Renato Ometto

Cardiac troponin I as diagnostic and prognostic marker in severe heart failure.

BACKGROUND Cardiac cell death has been shown to occur in heart failure and has been implicated as one of the mechanisms responsible for progression of the disease. Cardiac Troponin I (cTnI) represents a highly sensitive marker for myocardial cell death. Based on previous studies reporting that cTnI may be detected in patients with heart failure, we evaluated the clinical correlates and prognostic implications of detectable cTnI in a consecutive series of patients with severe heart failure. METHODS Thirty-four patients were examined. Upon admission, we measured serum levels of cTnI by conventional immunoenzymatic assay (Stratus Dade II). According to the results of this assay, patients were divided into 2 groups, based on the presence (cTnI+) or absence (cTnI-) of detectable cTnI. These 2 groups were compared by non-parametric analysis for their clinical characteristics, instrumental findings, and short-term outcome. RESULTS The cTnI+ group included 10 patients (29%) with a mean serum cTnI of 0.7 +/- 0.3 ng/ml. Compared with the cTnI- group, these patients had significantly lower left ventricular ejection fractions (20% +/- 5% vs 26% +/- 7%, p = 0.023) and a trend for higher systolic pulmonary artery pressure (59 +/- 17 mm Hg vs 49 +/- 13 mm Hg, p = 0.08). In cTnI+ patients, the correlation between cTnI levels upon admission and ejection fraction was r = -0.530 (p = 0.11). We found ischemic etiology was equally present in the 2 groups, whereas we never found histologic signs of acute myocarditis. Other clinical characteristics (functional class, daily diuretic dose, need for intravenous inotropes) were not statistically different in the 2 groups. In cTnI+ patients who improved after admission, cTnI became undetectable after a few days; in patients with refractory heart failure who were hospitalized until death, cTnI persisted in detectable levels throughout the observation period. Using the Cox proportional hazard model, a positive cTnI was the most powerful predictor of mortality at 3 months (p = 0.013; hazard ratio 6.86; 95% confidence interval 1.32 to 35.4). CONCLUSIONS These observations suggest that cTnI is detected in the blood of 25% to 33% of patients with severe heart failure; its presence may help to identify a high-risk sub-group who faces very poor short-term prognosis.

Detectable serum troponin I in patients with heart failure of nonmyocardial ischemic origin

Cardiac troponin I, a specific and sensitive marker of myocardial damage, was detected in the blood of 6 of 26 patients studied in our Heart Failure Clinic. In these patients functional class, ventricular function, and prognosis were significantly worse than in those without detectable troponin I. This study suggests that troponin I may represent the biochemical marker of myocardial damage occurring in severe heart failure.

Efficacy and safety of catheter ablation versus antiarrhythmic drugs for atrial fibrillation: a meta-analysis of randomized trials

Background Atrial fibrillation is the most common arrhythmia in clinical practice. Its treatment is still widely debated due to the large variety of therapeutic options. Radiofrequency catheter ablation (RFCA) around pulmonary vein ostia and in the left atrium has been proposed as a technique to cure atrial fibrillation and is now performed with increasing success worldwide. However, few randomized controlled trials (RCTs) are available. Some of these have been published recently and are not yet included in meta-analyses. Objectives We conducted a meta-analysis to summarize the current evidence base for the efficacy and safety of RFCA in patients with atrial fibrillation. Methods We searched electronic databases for relevant RCTs comparing RFCA with antiarrhythmic drugs for the management of atrial fibrillation. Recurrence of any atrial tachyarrhythmia (including atrial fibrillation, atrial flutter and atrial tachycardia) and rate of complications and adverse events were the end-points of the analysis. The results are reported as relative risk and 95% confidence interval, calculated using RevMan 5. Results A total of eight RCTs were identified including 844 patients. Overall, 98 (23.2%) of 421 patients in the treatment group and 324 (76.6%) of 423 patients in the control group had atrial tachyarrhythmia recurrence. RFCA decreased atrial tachyarrhythmia recurrence by 71% (relative risk 0.29, 95% confidence interval 0.20–0.41, P < 0.00001, with random effects model). Fewer complications and adverse events were reported in the ablation group compared with the control group (relative risk 0.72, 95% confidence interval 0.40–1.30, P = 0.28, with random effects model). Conclusion In selected patients with atrial fibrillation, RFCA is a relatively effective and well-tolerated procedure to cure atrial fibrillation. Even though the results of our systematic review favour ablation therapy, large, well-designed RCTs are needed to confirm the efficacy and safety of RFCA for the management of atrial fibrillation.

Left ventricular versus biventricular dysfunction in idiopathic dilated cardiomyopathy

Eighty-five consecutive patients with idiopathic dilated cardiomyopathy were categorized according to the presence (biventricular dysfunction) or absence (left ventricular [LV] dysfunction) of reduced right ventricular ejection fraction (<35%) along with reduced LV ejection fraction (<50%). Compared with the 36 patients with LV dysfunction, the 49 patients with biventricular dysfunction had significantly worse New York Heart Association functional class (2.7+/-0.6 vs 1.9+/-0.5; p <0.001), LV ejection fraction (26+/-10% vs 34+/-8%; p <0.0001), and outcome (transplant-free survival, 55% vs 89%; p <0.001). Thus, dilated cardiomyopathy is frequently characterized by biventricular involvement, which identifies a more severe disease and a worse long-term prognosis.

