Treatment of Second-Degree Heart Block

Introduction to Second-Degree Heart Block

The American College of Cardiology recommends that the treatment of second-degree heart block depends on the type (Mobitz I vs. Mobitz II), symptoms, and anatomical location of the block, with permanent pacemaker implantation being the definitive treatment for symptomatic patients and those with Mobitz type II block 1, 2

Mobitz Type I (Wenckebach) is characterized by progressive PR interval prolongation before a blocked P wave, usually occurring at the AV node level, according to the American College of Cardiology 3, 4
Mobitz Type II is characterized by constant PR intervals before and after blocked P waves, usually occurring within or below the His bundle, as stated by the American College of Cardiology 3, 4

For asymptomatic patients with Mobitz Type I without structural heart disease, observation is generally recommended as progression to higher-degree block is uncommon, as suggested by the American College of Cardiology 3, 1
For symptomatic patients with Mobitz Type I, permanent pacemaker implantation is recommended for patients with symptoms attributable to the block, such as syncope, presyncope, or fatigue, according to the American College of Cardiology and the European Heart Journal 1, 2
For all patients with Mobitz Type II, permanent pacemaker implantation is strongly recommended due to high risk of progression to complete heart block and sudden cardiac death, as recommended by the American College of Cardiology and the European Heart Journal 1, 2

For patients with Lyme carditis and AV block, parenteral antibiotics, such as ceftriaxone, are recommended for hospitalized patients, and temporary pacemaker may be required for advanced heart block, as stated by the Infectious Diseases Society of America 8
For athletes with AV block, permanent pacing is recommended as this indicates disease in the His-Purkinje system and has poor prognosis, according to the American College of Cardiology 1
Athletes with Wenckebach block who do not develop type II or complete heart block during exercise can participate in competitive sports, but those with Wenckebach block and coexisting bundle-branch block should undergo electrophysiological study, as recommended by the American Heart Association 6

For patients with Mobitz I not receiving pacemaker, regular ECG monitoring to detect progression to higher-degree block is recommended, and Holter monitoring may be useful to detect intermittent higher-degree block, as suggested by the American College of Cardiology 1, 7
For patients with pacemakers, regular device checks as per standard pacemaker follow-up protocols are necessary, according to the European Heart Journal 2