Predictors of all-cause mortality for patients undergoing transvenous lead extraction

Background

Risk assessment of TLE patients may be challenging due to incomplete knowledge about possible risk factors for post-TLE outcomes. The aim of this study was to identify predictors of 30-days and 1-year all-cause mortality including the novel parameter frailty in a large retrospective series of patients undergoing TLE at a high-volume centre.

Methods

Medical journals of 893 consecutive patients undergoing TLE between January 1, 2010 and December 31, 2018 were retrogradely analysed. Univariate logistic regression and multivariate analyses were performed to identify risk factors.

Results

A total of 893 patients were identified. Local infection was the dominant indication (41.1%) and pacemaker was the most common device (49.4%). Mean age was 65±16 years and 73.0% were males. The median follow up was 3.9 years (IQR, 4.5 years). Within the systemic infection group, Staphylococcus aureus was the main microorganism in the positive blood cultures (44.4%) and 69.4% of the patients had vegetations. The 30-days and 1 year mortality rates were 2.5% and 9.7%, respectively. Per-procedural mortality occurred in 1 patient. Significant risk factors for 30-days all-cause mortality at univariate analysis were anaemia, systemic infection, clinical frailty scales (CFS) 5–7 and stage 5 chronic kidney disease (CKD). Age, CRT-P/D (vs ICD), reduced ejection fraction, anaemia, BMI <25 kg/m2, CFS 4–7 and CKD stages 3–5 were identified as significant predictors of 1-year all-cause mortality. Within the systemic infection subgroup, leucocytosis and white blood cell count (WBC) 8.8–15x109/L were associated with significant 30-days and 1-year all-cause mortality and CRP 200–300 mg/L and low WBC count correlated with 1-year all-cause mortality. Local infection patients with CRP 100–150 mg/L had an elevated risk for 1-year all-cause mortality. Multivariate analysis identified CKD 5, CFS 5–7 and systemic infection for 30-days all-cause mortality and age, CKD 5, CFS 5–7, systemic infection and BMI <25 kg/m2 for 1-year all-cause mortality as independent risk factors.

Conclusions

Patient-related characteristics, comorbidities and systemic infection independently predicted worse post-TLE prognosis. Several parameters need to be considered when assessing patients for TLE in order to risk stratify the patients and optimize the post-TLE care. Frailty is a novel parameter with significant influence on short and long-term outcome.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Internal funding

Predictors of all-cause mortality for patients undergoing transvenous lead extraction

Funding Acknowledgements

Type of funding sources: None.

Background

Risk assessment of TLE patients may be challenging due to incomplete knowledge about possible risk factors for post-TLE outcomes. The aim of this study was to identify predictors of 30-day and 1-year mortality in a large retrospective series of patients undergoing TLE at a high-volume centre.

Methods

Medical journals of 893 consecutive patients undergoing TLE between January 1, 2010 and December 31, 2018 were analysed. Univariate logistic regression analysis was performed to identify risk factors.

Results

A total of 893 patients were identified. Local infection was the dominant TLE indication (40.5%), and pacemaker was the most common CIED (49.4%). Mean age was 65 + 16 years and 73.0% were males. The median follow up was 3.9 years (IQR, 2.0-6.4 years). Staphylococcus aureus was the most common microorganism found in blood cultures of the systemic infection group (39.9%). A total of 179 (69.4%) systemic infection patients had vegetations on echocardiography, where majority engaged the lead(s). The 30-day and 1 year mortality rates were 2.5% (86.4% had systemic infection) and 9.7% (64.4% had systemic infection), respectively. Per-procedural mortality occurred in 1 patient with systemic infection. Significant predictors of 30-day mortality were low haemoglobin, systemic infection as TLE-indication, clinical frailty scales (CFS) 5-7 and stage 5 chronic kidney disease (CKD). In case of 1-year mortality, age, CRT-P/D (vs ICD), reduced ejection fraction, anaemia, BMI <25 kg/m2, CFS 4-7 and CKD stages 3-5 were identified as significant predictors. In the systemic infection subgroup, elevated white blood cell (WBC) count was associated with 30-day and 1 year mortality. Additionally CRP interval 200-300, low WBC count and WBC interval 8.8-15 correlated signigicantly with 1-year mortality within the systemic infection cohort. In the local infection subgroup, a significant correlation between CRP interval 100-150 and 1-year mortality was found.

Conclusions

Systemic infection as TLE-indication carries a high 30-days post-TLE all-cause mortality rate and is significantly correlated with short and long-term mortality, where elevated inflammatory parameters carried additional mortality risk in this subgroup. Anaemia, chronic kidney disease, CRT compared to ICD, reduced EF and patient-related features as high clinical frailty scale levels and BMI <25 kg/m2 predicted worse prognosis in the entire TLE-cohort.

Endocardial pacing compared to epicardial left ventricle pacing and right ventricle pacing: a single center long term experience in a pediatric population

Introduction

Complete atrioventricular block (CAVB), either congenital or post heart surgery, are the main indications for cardiac pacing in the pediatric population.

