Gerardo Ansalone

Doppler myocardial imaging to evaluate the effectiveness of pacing sites in patients receiving biventricular pacing

OBJECTIVES The goal of this study was to compare the efficacy of biventricular pacing (BIV) at the most delayed wall of the left ventricle (LV) and at other LV walls. BACKGROUND Biventricular pacing could provide additional benefit when it is applied at the most delayed site. METHODS In 31 patients with advanced nonischemic heart failure, the activation delay was defined, in blind before BIV, by regional noninvasive Tissue Doppler Imaging as the time interval between the end of the A-wave (C point) and the beginning of the E-wave (O point) from the basal level of each wall. The left pacing site was considered concordant with the most delayed site when the lead was inserted at the wall with the greatest regional interval between C and O points (CO(R)). After BIV, patients were divided into group A (13/31) (i.e., paced at the most delayed site) and group B (18/31) (i.e., paced at any other site). RESULTS After BIV, in all patients LV end-diastolic (LVEDV) and end-systolic (LVESV) volumes decreased (p = 0.025 and 0.001), LV ejection fraction (LVEF) increased (p = 0.002), QRS narrowed (p = 0.000), New York Heart Association class decreased (p = 0.006), 6-min walked distance (WD) increased (p = 0.046), the interval between closure and opening of mitral valve (CO) and isovolumic contraction time (ICT) decreased (p = 0.001 and 0.000), diastolic time (EA) and Q-P(2) interval increased (p = 0.003 and 0.000), while Q-A(2) interval and mean performance index (MPI) did not change. Group A showed greater improvement over group B in LVESV (p = 0.04), LVEF (p = 0.04), bicycle stress testing work (p = 0.03) and time (p = 0.08) capacity, CO (p = 0.04) and ICT (p = 0.02). CONCLUSIONS After BIV, LV performance improved significantly in all patients; however, the greatest improvement was found in patients paced at the most delayed site.

Biventricular pacing in heart failure: back to basics in the pathophysiology of left bundle branch block to reduce the number of nonresponders

Cardiac resynchronization therapy is a novel nonpharmacologic approach to treating patients who have advanced heart failure with left bundle branch block (LBBB). Such a therapy is based on the original theory that synchronous biventricular pacing is able to reduce the interventricular delay caused by LBBB in patients with heart failure. Although there is convincing evidence that biventricular pacing increases the left ventricular ejection fraction, decreases mitral regurgitation, and improves symptoms caused by heart failure, the percentage of nonresponders to such therapy has been described as high as about one third of patients with heart failure having LBBB. Factors responsible for this relatively high prevalence are reviewed, the most important of them probably being left intraventricular dyssynchrony, which can persist after biventricular pacing, notwithstanding right and left interventricular resynchronization. Such a dyssynchrony, as evaluated by tissue Doppler imaging, may be because of the discordance between the site of the left ventricular pacing and the site of the left ventricular delay. Therefore, to characterize the pathophysiologic pattern of LBBB, the investigators suggest an assessment of the electromechanical dysfunction with a noninvasive reliable technique, such as tissue Doppler imaging, which can be repeated after biventricular pacing.

Oral nifedipine in the long-term management of severe chronic heart failure.

Summary We evaluated the hemodynamic effects of nifedipine in 10 symptomatic patients with chronic refractory heart failure due to idiopathic cardiomyopathy. Nifedipine significantly increased cardiac index (from 1.80 ± 0.4 to 3 ± 0.6 L min/m2), stroke volume index (from 21 ± 6 to 33 ± 8 ml/beat/m2), and stroke work index (from 17.9 ± 7 to 25.5 ± 7 g-m/m2). The drug also produced a significant decrease in left ventricular tilling pressure (from 24.6 ± 3 to 19 ± 2 mm Hg), mean blood pressure (from 86 ± 9 to 74 ± 5 mm Hg), mean pulmonary arterial pressure (from 31.9 ± 5 to 25.6 ± 3 mm Hg), total systemic vascular resistance (from 2.104 ± 329 to 1.088 ± 249 dyn/s/cm 5), and pulmonary vascular resistance (from 200 ± 71 to 107 ± 50 dyn/s/cm 5). Heart rate remained unchanged. In all patients maintained on nifedipine therapy, repeat hemodynamic studies at 2 months revealed sustained effects, and all patients had symptomatic improvement of at least one New York Heart Association (NYHA) functional class. Long-term treatment was well tolerated. Forty-eight hours after discontinuation of nifedipine administration the hemodynamic benefits were lost. We conclude that nifedipine may be of value for long-term ambulatory therapy of severe chronic heart failure.

Early and late QRS morphology and width in biventricular pacing: relationship to lead site and electrical remodeling.

