Direct heart rate: 260
Heart rhythm: Irregularly irregular
Heart rhythm disturbances: Suspect atrial fibrillation
Intensity of heart sound: Normal
Extra sounds – clicks or gallops: None
Murmur: No murmur
Precordial palpation: Normal precordial impulse, but no thrill

The CEG considers the following differential diagnosis as most likely (and why):The patient’s signalment, along with the complaint of respiratory distress and an arrhythmia makes cardiomyopathy the leading differential in this case. The patient’s decreased appetite, altered exercise tolerance, and lethargy would be common findings in cases of congestive heart failure compared to the many, more benign causes of cough. Hypertrophic cardiomyopathy is the most common type of heart disease in cats, but determining the type of cardiomyopathy would require an echocardiogram. The presence of the arrhythmia also leads us away from a diagnosis of primary respiratory disease, however we can not completely exclude the possibility of primary respiratory disease with an unrelated arrhythmia.

The CEG considers the following diagnostic tests as the highest priority:The highest priority diagnostic test to help determine the etiology for the clinical signs was thoracic radiographs. Benefits of thoracic radiographs in Cy’s case include assessment of the pulmonary vasculature and pulmonary parenchyma, along with assessment of the heart size. Because severe cardiomyopathy is often accompanied by cardiac dilation, thoracic radiographs are often useful at detection of atrial dilation. The electrocardiogram is equally critical to try and document whether supraventricular arrhythmias, ventricular arrhythmias, or a combination of the two are present. The type of arrhythmia present alters management protocols and level of risk for sudden cardiac death. Blood pressure assessment is valuable to rule out systemic hypertension as a cause of cardiac enlargement or to diagnose hypotension in a cat with congestive heart failure. The chemistry profile and urinalysis are important to evaluate renal function as we suspect cardiomyopathy and congestive heart failure account for the clinical signs. The presence of concurrent renal disease complicates management of congestive heart failure. The complete blood count, although not 100% specific, may provide insight into the presence of infectious or inflammatory pulmonary disease. Echocardiography is required for the confirmation of the type of cardiomyopathy.

Technical quality: Good quality
Subjective cardiac size: There is moderate-severe generalized cardiomegaly
VHS: Cardiac silhouette difficult to assess, but the VHS is estimated at 11.4
Pulmonary venous congestion: The pulmonary veins are indistinct but do appear enlarged
Pulmonary infiltrate distribution: Bilateral, perihilar
Pulmonary infiltrate pattern: Mild interstitial pattern
Other findings: Mild pleural effusion

Subjective – lesions of valves, myocardium, pericardial space: No pericardial effusion; mildly decreased systolic function of the left ventricle.
LV chamber size and thickness Normal wall thickness but high normal/mild LV dilation.
Left atrium: Severe left atrial dilation with spontaneous echo contrast (“smoke”).
LVIDd & LVIDs: Diastole (17 mm); Systole (13.3 mm)
LV shortening fraction: FS% = 22%
RA, RV and pulmonary artery: Severe dilation of the right atrium.
Effusions: Mild pleural effusion.
Doppler results: Mitral regurgitation; central jet of MR; velocity of MR predicts normal systemic pressures; No TR. Elevated mitral inflow velocities. Tissue Doppler indicates diastolic dysfunction.
Echocardiographic diagnosis:These findings are consistent with restrictive cardiomyopathy. This term is used for feline cardiomyopathies that do not display the “classic” finding of hypertrophic or dilated cardiomyopathy. In this cat, a combination of systolic dysfunction (low FS) and diastolic dysfunction with high-normal left ventricular diameter, normal LV wall thickness and severe biatrial enlargement suggest a restrictive cardiomyopathy. The noted mitral regurgitation may be secondary to primary valvular disease (rare in cats) or changes in annulus geometry due to myocardial disease (more common). The presence of left atrial spontaneous contrast suggests sluggish blood movement in the enlarged left atrium; this may predispose this patient to the formation of intracardiac thrombi. The mild pleural effusion detected is supportive of the radiographic diagnosis of congestive heart failure.

Technical quality, leads, paper speed, calibrations: Satisfactory recording; paper speed 50 mm/sec; calibration 10mm/mV
Artifacts: No significant
Rhythm- regular or irregular/ patterns: Irregularly irregular
P wave Abnormalities- morphology, amplitude, duration: No P waves identified.
QRS abnormalities- axis, morphology, amplitude, duration: Normal frontal axis, no significant increase in height or width. (insensitive measurement of chamber size)
Abnormal intervals- PR, QRS, QT: Normal intervals
ECG diagnosis: Atrial fibrillation

THE CEG Recommendations:
This is considered Stage C Cardiomyopathy. The CEG recommends therapy with pimobendan and furosemide to relieve the signs of congestive heart failure. Furosemide and pimobendan represent the highest priority medications to initiate. Clopidogrel is added to decrease the risk of intracardiac thrombus formation, based on the presence of spontaneous echo contrast (“smoke”) visible in the left atrium on the echocardiogram. Diltiazem, a calcium channel blocker, is recommended to slow conduction of the atrial fibrillation depolarizations through the atrioventricular (AV) node; this controlled AV block will decrease the ventricular rate response to the atrial fibrillation, thereby slowing heart rate. An ACE inhibitor is a helpful adjunct to controlling congestive heart failure chronically.
ACTUAL TREATMENT
Initial therapy:
Furosemide 12.5 mg: 1 tablet every 12 hours.
Enalapril 2.5mg: 1 tablet every 12 hours.
Pimobendan 1.25 mg: 1 tablet every 12 hours.
Diltiazem 30 mg tablets: 1/4 tablet every 8 hours.
Clopidogrel 75mg tablet: 1/4 tablet every 24 hours.
Follow-up plan:
1. Recheck thoracic radiographs in 7 days.
2. Recheck previously low blood pressure in 7 days.
3. Recheck renal chemistry values in 7 days. Lifestyle adjustments: Avoid high sodium treats and foods – such as processed meats, hot dogs, cheese, some table scraps.

There was no clear evidence of pulmonary edema, and the heart was nearly identical in size to the previous films. Stable heart failure with atrial fibrillation.
Another follow up exam was recommended in 6 months.
Comments: advantages of pursuing NT-proBNP testing in a patient with respiratory distress
Assessment of NT-proBNP concentrations in cats with respiratory distress allows increased certainty of a congestive heart failure diagnosis, and therefore, more rapid, successful therapy of congestive heart failure. An elevated NT-proBNP concentration in a cat that is not in congestive heart failure may provide valuable additional information regarding non-clinical heart disease that may affect tolerance of fluid administration (e.g. in a renal patient). Detection of preclinical heart disease via elevation of NT-proBNP concentration indicates that further diagnostic testing may be needed.