Epicardial pacing is preferred in small infants or for specific cardiac anomalies and some studies highlight a superior contraction pattern when pacing epicardially from the left ventricular apex region [1–3]. Endocardial pacing is more frequently used in children with a weight >20 kg and is less invasive [4].

Paced QRS duration seems to be independently associated with ventricular dysfunction irrespective of location or age at device implantation [5].

Purpose

Describe the echocardiographic and electrocardiographic changes after switch from epicardial to transvenous pacing in a pediatric population with CAVB.

Methods

Children (0–18 years), who underwent a switch from left- (LV) or right ventricle (RV) epicardial pacing to transvenous pacing at our center, were retrospectively studied. Clinical, ECG- and echocardiographic parameters before and after the switch of the PM-system were collected as well as the most recent FU data. Left ventricular end-diastolic diameter (LVDD) and fractional shortening (FS) values were transformed to a body surface-related and age-related z-score (z), respectively.

Results

Fifteen patients with CAVB who received an epicardial pacemaker (60% congenital, 40% post-cardiac surgery) were converted to a transvenous system at our center (2005–2021). The median age at the switch was 6.8 (2–13) years with a median weight of 21 (9–62) kg. The epicardial lead location was more frequently the RV wall (60%) than the LV wall (40%). The RV outflow tract and interventricular septum were the most common locations (73%) for the endocardial leads. The mean QRS duration during epicardial stimulation was 150 (IQR 26) ms vs. a median QRS duration with the transvenous system of 136 (IQR 19) ms and a median delta QRS duration of 13ms. A detailed comparison between RV and LV epicardial pacing are reported in Figure 1. Children with post-surgical AV block had a broader median QRS duration, both with epicardial and endocardial stimulation. Before the switch, there was only one abnormal observation of FS less than −2 z with normal LVDD. At the last available follow-up (mean time 7 years), all the children had normal LVDD and only one had FS less than −2 z.

Conclusions

Our report of pediatric patients after switch from epi to endo pacing, shows good results in terms of QRS duration with no significant echocardiographic or clinical evidence of deterioration of the cardiac function. Due to the small sample size the results could serve as a hypothesis generator, but larger prospective studies are needed to evaluate the electrocardiographic and echocardiographic impact of transvenous - compared to epicardial pacing.

Funding Acknowledgement

Type of funding sources: None. Comparison of QRS duration

Incidental finding of ”ghost” on echocardiography after transvenous lead extraction among systemic infection patients

Background

Ghosts are described as cylindrical and oscillating structures diagnosed after transvenous lead extraction (TLE) and may consist of thrombi, vegetations and fibrous sheaths. Presence of ghosts is found to be associated with poor outcomes.

Purpose

The aim of this study was to estimate the proportion of patients with ghosts and to describe the characteristic features of `'ghosts” seen post-TLE in a retrospective series of systemic infection patients.

Methods

Medical journals including echocardiography studies of systemic infection patients undergoing TLE between January 1, 2010 and December 31, 2018 were analysed.

Results

A total of 258 patients (72% males, mean age 71±12 years), underwent TLE due to systemic infection. Staphylococcus aureus was the dominant microorganism isolated in blood cultures (40%). Echocardiography identified ghosts as incidental findings in 15 (6%) patients, 1–23 day(s) (median, 5; mean, 7±6 days) post-TLE and ghosts remained up to 51 days post-TLE. Ghosts were described as tubular, echodense and mobile tissues with variety of dimensions (2–50 mm) on echocardiography, mostly localised in right atrium (40%). Ghosts were visually described by surgeons as vegetations on tricuspid valve, organised thrombotic material in superior/inferior vena cavae and more loose thrombotic materials in right atrium in 2 patients who underwent open heart surgery after TLE. Echocardiography could not certainly differentiate between non-infectious tissue and infectious vegetations, thereby endocarditis treatment was prolonged to at least 12 days (mean, 29±14 days) post-TLE in the ghost group.

Conclusion

Although this was a retrospective analysis and ghosts were incidental findings rather than differential diagnosis, which may have underestimated the proportion ghosts identified, ghosts were relatively common in this cohort. Presence of ghosts caused management challenges for clinicians. There is a great need for large multicentre studies enabling establishment of guidelines for diagnosis and management of this common post-TLE finding.

Funding Acknowledgement

Type of funding sources: None. Table 1Figure 1

Prevalence of left bundle branch block and CRT treatment in a large regional unselected ECG database

Introduction

Heart failure is a clinical syndrome in which signs and symptoms are due to functional and/or structural abnormalities of the heart which prevent the necessary supply of oxygenated blood or do so at the expense of high filling pressures. It has a prevalence of 1–2% in the western world and increasing prevalence with increasing age. While the prognosis for coronary heart disease has improved significantly, the same does not apply for heart failure, perhaps because some effective treatment methods have not been sufficiently implemented in health care. One effective but underutilized heart failure treatment is the cardiac resynchronisation therapy (CRT), that coordinates the contraction of the left and right ventricles via a pacemaker (PM). CRT treatment is an evidence based treatment recommended by among other the ESC guidelines for heart failure. Clinical studies have suggested decreases in mortality, hospitalization, morbidity and improvements in quality of life for heart failure patients receiving a CRT.

