AV Block
Posted: Tuesday, August 22nd, 2023 | Updated: Tuesday, August 22nd, 2023
Posted: Tuesday, August 22nd, 2023 | Updated: Tuesday, August 22nd, 2023
General Information:
AV block is most commonly caused by idiopathic fibrosis. Alternatively, it may be caused by structural heart disease, neoplasia, tickborne diseases, such as Lyme's disease, Chagas disease, increased vagal tone, myocarditis, electrolyte abnormalities, pheochromocytomas, and/or antiarrhythmic drugs. AV Block can lead to fainting, stumbling, or collapse episodes. Patients may also experience sudden cardiac arrest. Treatment of AV Block may require the placement of a pacemaker. This is a device consisting of a lead wire and a pulse generator. Pacemakers are battery operated and are set at a specific heart rate or range to optimize battery life and quality of life. They help prevent episodes of lethargy and collapse by sending a signal to the heart letting it know to beat. Strict rest is required for a minimum of 3 months to prevent complications or dislodgement of the pacemaker. Harnesses are preferred after pacemaker placement. Patients should not have collars or anything tugging at their neck. Additionally, patients should not go through any metal detectors or have an MRI while the pacemaker is in place. Often, the wire is placed through the right jugular vein and hence, this vein should not be used to obtain blood samples. Electrocautery is also contraindicated for use during surgical procedures. AV Block categories: 1st degree AVB, 2nd degree AVB (Type I and Type II), and 3rd degree AVB
AV block is most commonly caused by idiopathic fibrosis. Alternatively, it may be caused by structural heart disease, neoplasia, tickborne diseases, such as Lyme's disease, Chagas disease, increased vagal tone, myocarditis, electrolyte abnormalities, pheochromocytomas, and/or antiarrhythmic drugs. AV Block can lead to fainting, stumbling, or collapse episodes. Patients may also experience sudden cardiac arrest. Treatment of AV Block may require the placement of a pacemaker. This is a device consisting of a lead wire and a pulse generator. Pacemakers are battery operated and are set at a specific heart rate or range to optimize battery life and quality of life. They help prevent episodes of lethargy and collapse by sending a signal to the heart letting it know to beat. Strict rest is required for a minimum of 3 months to prevent complications or dislodgement of the pacemaker. Harnesses are preferred after pacemaker placement. Patients should not have collars or anything tugging at their neck. Additionally, patients should not go through any metal detectors or have an MRI while the pacemaker is in place. Often, the wire is placed through the right jugular vein and hence, this vein should not be used to obtain blood samples. Electrocautery is also contraindicated for use during surgical procedures. AV Block categories: 1st degree AVB, 2nd degree AVB (Type I and Type II), and 3rd degree AVB
Cases of AV Block (Mobitz Type II)
Patient: Adult Male Large Breed Canine
Presentation: Labored breathing, lethargy, inappetence, dazed and confused appearance, stumbling at times, 3/6 heart murmur, MMVD Stage B1, bradycardia
Diagnostics: ECG, Echo, Snap 4Dx (negative), bloodwork, chest radiographs, AUS
Diagnosis: 2nd Degree AVB Mobitz Type II
Treatment Included: Pacemaker placement (right jugular vein), sedation (Trazodone), and anti-inflammatory medications (Carprofen)
Presentation: Labored breathing, lethargy, inappetence, dazed and confused appearance, stumbling at times, 3/6 heart murmur, MMVD Stage B1, bradycardia
Diagnostics: ECG, Echo, Snap 4Dx (negative), bloodwork, chest radiographs, AUS
Diagnosis: 2nd Degree AVB Mobitz Type II
Treatment Included: Pacemaker placement (right jugular vein), sedation (Trazodone), and anti-inflammatory medications (Carprofen)