This is an 11-month-old clinically normal intact female Maine Coon cat presented for a 3/6 systolic heart murmur. Scanning revealed generalized left and right ventricular hypertrophy and a severely enlarged right atrium with bowing of the atrial septum to the left. Short axis views revealed similar right and left ventricular diastolic size with septal flattening suggesting increased right ventricular pressure. Ventricular septal bowing to the left could be noted in the apical views along with thickening of the papillary muscles of the right ventricle to create a double chamber effect. There is little movement of the septal TV leaflet in the RPSLA view but coaptation does appear to occur. At their joining, a jet of TV regurgitation is noted which measures 7.15m/s directed away from the transducer in the RPSLA 4C (brick) view and approximately 5m/s in the apical view. The PA velocity noted was 2.5m/s in an oblique LPSLA view of the PA. In the short axis view, in the right ventricle, just before the pulmonic valve, I can record a velocity of 5.5m/s (hypertrophied tissue). A mild pleural effusion is present along with passive congestion of the liver.
ARVC usually causes dilation of the right ventricle and right atrium and is more typical in older cats. Tricuspid dysplasia is a young cat condition but often is usually associated with volume overloading and eccentric hypertrophy. If TV dysplasia, could the hypertrophy be secondary to chronicity? There could be sub valvular pulmonic stenosis (primary or secondary) based on CWD findings. The PA velocity although elevated is not extreme. I couldn’t observe a VSD but that doesn’t mean it couldn’t exist.
Any thoughts would be appreciated.
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great post. Thats a lot of rv hypertrophy for just TV dysplasia as just TVD cases tend to be more insidious and chronic and manifest later. PS with TVD here most likely as that RV hypertrophy is acting like outflow obstruction and someone is stepping on his hose so to speak. The pv gate can be tricky here. I would do a bubble study to be complete to ensure the zebra dx of reverse pda isnt an issue or some other out of view shunt. Big rv in a young patient always think bubble study to catch the more complex dx RPDA, AP window, RVSD… Eisenmenger’s physiology in play here with the flattened IVS and the AS deviation. Ill see if peter can log on and do a deeper dive on this.
Hi I totally agree
This is clearly a pressure overload case (ARVC and TD cause volume overload and normal TI gradients). In Maine Coons I frequently see double chambered right ventricle. These are best appreciated from right sided short axis views. However, pressure gradients across the stenosis are difficult to assess because of alignment with the jet can be very tricky. Pulmonic stenosis is as well an option here but you would easily see the valvular stenosis. Primary infundibular stenosis is rarely seen and is a fibrous stenosis within the right outflow tract. A bubble study could help ruling out any right to left shunt but since the cat is clinically normal, I would assume that there isn’t a shunt. Hope this helps. Best wishes, Peter
Thank you!! I was thinking Eisnmenger too when looking for a VSD but I couldn’t see anything obvious. I was thinking less of PDA as there was little enlargement of the PA and the cat is eating and active but I guess they would all be on the table. If there was a right to left shunt such as a PDA, is that surgically correctable or would that put them into right heart failure? Is there a protocol for medical management if surgery is not an option for this condition or for this owner? I included a pic of the RSA outflow. Couldn’t send the clip due to space. Not the greatest as the bigger probe has the CWD.
Hi Yes, looks like DCRV. Atenolol can be tried, but there’s no evidence that this would prolong life. Interventional stent placement is an option here. Surgery would likely required CP bypass….
In case right sided CHF develops, diuretics are necessary of course
Thanks so much! I appreciate both your and Dr. L’s time. My absolute last question on this case; I’ve read a bit on the right sided feline heart issues – pathophysiology and medical management and I don’t see much about pulmonary thromboembolism. Is PTE less of an issue with right atrial enlargement compared to ATE from LA enlargement?
Yes, indeed there’s not much information out there re feline pulmonary TE. in my opinion there’s no evidence at all that right atrial dilation predisposes to PTE. FATE /or CATE (cariogenic arterial TE) is something encountered in cardiomyopathy cats. And these diseases almost always affect predominantly the left heart. Also, PHT is difficult to assess in cats due to the lack of insufficiencies (PI /TI) needed to quantify PA pressures. Also, cats do not suffer from protein losing diseases as much as dogs do. So, generally speaking, I would not put a cat with RAE on clopidogrel