Evaluation of atrial electromechanical functions in dipper and nondipper hypertension patients using left atrial strain P-wave dispersion and P terminal force.

OBJECTIVE: Nondippers are known to carry a high risk of cardiovascular morbidity and mortality. The aim of this study was to investigate the effects of dipper and nondipper status of hypertension on left atrial (LA) systolic and diastolic functions using two-dimensional speckle tracking echocardiography (2D-STE), P-wave dispersion (PWD), and P terminal force (PTF) in hypertensive patients. METHODS: A total of 72 patients and 39 healthy individuals were included in the study. The patients were classified as nondippers if their daytime ambulatory systolic and diastolic blood pressure did not decrease by at least 10% during the night. Atrial electromechanical delay times, LA strain values were obtained by 2D-STE with automated software and compared between the groups. PWD and PTF data were calculated on the electrocardiography. RESULTS: Inter-atrial (dippers: 25.5 ± 3.9, nondippers: 32.2 ± 7.4, P < .001), left-atrial (dippers: 14.9 ± 3.7, nondippers: 18.2 ± 6.0, P = .016), and right atrial (dippers: 10.5 ± 2.1, nondippers: 14.2 ± 5.2, P < .001) electromechanical delay times were significantly longer in nondippers. LA strain S (dippers: 34.2 [29.7-38.7], nondippers: 27.7 [22.7-32.2], P < .001), LA strain E (dippers: 18.2 [16.6-20.1], nondippers: 14.4 [11.6-16.8], P < .001), and LA strain A (dippers: 15.8 [13.5-17.9], nondippers: 12.7 [9.9-14.5], P < .001) were significantly lower in nondippers. Nondippers also had an increased values of maximum P-wave duration (dippers: 0.117 [0.10-0.12], nondippers: 0.126 [0.12-0.14], P < .001), PWD (dippers: 0.062 [0.06-0.07], nondippers: 0.069 [0.06-0.08], P = .004), and PTF (dippers: 0.055 ± 0.02, nondippers: 0.066 ± 0.02, P = .02). CONCLUSION: Nondipping pattern in hypertensive patients had a worse cardiac remodeling, and impaired mechanical LA function compared with dipping pattern. The PWD and PTF findings support these changes.

Red cell distribution width and neutrophil-to-lymphocyte ratio predict left ventricular dysfunction in acute anterior ST-segment elevation myocardial infarction.

OBJECTIVES: Red cell distribution width (RDW) and neutrophil-to-lymphocyte ratio (NLR) are the two markers used to determine risk of mortality and adverse cardiovascular outcomes in patients with acute myocardial infarction. The relationship between RDW, NLR, and left ventricular (LV) systolic functions has not been reported. In this report, we aimed to investigate the relationship between RDW, NLR, and LV systolic function in anterior ST-segment elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention (PCI). METHODS: RDW and NLR were measured on admission in 106 STEMI patients treated with primary PCI. Patients were divided into two groups according to left ventricular ejection fraction (LVEF), as Group I (systolic dysfunction, LVEF <50%) and Group II (preserved global left ventricle systolic function, LVEF ⩾50%). The first group included 47 patients and the second group included 59 patients. RESULTS: Mean RDW and NLR were significantly higher in Group I compared to Group II [13.7 ± 0.9% vs. 13.4 ± 0.7%, p = 0.03 and 5.86 (range, 0.66-40.50) vs. 2.75 (range, 0.51-39.39), p = 0.013, respectively]. CONCLUSION: Increased RDW and NLR on admission, in anterior STEMI patients treated with primary PCI are associated with LV systolic dysfunction.

The significance of the left atrial volume index in cardioversion success and its relationship with recurrence in patients with non-valvular atrial fibrillation subjected to electrical cardioversion: a study on diagnostic accuracy.

