Table 1.
Clinical data on feline samples.
| Ref no. | Breed | Age/Years | Gender | Immediately frozen at −80 | Cardiac Physical examination | Echocardiography | Pathology | Reason for Euthanasia | Cardiac diagnosis | Strength | Haploinsufficiency | Treatment |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| N1 | DSH | 11.4 | F | N (−20 for < 12 h) | No murmur, no arrhythmia, no gallop sound. SBP WNL | Not performed | Not performed | Ureteric Obstruction, Azotemia | Undetermined | * | No treatment | |
| N4 | Norwegian Forest | 10.4 | F | Y | No murmur, no arrhythmia, no gallop sound, increased bronchial wheeze. SBP not recorded | Normal cardiac structure | Normal gross and histopathology | Chronic Bronchitis/Low grade pneumonia | Normal | *** | Inhaled corticosteroid/antibiotics | |
| N7 | DLH | 13 | M | N (−20 < 14 day transferred to RVC on dry ice) | No murmur, no arrhythmia, no gallop sound. SBP WNL | Normal cardiac structure | Normal gross and histopathology | Hepatic Neoplasm | Normal | *** | No treatment | |
| N8 | DLH | 5 | M | N (−20 < 14 day transferred to RVC on dry ice) | No murmur, no arrhythmia, no gallop sound, SBP WNL | Normal cardiac structure | Normal gross and histopathology | Suspect mediastinal Carcinoma | Normal | *** | No treatment | |
| N9 | DSH | 3.5 | M | N (−20 < 14 day transferred to RVC on dry ice) | No murmur, no arrhythmia, no gallop sound, SBP WNL | Normal cardiac structure | Normal gross pathology, No myofiber disarray, mild infiltrate of macrophages in LV myocardial interstitium | FeLV related disease | Undetermined but not HCM | * | Corticosteroid, Ampicillin | |
| N11 | Tonkinese | 18.9 | F | Y | No murmur, no arrhythmia, no gallop sound, SBP not recorded | Normal cardiac structure | Normal gross and histopathology | pancreatic carcinoma | Normal | *** | Opioids, Ondansatron | |
| N12 | DSH | 10.5 | M | N (−20 < 14 day transferred to RVC on dry ice) | No murmur, no arrhythmia, no gallop sound, SBP WNL | Normal cardiac structure | Normal Gross and histopathology | Acute kidney injury | Normal | *** | IV fluid therapy | |
| H1 | DSH | 1.7 | F | Y | Grade IV sternal murmur and arrhythmia. Hypotensive SBP 75 mmHg | Cage side echo—diastolic symmetrical hypertrophy of LV consistent with HCM and enlarged LA | Gross pathology symmetrically thick LV walls—Myofiber disarray 15%, interstitial fibrosis consistent with HCM | Poor prognosis, financial constraints | HCM | *** | No treatment | |
| H2 | Sphynx | 9.7 | M | Y | Increased respiratory rate, arrhythmia and gallop sound, SBP WNL. | Enlarged left atrium and symmetrically thickened LV walls with one area of infarction of LVFW consistent with ES-HCM | Myofiber disarray 5-10%, multifocal replacement fibrosis including transmural LVFW, interstitial fibrosis, intramural arteriosclerosis—ES-HCM | Refractory congestive heart failure | HCM | *** | Clopidogrel, furosemide | |
| H3 | DSH | 8 | M | N (—20 for < 12 h) | Increased respiratory rate, hind limb paresis, pulseless and cold to touch, SBP (forelimb) WNL consistent with aortic thromboembolism. Cat diagnosed with HCM 3 years previously by echocardiography at the RVC. | Cage side echo—severe thickening of the LVFW, enlarged left atrium with spontaneous contrast present | Not performed | Suspected aortic thromboembolism | HCM | *** | Furosemide, LMW heparin | |
| H4 | DSH | 18.6 | F | N (—20 for < 12 h) | Increased respiratory rate, distress and vocalization, hind limb paresis, pulseless and cold to touch consistent with aortic thromboembolism, SBP not recorded | Not performed | Not performed | Suspected aortic thromboembolism/financial constraints | Cardiomyopathy likely but not confirmed | * | No treatment | |
| H5 | Ragdoll | 10 | M | N (−20 for < 12 h) | Increased respiratory rate, collapse, arrhythmia, gallop sound, pulmonary crackles. Grade II murmur. Homozygous MYBPC3 R820W. SBP WNL | Enlarged LA with poor systolic function and spontaneous contrast, mild/moderate hypertrophy of the IVS. LV systolic function reduced | Gross pathology—LV hypertrophy particularly affecting IVS, significantly enlarged LA | Chronic congestive heart failure | *** | |||
| H6 | Bengal | 4 | F | N (−20 for < 12 h) | Increased respiratory rate, hind limb paresis, pulseless and cold to touch consistent with aortic thromboembolism, SBP reduced 100 mmHg | Cage side echo—enlarged LA, focal severely thickened area of basal IVS, cardiomegaly and pulmonary oedema on radiography | Not performed | Suspected aortic thromboembolism | HCM | ** | —21% | Furosemide, LMW heparin, opioids |
| H7 | DSH | 10.8 | M | N (−20 for < 12 h) | Increased respiratory rate, Intermittent gallop sound, intermittent arrhythmia, ECG identified VPCs, SBP WNL | Enlarge LA with spontaneous contrast, thickened basilar IVS, and area of thin and hypomotile LVFW consistent with ES-HCM | Not performed | Aortic thromboembolism | HCM | ** | −30% | Furosemide, aspirin, benazapril |
| H8 | DSH | 10.1 | M | N (−20 for < 12 h) | Increased respiratory rate and harsh lung sounds, weak peripheral pulses, pulmonary oedema on radiography, signs consistent with aortic thromboembolism, SBP reduced 90 mmHg | Enlarged LA, mild hypertrophy of LV with poor systolic function | Not performed | Aortic thromboembolism and poor cardiac output | HCM | ** | −22% | Furosemide, clopidogrel, pimobendan |
