Augusto Achilli

Prediction of response to cardiac resynchronization therapy: The selection of candidates for CRT (SCART) study

Background: The aim of this study was to evaluate the ability of baseline clinical and echocardiographic parameters to predict a positive response to CRT.

Cardiac resynchronization therapy : Gender related differences in left ventricular reverse remodeling

Cardiac resynchronization refers to pacing techniques that change the degree of atrial and ventricular electromechanical asynchrony in patients with major atrial and ventricular conduction disorders. Atrial and ventricular resynchronization is usually accomplished by pacing from more than one site in an electrical chamber--atrium or ventricle--and occasionally by stimulation at a single unconventional site. Resynchronization produces beneficial hemodynamic and antiarrhythmic effects by providing a more physiologic pattern of depolarization. Atrial resynchronization may prevent atrial fibrillation in selected patients with underlying bradycardia or interatrial block. Its antiarrhythmic effect in the absence of bradycardia is unclear. Ventricular resynchronization is of far greater clinical value than atrial resynchronization. Biventricular (or single-chamber left ventricular) pacing is beneficial for patients with congestive heart failure, severe left ventricular systolic dysfunction, dilated cardiomyopathy (either ischemic or idiopathic), and a major left-sided intraventricular conduction disorder, such as left bundle branch block. The change in electrical activation from resynchronization, which has no positive inotropic effect as such, is translated into mechanical improvement with a more coordinated left ventricular contraction. Several recent randomized trials and a number of observational studies have demonstrated the long-term effectiveness of ventricular resynchronization in the above group of patients. The high incidence of sudden death among these patients has encouraged ongoing clinical trials to evaluate the benefit of a system that combines biventricular pacing and cardioversion-defibrillation into a single implantable device.Aim: Gender related differences in epidemiology, treatment, and prognosis of heart failure (HF) have been reported. We examined the sex influence in patients treated with cardiac resynchronization therapy (CRT).

Electrocardiographic pattern of Brugada syndrome disclosed by a febrile illness: clinical and therapeutic implications

BACKGROUND Recent studies have identified a direct link between the ionic mechanisms responsible for the electrocardiographic (ECG) pattern of the Brugada syndrome (BS) and the in vitro experimental temperature, pointing to the possibility that some BS patients may display the ECG phenotype only during a febrile state, being in this setting at risk of lethal arrhythmias. CASE REPORT A 53-year-old man referred to the emergency room for abdominal pain and fever. The ECG showed dome-shaped ST-segment elevation in V1-V3, as in the typical BS. The personal and family history were unremarkable for syncope and sudden death and physical, laboratory and ultrasound examinations were negative. On day 3, at normal body temperature, the patients ECG returned to normal and the ECG abnormalities were later reproduced with intravenous flecainide. The patient refused the implantation of a loop recorder and was discharged after 6 days. He has remained asymptomatic during 2 years of follow-up. CONCLUSIONS The typical ECG phenotype of BS disclosed by a febrile illness confirms the in vitro experimental data that previously established a correlation between ECG pattern of BS and temperature variations. The clinical and therapeutic implications of these findings are discussed.

Long-term effectiveness of dual site left ventricular cardiac resynchronization therapy in a patient with congestive heart failure.

This article describes a case of cardiac resynchronization therapy (CRT) performed with dual site left ventricular pacing. The main clinical and functional long‐term results are in agreement with the most recent data regarding traditional CRT. Furthermore, this innovative pacing modality allowed optimal inter‐ and intraventricular resynchronization. (PACE 2004; 27[Pt. I]:805–807)

Results of the SCART study: selection of candidates for cardiac resynchronisation therapy.

Objective To prospectively determine whether prespecified electrocardiographic, echocardiographic and tissue Doppler imaging (TDI) selection criteria may predict a positive response to cardiac resynchronisation therapy (CRT). Methods In this multicentre, prospective, non-randomised study, 96 heart failure patients with New York Heart Association class III–IV symptoms, an ejection fraction of ≤35%, and at least one marker of ventricular dyssynchrony according to prespecified electrocardiographic, echocardiographic or TDI criteria were enrolled. The primary endpoint was an improvement in the clinical composite score at 6 months. Results At enrolment, 70 patients fulfilled the electrocardiographic criterion (QRS duration ≥150 ms), 77 patients showed echocardiographic signs of dyssynchrony, and 37 patients met the TDI dyssynchrony criteria. The overall responder rate was 78/96 (81%). In particular, the primary endpoint was reached in 68 patients who fulfilled the echocardiographic criteria as compared with 10 patients who did not (88 vs. 53%, P = 0.001). The patients who met the echocardiographic criteria showed a significant greater reduction in left ventricular end-systolic diameter (P = 0.029) and a higher improvement in quality of life (P = 0.017) than patients who did not. Neither electrocardiographic nor TDI criteria seemed to predict a positive response to CRT. Conclusions In our patient population, mechanical indexes of dyssynchrony as assessed by echocardiography appeared to identify CRT responders. Although TDI is useful for evaluating ventricular dyssynchrony after CRT, the prespecified TDI inclusion criteria adopted in this investigation did not increase the number of CRT responders.