OBJECTIVE: The aim of this study was to assess the predictive value of the left atrial volume index (LAVI) in electrical cardioversion (ECV) and observe the recurrence rate of atrial fibrillation (AF) after a successful ECV in patients with non-valvular atrial fibrillation. METHOD: This study was designed as a diagnostic accuracy and prospective cohort study. Eighty patients (mean age 62±12 years; 52.5% female) were enrolled in study. LAVI was measured using the area-length method and the indexed body surface area. Patients in whom the sinus rhythm (SR) was established following the ECV were assessed according to the clinical and electrocardiography (ECG) findings at the first month and grouped as those with continued SR or recurrent AF. The Student's t, Mann-Whitney U, Fisher's exact, Chi-square tests, ROC and logistic regression analyses were used for statistical analysis. RESULTS: Subsequent to the ECV, SR was achieved in 62.5% (n=50) of the patients. In those where SR was established, the AP-Lad (4.32±0.62 vs. 4.77±0.4 cm/p=0.002) and LAVI (35.3±11.5 vs. 53.1±10.1 mL/m2/p<0.001) values were observed to be lower. ECV success was found to be associated only with the LAVI (OR:1.122, 95%CI: 1.058-1.191, p<0.001). The AUC was found as 0.892±0.041 for the LAVI (95% CI:0.075-0.285, p<0.001). During the controls at the end of the 1st month, SR was maintained in 72% (n=36) of the successful ECV group. Among the patients with maintained SR, the antero-posterior left atrial dimension (4.17±0.62 vs. 4.72±0.5 cm/p=0.004) and LAVI (30.8±6.2 vs. 46.8±13.9 mL/m2/p<0.001) values were also observed to be lower. Only the LAVI was found to be associated with the recurrence of the AF (OR:1.355, 95% CI: 1.154-1.591, p<0.001). The AUC was found as 0.950±0.029 for the LAVI (95% CI:0.063-0.313, p=0.003) CONCLUSION: Lower LAVI values before the ECV are strong and independent predictors of the success of the ECV and the maintenance of SR after a successful ECV.

Evaluation of the left ventricular regional function using two-dimensional speckle tracking echocardiography in patients with end-stage renal disease with preserved left ventricular ejection fraction.

OBJECTIVE: It is known that patients with end-stage renal disease (ESRD) more frequently develop a wide range of left ventricular (LV) structural and functional abnormalities. The aim of our study is to evaluate the left ventricular regional function using two-dimensional speckle tracking echocardiography (2D-STE) in ESRD patients with preserved left ventricular ejection fraction (PLVEF) undergoing haemodialysis treatment. METHODS AND RESULTS: In total 61 healthy individuals and 87 ESRD patients were enrolled. Using the 2D-STE method, the strain (S) and strain rate (SR(S): systolic, SR(E): early diastolic, SR(A): late diastolic) values belonging to the radial (R), circumferential (C), and longitudinal (L) functions of the LV have been measured and the SR(E/A) values were calculated. While the LVEF values in the ESRD group were found to be lower than in the healthy control group (64.39 +/- 5.7 vs. 65.49 +/- 3.95, P = 0.033; R(S) = 45.17 +/- 17.28 vs. 53.97 +/- 14.29, P = 0.001; L(S) = -19.71 +/- 3.1 vs. -30.13 +/- 2.1, P < 0.001; RSRE(E/A) = 1.55 +/- 0.85 vs. 2.04 +/- 0.96, P = 0.001; LSR(E/A) = 1.42 +/- 0.51 vs. 1.88 +/- 0.7, P < 0.001), no difference was observed in terms of the C(S) (19.42 +/- 7.14 vs. 18.57 +/- 4.12, P = 0.155) and CSR(E/A) (2.5 +/- 1.34 vs. 2.56 +/- 1.35, P = 0.869) values. The C(S) was observed as an independent predictor related to the LVEF (beta = 0.2, 95% CI: 0.126-0.207, P = 0.015). CONCLUSION: In patients with ESRD, although the longitudinal and radial systolic functions are reduced, the LVEF may remain within normal limits due to the preservation of the circumferential functions. 2D-STE has the potential to detect the severity of uraemic cardiomyopathy in the early stages of the disease and might provide useful information for the risk stratification in ESRD patients with PLVEF.