Abstract48 patients (40 Male), mean age 68 ± 8 years, in III–IV class, with intraventricular conduction delay, received a biventricular pacemaker. Heart failure aetiology was non-ischemic in 60%. Left ventricular lead positioning was inferior in 5 patients (10%), posterior in 12 (25%), lateral in 18 (37%) and anterior in 13 (27%). QRS duration and axis were evaluated in sinus rhythm, and during right ventricular pacing, left ventricular pacing and biventricular pacing, the last early after implant and late after 8.8 ± 4.3 months. QRS duration (ms) was 154 ± 29 in sinus rhythm, 175 ± 28 during right ventricular pacing, 196 ± 31 during left ventricular pacing, 122 ± 23 during biventricular pacing “early” and 120 ± 18 during biventricular pacing “late.” All the differences were statistically significant, but not between “early” and “late” biventricular pacing. Mean QRS axis (°) was −27 ± 32 in sinus rhythm, −75 ± 4 during right ventricular pacing, 112 ± 41 during left ventricular pacing, −82 ± 51 during biventricular pacing “early” and −80 ± 42 during biventricular pacing “late.” Only the difference between left ventricular pacing and all the other groups was statistically significant. QRS axis did not significantly differ according to left ventricular lead site during left and biventricular pacing. “Late” compared with “early” biventricular pacing axis showed variation >30° in 35% of patients, in spite of no significant changes in QRS duration and x-ray positioning. Conclusion: Biventricular pacing significantly reduced QRS width, which persisted long-term. Left and biventricular pacing axis was poorly related to left ventricular lead positioning. Biventricular pacing axis variability over time may suggest a role of electrical remodeling.

Observational study on Takotsubo-like cardiomyopathy: clinical features, diagnosis, prognosis and follow-up

Objectives The present study attempts to identify appropriate elements that may contribute to clarify the broad clinical features (diagnosis, care, complication and prognosis) of Takotsubo-like cardiomyopathy for improving its management. Design study Observational study. Setting Primary level of care referred to the emergency department of Vannini Hospital, Rome, Italy. Participants The study population consisted of 75 patients, 72 of the them were women and 3 were men with a mean age of 71.9±9.6 years. Methods From February 2004 to November 2010, prospectively included 84 consecutive patients diagnosed for suspected Takotsubo-like cardiomyopathy. To be eligible, patients had to meet all the Mayo clinic criteria in the absence of neurological trauma or intracranial haemorrhage. Moreover, those patients that at follow-up still presented alteration of acute phase at ECG and echocardiogram were excluded. Thus, 75 patients comprised the study population. To follow-up 19 patients were lost. Results None of 75 patients died in acute phase. All patients were promptly discharged (8.4±4.4 days), since they recovered their normal functional status without symptoms. Follow-up information was available for 56 patients. At a mean follow-up time of 2.2±2 years (range, 0.1–6.8 years) two octogenarian patients (2.6%) died because of sudden cardiac death and pulmonary embolism, respectively. The Takotsubo-like cardiomyopathy recurred in one patient. Conclusions The results of this study support the previous reports about the good prognosis, also in critically ill patients, of Takotsubo-like cardiomyopathy. Further assessment will be needed to determine a careful and sustained follow-up for choosing the best care and foreseeing the recurrences of this emerging condition.

Triple-site pacing in patients with biventricular device-incidence of the phenomenon and cardiac resynchronization benefit.

AbstractBackground: In patients with biventricular pacing (BIV), triple-site pacing (TSP), i.e. standard biventricular cathodal pacing of the right and the left ventricle plus additional anodal capture of the right ventricle, is sometimes present. Aims: To evaluate the incidence of TSP phenomenon, to examine TSP-related QRS changes, and to assess the effect of TSP on intraventricular resynchronization by means of tissue Doppler imaging (TDI). Methods and results: 23 patients with a first generation biventricular device (Medtronic 8040) and 16 patients with a new generation device (Medtronic 8042) were evaluated to look for the presence of TSP. TSP was found in 6 patients (26%) with the Medtronic 8040 (group I) and in 13 patients (81%) with the Medtronic 8042 device (group II). QRS duration decreased by 10 to 20 ms and QRS amplitude of leads I and aVL increased in almost all patients in group I during TSP modality. In group II, QRS morphology, duration and amplitude did not change as obviously. TDI analysis of the left ventricular (LV) basal segments showed significant shortening of the systole, together with a corresponding prolongation of the diastole, at the inferior wall of the LV, during TSP compared to standard BIV in all patients (p < 0.01). Other LV segments did not show any change. Qualitative TDI electro-mechanical activation pattern of all LV segments improved in 22%, while it remained unchanged in 72%. Conclusions: TSP phenomenon can be identified in approximately a quarter of patients with the first-generation biventricular devices on the basis of the QRS morphology changes. In the second-generation biventricular pacemakers it can be demonstrated in the vast majority of patients. TSP may increase the effectiveness of cardiac resynchronization therapy by counteracting the regional activation delay located at the inferior wall of the LV.

Stress cardiomyopathy: transient basal ballooning.

