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Biomedical subjects

Gabe B Bleeker

Publications and source records attributed to Gabe B Bleeker.

31 records · Page 2Linked to original sources
PubMed2005

Comparison of effectiveness of cardiac resynchronization therapy in patients <70 versus > or =70 years of age.

In the present study, the effects of cardiac resynchronization therapy (CRT) in elderly patients were evaluated. The study included 170 consecutive patients whose clinical and echocardiographic improvements were evaluated after 6 months of follow-up. Survival was evaluated up to 2 years. The effects of CRT in elderly patients (age > or =70 years) were compared with those in younger patients (age <70 years).

Age Factors↗
PubMed2005

Effect of cardiac resynchronization therapy on inducibility of ventricular tachyarrhythmias in cardiac arrest survivors with either ischemic or idiopathic dilated cardiomyopathy.

We evaluated whether long-term cardiac resynchronization therapy affects the inducibility of ventricular tachyarrhythmias in relation to reverse remodeling in cardiac arrest survivors with either ischemic or idiopathic dilated cardiomyopathy. Clinical, electrophysiologic, and echocardiographic data of 18 patients were obtained before and after 6 months of cardiac resynchronization.

Adult↗
PubMed2005

Frequency of left ventricular dyssynchrony in patients with heart failure and a narrow QRS complex.

Cardiac resynchronization therapy (CRT) is considered a major advance in the treatment of patients with heart failure. The presence of left ventricular (LV) dyssynchrony seems mandatory for a positive response to CRT. Currently, only patients with wide QRS complexes are considered for CRT, although patients with narrow QRS complexes may also have LV dyssynchrony. In the present study, the incidence of LV dyssynchrony was prospectively evaluated in 64 patients with heart failure and narrow QRS complexes using tissue Doppler imaging.

Arrhythmias, Cardiac↗
PubMed2005

Dispersion of repolarization in cardiac resynchronization therapy.

BACKGROUND: Proarrhythmic effects of cardiac resynchronization therapy (CRT) as a result of increased transmural dispersion of repolarization (TDR) induced by left ventricular (LV) epicardial pacing in a subset of vulnerable patients have been reported. The possibility of identifying these patients by ECG repolarization indices has been suggested. OBJECTIVES: The purpose of this study was to test whether repolarization indices on the ECG can be used to measure dispersion of repolarization during pacing. METHODS: CRT devices of 28 heart failure patients were switched among biventricular, LV, and right ventricular (RV) pacing. ECG indices proposed to measure dispersion of repolarization were calculated. The effects of CRT on repolarization were simulated in ECGSIM, a mathematical model of electrocardiogram genesis. TDR was calculated as the difference in repolarization time between the epicardial and endocardial nodes of the heart model. RESULTS PATIENTS: The interval from the apex to the end of the T wave was shorter during biventricular pacing (102 +/- 18 ms) and LV pacing (106 +/- 21 ms) than during RV pacing (117 +/- 22 ms, P < or =.005). T-wave amplitude and area were low during biventricular pacing (287 +/- 125 microV and 56 +/- 22 microV.s, respectively, P = .0006 vs RV pacing). T-wave complexity was high during biventricular pacing (0.42 +/- 0.26, P = .004 vs RV pacing). Simulations: Repolarization patterns were highly similar to the preceding depolarization patterns. The repolarization patterns of different pacing modes explained the observed magnitudes of the ECG repolarization indices. Average and local TDR were not different between pacing modes. CONCLUSION: In patients treated with CRT, ECG repolarization indices are related to pacing-induced activation sequences rather than transmural dispersion. TDR during biventricular and LV pacing is not larger than TDR during conventional RV endocardial pacing.

Aged↗
PubMed2005

Does a gender difference in response to cardiac resynchronization therapy exist?

