation, causing infarction. Therefore, ATE in cats is a serious condition. This review describes the results of the latest research on HCM and ATE, the most common heart conditions in cats.

Background: Hypertrophic cardiomyopathy is the most common acquired cardiovascular disease in the feline species. A frequent complication of this cardiomyopathy is the development of cardiac congestive failure, left atrial enlargement and subsequent development of arterial thromboembolism. In a significant percentage of affected animals there is progression to congestive heart failure, resulting in cyanosis and dyspnea, often the first clinical signs reported by owners. This is a report of a 10-year-old Persian cat with hypertrophic cardiomyopathy and venous and arterial thromboembolism of non-cardiogenic origin.Case: The patient was referred for cardiac evaluation, arterial thromboembolism was the suspected cause of tetraparesis. On clinical examination, a metacarpal pulse was present in all limbs; there was no cyanosis or peripheral hypothermia thus, ruling out a thromboembolic event in the limbs. Changes consistent with feline asthma and pulmonary edema were seen on radiographs, therefore hypertrophic cardiomyopathy was suspected. Treatment with enalapril (0.25 mg/kg every 12 h) for the heart condition and prednisolone (1 mg/kg every 24 h) for asthma was started. Nine days later, the patient developed mixed dyspnea (inspiratory and expiratory) and was hospitalized with signs consistent with arterial thromboembolism: paralysis and cold extremities in the right and left pelvic limbs. The patient was euthanized due to the poor prognosis. Post mortem and histopathological findings revealed left ventricular concentric hypertrophy, with no valvular changes; disseminated intravascular coagulation, with thrombi in the arterial (iliac arteries, pancreatic and renal vessels) and venous (pulmonary and renal veins) beds; as well as multiple neoplastic lung masses, identified as scirrhous pulmonary adenocarcinoma, responsible for increased interstitial radiopacity. Metastasis was also identified at the tracheal bifurcation, causing radiographic changes similar to the alveolar pattern of pulmonary edema.Discussion: The origin of the concentric left ventricular hypertrophy was not established. Both primary hypertrophy, due to breed-related genetic predisposition or secondary hypertrophy, due to systemic hypertension from chronic kidney disease are possibilities. However, despite the left ventricular concentric hypertrophy and the presence of thrombus under the mitral valve, it was not thought that the patient had cardiogenic thromboembolism, since this would not explain the venous thrombi. The arterial and venous thromboembolism in this case were the result of paraneoplastic syndrome due to pulmonary adenocarcinoma, which was a triggering factor for disseminated intravascular coagulation and multiple thrombus formation, both in arterial and venous beds. Tumor cells may promote direct and indirect modifications in the coagulation cascade and, thus hypercoagulability. The hypercoagulatory state promoted by the tumor associated with the Virchow triad seen in feline species, explains the occurrence of thrombosis in this case report. Sensitive imaging tests, such as computed tomography or magnetic resonance imaging, may be required in middle-aged cats with hypertrophic cardiomyopathy and clinical presentations of thromboembolism or respiratory signs, in order to exclude pulmonary neoplasm as a differential diagnosis for thrombus formation and dyspnea. Furthermore, it is speculated that the antitumor effect of heparin used in the treatment for arterial thromboembolism may delay the diagnosis of lung neoplasia in cats.

Single-cell transcriptomics provides insights into hypertrophic cardiomyopathy.

A prospective study of left atrial spontaneous echo contrast and thrombus in 100 consecutive patients referred for balloon dilation of the mitral valve.

Background Patients with hypertrophic cardiomyopathy (HCM) are at increased risk of atrial fibrillation (AF) and stroke, especially at an advanced disease stage. To date, however, the incidence and factors associated with cardioembolic events in HCM patients without AF remain unresolved. Purpose To determine the incidence of stroke in HCM patients in whom cardiac rhythm was monitored with a cardiac implantable electronic device (CIED). The association of stroke with left atrial (LA) enlargement was also examined. Methods Retrospective cohort study in an outpatient clinic in a tertiary HCM Referral Center. All consecutive patients diagnosed with HCM and referred for CIED implantation with >16 years at diagnosis and >1 year follow-up post CIED implantation were reviewed. Severe LA dilatation was defined as a LA dimension (LAD) of >48mm at echocardiogram. Based on CIED monitoring, patients were classified as: Pre-existing AF (diagnosed with AF prior to CIED); De novo AF (diagnosed with AF after CIED implantation); Sinus Rhythm (SR): no episodes of AF. Incidence of stroke after CIED implantation was the primary outcome. Results A total of 185 patients (57% men, age: 54±17 years) were implanted with a CIED and were included. Pre-existing AF was present in 72 (36%) patients and de novo AF in 24 (13%); whereas 89 (48%) remained in SR. After 5 [2–9] years, stroke was reported in 19 (10.3%) patients: 7 occurred in patients with pre-existing AF (1.1%/year), 3 in patients with de novo AF (2.2%/year), and 9 in patients with SR (2.3%/year). No difference was captured by CHA2DS2-VASc score among rhythm categories. Patients with AF had larger LAD at baseline. Among patients in SR, those with a LAD>48mm had the greatest risk of stroke (4.8%/year vs 0.5%/year, p<0.01; Hazard Ratio [HR]: 8.56, 95% C.I. 2.03–36.15). At Cox multivariable regression analysis, LA (HR: 1.104, 95%C.I. 1.039–1.173, p=0.001) and AF (HR: 0.310, 95% C.I. 0.102–0.939, p=0.038) were associated with incident stroke. Conclusions In HCM patients with CIED long-term monitoring and no prior history of AF, stroke rates were similar in those with de novo AF or stable sinus rhythm. CHA2DS2-VASc considerably underestimated risk, whereas severe LA dilatation was a powerful predictor of risk, irrespective of AF. Funding Acknowledgement Type of funding sources: None.

