The exercise can also assess the type and severity of sinus node dysfunction present, based on the heart rate and rhythm response to the stress.
Certain endocrine problems, most commonly hypothyroidism (underactive thyroid), can imitate sinus node dysfunction, and therefore blood tests to assess the thyroid are usually performed in the workup
The indications for temporary pacemaker insertion reason were: in the biatrial group- sinus node dysfunction in 7 patients, type II 2nd degree AV block in 2 patients and complete AV block in one patient; in the bicaval group-type II 2nd degree AV block in 2 patients and persistent bradycardia one patient.
In the standard group implantable cardioverter defibrillator (ICD) implantation was applied to one patient due to the sinus node dysfunction the permanent pace and to one patient due to the ventricular tachycardia attacks.
Sinus node dysfunction is one of the reasons of morbidity after orthotopic heart transplantation.
The 70-year-old patient had sinus node dysfunction
Similarly, during RCA percutaneous interventions, distal embolization of plaque components after balloon inflation and stent implantation may cause sinus node dysfunction
, severe bradycardia, which are mostly expected to occur during proximal RCA interventions as a consequence of plaque shifting into a proximally located SAN artery.
The mechanisms of SND during exercise are thought to be mainly due to increased provocation of the Bezold-Jarisch reflex caused by inferior ischemia or direct sinus node ischemia or coronary angiography or intrinsic sinus node dysfunction
Indications for pacing included atrioventricular block in 76% and sinus node dysfunction in 22% patients.
Pacing indications: Indications for pacemaker implantation included advanced second- or third degree surgical/acquired (n=84, 54%), congenital (n=38, 25%) atrioventricular block (AVB), sinus node dysfunction (SND) (n=29, 19%) and other reasons such as long QT syndrome and hypertrophic cardiomyopathy (n=4, 3%) (Table 1).
Pacing indications and symptoms related required pacemaker therapy Pacing indications n (%) Surgical or acquired AV block 84 (54) VSD closure operation 21 TOF operation 18 Subaortic resection operation 13 Cardiomyopathy and/or myocarditis 7 Other cardiac operations 25 Congenital reasons 67 (43) Atrioventricular block 38 Sinus node dysfunction 29 Other Long QT syndrome and hypertrophic 4 (3) cardiomyopathy 4 (3) Pacing symptoms n (%) Postoperative status 77 (50) Bradycardia related seizures, syncope, presyncope 19 (12) Bradycardia related exercise intolerance 21 (13.
Sinus node dysfunction
had its own image on the RCGm--there were supracompensative pauses after extrasystole, Wenckebach's or Mobitz's periodics.