Complete AV block and cardiac syncope in a patient with Duchenne muscular dystrophy.

Duchenne muscular dystrophy is an X linked hereditary progressive neuromuscular disease and it is characterized by development of weakness and atrophy in affected muscles. In late phases of disease with involvement of respiratory and cardiac muscles, patients die because of respiratory and cardiac failure. Cardiomyopathy is a common complication and various types of arrhythmia because of conduction system involvement can be seen. Herein we present a case with Duchenne muscular dsytrophy who was admitted to our clinic at an older age because of complete atrioventricular block without cardiomyopathy.

Acquired QT interval prolongation and ventricular arythmias associated with brucellosis: A case report and review of literature.

Brucellosis is a zoonosis caused by Brucella species and usually involves the lymphoreticular system. Cardiovascular involvement is rare but fatal. Endocarditis is the most common cardiovascular manifestation of brucellosis. Herein we report a case of brucellosis with a presentation of acquired QT prolongation and ventricular tachycardia without a clear clinical picture of endocarditis and myocarditis.

Relationship of paroxysmal atrial tachyarrhythmias to volume overload: assessment by implanted transpulmonary impedance monitoring.

BACKGROUND: Clinical experience suggests that atrial tachyarrhythmias (ATs) are a frequent comorbidity in heart failure patients with left ventricular systolic dysfunction and that volume overload may increase AT susceptibility. However, substantiating this apparent relationship in free-living patients is difficult. Recently, certain implantable cardioverter-defibrillators provide, by measuring transpulmonary electric bioimpedance, an index of intrathoracic fluid status (OptiVol index [OI]). The goal of this study was to determine whether periods of greater intrathoracic fluid congestion (as detected by OI) correspond with increased AT event frequency. METHODS AND RESULTS: This analysis retrospectively assessed the relation between AT events and OI estimate of volume overload in patients with left ventricular systolic dysfunction and OI-capable implantable cardioverter-defibrillators. OI values were stratified into 3 levels: group 1, <40; group 2, 40 to 60; and group 3, >60. An OI threshold-crossing event was defined as OI > or = 60, a value previously associated with clinically significant volume overload. Findings in 59 patients (mean left ventricular ejection fraction, 24%) with 225 follow-up visits (mean, 3.8 visits per patient) were evaluated. AT prevalence was 73%. AT frequency (percent of patients visits with at least 1 episode of AT since previous device interrogation) was greater in group 3 versus group 1 (P=0.0342). Finally, in terms of temporal sequence, AT episodes preceded OI threshold-crossing event in 43% of incidences, followed threshold-crossing event in 29%, and was simultaneous or indeterminate in the remainder. CONCLUSIONS: These findings not only support the view that worsening pulmonary congestion is associated with increased AT frequency in patients with left ventricular dysfunction but also suggest that AT events may be responsible for triggering episodic pulmonary congestion more often than previously suspected.

Association of increased QTc dispersion and right ventricular hypertrophy.

BACKGROUND: There have been reports demonstrating an association between increased QT dispersion and ventricular arrhythmia in a variety of pathological cardiac conditions, including left ventricular hypertrophy. However, there are limited data about an association of right ventricular hypertrophy (RVH) and corrected QT (QTc) dispersion. MATERIAL/METHODS: Eighty-five persons who emigrated from a high-altitude region (2800-4200 m) of Afghanistan to Van, Turkey, (altitude: 1700-1800 m) 25 years ago were referred to our hospital for transthoracic examination between April 2003 and May 2007. RVH was detected in 37 of the persons, 12 of whom were not included in the study due to coexisting systemic hypertension, COPD, or pulmonary hypertension. Twenty-five individuals of the same population with normal echocardiographic findings were enrolled as the control group. Symptoms that may be consequent to arrhythmia (such as palpitation, dizziness, and syncope) were not reported by the study population. Twelve-lead electrography was performed to measure the heart rate, QTc intervals, and QTc dispersion values. RESULTS: The age and gender of both the patient and control groups were similar. There was no significant difference between patients and controls with respect to QTmax, QTmin, and heart rate. However, mean QTc dispersion values were significantly increased in patients with RVH compared with the control group (59.0+/-14.7 vs. 35.9+/-11.4 ms, p<0.001). CONCLUSIONS: Right ventricular hypertrophy is associated with an increase in QTc dispersion.