BACKGROUND: Cardiac resynchronization therapy (CRT) has a beneficial effect on clinical symptoms, exercise capacity, and systolic left ventricular (LV) performance in patients with heart failure. The aim of the current study was to evaluate whether a gender difference exists in response to CRT. METHODS: Consecutive patients with end-stage heart failure (New York Heart Association, NYHA, class III-IV), LV ejection fraction (LVEF) < or =35%, QRS duration >120 ms, and left bundle branch block configuration underwent CRT. At baseline and 6 months post-CRT, clinical and echocardiographic parameters were evaluated; follow-up was obtained up to 5 years. The effects of CRT were compared between women and men. RESULTS: The study population comprised 137 men and 36 women (mean age 66 +/- 11 years). No differences in baseline characteristics were observed except that nonischemic cardiomyopathy was more frequent in women than men (67% vs 38%, P < 0.05). In all patients, clinical and echocardiographic parameters improved significantly at 6-month follow-up. The magnitude of improvement in different parameters was similar between women and men, e.g., the improvement in NYHA Class was 0.9 +/- 0.6 in women and 1.0 +/- 0.7 in men (NS) and the increase in LVEF was 8 +/- 8% in women as compared to 7 +/- 9% in men (NS). The percentage of individual responders was not different between women and men (76% vs 80%, NS) and 2-year survival was comparable for women and men (84% vs 80%, NS). CONCLUSION: No gender differences were observed in response to CRT and long-term survival after CRT.

Cardiac Pacing, Artificial↗
PubMed2005

Long-term follow-up of cardiac resynchronization therapy in patients with end-stage heart failure.

UNLABELLED: Long-term follow-up of cardiac resynchronization therapy. INTRODUCTION: Cardiac resynchronization therapy (CRT) has been introduced to treat patients with end-stage heart failure, and results of this technique are promising. The aim of our study was to assess the sustained benefit of CRT in a large patient cohort with end-stage heart failure at long-term follow-up. In addition, the prognosis of responders and nonresponders was evaluated. METHODS AND RESULTS: 125 patients with end-stage heart failure, NYHA class III or IV, LVEF<35%, QRS duration>120 msec and left bundle branch block morphology received a biventricular device. At baseline and 6 months after implantation the following parameters were evaluated: NYHA class, Minnesota Quality of life score, QRS duration on surface ECG, 6-minute walking distance and LVEF. Follow-up was obtained up to 3 years. After 6 months, patients were divided in clinical responders and nonresponders according to improvement in NYHA class. All clinical parameters improved significantly at 6-month follow-up. Hospitalization for heart failure was 3.8+/-4.9 days/year before and 0.7+/-1.6 days/year after CRT. Survival at 1-, 2-, and 3-year follow-up was 93%, 88%, and 85%, respectively. Responders (78%) showed a significantly better survival than nonresponders at 2- and 3-year follow-up (96% and 93% for responders versus 81% and 73% for nonresponders, P<0.05). CONCLUSION: The improvement in functional status and symptoms after CRT is maintained at long-term follow-up (up to 3 years). The clinical improvement was associated with a significant reduction in hospitalization rate which was also maintained over the years. Preimplantation selection of responders may result in even better long-term survival.

Aged↗
PubMed2004

Comparison of response to cardiac resynchronization therapy in patients with sinus rhythm versus chronic atrial fibrillation.

Cardiac resynchronization therapy (CRT) is a new therapeutic option for patients who have drug-refractory end-stage heart failure. Much information has been obtained from patients who have sinus rhythm, but the use of CRT in patients who have chronic atrial fibrillation (AF) has not been studied extensively. Accordingly, we evaluated the clinical response and long-term survival rate of CRT in patients who had heart failure and chronic AF, and the results were compared with those in patients who had sinus rhythm and who underwent CRT. Sixty patients who had end-stage heart failure (30 had sinus rhythm and 30 had chronic AF), New York Heart Association classes III to IV, left ventricular ejection fraction <35%, QRS interval >120 ms, and a left bundle branch block received a biventricular pacemaker. New York Heart Association class, Minnesota Quality of Life score, and 6-minute walking distance were evaluated at baseline and after 6 months of CRT. Long-term follow-up was </=2 years. New York Heart Association class, Minnesota Quality of Life score, and 6-minute walking distance improved significantly in the 2 groups after 6 months of CRT. The number of nonresponders was greater among patients who had AF. Nevertheless, the long-term survival rate was comparable between patients who had sinus rhythm and those who had AF. Patients who had AF demonstrated comparable benefit from CRT as those who had sinus rhythm.

Aged↗
PubMed2004

Left ventricular dyssynchrony predicts response and prognosis after cardiac resynchronization therapy.

