Congestive Heart Failure

The signs of CHF depend on which side of the heart is failing and how quickly fluid is accumulating. Any sudden change in breathing is a warning sign that requires same-day evaluation:

• Rapid, labored, or open-mouth breathing — the most urgent sign of left-sided CHF and pulmonary edema (fluid in the lungs)
• An elevated resting respiratory rate — more than 30 breaths per minute in a sleeping dog or cat is a red flag even before obvious distress develops
• Persistent coughing, especially at night or in the early morning (dogs; cats rarely cough with CHF)
• Progressive abdominal distension from ascites (fluid accumulation in the belly) — a hallmark of right-sided CHF
• Pleural effusion (fluid around the lungs) — causes muffled breathing sounds and may cause rapid breathing without coughing
• Exercise intolerance, sudden reluctance to walk or play
• Weakness, collapse, or fainting episodes
• Gray or bluish gum color (cyanosis) — a sign of severe oxygen deprivation requiring immediate emergency care

If your pet is breathing with their mouth open, using their belly to breathe, or simply will not lie down, treat this as an emergency and call us immediately.

CHF is the end-stage result of progressive heart disease. Understanding the underlying cause shapes treatment decisions and long-term prognosis:

• Myxomatous mitral valve disease (MMVD) — accounts for the majority of CHF cases in dogs; small and toy breeds are disproportionately affected, and Cavalier King Charles Spaniels have a strong hereditary predisposition
• Dilated cardiomyopathy (DCM) — a weakened, enlarged heart muscle seen in large and giant breeds such as Doberman Pinschers, Great Danes, and Irish Wolfhounds; often progresses rapidly to biventricular failure
• Hypertrophic cardiomyopathy (HCM) — the leading cause of CHF in cats; the thickened heart wall becomes stiff and impairs filling, ultimately causing left-sided or biventricular failure
• Congenital defects (present from birth) — patent ductus arteriosus (PDA), pulmonic stenosis, and subaortic stenosis can overload the heart over time
• Arrhythmias — sustained abnormal heart rhythms reduce pumping efficiency and can trigger acute failure
• Hypertension — chronically elevated blood pressure forces the heart to work harder and accelerates progression of underlying valve or muscle disease

Diagnosing CHF and identifying the underlying cause requires combining several tests, many of which are available on-site at our Calabasas hospital:

• Chest radiographs (X-rays) — the first step when breathing distress is present; show heart enlargement, fluid in the lungs (pulmonary edema), and pleural effusion at a glance
• Echocardiogram (cardiac ultrasound) — performed on-site by Dr. D'Urso; measures chamber dimensions, valve function, and the heart's pumping strength; essential for identifying the cause of CHF and guiding treatment
• Home resting respiratory rate (RRR) monitoring — owners count breaths per minute while their pet is asleep; rates consistently above 30 breaths per minute are an early warning sign before obvious distress appears, and trends over time help the team fine-tune diuretic dosing
• NT-proBNP blood test — a cardiac biomarker (a protein released when the heart wall is under stretch) that rises proportionally with the severity of heart failure; useful for monitoring treatment response and for screening cats with suspected HCM
• Blood chemistry panel and electrolytes — diuretic therapy alters kidney function and potassium levels; baseline and recheck values guide safe dosing adjustments
• Blood pressure measurement — hypertension co-exists with or worsens cardiac disease and is treated separately
• Electrocardiogram (ECG) — detects arrhythmias that may be contributing to or complicating failure

CHF management centers on removing accumulated fluid, reducing the heart's workload, and improving its pumping efficiency. Most patients require a combination of medications, and dosing is refined over time based on clinical response and monitoring:

• Furosemide or torasemide (diuretics) — the cornerstone of CHF treatment; these medications promote urine production to eliminate excess fluid from the lungs and body cavities; dose is titrated against the pet's resting respiratory rate and kidney values
• Pimobendan (Vetmedin) — strengthens heart contractions and dilates blood vessels simultaneously; used in dogs with MMVD or DCM in failure, and in cats with systolic dysfunction; supported by landmark clinical trials
• ACE inhibitors (enalapril, benazepril) — reduce the hormonal cascade that causes the body to retain salt and water; typically added once a pet is stable on diuretics
• Spironolactone — an aldosterone-blocking diuretic that complements furosemide and may slow cardiac remodeling over time
• Sodium-restricted diet — reducing dietary sodium helps limit fluid retention; especially important in dogs with advanced disease
• Home respiratory rate monitoring — owners count breaths once or twice daily while the pet is asleep; a sustained rise of more than 5 breaths per minute above baseline prompts a call to the care team for a possible dose adjustment before a crisis develops
• Thoracocentesis or abdominocentesis — if large volumes of fluid have accumulated around the lungs or in the abdomen, draining them directly provides immediate relief while medications take effect

CHF is a managed, not cured, condition — but many patients are comfortable and active for a year or more with appropriate therapy and diligent monitoring.

If your dog or cat is breathing rapidly at rest, seems unable to get comfortable, is coughing persistently, or has a visibly swollen abdomen, call Dog & Cat Hospital Calabasas right away — these signs may indicate active heart failure. An elevated resting respiratory rate (above 30 breaths per minute while asleep) is often the first detectable sign of fluid building in the lungs, and catching it early avoids a crisis. For pets already diagnosed with CHF, regular rechecks with Dr. D'Urso allow medication adjustments before symptoms escalate. Dr. D'Urso provides the full spectrum of cardiac care on-site — echocardiogram, fluid drainage, and long-term management planning — so your pet can be seen and treated the same day. Book an appointment and bring any respiratory rate logs you have been keeping at home.