Reduced atrial tachyarrhythmia susceptibility after upgrade of conventional implanted pulse generator to cardiac resynchronization therapy in patients with heart failure.

OBJECTIVES: We sought to identify the impact of cardiac resynchronization therapy (CRT) on atrial tachyarrhythmia (AT) susceptibility in patients with left ventricular (LV) systolic dysfunction in whom worsening heart failure (HF) resulted in upgrade from conventional dual-chamber pulse generator to cardiac resynchronization therapy-defibrillator (CRT-D). BACKGROUND: Cardiac resynchronization therapy with a defibrillator improves survival rates and symptoms in patients with LV systolic dysfunction but little is known about its effects on AT incidence in the same patient population. METHODS: Twenty-eight consecutive HF patients who underwent device upgrade to CRT-D were included. Patients had > or =2 device interrogations in the 1 year before upgrade and > or =3 interrogations in the 18- to 24-month follow-up after upgrade. Echocardiographic parameters were assessed before and at 3 to 6 months after CRT-D. Additional observations included number of hospital stays, HF clinical status, and concomitant pharmacological therapy. By virtue of this study design, each patient served as his/her own control. Statistical analysis was performed by 2-tailed paired t test and with nonparametric tests where appropriate. RESULTS: Within 3 months after CRT, the number of HF patients with documented AT decreased significantly from the immediate pre-CRT value and tended to decline with time. At 1-year follow-up, 90% of patients were AT-free compared with 14% of patients 3 months before CRT (p < 0.001). Furthermore, the number of AT episodes/year and their maximum duration decreased after CRT (mean +/- SD; 181 +/- 50 vs. 50 +/- 20.2, p < 0.05, and 220.8 +/- 87 s vs. 28 +/- 21 s, p < 0.05, respectively). Finally, CRT was associated with improved LV ejection fraction (mean +/- SD; from 26 +/- 5.3% to 31 +/- 7%, p < 0.001) and reduced number of HF or arrhythmia hospital stays (p < 0.05). CONCLUSIONS: Our findings support the view that CRT might decrease AT susceptibility in HF patients with LV systolic dysfunction.

Optimal programming in cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) has been shown to improve cardiac function, diminish hospitalization frequency, and enhance quality of life in selected heart failure patients. This benefit is mostly due to improved synchronization of ventricular contraction in the diseased heart. Since heart failure patients represent a heterogeneous group, cardiac resynchronization therapy must be tailored to each patient. Thus the best performance can be achieved by optimal programming of the device for each individual. This communication discusses different methods used for optimal programming for individuals who undergo CRT device implantations.

Comparison of ventricular arrhythmia burden, therapeutic interventions, and survival, in patients < 75 and patients >or= 75 years of age treated with implantable cardioverter defibrillators.

