Sinus nodal response to adenosine relates to the severity of sinus node dysfunction.

AIMS: It is unknown as to whether the result of adenosine testing for the diagnosis of sinus node dysfunction (SND) depends on the clinical presentation. We investigated whether syncope or presyncope are associated with a more pronounced sinus nodal inhibition by adenosine in SND. METHODS AND RESULTS: We studied 46 patients with SND, 33 with syncope or presyncope and 13 without such history. Controls were 30 subjects undergoing electrophysiological studies for supraventricular tachycardia or unexplained syncope. We calculated the corrected sinus node recovery time after intravenous adenosine 0.15 mg/kg (ADSNRT) as well as after atrial pacing (CSNRT). Corrected sinus node recovery time values >525 ms were considered abnormal. Corrected sinus node recovery time after adenosine injection was more prolonged in SND patients with syncope or presyncope as compared with those without such history [median: 4900 inter-quartile range (IQR): 920-8560 ms vs. median: 280 IQR: 5-908 ms; P< 0.005]. In SND patients with syncope or presyncope ADSNRT was more prolonged than CSNRT (median: 4900 IQR: 920-8560 ms vs. median: 680 IQR: 359-1650 ms, P< 0.01). In SND patients without syncope or presyncope no statistical difference was noted between ADSNRT and CSNRT (median: 280 IQR: 5-908 ms vs. median: 396 IQR: 270-600 ms, P = 0.80). The sensitivity of CSNRT for SND diagnosis was 57% and the specificity was 100%. A cut-off of 1029 ms for ADSRNT yields the same sensitivity with a specificity of 96.6%. CONCLUSION: In patients with SND syncope or presyncope relate to an exaggerated sinus nodal suppression by adenosine. Prolonged ADSNRT can diagnose cases with severe underlying SND where a more aggressive management strategy is probably warranted.

A case of exhaustion of implantable cardioverter defibrillator therapies due to inappropriate programming.

Strategically chosen tachycardia detection and therapy options targeting non-sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) can efficiently reduce the morbidity related to implantable cardioverter defibrillator (ICD) therapy. We report a case of a 60-year-old woman with ischemic cardiomyopathy who underwent ICD implantation due to frequent episodes of non-sustained VT. In this case, the inappropriate setting for VF detection in addition to the limited flexibility in device programming for tachycardia confirmation led to the rapid exhaustion of all available shock therapies.

Beneficial effect of ischemic preconditioning on post-infarction left ventricular remodeling and global left ventricular function.

BACKGROUND: Preinfarction angina (PA) is a clinical analogue of ischemic preconditioning that improves postinfarct prognosis. Data concerning the association of PA with post infarction left ventricular (LV) remodeling and LV diastolic function are limited. We aimed to evaluate this association in patients with acute myocardial infarction (AMI) in the modern clinical era of widespread use of revascularization and antiremodeling medical treatment. METHODS: We studied 53 patients with anterior AMI who underwent complete reperfusion and received up to date antiremodeling medical treatment. LV remodeling, systolic and diastolic function were assessed using 2D echocardiography at baseline and 6 at months follow-up. Patients were divided into two groups regarding the presence or absence of PA. RESULTS: LV remodeling at follow-up was less frequent in the PA group (25 vs. 55 %, P<.05). Patients with PA had lower end-systolic volume index at baseline and follow up (24.1±6 vs. 30.1±14 ml/m(2), P<.001 and 25.3±8 vs. 35.6±2 ml/m(2), P=.001 respectively). Additionally at 6 months, they had better LV ejection fraction (52.1±9 vs. 42.9±10 %, P=.002) and exhibited improved diastolic filling as reflected by mitral E/e' (14.6±5 vs. 18.8±8, P=.05). CONCLUSIONS: Ischemic preconditioning in the form of PA promotes better LV systolic and diastolic function in the mid-term and is associated with less postinfarct LV remodeling in this specific study population. The results of the study underline the possible need for further risk stratification of AMI patients regarding the absence of PA.