Objective To evaluate the characteristics of left ventricular structure, function, myocardial mechanics, hemodynamics and synchrony in different phenotypes of hypertrophic cardiomyopathy (HCM) using state-of-the-art echocardiography. Methods A consecutive series of 85 adult HCM patients who were admitted to the Xi Jing HCM center from January 2016 to November 2017 were collected. According to the peak left ventricular outflow tract pressure gradient in exercise stress echocardiography, the patients were divided into three groups: patients with non-obstructive HCM (n=28), those with labile-obstructive HCM (n=27), and those with obstructive HCM (n=30). In addition, 16 normal family members of HCM patients were included as control group. Two-dimensional speckle tracking imaging, tissue Doppler imaging and exercise stress echocardiography were used to evaluate the left ventricular function in resting and exercise states. Results ①As compared with the control group, left ventricular end-diastolic diameter decreased and left ventricular ejection fraction increased in all three HCM groups(all P 0.05). The obstructive HCM had the lowest mitral annular plane systolic excursion (MAPSE) and s′, and the longest systolic peaking time standard deviation(Ts-SD) and early diastolic peaking time standard deviation(Te-SD) (all P<0.05). The left ventricular diastolic function of obstructive HCM (e′, the E/e′ ratio and the left atrial volume index) was the worst, labile-obstruction and non-obstructive HCM were better, and the control group was the best (all P<0.001). ③During exercise, the GLS, GCS, GRS, twist of the left ventricle and the MAPSE were the lowest in the obstructive HCM, which increased in the labile-obstructive and non-obstructive HCM, and were best in the control group. The Ts-SD and Te-SD were the shortest in the control group, were prolonged in non-obstructive and labile-obstruction HCM, and were longest in obstructive HCM (all P<0.05). Additionally, the exercise time of the control group was the longest, followed by non-obstructive and labile-obstruction HCM, and the shortest in the obstructive HCM (all P<0.05). The METs of obstructive HCM were significantly lower than the other three groups (all P<0.05). Conclusions In obstructive HCM, the left ventricular systolic strain and synchronization, as well as the MAPSE, are significantly impaired in patients both at rest and during exercise. The patients with labile-obstructive and non-obstructive HCM have reduced left ventricular GLS, twist, and e′, but normal left ventricular GCS, GRS, synchrony, and MAPSE at rest, which are all impaired during exercise. Key words: Two-dimensional speckle tracking imaging; Tissue Doppler imaging; Hypertrophic cardiomyopathy; Exercise stress echocardiography; Myocardial mechanics; Synchrony

Effect of hypertrophic cardiomyopathy on the prediction of thromboembolism in patients with nonvalvular atrial fibrillation

ypertrophic cardiomyopathy (HCM) is a fascinatingdisease that has intrigued and challenged cardiolo-gists for decades. Initially a diagnosis made bymaster clinicians adept at translating bedside dynamic aus-cultation into hemodynamic pathophysiology, HCM contin-ues to challenge the frontiers of diagnosis and technology.The development of 2D and Doppler echocardiography pro-vided the greatest increment in understanding the complexityof HCM. While clinicians at large became skilled at thebedside detection of dynamic left ventricular outflow obstruc-tion, echocardiography revealed that many more patients hadunexplained left ventricular hypertrophy (LVH) consistentwith HCM but without evidence of obstruction. In fact, thenonobstructive, “silent” forms are more frequent than theobstructive, “noisy” variants. The pattern and severity ofLVH are now appreciated as heterogeneous and diastolicdysfunction as highly prevalent.

Relations between left atrial appendage blood flow velocity, spontaneous echocardiographic contrast and thromboembolic risk in vivo

ObjectiveThe purpose of this article is to review how cardiac MRI provides the clinician with detailed information about the hypertrophic cardiomyopathy (HCM) phenotypes, assessing its morphological and functional consequences.ConclusionAn understanding of cardiac MRI manifestations of HCM phenotypes will aid early diagnosis recognition and its functional consequences.Teaching Points• The phenotypic variability of HCM expands beyond myocardial hypertrophy, to include morphological and functional manifestations, ranging from subtle anomalies to remodelling of the LV with progressive dilatation and thinning of its wall.• The stages of HCM, which are based on the clinical evidence of disease progression, include subclinical HCM, the classic HCM phenothype, adverse remodelling and overt dysfunction, or end-stage HCM.• Cardiac MRI provides the clinician with detailed information regarding the HCM phenotypes and enables the assessment of its functional consequences.