AIM: Implantable cardioverter defibrillators (ICD) reduce arrhythmic mortality in a wide range of patients with poor left ventricular (LV) function. However, whether ICD therapy is equally effective in younger and older patients remains uncertain. To address this question, we compared ICD-documented ventricular tachyarrhythmia burden in patients < 75 years of age (Group 1) and >or= 75 years of age (Group 2). METHODS: Data were obtained from 208 consecutive ICD-treated patients: 159 Group 1 (mean age 59 +/- 12), and 49 Group 2 (mean age 79 +/- 3). Demographic and clinical features including presenting arrhythmias, LV ejection fraction, and nature of heart disease were similar. Medications were comparable except that amiodarone use was more frequent in Group 2. RESULTS: The numbers of combined ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes per month were 0.4 +/- 2 and 0.3 +/- 2 for groups 1 and 2, respectively (P = 0.7). Individually, VT episodes per month were 0.4 +/- 2 and 0.3 +/- 2 (P = 0.7) and VF episodes per month were 0.003 +/- 0.01 and 0.03 +/- 0.2 (P = 0.2) for the two groups, respectively. The mean duration and average cycle length of arrhythmias were 3.1 +/- 20.4 s and 275 +/- 119 ms in Group 1, and 6 +/- 45 s and 285 +/- 114 ms in Group 2 (P values, 0.6 and 0.8). The mean time between the ICD implantation and the first episode of a device-treated arrhythmia was comparable in the two groups. Thirty-six patients died during follow-up; 22 (14%) Group 1 and 14 (29%) Group 2 (P = 0.02), almost exclusively on a non-sudden cardiac basis. Thus, despite higher ultimate mortality in older patients, both the nature and characteristics of spontaneous arrhythmia recurrence, and the time to first apparently beneficial therapy, were similar during follow-up in the two groups. CONCLUSION: In terms of reversing potentially life-threatening arrhythmias, the rationale for ICD therapy is comparable in older and younger individuals.

Cardiac resynchronization pacing without defibrillator capability: is this a viable option?

Improved cardiac resynchronization by pacemakers (CRT-P) and implantable defibrillators (CRT-D) benefits cardiac function, reduces heart failure (HF) admissions, and diminishes mortality in patients with severe left ventricular (LV) dysfunction. In terms of mortality benefit, current evidence suggests that CRT-D may be better than CRT-P alone when a broad range of HF patients is considered. However, the differential benefit may be small in certain patients. In individuals with severe and worsening HF due to systolic LV dysfunction, HF complications other than ventricular tachyarrhythmias contribute importantly to both quality-of-life (QoL) and duration of survival; these patients may be served cost-effectively by CRT-P enhancing QoL. A clinical trial evaluating CRT-D vs. CRT-P in terms of QoL and survival in such patients would assist physicians and payers to understand better the relative roles of CRT-P and CRT-D in the care of the sickest HF patients.

Impact of upgrade to cardiac resynchronization therapy on ventricular arrhythmia frequency in patients with implantable cardioverter-defibrillators.

OBJECTIVES: This study compared cardiac resynchronization therapy's (CRT) impact on ventricular tachyarrhythmia susceptibility in patients who, due to worsening heart failure (HF) symptoms, underwent a replacement of a conventional implantable cardioverter-defibrillator (ICD) with a CRT-ICD. BACKGROUND: Cardiac resynchronization therapy is an effective addition to conventional treatment of HF in many patients with left ventricular systolic dysfunction. However, whether CRT-induced improvements in HF status also reduce susceptibility to life-threatening arrhythmias is less certain. METHODS: Clinical and ICD electrogram data were evaluated in 18 consecutive ICD patients who underwent an upgrade to CRT-ICD. Pharmacologic HF therapy was not altered during follow-up. The definition of ventricular tachycardia (VT) and ventricular fibrillation (VF) for each patient was as determined by device programming. Statistical comparisons used paired t tests. RESULTS: Findings were recorded during two time periods: 47 +/- 21 months (range 24 to 70 months) before and 14 +/- 2 months (range 9 to 18 months) after CRT upgrade. At time of upgrade, patient age was 69 +/- 11 years and ejection fraction was 21 +/- 8%. Before CRT the frequency of VT, VF, and appropriate ICD shocks was 0.31 +/- 1.23, 0.047 +/- 0.083, and 0.048 +/- 0.085 episodes/month/patient, respectively. After CRT-ICD, VT and VF arrhythmia burdens and frequency of shocks were respectively 0.13 +/- 0.56, 0.001 +/- 0.004, and 0.003 +/- 0.016 episodes/month/patient (p = 0.59, 0.03, and 0.05 vs. pre-CRT). CONCLUSIONS: Arrhythmia frequency and number of appropriate ICD treatments were reduced after upgrade to CRT-ICD for HF treatment. Thus, apart from hemodynamic benefits, CRT may also ameliorate ventricular tachyarrhythmia susceptibility in HF patients.

