Three cases of pacemaker-mediated tachycardia

Pacemaker-mediated tachycardia (PMT) is a well-known complication of dual-chamber pacemaker with atrioventricular sensing and pacing (DDD) or atrial synchronous, ventricular demand pacemaker (VDD). PMT usually starts with sensing a retrograde P waves linked to ventricular extrasystole with retrograde ventriculoatrial conduction and forms reentrant or circus movement tachycardia with the pacemaker itself as an antegrade limb and the conducting tissue of the heart as a retrograde limb. Recently, a number of pacemaker manufactures have incorporated in their devices a variety of relatively complex algorithms to prevent PMT. Despite these measures, PMT may still occur because of inappropriate programming or unpredictable variations of ventri-culoatrial conduction. We report two cases of PMT in 78 year-old man and 60 year-old man who received DDD type pacemakers due to sick sinus syndrome, and a case of PMT in 69 year-old man who had suffered complete heart block and received a VDD type pacemaker. In these cases, we investigate symptoms, mechanism of PMT, programed parameters of pacemaker and treatments of PMT.

The Difference of Autonomic Dysfunction according to the Absence or Presence of Nephropathy in NIDDM Patients / 대한신장학회잡지

In order to assess the difference of autonomic dysfunction according to the absence or presence of nephropathy in patients with NIDDM, tests for cardiovascular autonomic function were performed in 23 NIDDM patients without nephropathy(M : F 14 : 9, mean age 50+/- 8) and in 21 patients with nephropathy (M : F 13 : 8, mean age 57+/-12). Tests for cardiovascular autonomic function included the R-R interval changes in response to respiration, Valsalva maneuver, and lying-standing, the blood pressure changes in response to lying-standing and sustained handgrip exercise. The prevalence of autonomic dysfunction was different between the patients without and with nephropathy(69.6% vs 85.7%). For patients without symptoms suggesting autonomic neuropathy, the significant differences were found in the change of R-R interval in response to respiration(22.16+/-21.30 vs 11.73+/-10.83; p=0.0390), in the change of lying-standing blood pressure(10.63+/-9.70 vs 22.00+/-13.67; p= 0.0044) and in the change of blood pressure during handgrip exercise(16.89+/-10.28 vs 8.40+/-7.24; p=0.0065). These results suggested that autonomic neuropathy may occur more frequently in patients with diabetic nephropathy than diabetes mellitus without neuropathy.

A Case of an Aortic Embolism and Systemic Embolism in Infective Endocarditis

In spite of advanced diagnostic teclmology and better antimicrpbial therapy, infective endocarditis is relatively common, life-threatening infection. Heart failure and systemic embolism are the common and serious complications associated with the infective endocarditis. Because embolic event caR result in irreversible organ dysfunction or death, prevention is a desirable goal. Identification of pltients who are in the high risk of embolism and who can be helped by early surgical intervenCion is very important. Echocardiography has been generally accepted as the technique of choice for noninvasive diagnosis of infective endocarditis because of its potential for direct visualization of endocarditis-induced lesions. We experienced a case of an aortic embolism and systemic embolism in infective endocarditis in 21 year old male patient. He adrnitted for abdominal pain and dark colored urine for 30 days. Diagnosis of infective endocarditiis was made by clinical manifestation and echocardiography. Abdominal CT showing a low density areas in the spleen and the right kidney suggestive of a splenic infarction and a renal infarction. Aortography revealed dilatation of the bifurcation site of the aorta into common iliac artery and nonvisualization of left common iliac artery. Aortoiliac bypass surgery and splenectomy were done. After antibiotics and anticoagulation therapy, the patient was discharged relatively good condition.