ABSTRACT
BACKGROUND: Pseudo ischemic ST segment changes during supraventricular tachycardia (SVT) are not yet fully understood. Our aim was to determine whether venticulo-atrial (VA) conduction during SVT may be a possible mechanism for ST depression (STd) in SVT. METHODS: Patients undergoing SVT ablation (2010-2012) were analyzed (n = 72).Typical atrioventricular node reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) were included. Those with STd were compared to those without STd. VA interval length, tachycardia cycle length (TCL), and retrograde P-wave activation during SVT were assessed. Retrograde P waves arriving simultaneously with the ST segment (PWST) during SVT were considered, whenever an atrial electrogram (measured from the high right atrium) was "on time" with the ST segment. RESULTS: Patients with STd during SVT presented longer VA intervals than those without STd (VA 100 ± 37 ms vs VA 69 ± 22 ms; P = 0.006). No differences in TCL were observed (TCL 333 ± 35 ms vs TCL 360 ± 22 ms; P = 0.1). PWST was observed in 38.5% of patients with AVNRT and STd versus 0% in those without STd. The TCL was similar in both groups (355 ± 25 ms vs 334 ± 18 ms; P = 0.1). In patients with AVRT and STd, PWST was present in 81% of cases versus 0% in those without STd. The TCL was also similar (330 ± 29 ms vs 346 ± 17 ms; P = 0.1). CONCLUSIONS: STd during SVT is observed at long VA intervals when the retrograde P wave matches the ST segment, without dependence on the TCL. This suggests that STd is not necessarily rate dependent but a result of a fusion between the ST segment and the P wave.
Subject(s)
Myocardial Ischemia/physiopathology , Tachycardia, Atrioventricular Nodal Reentry/physiopathology , Tachycardia, Atrioventricular Nodal Reentry/surgery , Tachycardia, Supraventricular/physiopathology , Tachycardia, Supraventricular/surgery , Arrhythmias, Cardiac/physiopathology , Arrhythmias, Cardiac/surgery , Atrioventricular Node/physiopathology , Brugada Syndrome , Cardiac Conduction System Disease , Cardiac Electrophysiology , Electrocardiography , Female , Heart Conduction System/abnormalities , Heart Conduction System/physiopathology , Heart Conduction System/surgery , Humans , Male , Middle Aged , Risk Assessment , Risk FactorsABSTRACT
BACKGROUND: Few studies that have assessed the effect of abbreviated oral N-acetylcysteine (NAC) regimens in radiocontrast-induced nephropathy (RCIN) yield mixed results. OBJECTIVE: To evaluate the renoprotective effect of high periprocedural oral doses (HPOD) of NAC in patients with chronic renal impairment undergoing a same-day angiography. METHODS: Sixty one patients with renal impaired function scheduled to undergo a same-day angiography were randomly assigned to NAC 1200 mg orally 3 hours before and 3 after the procedure, or a placebo. All patients received 0.9% saline intravenous. RCIN was defined as an increase in SCC > 0.5 mg/dl 48 hours after the procedure. RESULTS: The mean baseline SCC for all patients was 1.44 +/- 0.42 mg/dl. A significant difference in SCC change at 48 hours after the angiography was found (-0.07 mg/dl NAC, 0.09 mg/dl placebo, P = 0.04). RCIN occurred in 1 (3%) patient of NAC group and in 2 (7.1%) patients of placebo group (P = 0.59). Adverse effects were similar in both groups. CONCLUSIONS: In patients with mild renal impairment patients undergoing angiographic procedures, HPOD of NAC were more effective than placebo in preventing SCC change 48 hours. A non significant benefit in RCIN incidence was found.
Subject(s)
Acetylcysteine/therapeutic use , Antioxidants/therapeutic use , Contrast Media/adverse effects , Kidney Failure, Chronic/prevention & control , Acetylcysteine/administration & dosage , Administration, Oral , Aged , Angiography , Antioxidants/administration & dosage , Double-Blind Method , Female , Humans , Kidney Failure, Chronic/chemically induced , Male , Prospective StudiesABSTRACT
BACKGROUND: Few studies that have assessed the effect of abbreviated oral N-acetylcysteine (NAC) regimens in radiocontrast-induced nephropathy (RCIN) yield mixed results. OBJECTIVE: To evaluate the renoprotective effect of high periprocedural oral doses (HPOD) of NAC in patients with chronic renal impairment undergoing a same-day angiography. METHODS: Sixty one patients with renal impaired function scheduled to undergo a same-day angiography were randomly assigned to NAC 1200 mg orally 3 hours before and 3 after the procedure, or a placebo. All patients received 0.9
saline intravenous. RCIN was defined as an increase in SCC > 0.5 mg/dl 48 hours after the procedure. RESULTS: The mean baseline SCC for all patients was 1.44 +/- 0.42 mg/dl. A significant difference in SCC change at 48 hours after the angiography was found (-0.07 mg/dl NAC, 0.09 mg/dl placebo, P = 0.04). RCIN occurred in 1 (3
) patient of NAC group and in 2 (7.1
) patients of placebo group (P = 0.59). Adverse effects were similar in both groups. CONCLUSIONS: In patients with mild renal impairment patients undergoing angiographic procedures, HPOD of NAC were more effective than placebo in preventing SCC change 48 hours. A non significant benefit in RCIN incidence was found.