Effect of cough on heart rate and blood pressure in patients with "cough syncope".

BACKGROUND: "Cough syncope" is uncommon, and its mechanism remains controversial. OBJECTIVES: This study evaluated susceptibility to cough-triggered neural reflex hypotension-bradycardia among cough syncope patients. We hypothesized that individuals with cough syncope would manifest not only more profound cough-triggered hypotension than do other fainters but also an inappropriate chronotropic response accompanying cough-induced hypotension, thereby supporting the notion that a neural reflex hypotension-bradycardia contributes to the condition. METHODS/RESULTS: Three patient groups were studied. Group 1 patients (n = 9) had "cough syncope." The remaining patients had recurrent faints of other causes: group 2 (n = 13) had a positive head-up tilt test, and group 3 (n = 18) had a negative tilt test. With cough, group 1 patients exhibited a greater drop in systolic pressure (-51 +/- 19.3 mmHg) than did either group 2 (-23 +/- 11.1 mmHg, P < .04) or group 3 patients (-28 +/- 12.4 mmHg, P < .05). Recovery time to normalization of systolic pressure was greater in group 1 (25 +/- 9.1 seconds) than in group 2 or 3 (8 +/- 2.7 seconds and 9 +/- 6.1 seconds, respectively, both P < .01 vs group 1). The expected positive chronotropic response accompanying cough-induced hypotension was diminished in group 1 patients (0.16 +/- 0.21 bpm/mmHg) compared with that in either group 2 (0.74 +/- 0.60 bpm/mmHg, P < .05 vs group 1) or group 3 (0.33 +/- 0.15 bpm/mmHg, P = .06 vs group 1). CONCLUSION: Cough syncope patients not only exhibit more pronounced hypotension in response to cough than other fainters, but they also manifest an inappropriate cough-triggered blood pressure-heart rate relationship. These findings argue in favor of the importance of a neurally mediated reflex contribution to symptomatic hypotension in cough syncope.

Comparison of ventricular arrhythmia frequency in patients with ischemic cardiomyopathy versus nonischemic cardiomyopathy treated with implantable cardioverter defibrillators.

Implantable cardioverter defibrillators have been shown to provide similar survival benefits for patients who have left ventricular dysfunction due to ischemic heart disease and for subsets of patients who have nonischemic cardiomyopathy. Findings in this study extend these observations by showing that patients who have ischemic or nonischemic heart disease and receive implantable cardioverter defibrillators not only have comparable mortality rates but also similar tachyarrhythmia frequencies during follow-up; further, mortality and tachyarrhythmia outcomes are independent of initial arrhythmia indication.

Assessment of percutaneous coronary intervention on regional and global left ventricular function in patients with chronic total occlusions.

BACKGROUND: The improvement of regional and global ventricular function following percutaneous coronary intervention (PCI) with reperfusion of the artery supplying the infarct area in acute myocardial infarction is well-described. However, little is known of the potential effects of late recanalization of chronic coronary artery occlusion on left ventricular function. OBJECTIVE: To determine whether PCI improves regional and global left ventricular function in patients with chronic coronary artery occlusions. PATIENTS AND METHODS: Thirty-five patients having at least one coronary artery occluded for six weeks or longer were included in the present prospective study. Exercise thallium-201 myocardial perfusion scintigraphy, multiple-gated acquisition ventriculography and two-dimensional echocardiography were performed in 19 patients (16 men; mean age of 58+/-5 years) who underwent a successful PCI to assess both regional and global left ventricular function before and six weeks following the procedure. RESULTS: The mean ejection fractions before and after reperfusion were 51+/-7% and 58+/-6% using Simpson's method (P<0.001) by echocardiography, and 45+/-1% and 53+/-1% (P=0.01) by multiple-gated acquisition ventriculography, respectively. The echocardiographic wall motion score was 24+/-9 before and 15+/-6 after PCI (P<0.001). The exercise perfusion score (21+/-1 and 14+/-1 [P=0.01]), rest perfusion score (15+/-1 and 12+/-1 [P=0.02]) and reinjection perfusion score (14+/-1 and 11.1+/-1 [P=0.07]) also improved after PCI. The presence of angina was strongly associated with an improvement in left ventricular function and wall motion score (P<0.01). CONCLUSIONS: PCI significantly improved the regional and global left ventricular function in patients with chronic total coronary occlusion. This procedure may provide symptom benefits in selected patients.