Stress cardiomyopathy is a reversible left ventricular dysfunction triggered by emotional stress. We describe a variant of transient left ventricular ballooning in a patient in which basal and midventricular segments are affected. This confirms that there is not just one ventricular dysfunction pattern in Takotsubo cardiomyopathy. The involvement of only the basal and midventricle segments is an intriguing observation with no clear explanation; furthermore, there are no predictive factors for the differently sited wall motion abnormalities.

Indications for dual-chamber (DDD) pacing in implantable cardioverter-defibrillator patients.

New technologic development of implantable cardioverter-defibrillators (ICDs) keeps up with the exponential increase of their use for primary and secondary prevention of sudden cardiac death. The first-generation ICD with limited shock capability alone could be considered adequate in most cardiac arrest victims, but it was not suitable for sudden death prevention in all high-risk patients with cardiac disease. The second-generation ICD was comprised of hybrid pacemaker-defibrillator systems that provided on-demand ventricular antibradycardia pacing. The third-generation devices include additional functions, such as antitachycardia pacing for ventricular tachycardia (VT) reversion and low-energy ventricular cardioversion, in addition to ventricular defibrillation and single-chamber ventricular demand pacing. In the near future, advanced dual-chamber atrioventricular (AV) pacing and defibrillating systems will also be available. The dual chamber ICD will allow atrial inhibited/dual-chamber (AAI/DDD) rate-responsive pacing, simultaneous atrial and ventricular sensing to optimize the arrhythmia identification, and ICD shock delivery in the proper arrhythmia-related chamber. Clinical benefits of these devices compared with their cost and complexity will require careful evaluation.

Late enhancement detected by cardiac magnetic resonance imaging in acute myocarditis mimicking acute myocardial infarction: location patterns and lack of correlation with systolic function.

Objective Clinical recognition of acute myocarditis is difficult. Late enhancement (LE) detected by magnetic resonance imaging appears to be a valuable tool for evaluating and monitoring inflammatory myocardial diseases. However, patterns of myocardial enhancement and its correlation with systolic function are not yet well defined. The aim of this study was to assess the extent and location of LE during the acute phase of active myocarditis mimicking acute myocardial infarction and at follow-up, in order to correlate LE with systolic function and to monitor disease progression. Methods Magnetic resonance imaging was performed in 13 patients with clinical symptoms and signs of acute myocarditis. Results All patients showed LE, which was located in the lateral free wall in 11 (85%) patients, at the basal level in eight (61%), at the mid level in nine (69%), and at the distal level in 10 (77%). Moreover, six (46%) patients showed LE in the posterior and inferior wall (P = 0.099 versus lateral wall), four (31%) patients in the septum and inferior wall (P = 0.017 versus lateral wall) and three (23%) patients in the anterior wall (P = 0.006 versus lateral wall). Left ventricular ejection fraction was 0.50 ± 10 and it was severely reduced only in one patient (0.20). Conversely, in the remaining patients, left ventricular ejection fraction was preserved (≥0.45) (P < 0.001). Multifocal LE was detected in eight (61%) patients, whereas pericardial effusion was observed only in two (15%) patients (P = 0.002). Twelve patients showed ST-segment elevation and chest pain, as it occurs in acute myocardial infarction, whereas one patient showed non-ST-segment elevation with dyspnoea, as it occurs in non-ST-elevation myocardial infarction. The mean follow-up duration was 4 ± 12 months, and follow-up was complete for all but one patient who died. LE extent decreased in 11 (92%) patients, whereas new areas of LE were detected in one (8%) patient (P < 0.001). Conclusions Contrast enhancement is a frequent finding in the clinical setting of suspected myocarditis and is associated with active and/or persistent myocardial inflammation. Myocarditis detected by magnetic resonance imaging predominantly occurs in the lateral free wall and very rarely affects systolic function.

Lack of correlation between ventricular late potentials and left ventricular mass in top-level male athletes.

PURPOSE The aim of this study was to establish: 1) the prevalence of abnormal signal-averaged electrocardiogram (SAECG) in a large population of top-level athletes and 2) the relationship between SAECG parameters and left ventricular mass. One-hundred and fifty-three elite male athletes without apparent heart disease, symptoms, or arrhythmias were studied. METHODS Fifty-six athletes (37%) had increased left ventricular mass (> 134 g.m(-2)). All athletes underwent time-domain SAECG on 300-400 heart beats recorded at rest from three bipolar orthogonal tests with a filter setting of 40-250 Hz. Criteria for abnormality were 1) filtered QRS duration > 114 ms, 2) duration of low-amplitude signals > 38 ms, or 3) root mean square voltage of the last 40 ms of the filtered QRS < 20 microV. RESULTS The prevalence of abnormal SAECG was 7.2% (abnormality of one parameter), 6.5% (abnormality of two parameters), and 5.8%(abnormality of three parameters). The prevalence of abnormal SAECG was similar in athletes with or without increased left ventricular mass. CONCLUSIONS In conclusion, this study showed: 1) the low rate of positive results of SAECG parameters in top-level male athletes, similar to that found in healthy sedentary subjects; and 2) the lack of correlation between left ventricular mass and overall SAECG parameters.