Ventricular late potentials, interstitial fibrosis, and right ventricular function in patients with ventricular tachycardia and normal left ventricular function

We examined 40 patients with ventricular tachycardia (VT) and no evidence of heart disease, and found a 50% prevalence of ventricular late potentials (VLPs) on the signal-averaged electrocardiogram. This finding was associated with a significantly higher content of fibrous tissue on endomyocardial biopsy and a lower right ventricular ejection fraction. Thus, VLPs are frequently found in idiopathic VT, are a marker for subclinical anatomic and functional abnormalities of the right ventricle, and may be associated with a worse outcome.

Long-term follow-up after atrioventricular nodal ablation and pacing: low incidence of sudden cardiac death.

Sudden cardiac death (SCD) has been reported in patients with drug refractory AF who underwent AV nodal ablation and pacing. However, whether SCD in these patients is related to the underlying heart disease or to the ablating and pacing procedure remains uncertain. Between May 1987 and January 1997, AV nodal ablation was performed in 585 patients (mean age 66 ± 11 years) with drug‐resistant, paroxysmal (n = 308) or chronic (n = 277) AF in 12 Italian centers. Lone AF was present in 133 patients. After AV junction ablation, patients underwent VVIR (454 patients) or DDDR (131 patients) pacemaker implantation. At a follow‐up of 33.6 ± 24.2 months, 80 (13.7%) deaths were recorded: 40 noncardiac, 23 nonsudden, and 17 sudden cardiac death (3%, 1.04% per year). Among five variables, including age, NYHA functional class, presence of heart disease, paroxysmal or chronic AF, previous embolic events, and LVEF, the presence of heart disease (P = 0.007) and a LVEF < 0.45, (P = 0.003) were associated with a higher risk of SCD. Analysis of SCD‐free survival by log‐rank test showed a higher incidence of SCD in patients with LVEF < 0.45 (P = 0.0001) and with coronary artery disease (P = 0.005). In this large cohort, a low incidence of long‐term SCD after AV nodal ablation and pacing for drug‐refractory AF was observed. The presence of underlying heart disease and the extent of baseline LV dysfunction were associated with an increased likelihood of SCD.

Torsade de Pointes Ventricular Tachycardia During Low Dose Intermittent Dobutamine Treatment in a Patient with Dilated Cardiomyopathy and Congestive Heart Failure

The authors describe the case of a 56‐year‐old woman with chronic, severe heart failure secondary to dilated cardiomyopathy and absence of significant ventricular arrhythmias who developed QT prolongation and torsade de pointes ventricular tachycardia during one cycle of intermittent low dose (2.5 mcg/kg per min) dobutamine. This report of torsade de pointes ventricular tachycardia during intermittent dobutamine supports the hypothesis that unpredictable fatal arrhythmias may occur even with low doses and in patients with no history of significant rhythm disturbances. The mechanisms of proarrhythmic effects of Dubutamine are discussed.

Physiopathologic Correlates of Intrathoracic Impedance in Chronic Heart Failure Patients

Background: Increased plasma levels of amino‐terminal fraction of brain natriuretic peptide (NT‐proBNP) and alterations of diastolic filling as described by Doppler transmitral flow pattern are well‐known markers of decompensated heart failure (HF). Recently, some implantable defibrillators have allowed monitoring of intrathoracic impedance, which is related to lung water content, potentially indicating HF deterioration. The aim of this study was to assess the correlation between intrathoracic impedance and NT‐proBNP and echo‐Doppler transmitral flow indexes.

Radiofrequency Catheter Ablation of the Slow Reentrant Pathway of Sustained Ventricular Tachycardia

The article reports the cases of two patients with severe coronary artery disease and associated recurrent sustained ventricular tachycardia successfully treated with radiofrequency catheter ablation. In the first patient, two different types of ventricular tachycardia (one incessant) were eliminated. In all procedures, an area of slow conduction critical for tachycardia maintenance was localized by endocardial mapping techniques. Radiofrequency energy delivered to this area could permanently modify the anatomical substrate of the arrhythmia. After single follow‐ups of 19, 14, and 13 months regarding the arrhythmic entities, the patients are well and free from spontaneous recurrences.

Multicenter clinical evaluation of a new SSIR pacemaker.

A multicenter clinical evaluation of Sorin Swing 100, a new SSIR pacemaker with a gravimetric sensor, was performed by seven different centers enrolling a total of 89 patients, 56 men and 33 women, mean age 73.1 years, for pacemaker implantion (73 patients) or pacemaker replacement (16 patients). Pacing mode was VVIR in 73 patients and AAIR in 16. The behavior of pacing rate was evaluated 3 months after the implant by performing a 24‐hour Holter monitor, an exercise stress test, and tests for the assessment of mechanical external interference (MEI). A physiological behavior of the paced rate was always observed during Holter monitoring. In 52 completely paced patients mean diurnal, nocturnal, and maximal heart rate were, respectively, 74.9 ± 5.7 ppm, 58.1 ± 5.8 ppm, and 113.4 ± 12.7 ppm; a paced rate exceeding 100 ppm was reached on the average 5.6 times/Holter monitor. In all but two patients the sleep rate (55 ppm) was reached during the night or long resting time. During exercise stress test a direct correlation between the increase in pacing rate and the increase in workload was observed; the mean maximal heart rate reached in 49 completely paced patients was, respectively, 102.8 ± 9 ppm in 17 patients who accomplished stage 1, 116.2 ± 13.6 ppm in 28 patients who accomplished stage 2, and 133 ± 6.7 ppm in 10 patients who accomplished stage 3 of the Bruce protocol. MEI testing never increased the pacing rate over the noise rate (10 ppm over the basic rate). In only seven patients the results obtained suggested to change the nominal set up of the pacemaker. Our experience clearly indicates that Swing 100 is an effective, reliable, and easy to use SSIR pacemaker. The availability of the sleep rate allows a more physiological pattern of pacing rate and can lead to significant energy saving.