Biventricular implantable cardioverter defibrillators improve survival compared with biventricular pacing alone in patients with severe left ventricular dysfunction.

INTRODUCTION: Biventricular cardiac pacemakers provide important hemodynamic benefit in selected patients with heart failure and severe left ventricular (LV) dysfunction. Nevertheless, these patients remain at high mortality risk. To address this issue, we examined mortality outcome in patients with heart failure treated with biventricular pacemakers alone and those treated with biventricular implantable cardioverter defibrillators (ICDs). METHODS AND RESULTS: The study population consisted of 126 consecutive patients with LV dysfunction and heart failure who received either a biventricular ICD (n = 62) or a biventricular pacemaker (n = 64) between January 1998 and December 2002. A minimum 12 months of follow-up was obtained in all survivors. ICD indications were conventional in all patients. Kaplan-Meier actuarial method and log rank statistics were used to calculate and compare survival rates in both groups. Comparison of mortality rates utilized Chi-square test. The two groups had similar clinical and demographic features, LV ejection fraction, and medication use. Average follow-up times were 13 +/- 11.8 months (range 4-60) and 18 +/- 13.2 months (range 0.5-53) for biventricular ICD and pacemaker groups, respectively. Overall mortality rate was significantly lower in the biventricular ICD group (13%, 8 deaths) compared to the pacemaker group (41%, 26 deaths) (P = 0.01). Further, the predominant survival benefit for ICD-treated patients becomes evident after the first 12 months of follow-up. CONCLUSION: The findings in this study, although necessarily limited in their interpretation by the absence of treatment randomization, suggest that biventricular ICDs offer a survival benefit compared to biventricular pacing alone. Furthermore, this benefit may be most apparent if other clinical factors do not preclude patient survival >1 year postimplant.

Impact of age and blood pressure on the lower arterial pressure limit for maintenance of consciousness during passive upright posture in healthy vasovagal fainters: preliminary observations.

Maintenance of consciousness importantly depends on systemic arterial blood pressure (BP) remaining above the lower pressure limit for cerebrovascular autoregulation. This study evaluated the impact of age and baseline arterial blood pressure (BP) on the BP recorded at onset of syncope in otherwise healthy individuals undergoing passive head-up tilt (HUT) testing for suspected vasovagal syncope. Since hypertension is thought to shift the lower autoregulation point to higher values, and since older healthy patients tend to have higher BP than younger individuals, we hypothesized that even among healthy individuals HUT-induced syncope would occur at higher BP in older compared with younger subjects. Three groups of otherwise healthy individuals who had positive HUT were identified: Group 1: <25 years, n=17; Group 2: 25-59 years, n=18; and Group 3: > or =60 years, n=7. As expected, baseline arterial systolic blood pressure of patients > or =60 years (162+/-37 mmHg) was significantly higher than in the other two groups (Group 1: <25 years, 116+/-15 mmHg; Group 2: 25-59 years, 128+/-12 mmHg). Further, the > or =60 age group tolerated upright posture for a longer period before syncope than did younger patients. However, despite a trend for BP at syncope to increase with age, differences were small (Group 3: > or =60 years, 61+/-15 mmHg, Group 2: 25-59 years, 58+/-6 mmHg, and Group 1: 54+/-16 mmHg) and were not statistically significant. Thus, in generally healthy individuals, age and baseline BP has only a minor effect on the lower limit of BP necessary for maintenance of consciousness. On the other hand, higher baseline BP provides older individuals a greater blood pressure 'reserve' for maintenance of consciousness compared with younger subjects.