Chronotropic incompetence: a common and progressive finding in pacemaker patients.

Thirty-eight patients (ages 40 to 77 years, mean 63) followed in a pacemaker clinic underwent exercise treadmill tests to determine chronotropic incompetence. There were 28 men and 10 women. Twenty-seven patients had atrioventricular (AV) block and 11 patients had sick sinus syndrome. All patients were exercised to fatigue. None of the patients were receiving beta-blockers or other drugs that could reduce heart rate. Maximum heart rate (MHR) and percent predicted maximum heart rate (% PMHR) were used as an index of chronotropic incompetence. Chronotropic incompetence was defined as inability to achieve a % PMHR of greater than 80%. The overall incidence of chronotropic incompetence was 58% (22 of 38 patients). We examined the relationship between chronotropic incompetence and the time to pacemaker implantation. We found that in patients who had pacemakers for less than 2 years, the mean MHR was 125 +/- 21.6 beats/min compared with 111.9 +/- 23.6 beats/min for patients who had pacemakers implanted for longer than 4 years. Similarly, the mean % PMHR decreased from 76.5 +/- 12.5% to 68.7 +/- 15.4% in patients with pacemakers less than 2 years versus those with pacemakers for more than 4 years. Fifty-three percent of the patients with a pacemaker less than 2 years old were chronotropic incompetent versus 70% of the patients with a pacemaker more than 4 years old. These data suggest that chronotropic incompetence worsens with time after pacemaker implant. To further support this, eight patients with AV block underwent a second stress test an average of 2 years following the first.(ABSTRACT TRUNCATED AT 250 WORDS)     

Supernormal ejection performance is isolated to the ipsilateral congenitally pressure-overloaded ventricle

Congenital left ventricular pressure overload is associated with "excessive" hypertrophy that leads to subnormal afterload (wall stress), permitting enhanced ventricular ejection performance. Whether congenital right ventricular pressure overload is associated with a similar phenomenon is uncertain. It is also unknown whether supranormal ejection performance affects only the overloaded ventricle or is a general process affecting both ventricles. Conflicting data exist about whether the hypertrophic process associated with pressure overload is induced primarily by local loading conditions or by neuroendocrine influences. If the former postulate is true, the hypertrophic response should be confined to the overloaded ventricle; if the latter is true, one might predict that both ventricles would be affected by a less specific response to circulating catecholamines. To help resolve these issues, both right and left ventricular performance was examined in seven patients with isolated congenital pulmonary stenosis (average pulmonary pressure gradient 78 +/- 13 mm Hg), six patients with isolated congenital aortic stenosis (average gradient 80 +/- 10 mm Hg) and six normal subjects. Right ventricular ejection fraction was increased in patients with pulmonary stenosis (61 +/- 2%) compared with the value in normal subjects (53 +/- 2%, p less than 0.01) and in patients with aortic stenosis (50 +/- 3%, p = 0.007). Left ventricular ejection fraction was increased in patients with congenital aortic stenosis (84 +/- 4%) compared with the value in normal subjects (70 +/- 4%, p less than 0.01) and in patients with congenital pulmonary stenosis (65 +/- 2%, p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)     

Quantitative assessment of muscular stiffness in children with cerebral palsy using acoustic radiation force impulse (ARFI) ultrasound elastography

Purpose

To evaluate the feasibility of quantitative analysis of muscle stiffness in the medial gastrocnemius muscle (GCM) by acoustic radiation force impulse (ARFI) ultrasound elastography in children with spastic cerebral palsy (CP).

Methods

Seventeen children with spastic CP and 25 healthy children participated in the study between the years 2016–2017. The medial GCM in the CP group was assessed using the Modified Ashworth Scale (MAS) by a physiatrist. ARFI was used to measure the shear-wave velocities (SWVs) of the medial GCM. The mean SWV value for each MAS score was calculated and used for statistics.

Results

The mean SWV values of the medial GCM in the CP and healthy groups were 3.17 ± 0.81 m/s (mean ± SD) and 1.45 ± 0.25 m/s (mean ± SD), respectively. The SWV of the medial GCM significantly increased in the CP patients when compared with controls (p < 0.001). In addition, the SWV values were correlated with the MAS scores (p < 0.001). The interobserver agreement expressed as the interclass correlation coefficient was 0.65 (95% CI 0.33–0.84, p < 0.001).

Conclusions

ARFI imaging demonstrated a difference in muscle stiffness in the medial GCM between the CP and healthy groups. This method is a feasible imaging modality for the noninvasive assessment of contracting muscles in children with CP.

     

Initiation of monomorphic ventricular tachycardia: electrophysiological,clinical features,and drug therapy in patients with implantable defibrillators

At least 2 distinct patterns of sustained monomorphic ventricular tachycardia (MVT) have been ascribed during analysis of stored intracardiac electrograms retrieved from implantable cardioverter defibrillators and Holter recordings in patients with ventricular arrhythmia. We aimed to investigate the electrophysiological features of MVT with different initiation patterns in patients with implantable cardioverter defibrillators and to assess whether there is a relationship of the initiation patterns of sustained MVT with clinical characteristics and efficacy of antiarrhythmic therapy. Seventy-four stored intracardiac electrograms in 21 patients (mean age of 68.2 +/- 4.2 years) with MVT were evaluated. Cardiovascular diagnosis included coronary artery disease in 85.7% of the patients. All MVT episodes were classified as those initiating with ventricular premature beats (nonsudden onset MVT) and those without ventricular ectopy preceding tachycardia (sudden onset MVT). There was significant difference in left ventricular ejection fraction between MVTs with different initiation pattern, being the lower in those with nonsudden onset (33.6% +/- 38.4% vs. 38.4 +/- 7.0%, P <.04). Ventricular tachycardia cycle length was shorter in group of MVT with nonsudden onset as compared with sudden onset (338.5% +/- 48.1% vs. 376.8% +/- 57.0%, P <.02). Tachycardia with sudden onset was associated with shorter preceding RR interval than tachycardia with nonsudden onset (821.8 +/- 136.2% vs. 748.7 +/- 107.7%, P <.01). There were no significant differences in the type of antiarrhythmic drug therapy used between groups (P >.05). Monomorphic ventricular tachycardias with nonsudden onset occurred more frequently than with sudden onset, without precipitating RR cycles shortening, are faster in rate, associating with lower ejection fraction. Monomorphic ventricular tachycardias with sudden onset are characterized by preceding shortening of RR intervals, slower cycle length, and less worsening of ejection fraction.     

