Structured Follow-Up for Cardiac Patients: A Practical Guide

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Once a dog or cat is diagnosed with heart disease and started on medication, structured follow-up evaluations are essential to assess treatment efficacy, disease progression, and the need for therapy adjustments. Below is an evidence-based, practical approach aligned with ACVIM staging and current cardiology standards.

When to Schedule Follow-Up Visits

Follow-up frequency depends on disease severity, medication changes, and patient stability:

Dogs

  • Stage B2 (preclinical MMVD/DCM, starting pimobendan):
    • Initial follow-up at 4–8 weeks to confirm clinical tolerance, owner adherence, and to address questions. 
    • Once stable, reassess every 1–3 months, then every 6 months (or sooner if signs change).
  • Stage C/D (CHF, on diuretics):
    • Recheck 3–7 days after discharge or dose adjustment.
    • Re-evaluate in 2–4 weeks to confirm stabilization.
    • Stable patients: Every 1–2 months (sooner if tachypnea, cough, syncope, or appetite changes).

Cats

  • HCM (preclinical):
    • Mild disease: Every 3–6 months.
    • Monitor more frequently if remodeling progresses, NT-proBNP rises, or hypertension develops.
  •  CHF (recently diagnosed):
    • Recheck 3–7 days after starting therapy, then every 2–4 weeks until stable.

 

 

Key Components of Follow-Up Evaluations

1. Clinical History & Home Monitoring

  • Owner-reported metrics:
    • Sleeping respiratory rate (SRR) – Goal: ≤25–30/min (persistent elevation suggests CHF relapse).
    • Cough (dogs), exercise tolerance, syncope, appetite, thirst/urination, weight trends.
    • Cats: Stress levels, open-mouth breathing, acute paralysis with pain (ATE likely)
  • Medication adherence: Confirm proper dosing and timing (e.g., pimobendan’s BID schedule).

2. Physical Exam

  • Cardiac:
    • Murmur intensity/location (changes may indicate progression).
    • Gallop sounds (S3/S4 suggest worsening CHF).
    • Arrhythmias (irregular pulse, syncope risk).
  • Respiratory: Crackles, pleural effusion (cats), increased effort.
  • Perfusion: Pulse quality, mucous membranes, jugular distension.
  • Hydration/weight: Sudden weight loss/gain may reflect fluid shifts.
  • Blood pressure: Treat hypertension (≥160 mmHg systolic in cats).

3. Diagnostic Testing (Tailored to Stage & Stability)

A. Thoracic Radiographs

  • When:
    • Suspected CHF relapse, new/worsening respiratory signs.
    • MMVD with CHF: primary tool to titrate diuretics and track congestion. Repeat at decompensation, 7–14 days after significant dose changes, and any time SRR rises or cough/dyspnea/weight-appetite changes occur.
    • DCM/other CHF: use with clinical metrics; frequency driven by signs and therapy changes.
  • Key findings:
    • Pulmonary edema (adjust diuretics if unresolved).
    • Cardiomegaly (VHS/VLAS) – Track progression.
    • Pleural effusion (cats: may need thoracocentesis).

B. Echocardiography

  • Baseline at diagnosis for all.
  • Preclinical (B1/B2 MMVD, DCM risk; feline HCM): every 6–12 months, sooner if remodeling, BP, arrhythmia, or biomarkers change.
  • MMVD with CHF: not routine. Do a focused echo only with clinical change, poor response, suspected chordal rupture, pulmonary hypertension, new/worsening arrhythmia, or concern for systolic dysfunction (also for pre-anesthesia/advanced therapy decisions).
  • DCM with CHF (dogs): repeat about every 3–6 months or with clinical change.
  • Feline HCM/HOCM ± CHF: repeat about every 3–6 months or with clinical change to monitor LA size, LVOT gradient/SAM, and thrombus/ Spontaneous echocardiographic contrast (SEC) – ”smoke”; guides beta-blockers/antithrombotics

C. ECG & Arrhythmia Monitoring

  • CardioBird AI-ECG and Holter:
    • Rapid rhythm analysis for dose adjustments (e.g., diltiazem in AF)
    • Suspected arrhythmia (e.g., irregular pulse).
    • Syncope, high VPC burden, or atrial fibrillation.

D. Laboratory Tests

  • Renal panel + electrolytes (K+, Na+, Cl⁻):
    • Check 3–7 days after starting/changing diuretics, ACEi, or spironolactone.
    • Azotemia: Determine cause first. If pre-renal (overdiuresis/dehydration), reduce diuretics and rehydrate; otherwise treat the cause and reassess RAAS/diuretic doses; recheck labs in 24–72 h.
    • Hypokalemia? Supplement or add spironolactone.
  • NT-proBNP:
    • Rising levels suggest cardiac stress; falling trends indicate control.
    • Useful for ambiguous cases (e.g., cough vs. cardiac vs. respiratory disease).
  • Thyroid (cats): Check T4 if > 7 years old.

 

 

How Test Results Guide Treatment Adjustments

1. Diuretics (Furosemide/Torsemide)

  • Increase dose/frequency if:
    • SRR >30/min, recurrent edema, or worsening radiographs.
  • Do not routinely reduce once CHF is controlled; maintain the effective dose to prevent relapse. Reduce only if dehydration is likely (vomiting, diarrhea, anorexia, poor intake) or if the underlying disease is resolved/surgically correctable (e.g., PDA, MMVD).
  • Refractory CHF: consider torsemide; if adding hydrochlorothiazide, use extreme caution and monitor electrolytes/renal values closely.

2. Pimobendan

  • Dogs (MMVD/DCM): Continue indefinitely unless contraindicated.
  • Cats (CHF): Use cautiously with LVOTO; monitor for improved perfusion.

3. RAAS Blockade (ACEi/Spironolactone)

  • ACE inhibitors (e.g., enalapril):
    • Start when hemodynamically stable; monitor for azotemia/hyperkalemia.
  • Spironolactone:
    • Add in CHF for antifibrotic/K⁺-sparing effects.

4. Arrhythmia Management

  • Atrial fibrillation: Diltiazem ± digoxin (dogs); titrate via ECG and monitor serum digoxin level.
  • Ventricular arrhythmias: Sotalol/mexiletine if high burden or syncope.

5. Feline-Specific Considerations

  • HCM with LVOTO: Beta-blockers (e.g., atenolol) if stable.
  • Thromboembolism risk: Clopidogrel for LA enlargement/Spontaneous echocardiographic contrast (SEC) – ”smoke”.
  • Pleural effusion: Teach owners to recognize tachypnea/dyspnea; plan for thoracocentesis.

 

 

Signs of Control vs. Progression

✅ Controlled Disease:

  • SRR ≤30/min, stable weight/appetite, no edema on radiographs, stable NT-proBNP/renal values.

⚠️ Worsening Disease:

  • SRR >30/min, recurrent edema, enlarging LA/LV, rising NT-proBNP, new arrhythmias.

 

 

Client Communication & Home Care

  • Teach SRR monitoring and provide a written “rescue plan” for early CHF signs.
  • Emphasize: Medication adherence, low-stress handling (cats), weight logs.
  • Remote monitoring: Use CardioBird for rhythm checks after medication changes.

When to Refer to a Cardiologist

  • Uncontrolled CHF despite standard therapy.
  • Complex arrhythmias requiring advanced management.
  • Rapid disease progression (e.g., sudden LA enlargement, refractory effusions).

—The CardioBird Team 🚀🐾