Search

Background: Estimating contractility of the left ventricle with noninvasive techniques is an important yet elusive goal. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). Aim: To assess the feasibility of a noninvasive estimation of force-frequency relation (FFR) during pacing stress in the echo lab in patients with permanent pacemaker (PM). Methods: Transthoracic stress pacing echocardiography was performed in 26 patients with a permanent pacemaker (age 69+/-11 years; 21 men, 5 women). Seven patients had normal function at baseline and during stress ("normals"); eight had angiographically assessed coronary artery disease (three with and five without induced ischemia with stress echo); eleven patients had dilated cardiomyopathy (DC). To build the FFR, the force was determined at different steps as the ratio of the systolic pressure (SP, cuff sphygmomanometer)/end-systolic volume index (ESV, biplane Simpson rule/body surface area). Heart rate was determined from ECG. Results: The absolute value of the FFR slope was highest in controls and lowest in DC patients. A flat-downsloping FFR was found in 12/19 patients but not for normals (p<0.01). Conclusions: Noninvasive pacemaker stress echocardiography (PASE) is a simple and efficient option to assess left ventricular (LV) contractility in patients with permanent pacemaker. [ABSTRACT FROM AUTHOR]

Background: High-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility. Methods: The pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson rule). The heart rate is determined from ECG. Conclusion: Two-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker. The force-frequency can be defined as up- sloping (normal) when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress values, biphasic with an initial up- sloping followed by a later down-sloping trend, or flat or negative when peak stress pacing systolic pressure/end-systolic volume index is equal or lower than baseline stress values. This approach is certainly highly feasible and allows a conceptually immaculate definition of contractility with prognostic usefulness, but its therapeutic implications remains to be established. Bowditch treppe, assessed with pacing stress, can be used to assess the optimal stimulation frequency and to optimise the patient's chronotropic response in programming rate-adaptive pacemakers. [ABSTRACT FROM AUTHOR]

A letter to the editor in response to the article "Closure of secundum atrial septal defects with the Amplatzer septal occluder device: techniques and problems" by R. W. Harper, P. M. Mottram and D. J. McGaw in the 2002 issue is presented.

Abstract: Background: Common clinical practice recommends dual antiplatelet therapy (DAPT) for transcatheter aortic valve implantation (TAVI). The aim of the study was to evaluate, in a double blind randomized study, the safety of TAVI, with adjunctive pharmacotherapy consisting of single antiplatelet therapy. Methods and results: From April 2010 to April 2011, 120 consecutive patients, undergoing TAVI, have been enrolled in the study. Patients were randomly assigned to DAPT group (aspirin and clopidogrel 75mg/qd or ticlopidine 500mg/bid) or ASA group (aspirin only). TAVI device was the Sapien XT-Novaflex Delivery System (Edwards Lifesciences, Inc.). All patients were followed up to 6months. Device success was achieved in 100% of patients. No difference in the VARC combined 30day safety endpoint, all cause and cardiovascular mortality was observed. At 30days vascular complications were reduced in the ASA group (p <0.05). No differences in the clinical status were detected between the groups up to 6months. Conclusions: This study suggests that TAVI procedures can be performed without DAPT without increasing the morbidity and mortality. These findings, if confirmed in a larger multicenter randomized trial, will no longer support the use of DAPT for TAVI. [Copyright &y& Elsevier]

Background: Tako-tsubo syndrome (TTS) in its typical (apical) and atypical (non-apical) forms is being increasingly recognized in the West owing to early systematic coronary angiography in acute coronary syndromes (ACS). Aim of the study: To assess the incidence, the clinical characteristics and the outcome of TTS in a single high volume cath lab in Southern Italy over the last 6 years. Methods: Among 1674 consecutive patients (pts) referred to our coronary care units in the last 6 years (2001-2006) for ACS we selected 6 (0.5%) pts (6 women; age 57 ± 6 years) who fulfilled the following 4 criteria: 1) transient left ventricular wall motion abnormalities resulting in ballooning at contrast ventricolographic or echocardiographic evaluation; 2) normal coronary artery on coronary angiography performed 5 ± 9 hours from hospitalization; 3) new electrocardiographic ischemic-like abnormalities (either ST-segment elevation or T-wave inversion) and 4) emotional or physical trigger event. Results: At admission all pts had presumptive diagnosis of ACS and ECG revealed ST elevation in 3 (50%) and T wave inversion with QT elongation in 3 (50%). In the acute phase cardiogenic shock occurred in 2 (33%) and heart failure in 1(16%). Presenting symptoms were chest pain in 6 (100%), dyspnoea in 2 (33%) and lipotimia in 1 (16%). At echocardiographic-ventricolographic assessment, the mechanical dysfunction (ballooning) was apical in all 6 pts ("classic" TTS). In all patients wall motion abnormalities completely reversed within 4.5 ± 1.5 days. The region of initial recovery was the anterior and lateral wall in 4 cases and the lateral wall in 2 cases. Ejection fraction was 35 ± 8% in the acute phase and increased progressively at discharge (55 ± 6%) and at 41 ± 20 months follow-up (60 ± 4%, p < 0.001 vs. baseline). All patients remained asymptomatic with minimal (aspirin, beta blockers, antihypertensive and antidislipidemic therapy) treatment. Conclusion: Classic TTS is a frequent serendipitous diagnosis after coronary angiography showed "surprisingly" normal findings in a clinical setting mimicking an ACS. Despite its long-term good prognosis life threatening complications in the acute phase can occur. [ABSTRACT FROM AUTHOR]

Background: Little is known regarding the long-term performance of coronary sinus (CS) leads, which have an effect on the longevity of cardiac resynchronization therapy (CRT) systems. Methods: This study included 109 patients (79 men) whose mean age was 68 ± 9 years, New York Heart Association (NYHA) functional class 3.2 ± 0.5, and left ventricular ejection fraction 25.6 ± 6.6%, and who underwent CRT (n = 45) or CRT-D (n = 64) systems implants for management of idiopathic (53%), ischemic (40%), or miscellaneous (7%) dilated cardiomyopathy. Unipolar (n = 57) or bipolar (n = 52) leads were placed into the CS venous system. Results: At implant, no significant difference was observed between unipolar and bipolar leads with respect to mean sensing performance (14 ± 6 mV vs 14 ± 8 mV, P = 0.97), pacing impedance (875 ± 234 ohms vs 943 ± 331 ohms, P = 0.24), and stimulation energy threshold (2 ± 3.2 μJ vs 1.13 ± 1.5 μJ, P = 0.08). At a median follow-up of 33 months, a significant decrease in stimulation impedance and increase in stimulation energy threshold was observed with unipolar (689 ± 122 vs 875 ± 234 ohms, P < 0.01, and 8.34 ± 10.4 μJ vs 2 ± 3.2 μJ, P < 0.001, respectively) as well as with bipolar (735 ± 268 ohms vs 943 ± 331 ohms, P < 0.01, and 4.81 ± 9.92 vs 1.13 ± 1.5 μJ, P = 0.02, respectively) leads. No significant difference in sensing performance was observed with either type of lead (10 ± 5 mV vs 14 ± 6 mV and 10 ± 6 mV vs 14 ± 8 mV, respectively). At long-term follow-up, no significant difference among any sensing or stimulation parameter was observed between unipolar and bipolar leads. Conclusions: At long-term follow-up, a significant increase in the energy required for stimulation was observed, whereas sensing performance remained unchanged. The increase in energy capture threshold was less marked with bipolar than with unipolar leads. [ABSTRACT FROM AUTHOR]