The potential role of purine-rich element binding protein (PUR) alpha as a novel treatment target for hormone-refractory prostate cancer

BACKGROUND: Hormonal therapy for advanced prostate cancer is typically effective at first, but almost all men suffer refractory disease which often is life threatening. The nuclear matrix comprises not only of the structural elements of the nucleus, but is associated with many components of the molecular machinery. Our aim is to find novel targets for the treatment of hormone-refractory prostate cancer (HRPC) by focusing on the composition of the nuclear matrix proteins (NMPs). METHODS: LN96 cells were established at our Institution after long-term culturing of LNCaP cells under androgen deprived conditions. The composition of NMPs of LNCaP cells and LN96 cells were analyzed by two-dimensional (2D) electrophoresis and spots differentially expressed were investigated by mass spectrometry for identification. Among the spots identified, we analyzed the potential functional role of the identified proteins in prostate cancer cells by establishing stable overexpressed cells. RESULTS: We found that purine-rich element binding protein (PUR)alpha was significantly repressed not only in NMPs but also in total protein and mRNA levels of LN96 cells in comparison to LNCaP cells under the same steroid deprived conditions. Moreover, PURalpha was decreased in its expression both at the protein and mRNA levels in the androgen-independent prostate cancer cell lines, PC3 and DU145 in comparison to LNCaP cells. Stably overexpressing PURalpha in PC3 and DU145 cells negatively regulates cell proliferation, resulting in decreases in PCNA expression. CONCLUSION: Further dissection of the role of PURalpha in cell growth regulation may reveal a novel target for HRPC.     

Peer Reviewed: Influence of Family History of Diabetes on Health Care Provider Practice and Patient Behavior Among Nondiabetic Oregonians

Introduction

People with a family history of diabetes are at increased risk of developing diabetes; however, the effect of family history of diabetes on health care provider practice and patient behavior has not been well defined.

Methods

We analyzed data from the 2005 Oregon Behavioral Risk Factor Surveillance System, a state-based, random-digit–dialed telephone survey, to evaluate, among people with diabetes, associations between family history of diabetes and 1) patients'' reports of health care provider practices, 2) patients'' perceived risk of developing diabetes, and 3) patients'' behaviors associated with an increased risk of developing diabetes.

Results

Compared with respondents at average risk, respondents with a positive family history (strong or moderate familial risk for diabetes) were more likely to report that their health care provider collects family history information about diabetes, discusses the risk of developing diabetes or other chronic conditions, and makes recommendations to change their diet or exercise behaviors to reduce the chance of developing diabetes. Respondents with a strong family history of diabetes were 5 times more likely to be very or somewhat worried about developing diabetes than were people at average risk (odds ratio [OR], 5.0; 95% confidence interval [CI], 4.0-6.2). Compared with respondents at average risk, respondents with a strong family history were more likely to report making changes in diet and exercise (OR, 1.7; 95% CI, 1.4-2.1).

Conclusion

Integrating family history of diabetes into clinical practice offers opportunities to improve the effectiveness of diabetes detection and to promote interventions aimed at preventing or delaying the development of diabetes in people at high risk.     

Health-Related Quality of Life and Treatment Satisfaction in North American Patients with Primary Immunedeficiency Diseases Receiving Subcutaneous IgG Self-Infusions at Home

The lifelong IgG replacement therapy for patients with primary immunedeficiencies (PIDD) may be provided by intravenous (IVIG) or by subcutaneous IgG (SCIG) infusions. We investigated the impact of weekly SCIG self-infusions at home on the health-related quality of life, treatment satisfaction, and preferences in patients treated with IVIG at the hospital/doctor's office (Group A) or at home (Group B) before the study started. Forty-four adult North American PIDD patients were included in the study, 28 patients in Group A and 16 in Group B. Patients in Group A reported significantly less limitations with their work/daily activities, a significantly improved vitality, and better general health. Treatment satisfaction was significantly improved in Group A. The preference for the subcutaneous route and for home therapy was respectively 81% and 90% in Group A. In Group B, 69% preferred the subcutaneous route and 92% home therapy.     

Right ventricular thrombus with Behçet's syndrome: successful treatment with warfarin and immunosuppressive agents

Beh?et's syndrome is a chronic multisystem disease that presents with recurrent oral and genital ulceration and recurrent uveitis. Cardiac involvement is an extremely rare manifestation of this disorder. A 33-year-old man with Beh?et's syndrome was admitted to our department with a history of cough, fever, chest pain, hemoptysis, and weight loss. Transthoracic and transesophageal echocardiography revealed a right ventricular thrombus. After 1 month of treatment with warfarin, cyclophosphamide, and corticosteroid, the intracardiac thrombus resolved.