Three-Dimensional Printed Models of the Heart Represent an Opportunity for Inclusive Learning.

Three-dimensional (3D) printed models of anatomic structures offer an alternative to studying manufactured, "idealized" models or cadaveric specimens. The utility of 3D printed models of the heart for clinical veterinary students learning echocardiographic anatomy is unreported. This study aimed to assess the feasibility and utility of 3D printed models of the canine heart as a supplementary teaching aid in final-year vet students. We hypothesized that using 3D printed cardiac models would improve test scores and feedback when compared with a control group. Students (n = 31) were randomized to use either a video guide to echocardiographic anatomy alongside 3D printed models (3DMs) or video only (VO). Prior to a self-directed learning session, students answered eight extended matching questions as a baseline knowledge assessment. They then undertook the learning session and provided feedback (Likert scores and free text). Students repeated the test within 1 to 3 days. Changes in test scores and feedback were compared between 3DM and VO groups, and between track and non-track rotation students. The 3DM group had increased test scores in the non-track subgroup. Track students' test scores in the VO group increased, but not in the 3DM group. Students in the 3DM group had a higher completion rate, and more left free-text feedback. Feedback from 3DM was almost universally positive, and students believed more strongly that these should be used for future veterinary anatomy teaching. In conclusion, these pilot data suggest that 3D printed canine cardiac models are feasible to produce and represent an inclusive learning opportunity, promoting student engagement.

Predicting Development of Hypertrophic Cardiomyopathy and Disease Outcomes in Cats.

Echocardiography is the gold standard imaging modality to diagnose hypertrophic cardiomyopathy (HCM) in cats. Echocardiographic features can predict both cats at an increased risk of developing HCM and cats with HCM at an increased risk of developing cardiovascular events or experiencing cardiac death. Left atrial dysfunction seems to be an important feature of HCM, as it is an early phenotypic abnormality and is also associated with worse outcome.

Natural history of hypertrophic cardiomyopathy in cats from rehoming centers: The CatScan II study.

BACKGROUND: The natural history of hypertrophic cardiomyopathy (HCM) in cats has been mainly studied in cats referred for suspected heart disease, which can skew the results towards cats with clinical signs. Few data are available on factors associated with development of HCM in cats. HYPOTHESES: (1) Clinical variables can predict which cats will develop HCM; (2) HCM in cats not referred for suspected heart disease is associated with a low rate of cardiovascular events. ANIMALS: One hundred seven cats from rehoming centers without a history of clinical signs of cardiac or systemic disease at the time of adoption. METHODS: Prospective longitudinal study. After rehoming, shelter cats were reexamined for serial echocardiograms. Cox regression analysis was used to identify predictors of development of HCM in cats that were normal at baseline. Adverse cardiovascular events including heart failure, thromboembolism, or sudden death were recorded. RESULTS: Cats were monitored for a median of 5.6 [1.2-9.2] years. At baseline, 68/107 cats were normal, 18/107 were equivocal and 21/107 had HCM. Nineteen cats developed HCM during the study period. The factors at baseline associated with increased hazard of developing HCM were lower left atrial fractional shortening, higher left ventricular fractional shortening, and higher body weight. Cardiovascular events were observed in 21% of cats with HCM. CONCLUSIONS AND CLINICAL IMPORTANCE: Cardiovascular events were common in cats with HCM from a rehoming center study sample. Lower left atrial systolic function appears to precede overt HCM.

Effect of preoperative administration of atenolol to dogs with pulmonic stenosis undergoing interventional procedures.

