Complete atrioventricular block during ablation of atrial flutter.

We report the case of a 51-year-old patient who developed a complete atrioventricular (AV) block during the isthmic radiofrequency catheter ablation of a typical atrial flutter. The cause was an acute occlusion of the segment three of the right coronary artery. His recanalization was associated with the immediate restoration of a normal AV conduction. The complication is exceptional (one of 740 consecutive atrial flutter ablations). (PACE 2010; 516-519).

Nitrate-enhanced gated SPECT in patients with primary angioplasty for acute myocardial infarction: evidence of a reversible and nitrate-sensitive impairment of myocardial perfusion.

PURPOSE: Reperfusion of myocardial infarction (MI) leads to a reversible dysfunction of coronary vessels. We hypothesised that vasodilating drugs such as nitrates might improve sestamibi uptake within viable areas of recently reperfused MI, thereby enhancing prediction of subsequent improvements in perfusion and contractility. This study was aimed at assessing nitrate-enhanced sestamibi gated SPECT after MI reperfusion. METHODS: Twenty-nine patients underwent rest followed by nitrate sestamibi gated SPECT at 9 +/- 3 days after primary angioplasty for acute MI and at follow-up, 4-10 months later. Four MBq/kg of (99m)Tc-sestamibi was injected at rest, and 12 MBq/kg after nitroglycerin spray. RESULTS: Follow-up improvements were documented for both perfusion (P+) and contractility (C+) in 18% of the 180 initially abnormal segments, in neither perfusion (P-) nor contractility (C-) in 44%, in contractility only (C+P-) in 16% and in perfusion only (C-P+) in 22%. Perfusion improvement was related to lower sestamibi uptake on baseline rest SPECT (P+: 42 +/- 15% vs P-: 50 +/- 15%, p = 0.001) and, moreover, to a higher increase between rest and nitrate uptake (P+: +9.5 +/- 6.5% vs P-: +2.0 +/- 5.9%, p < 0.001). Contractility improvement was related to sestamibi uptake on baseline nitrate SPECT (C+: 58 +/- 15% vs C-: 38 +/- 16%, p < 0.001), a variable enhancing the prediction provided by sestamibi uptake at rest (p < 0.05). CONCLUSION: The improvement in perfusion which is documented in the months following MI reperfusion is predicted by initial nitrate enhancement of sestamibi uptake, suggesting a mechanism of reversible vascular injury. In this particular setting, sestamibi uptake is a better predictor of contractility recovery when determined after nitrate administration rather than under conventional resting conditions.

Detection of myocarditis by contrast-enhanced MRI in patients presenting with acute coronary syndrome but no coronary stenosis.

PURPOSE: To prospectively assess the use of cardiac MRI with delayed contrast enhancement (DCE) for identifying patients with active myocarditis among those presenting with acute coronary syndrome (ACS) but no coronary stenosis. MATERIALS AND METHODS: A total of 27 consecutive patients (age = 45 +/- 17 years; 14 male) presenting with ACS (chest pain, positive troponin-I) and no coronary stenosis, underwent cardiac MRI 9 +/- 7 days after pain onset and 8 +/- 5 months later (N = 19). Steady-state free-precession pulse (SSFP) sequence was applied for the assessment of myocardial function and both inversion-recovery (IR) and SSFP sequences were used for analyzing the topography and extent of DCE areas. Rest sestamibi-gated-single photon emission CT (SPECT) was also systematically performed. RESULTS: Subepicardial DCE pattern typical of acute myocarditis was documented in 12 patients (44%). Ischemic DCE pattern (transmural or subendocardial focal DCE) was documented in 12 of the 15 remaining patients (44%). Patients with subepicardial DCE had: higher C-reactive protein (CRP) levels (38 +/- 32 vs. 14 +/- 24 mg/mL; P = 0.04), lower Framingham cardiovascular risk (3 +/- 3% vs. 9 +/- 5%; P < 0.001), lower incidence of perfusion SPECT defects (17% vs. 73%; P = 0.01), higher left ventricular (LV) end-diastolic volume (77 +/- 16 vs. 64 +/- 10 mL/m(2); P = 0.02), and higher regression of DCE areas at follow-up (-65 +/- 17% vs. -18 +/- 23%; P = 0.002). CONCLUSION: DCE pattern of active myocarditis can be seen in patients presenting with ACS but no coronary stenosis.

Modulation of natural killer (NK) receptors on NK (CD3-/CD56+), T (CD3+/CD56-) and NKT-like (CD3+/CD56+) cells after heart transplantation.

