In which cases does a permanent pacemaker need to be installed? And which conditions are not indications for pacemakers? Based on medical practice and especially on the results of recent evidence-based studies, the cardiovascular disease committees in the United States, Europe and China have developed very detailed guidelines for the implantation of permanent pacemakers, which are followed by cardiovascular specialists according to the patient’s specific situation. There are some differences between these guidelines, but the basic spirit is the same. According to the latest guidelines, they are briefly summarized as follows.
1. Recognized indications for pacemakers
1.1 Sick sinus node syndrome (SSS): and with symptoms directly related to slow arrhythmias.
(1) Bradycardia leading to a decrease in cardiac output, causing symptoms such as dizziness, dark haze, heart failure and syncope;
(2) Bradycardia-tachycardia syndrome and the need to control the tachycardia with drugs.
1.2 Atrioventricular block (AVB): It mainly depends on the presence or absence of symptoms and the site of block.
(1) Symptomatic AVB of degree II or greater, regardless of the presence or absence of symptoms and type;
(2) Asymptomatic AVB of degree II or higher, but with a ventricular rate <40 beats/min, or confirmed cardiac arrest >3 seconds;
(3) Rapid ectopic arrhythmias induced by high AVB requiring pharmacological treatment;
(4) Three-branch conduction block.
1.3 Others
(1) Carotid sinus hypersensitivity: definite recurrent syncope or light pressure on the carotid artery causing >3 seconds of cardiac arrest;
(2) Hypertrophic obstructive cardiomyopathy: reduction of left ventricular outflow tract obstruction by apical pacing of the right ventricle;
(3) Severe systolic insufficiency heart failure: treatment of heart failure by biventricular synchronized pacing (cardiac resynchronization therapy CRT, which is one of the major advances in pacemaker therapy in the last decade. This treatment involves the implantation of left ventricular electrodes through the coronary venous system in addition to separate electrodes in the right atrium and right ventricle. Most of the patients with heart failure implanted with CRT showed a great improvement in cardiac function). .
2. Controversial indications for pacemakers (i.e., conflicting evidence and divergent opinions on the benefit/effectiveness of pacemakers for patients in such cases)
(1) Patients with SSS with a heart rate <40 beats/min, asymptomatic or with no proven association with symptoms;
(2) Asymptomatic patients with II degree I AVB, block sites at or below the Hirschsprung bundle, or asymptomatic II degree II patients;
(3) Asymptomatic degree III AVB with ventricular rate > 40 beats/min.
3. Non-pacing indications (i.e., those recognized as not requiring permanent cardiac pacing implantation)
(1) SSS patients with proven symptoms unrelated to bradycardia;
(2) AVB of degree I;
(3) Asymptomatic AVB of degree II, type I, with block above the Hitchcock bundle;
(4) Simple branch block or asymptomatic branch block with degree I AVB.
The above is only a brief introduction. Whether a permanent pacemaker should be installed and what type of pacemaker should be installed requires a detailed examination by a qualified cardiologist, including intracardiac electrophysiological examination, to clarify the diagnosis and make an assessment.