Identification of Viable Myocardium by Nitrate Echocardiography After Myocardial Infarction: Comparison with Planar Thallium Reinjection Scintigraphy

Background: The aim of this study was to validate a new diagnostic tool, nitrate echocar diography (NE), for the identification of viable noncontracting myocardium in patients with a history of prior myocardial infarction (MI). Nitroglycerin (NTG) may be useful for this purpose for its peculiar pharmacodynamic action and may represent an option other than dobutamine echocardiography for the detection of hibernating segments in the presence of severely reduced coronary reserve. Methods: Twenty selected patients (pts) with an old MI were studied with NE and planar thallium scintigraphy with reinjection. NE was performed by administering IV NTG starting at 0.4 mcg/kg/minute with equal increments every five minutes up to 2 mcg/kg/minute or to early interruption of the test (decrease of systolic blood pressure ≥ 20% or improvement of previously akinetic segments). Left ventricular wall motion was analyzed by dividing the left ventricle (LV) into 16 segments, and a wall motion score index (WMSI) was calculated. Thallium images were obtained at peak exercise, at four hours, and after reinjection. Myocardial viability was defined as an improvement in thallium uptake after reinjection in fixed defects. (continued on next page) Results: Basal echo demonstrated 74 akinetic segments; of these 21 (28%, 11 pts) showed improved contractility during NTG infusion at a mean dose of 0.87 ±0.33 mcg/kg/minute. WMSI decreased from 1.69 ±0.29 to 1.46 ±0.31 (P=.001). The only hemodynamic response was a drop in systolic blood pressure (136 mmHg to 124; P=.02). Thallium studies showed 29 segments with a four-hour reversible defect and 79 segments with a four-hour fixed defect; of the latter, 14 regions demonstrated improvement in tracer uptake after reinjection (17.7%; 10 pts). Nine pts had a positive echo and thallium study, while 8 showed no improvement either during NE or after thallium reinjection. Two pts had a false-positive nitrate echocardiogram. Therefore, according to an echo/thallium study match, sensitivity, specificity, and accuracy are 90%, 80%, 85%, respectively. Conclusion: NE is a reliable and low-cost method for the detection of viable noncon tracting myocardium in selected patients with CAD but needs further validation for wide spread application.

Acute Myocardial Infarction Shortly After a Normal Exercise Stress Test Case Reports

The authors describe 3 cases of AMI occurring shortly after a negative bicycle ergometer stress test. These cases represent an unfortunate but extremely rare complication of a relatively safe diagnostic procedure. The authors also focus on the pathogenesis of the ischemic event, which may be attributed either to intraplaque hemorrhage or to platelet aggregation, both exercise- induced. The prevalence of AMI in this paper (0.06%) is similar to the data described in literature.

Effectiveness of cardiac resynchronisation therapy in patients with echocardiographic evidence of mechanical dyssynchrony.

Objective Cardiac resynchronisation therapy has proven to be effective in refractory heart failure (HF) patients with QRS >120–130 ms. Therefore, the aim of our study was to verify the long-term effectiveness of cardiac resynchronisation therapy in HF patients with echocardiographic evidence of mechanical asynchrony regardless of QRS duration. Methods One hundred and six patients with New York Heart Association class II–IV HF and echocardiographic documentation of interventricular and intraventricular asynchrony underwent biventricular stimulation. A clinical and functional evaluation was performed at baseline, 1, 3, 6 months, and every 6 months thereafter. Results After a median follow-up of 16 months, a significant improvement was noted in ejection fraction, left ventricular diameters, mitral regurgitation jet area, interventricular and intraventricular echocardiographic indexes of asynchrony, and the 6-min walking distance (P < 0.001 for all). Death rates for all causes and for cardiac causes were 18.2 (95% confidence interval 12.8–25.9) and 13.5 (95% confidence interval 9.0–20.3) per 100 person-years, respectively. Patients in New York Heart Association class IV had an almost three-fold increase in risk of dying as compared to class II–III (hazard ratio 2.97, 95% confidence interval 1.30–6.79). Conclusions Interventricular and intraventricular asynchrony at echocardiography may be useful in identifying HF patients suitable for cardiac resynchronisation therapy, with results comparable to those obtained with QRS duration selection criteria.