BACKGROUND: Beta-blockade is sometimes used in dogs with pulmonic stenosis with the intent of reducing frequency of ventricular arrhythmias during right heart catheterization. OBJECTIVES: To evaluate if pretreatment with atenolol reduces frequency of ventricular arrhythmias, anesthetist interventions, or shortens procedure time. ANIMALS: Thirty dogs with pulmonic stenosis scheduled for interventional procedures. METHODS: Single center, prospective, randomized, open-label study. Dogs were randomized to treatment with atenolol or no treatment preoperatively for a minimum of 10 days. Variables recorded included heart rate, arrhythmias and complexity, total procedure time and administration of antiarrhythmic treatment, vasopressors, positive chronotropes, or fluid boluses. RESULTS: Fifteen dogs were enrolled in each group. Dogs receiving atenolol had lower mean heart rates during the procedure (atenolol 100 ± 11 bpm vs untreated 115 ± 19 bpm, P = .01). There were no significant differences between the atenolol and untreated groups in the frequency of ventricular ectopic complexes (535 [6-5296] vs 553 [79-2863], P = .9), ventricular couplets (46 [0-481] vs 29 [3-121], P = .59), ventricular triplets (20 [0-265] vs 16 [1-82], P = .67), ventricular tachycardia (8 [0-224] vs 8 [1-118], P = .99), proportion exhibiting R-on-T phenomenon (11/15 vs 14/15, P = .33), proportion receiving intraoperative lidocaine (1/15 vs 3/15, P = .6), vasopressors/positive chronotropes (11/15 vs 5/15, P = .06), or fluid boluses (12/15 vs 7/15, P = .13). The procedure time was similar (atenolol 41 [23-68] min vs untreated 35 [18-98] min, P = .91). CONCLUSIONS AND CLINICAL IMPORTANCE: No benefit of preoperative atenolol treatment was identified in this small group of dogs.

Prevalence of sudden cardiac death in dogs with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with increased risk of sudden cardiac death (SCD) in humans, independent of secondary risk factors such as thrombogenic disorders. In dogs, SCD is described in a number of heart diseases, but an association between AF and SCD is unreported. HYPOTHESIS: (a) A higher proportion of dogs with AF will experience SCD, and (b) SCD will be associated with complex ventricular arrhythmias. ANIMALS: One-hundred forty-two dogs with AF, and 127 dogs without AF. METHODS: Retrospective, multicenter, case-control study. Dogs included in the AF group were compared to a control group of dogs in sinus rhythm, matched for echocardiographic diagnosis. Descriptive statistics were used to identify proportions of each group suffering SCD, compared using chi-squared testing. Risk factors for SCD in dogs with AF were evaluated at the univariable and multivariable level using binary logistic regression. Significance was P < .05. RESULTS: A significantly higher proportion of dogs with AF suffered SCD than dogs in the control group (14.8% vs 5.5%; P = .01). Younger age at diagnosis, larger left atrial size, and a history of syncope all were independent predictors of SCD in dogs with AF (χ2 , 16.3; P = .04). CONCLUSIONS AND CLINICAL IMPORTANCE: Atrial fibrillation was associated with a higher prevalence of SCD in dogs. A history of syncope may be a useful predictor of SCD risk.

Erratum to "Inter-observer variability for cardiac ultrasound measurements in cats repeated at different time points in early adult life" [5C (June 2018) 44-46].

[This corrects the article DOI: 10.1016/j.vas.2018.03.002.].

Long-term incidence and risk of noncardiovascular and all-cause mortality in apparently healthy cats and cats with preclinical hypertrophic cardiomyopathy.

BACKGROUND: Epidemiologic knowledge regarding noncardiovascular and all-cause mortality in apparently healthy cats (AH) and cats with preclinical hypertrophic cardiomyopathy (pHCM) is limited, hindering development of evidence-based healthcare guidelines. OBJECTIVES: To characterize/compare incidence rates, risk, and survival associated with noncardiovascular and all-cause mortality in AH and pHCM cats. ANIMALS: A total of 1730 client-owned cats (722 AH, 1008 pHCM) from 21 countries. METHODS: Retrospective, multicenter, longitudinal, cohort study. Long-term health data were extracted by medical record review and owner/referring veterinarian interviews. RESULTS: Noncardiovascular death occurred in 534 (30.9%) of 1730 cats observed up to 15.2 years. Proportion of noncardiovascular death did not differ significantly between cats that at study enrollment were AH or had pHCM (P = .48). Cancer, chronic kidney disease, and conditions characterized by chronic weight-loss-vomiting-diarrhea-anorexia were the most frequently recorded noncardiovascular causes of death. Incidence rates/risk of noncardiac death increased with age in AH and pHCM. All-cause death proportions were greater in pHCM than AH (65% versus 40%, respectively; P < .001) because of higher cardiovascular mortality in pHCM cats. Comparing AH with pHCM, median survival (study entry to noncardiovascular death) did not differ (AH, 9.8 years; pHCM, 8.6 years; P = .10), but all-cause survival was significantly shorter in pHCM (P = .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: All-cause mortality was significantly greater in pHCM cats due to disease burden contributed by increased cardiovascular death superimposed upon noncardiovascular death.