BACKGROUND: After undergoing heart transplantation and the subsequent compulsive immunosuppressive treatments, patients are at risk of rejection episodes, infectious complications or cancer development. Thus, it is probable that the various subsets of peripheral cytotoxic lymphocytes are modulated in such patients. This area of study can now be investigated by examining the numerous recently described natural killer (NK)-cell-related surface receptors. METHODS: A prospective cohort of 60 heart transplant recipients and 60 controls was studied. The partitioning of lymphocyte subsets, especially NK (CD3-/CD56+), T (CD3+/CD56-) and NKT-like (CD3+/CD56+) cells, was compared in both groups using multi-parametric flow cytometry. Moreover, expression of a series of seven NK-related receptors was compared on the three subsets defined by CD56 expression. RESULTS: A significant increase in NK-cell levels was observed in transplanted patients, as compared with controls, whereas T and NKT-like cells were in similar proportions in both groups. Two NK-related receptors showed significantly different levels of expression in heart transplant recipients: the cytotoxic effector, CD244, which was in a significantly increased proportion on T and NKT-like cells; and the activating receptor, CD161, which was expressed significantly less on NK and NKT-like cells, but more on T cells. CONCLUSIONS: These findings indicate that cytotoxic NK-related cells, increased in proportion, also display increased levels of activity-associated markers in heart transplant recipients. Viral infection or the immunosuppressive regimen could be responsible for the modulation of regulatory receptors on NK and NKT-like cells in heart transplant recipients.

Noninvasive quantitation of blood flow turbulence in patients with aortic valve disease using online digital computer analysis of Doppler velocity data.

Previous experimental studies have demonstrated that aortic valve disease is associated with significant downstream turbulence (T). In this study, we developed a noninvasive method on the basis of Doppler velocity recording for quantitating aortic blood flow T in patients with aortic valve disease. The instantaneous blood velocity at a point in the aorta is equal to the sum of a mean periodic velocity component with a random or turbulent velocity component. According to the ensemble average method, time mean absolute T intensity is the root-mean-square value of turbulent velocity averaged over time and T is better quantitated by the relative T intensity (TIr), which is the ratio of absolute T intensity to the ensemble average velocity averaged over time. We computed TIr in 18 patients with mild to severe aortic stenosis and in 13 healthy volunteers from instantaneous modal velocities of 70 cycle length-matched heart beats recorded in the proximal part of the descending aorta by pulsed Doppler using an ultrasound system with an output port for online digital data transfer into a microcomputer. TIr was greater in patients with aortic valve disease (18.4 +/- 5.1%, range 11.2%-28.9%) than in control patients (7.9 +/- 1.9%, range 4.8%-9.8%; P =.0001). In patients with aortic valve disease, TIr was better linearly related to the ratio of postvalvular aorta to valvular orifice cross-sectional areas (r = 0.89, P =.0001) than to other parameters of valve restriction: transvalvular pressure gradient (r = 0.78, P =.0001); valve area (r = -0.56, P =.01); and valve resistance (r = 0.72, P =.0002). Thus, T that can be computed noninvasively from direct digital transfer of Doppler velocity data appears to be linearly related to indices of aortic valve restriction. Our data support the concept of the postvalvular aorta to valvular orifice cross-sectional areas ratio as a new important hemodynamic parameter in patients with aortic valve disease.

Benefits of cerebral protection during carotid stenting with the PercuSurge GuardWire system: midterm results.

PURPOSE: To examine the possible beneficial effect of a new cerebral protection device based on balloon occlusion of the distal internal carotid artery (ICA) and debris aspiration for patients undergoing carotid artery stenting (CAS). METHODS: One hundred and eighty-four CAS procedures were attempted under cerebral protection using the PercuSurge GuardWire system in 167 patients (129 men; mean age 70.5 +/- 9.2 years, range 40-91)). The lesions were mainly atherosclerotic, and half (n = 93) were asymptomatic. Eighteen restenotic and 7 post-radiation stenoses were also treated. RESULTS: Technical success was 99.5%. All lesions were stented except 3 postangioplasty restenoses. Prophylactic occlusion during balloon dilation and stenting was well tolerated in 176 (95.7%) patients. Microscopic analysis of the aspirated blood showed different types of particles numbering between 7 and 145 per procedure with a mean diameter of 250 microm (56-2652 microm). The 30-day stroke and death rate was 2.7%: 3 periprocedural complications at <48 hours (1 major stroke and 2 transient ischemic attacks), 1 intracerebral hemorrhage at 3 days, and 1 death of cardiac failure at 3 weeks. CONCLUSIONS: This study yielded a favorably low rate of periprocedural embolic events comparable with standard CAS series. Protection devices may play an important role in future carotid interventions and expand the applicability of the procedure. Randomized studies (surgery versus CAS with and without cerebral protection) are awaited.