OBJECTIVES: This study was designed to predict the response and prognosis after cardiac resynchronization therapy (CRT) in patients with end-stage heart failure (HF). BACKGROUND: Cardiac resynchronization therapy improves HF symptoms, exercise capacity, and left ventricular (LV) function. Because not all patients respond, preimplantation identification of responders is needed. In the present study, response to CRT was predicted by the presence of LV dyssynchrony assessed by tissue Doppler imaging. Moreover, the prognostic value of LV dyssynchrony in patients undergoing CRT was assessed. METHODS: Eighty-five patients with end-stage HF, QRS duration >120 ms, and left bundle-branch block were evaluated by tissue Doppler imaging before CRT. At baseline and six months follow-up, New York Heart Association functional class, quality of life and 6-min walking distance, LV volumes, and LV ejection fraction were determined. Events (death, hospitalization for decompensated HF) were obtained during one-year follow-up. RESULTS: Responders (74%) and nonresponders (26%) had comparable baseline characteristics, except for a larger dyssynchrony in responders (87 +/- 49 ms vs. 35 +/- 20 ms, p < 0.01). Receiver-operator characteristic curve analysis demonstrated that an optimal cutoff value of 65 ms for LV dyssynchrony yielded a sensitivity and specificity of 80% to predict clinical improvement and of 92% to predict LV reverse remodeling. Patients with dyssynchrony >/=65 ms had an excellent prognosis (6% event rate) after CRT as compared with a 50% event rate in patients with dyssynchrony <65 ms (p < 0.001). CONCLUSIONS: Patients with LV dyssynchrony >/=65 ms respond to CRT and have an excellent prognosis after CRT.

Aged↗
PubMed2004

Effect of left ventricular remodeling after cardiac resynchronization therapy on frequency of ventricular arrhythmias.

We evaluated whether cardiac resynchronization therapy affects the prevalence of ventricular tachycardia in relation to reverse remodeling in patients with end-stage heart failure. Clinical, echocardiographic, and implantable cardioverter-defibrillator (ICD) data of 17 patients with ICDs were obtained before and after they had received an upgrade to an ICD-cardiac resynchronization therapy device.

Adult↗
PubMed2004

Relationship between QRS duration and left ventricular dyssynchrony in patients with end-stage heart failure.

INTRODUCTION: Patients with end-stage heart failure and a wide QRS complex are considered candidates for cardiac resynchronization therapy (CRT). However, 20% to 30% of patients do not respond to CRT. Lack of left ventricular dyssynchrony may explain the nonresponse. Accordingly, we evaluated the presence of left ventricular dyssynchrony using tissue Doppler imaging (TDI) in 90 consecutive patients with heart failure. METHODS AND RESULTS: Ninety patients with severe heart failure (left ventricular ejection fraction <35%, New York Heart Association class III-IV) were prospectively evaluated. Based on QRS duration, 30 consecutive patients with a narrow QRS complex were included (QRS duration 150 ms). All patients underwent TDI to assess left ventricular dyssynchrony. Extensive left ventricular dyssynchrony was defined as an electromechanical delay on TDI between the septum and lateral wall, the so-called septal-to-lateral delay, of >60 ms. Severe dyssynchrony was observed in 27% of patients with narrow QRS complex, 60% with intermediate QRS duration, and 70% with wide QRS complex. No relation existed between QRS duration and septal-to-lateral delay. CONCLUSION: From 30% to 40% of heart failure patients with QRS duration >120 ms do not exhibit left ventricular dyssynchrony, which may explain the nonresponse to CRT. Alternatively, 27% of patients with heart failure and a narrow QRS complex show significant left ventricular dyssynchrony and may be candidates for CRT.

Aged↗
PubMed2003

Left ventricular dyssynchrony predicts benefit of cardiac resynchronization therapy in patients with end-stage heart failure before pacemaker implantation.

We evaluated patients with end-stage heart failure who have a high likelihood of response to cardiac resynchronization therapy (biventricular pacing). It appears that 20% of patients do not respond to this expensive therapy despite the use of selection criteria (dilated cardiomyopathy, heart failure, New York Heart Association class II or IV, left ventricular ejection fraction <35%, left bundle branch block, and QRS >120 ms). The presence of left ventricular dyssynchrony is needed to result in improvement after cardiac resynchronization therapy.

Aged↗