Inter-observer variability for cardiac ultrasound measurements in cats repeated at different time points in early adult life.

A high degree of accuracy is required when using echocardiography to diagnose hypertrophic cardiomyopathy (HCM) in cats, as variation in measurements of 0.5 mm may affect classification of individuals as 'abnormal'. This study in adult cats examined at different time points inter-observer variability between two Board certified echocardiographers in veterinary cardiology. Twenty-four female European shorthair cats were examined at 12, 18 and 24 months of age by observer 1. Two dimensional (2D) echocardiographic images were collected in conscious cats to measure left ventricular, aortic and left atrial dimensions. Measurements were repeated by observer 2 on stored images, and analysed for effect of time, observer and time-observer interaction. Based on end-diastolic left ventricular wall thickness, cats were diagnosed as 'normal' or 'abnormal'. Linear mixed models (generalized when appropriate) were performed. A significant difference between observers was found for all septal (IVSd) and free wall (LVFWd) thickness measurements and left ventricular internal diameters but not for aortic or left atrial measurements. All measurement coefficients of variation (CV) were < 10%. The CV for IVSd was higher than the CV for LVFWd. There was a significant effect of time on IVSd, aortic measurements and left ventricular internal diameter measurements. No significant time-observer interaction was found for any parameter. Diagnosis of cats as 'abnormal' (>5 mm in cats > 6 kg bodyweight) was significantly different between observers for IVSd but not LVFWd. Caution is warranted when diagnosing as 'abnormal' or interpreting small changes based on IVSd, due to significant inter-observer differences in this measurement.

International collaborative study to assess cardiovascular risk and evaluate long-term health in cats with preclinical hypertrophic cardiomyopathy and apparently healthy cats: The REVEAL Study.

BACKGROUND: Hypertrophic cardiomyopathy is the most prevalent heart disorder in cats and principal cause of cardiovascular morbidity and mortality. Yet, the impact of preclinical disease is unresolved. HYPOTHESIS/OBJECTIVES: Observational study to characterize cardiovascular morbidity and survival in cats with preclinical nonobstructive (HCM) and obstructive (HOCM) hypertrophic cardiomyopathy and in apparently healthy cats (AH). ANIMALS: One thousand seven hundred and thirty client-owned cats (430 preclinical HCM; 578 preclinical HOCM; 722 AH). METHODS: Retrospective multicenter, longitudinal, cohort study. Cats from 21 countries were followed through medical record review and owner or referring veterinarian interviews. Data were analyzed to compare long-term outcomes, incidence, and risk for congestive heart failure (CHF), arterial thromboembolism (ATE), and cardiovascular death. RESULTS: During the study period, CHF, ATE, or both occurred in 30.5% and cardiovascular death in 27.9% of 1008 HCM/HOCM cats. Risk assessed at 1, 5, and 10 years after study entry was 7.0%/3.5%, 19.9%/9.7%, and 23.9%/11.3% for CHF/ATE, and 6.7%, 22.8%, and 28.3% for cardiovascular death, respectively. There were no statistically significant differences between HOCM compared with HCM for cardiovascular morbidity or mortality, time from diagnosis to development of morbidity, or cardiovascular survival. Cats that developed cardiovascular morbidity had short survival (mean ± standard deviation, 1.3 ± 1.7 years). Overall, prolonged longevity was recorded in a minority of preclinical HCM/HOCM cats with 10% reaching 9-15 years. CONCLUSIONS AND CLINICAL IMPORTANCE: Preclinical HCM/HOCM is a global health problem of cats that carries substantial risk for CHF, ATE, and cardiovascular death. This finding underscores the need to identify therapies and monitoring strategies that decrease morbidity and mortality.

