title: Effect of atenolol on heart rate, arrhythmias, blood pressure, and dynamic left ventricular outflow tract obstruction in cats with subclinical hypertrophic cardiomyopathy.
abstract: OBJECTIVE
  To investigate the negative chronotropic, antiarrhythmic, and obstruction-relieving effects of atenolol in cats with subclinical hypertrophic cardiomyopathy (HCM).
  
  
  METHODS
  Seventeen cats with HCM.
  
  
  METHODS
  Results for echocardiography, electrocardiography, Doppler blood pressure, and 24 h Holter monitoring were compared in cats before and 2-4 weeks after atenolol therapy (6.25-12.5 mg PO q 12 h).
  
  
  RESULTS
  The left ventricular outflow tract maximum velocity (LVOT Vmax) decreased after atenolol administration (mean Vmax pre-treatment 3.3 m/s ± 1.8 m/s; post-treatment 1.6 m/s ± 1.0 m/s, p < 0.0001). Heart rate (HR) decreased after atenolol for all HR modalities. The total number of ventricular origin complexes (TotVent) and ventricular premature complexes (VPCs) decreased after atenolol. The VPCs decreased from a geometric mean of 61 complexes/24 h (range, 11-620 complexes/24 h) to 15 complexes/24 h (range, 1-1625 complexes/24 h) (p < 0.0001). Murmur grade decreased after atenolol from a median grade of 3/6 to 2/6 (p < 0.0001). The systolic blood pressure did not change (mean pre-treatment 130 mmHg ± 16 mmHg, mean post-treatment 123 mmHg ± 20 mmHg, p = 0.2).
  
  
  CONCLUSIONS
  Atenolol decreases HR, murmur grade, and LVOT obstruction, and to a lesser degree, frequency of ventricular ectopy, in cats with subclinical HCM. Further studies are needed to determine if sudden cardiac death or long-term outcome is influenced by atenolol administration.
authors.affiliation: MedVet Medical & Cancer Centers for Pets, 300 East Wilson Bridge Rd, Worthington, OH 43085, USA. Electronic address: bethanyjacksondvm@gmail.com.
authors.forename: Bethany L
authors.initials: BL
authors.lastname: Jackson
authors.affiliation: MedVet Medical & Cancer Centers for Pets, 300 East Wilson Bridge Rd, Worthington, OH 43085, USA.
authors.forename: Darcy B
authors.initials: DB
authors.lastname: Adin
authors.affiliation: MedVet Medical & Cancer Centers for Pets, 300 East Wilson Bridge Rd, Worthington, OH 43085, USA.
authors.forename: Linda B
authors.initials: LB
authors.lastname: Lehmkuhl
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000662:veterinary*; D001262:Atenolol / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D002312:Cardiomyopathy, Hypertrophic / Q000188:drug therapy / Q000662:veterinary*; D002371:Cat Diseases / Q000188:drug therapy*; D002415:Cats; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D014694:Ventricular Outflow Obstruction / Q000188:drug therapy
chemical_list: D000889:Anti-Arrhythmia Agents; D001262:Atenolol
keywords: Beta blocker; Echocardiography; Feline; Holter monitor