| H10 | DSH | 12.7 | M | N (−20 for < 12 h) | Hypothermia, persistent arrhythmia, pelvic limb paresis and cold to touch. SBP not recorded | Cage side echo—enlarged poorly motile LA with thrombus visualized, LV hypomotile with diastolic thickening of IVS | Not performed | Aortic thromboembolism, financial constraints | HCM | ** | −22% | No treatment |
| H11 | DSH | 4.6 | M | Y | Increased respiratory rate, crackles over lung fields, arrhythmia. SBP not recorded | Cage side echo—enlarge LA and symmetrical LV hypertrophy | Gross pathology symmetrical LV hypertrophy. Myofiber disarray 30%, moderate interstitial fibrosis, intramural arteriosclerosis, replacement fibrosis papillary muscles | Poor prognosis, financial constraints | HCM | *** | Furosemide | |
| H12 | BSH | 3 | M | Y | Increased respiratory rate—pleural effusion on thoracic ultrasound. SBP low 110 mmHg | Cage side echo—Severe left ventricular hypertrophy, very dilated left atrium, very poor left atrial function | Gross pathology symmetrical severe LV hypertrophy. Myofiber disarray, moderate interstitial fibrosis and intramural arteriosclerosis | Refractory congestive HF and azotemia | HCM | *** | Furosemide, oxygen | |
| H13 | DSH | 14 | F | N (−20 < 14 day transferred to RVC on dry ice) | Distress, increased respiratory rate, open mouth breathing, arrhythmia. SBP not recorded | Not performed, brief thoracic U/S revealed pleural effusion and enlarged atria—ventricular morphology not fully assessed. | Gross pathology moderate LV hypertrophy. Endocardial fibrosis and myocardial disarray on histopathology consistent with HCM | Refractory congestive HF | HCM | *** | Thoracentesis furosemide oxygen | |
| H14 | DSH | 4 | M | Y | Distressed, increased respiratory rate and effort. Tachycardia and gallop sound, bilateral pulmonary crackles. Both hind limbs had no motor function and were cold to the touch no femoral pulse was palpable. SBP was not recorded | Enlarged LA with reduced systolic function, severe hypertrophy of LVFW adequate LV systolic function, incidental false tendon, small volume pericardial effusion. | Not performed | Congestive HF and suspected aortic thromboembolism, financial constraints | HCM | ** | −44% | Furosemide |
| H15 | DSH | 12 | M | Y | Distressed, hypothermia, increased respiratory rate increased and effort, open mouth breathing. Arrhythmia detected. Both hind limbs had no motor function and were cold to the touch no femoral pulse was palpable. SPB was not recorded | Not performed | Not performed | Suspected aortic thromboembolism and severe CHF, poor prognosis | HCM/other cardiomyopathy | * | None given | |
| H16 | Maine Coone | 11 | M | N (−20 < 14 day transferred to RVC on dry ice) | Increased respiratory rate, pulmonary crackles. SBP WNL | Symmetrical moderate LV hypertrophy, LA dilation and poor LA function | Myofiber disarray 5%, interstitial fibrosis, intramural arteriosclerosis consistent with HCM (incidental solid pulmonary carcinoma) identified at PM | CHF, financial constraints | HCM | *** | −19% | |
| H17 | Ragdoll | 7 | F | N (−20 < 14 day transferred to RVC on dry ice) | Collapse/seizure—cardiac auscultation unremarkable. Hypotensive SBP 80 mmHg | Not performed | Gross pathology moderate symmetrical LV hypertrophy. Histopathology Myofiber disarray <5%, mild interstitial fibrosis, occasional intramural arteriosclerosis equivocal for HCM | Chronic lethargy/collapse | HCM | ** | ||
| H18 | DSH | 8 | F | N (−20 < 14 day transferred to RVC on dry ice) | Cardiac auscultation unremarkable. SBP WNL | Not performed | Gross pathology mild LV hypertrophy. Histopathology multifocal myocyte hypertrophy and mild myofiber disarray. Histopathology equivocal for HCM | Pneumothorax/financial constraints | HCM | * | ||
| H19 | DSH | 7 | F | N (−20 < 14 day transferred to RVC on dry ice) | Increased respiratory rate, tachycardia. SBP not recorded | Cage side—pleural effusion and enlarged atria on U/S. LV morphology not determined | Not performed | Chronic Chylothorax and uncontrolled hyperthyroidism | HCM/hyperthyroid cardiomyopathy | * |
N1-N12 describe myocardial samples from cat without structural heart disease and H1-H19 describe myocardial samples from cats with HCM. Cat breed is shown in column 2, pedigree cat breeds are shown in green. BSH = British Short Hair, DSH/DLH = Domestic Short/Long Hair Based on clinical examination, echocardiography, histology and cause of death, or euthanasia we scored the diagnosis. Overall certainty of diagnosis is given as = probable, ** = highly likely, *** = definitive; see methods section for clinical criteria. The yellow shaded cats were studied by in vitro motility assay (IVMA). The MYBPC3 R820W mutant Ragdoll cat is sample H5.
Diagnostic criteria:
***
HCM or normal heart diagnosed by echocardiography (end diastolic LV wall thickness > 6 mm—see Section Materials and Methods for further details) and by pathological assessment with appropriate clinical signs.
**
HCM or normal heart diagnosed by either echocardiography or pathological assessment with appropriate clinical signs.
*
Either equivocal findings on echocardiography and or pathology or neither echocardiography nor pathology performed the cat must have had appropriate clinical signs.