Cardiomyopathy prevalence in 780 apparently healthy cats in rehoming centres (the CatScan study).

OBJECTIVES: Hypertrophic cardiomyopathy (HCM) appears to be common in cats and, based on pilot data, a prevalence of 15% has been hypothesized. The objectives were to screen a large population of apparently healthy adult cats for cardiac disease, and identify factors associated with a diagnosis of HCM. ANIMALS: A total of 1007 apparently healthy cats ≥ 6 months of age. METHODS: In this prospective, cross-sectional study, the inclusion criteria were: apparently healthy cats, aged ≥ 6 months, available for rehoming over a 17-month period from two rehoming centres. Hypertensive or hyperthyroid cats were excluded. Body weight, body condition score, auscultation, systolic blood pressure and two-dimensional (2-D) echocardiography were evaluated. Cats with left ventricular end-diastolic wall thickness ≥ 6 mm on 2-D echocardiography were considered to have HCM. RESULTS: Complete data were obtained in 780 cats. Heart murmur prevalence was 40.8% (95% confidence interval (CI) 37.3-44.3%), 70.4% of which were considered functional. The prevalence of HCM was 14.7% (95% CI 12.3-17.4%), congenital disease 0.5% (95% CI 0.1-1.3%), and other cardiomyopathies 0.1% (95% CI 0.0-0.7%). The HCM prevalence increased with age. The positive predictive value of a heart murmur for indicating HCM was 17.9-42.6% (higher in old cats), and the negative predictive value was 90.2-100% (higher in young cats). The factors associated with a diagnosis of HCM in binary logistic regression models were male sex, increased age, increased body condition score and a heart murmur (particularly grade III/VI or louder). CONCLUSIONS: Hypertrophic cardiomyopathy is common in apparently healthy cats, in contrast with other cardiomyopathies. Heart murmurs are also common, and are often functional.

Comparison of auscultatory and echocardiographic findings in healthy adult cats.

OBJECTIVES: This pilot study was performed to investigate murmur prevalence and to explore the association between auscultatory and echocardiographic findings in apparently healthy cats in order to design a larger study. ANIMALS, MATERIALS AND METHODS: Adult cats in 4 rehoming centres were screened by auscultation and echocardiography (echo) over 2 periods of 2 weeks each. In the first period, echo was attempted only in cats with murmurs. In the second period, all cats underwent auscultation by 2 observers and echo. LVH was defined in 5 ways: maximal diastolic left ventricular (LV) wall thickness ≥ 6 mm or ≥ 5.5 mm with 2D (LVH(6 2D), LVH(5.5 2D), respectively) or M-Mode echo (LVH(6 MM) or LVH(5.5 MM) respectively), or LV wall thickness ≥ 6 mm (2D) for >50% of a wall segment (LVH(50%)). RESULTS: 67/199 (34%) cats had a murmur. Interobserver agreement on murmur presence was moderate (κ 0.47). 61 cats with a murmur and 31 cats without underwent both auscultation and echo. Depending on the criteria, LVH was present in 31 (LVH(6 2D)), 21 (LVH(50%)) and 11 (LVH(6 MM)) scanned cats. 18-62% of cats with murmurs had LVH, depending on the echo criteria used. Agreement was best between observers in identifying LVH using LVH(6 2D) and LVH(50%) (κ = 1.0). CONCLUSIONS: Heart murmurs are common in apparently healthy cats. The prevalence of LVH varies depending on the criteria used.