Purpose

To find a new clinical pathway to improve CRT implementation and to evaluate if it might be optimized through ECG-based surveillance and thus improving prognosis.

Methods

In a population of approximately 2.5 million people in our region we investigated the University Hospital's ECG database between 2000 and 2018. During which time 432 108 adult patients with 1 482 489 ECG's presented to the hospital. We searched and found 5 511 unique patients with the following ECG criteria: QRS ≥150 ms at any time, LBBB and Non pace. According to the Pacemaker Registry we excluded 771 patients that had previously received a PM/CRT. We also identified patients with diagnosis of heart failure by using the ICD-10 codes (I42.0 and I50).

Results

Our final cohort consists of 4 740 patients. The median age was 75 (19–112) years, 34.5% were female and 14.9% were subsequently implanted with a CRT (60% with CRT-D). The median time to CRT implantation from the first ECG with LBBB was 244 (IQR 994) days. Of the 4 740 patients 20.6% had a previous hospitalistion for heart failure with a median delay from the hospitalisation to CRT implantation of 5 (IQR 5.4) years.

Conclusions

Our observational data from a large real-life regional ECG database show there is a considerable number of heart failure patients that could benefit from CRT treatment. Using an existing ECG database could be useful in finding patients with indication for CRT implantation. This could possibly influence morbidity and mortality in a regional heart failure population by minimizing the delay of CRT treatment.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Karolinska University Hospital Research Fund

The HLA locus contains novel foetal susceptibility alleles for congenital heart block with significant paternal influence

OBJECTIVE

The main aim of this study was to identify foetal susceptibility genes on chromosome six for Ro/SSA autoantibody-mediated congenital heart block.

SUBJECTS AND DESIGN

Single nucleotide polymorphism (SNP) genotyping of individuals in the Swedish Congenital Heart Block (CHB) study population was performed. Low-resolution HLA-A, -Cw and -DRB1 allele typing was carried out in 86 families comprising 339 individuals (86 Ro/SSA autoantibody-positive mothers, 71 fathers, 87 CHB index cases and 95 unaffected siblings).

RESULTS

A case-control comparison between index cases and population-based out-of-study controls (n = 1710) revealed association of CHB with 15 SNPs in the 6p21.3 MHC locus at a chromosome-wide significance of P < 2.59 × 10(-6) (OR 2.21-3.12). In a family-based analysis of association of SNP markers as well as distinct MHC class I and II alleles with CHB, HLA-DRB1*04 and HLA-Cw*05 variants were significantly more frequently transmitted to affected individuals (P < 0.03 and P < 0.05, respectively), whilst HLA-DRB1*13 and HLA-Cw*06 variants were significantly less often transmitted to affected children (P < 0.04 and P < 0.03). We further observed marked association of increased paternal (but not maternal) HLA-DRB1*04 transmission to affected offspring (P < 0.02).

CONCLUSIONS

HLA-DRB1*04 and HLA-Cw*05 were identified as novel foetal HLA allele variants that confer susceptibility to CHB in response to Ro/SSA autoantibody exposure, whilst DRB1*13 and Cw*06 emerged as protective alleles. Additionally, we demonstrated a paternal contribution to foetal susceptibility to CHB for the first time.

Cardiac resynchronization therapy: a breakthrough in heart failure management

Heart failure is now considered an epidemic. In patients with heart failure, electrical and mechanical dyssynchrony, evident primarily as prolongation of the QRS-complex on the surface electrocardiogram, is associated with detrimental effects on the cardiovascular system at several levels. In the past 10 years, studies have demonstrated that by stimulating both cardiac ventricles simultaneously, or almost simultaneously [cardiac resynchronization therapy (CRT)], the adverse effects of dyssynchrony can be overcome. Here, we provide a comprehensive overview of different aspects of CRT including the rationale behind and evidence for efficacy of the therapy. Issues with regard to gender effects and patient follow-up as well as a number of unresolved concerns will also be discussed.

A population-based investigation of the autoantibody profile in mothers of children with atrioventricular block

The objective of the study was to investigate the antigen specificity and occurrence of individual autoantibodies in mothers of children diagnosed with atrioventricular (AV) block in a nation-wide setting. Patients with AV block detected before 15 years of age were identified using national quality registries as well as a network of pediatric and adult cardiologists and rheumatologists at the six university hospitals in Sweden. Patients with gross heart malformations, surgically or infectiously induced blocks were excluded. Blood samples were obtained from the mothers and maternal autoantibody profile, including the occurrence of antibodies against Ro52, Ro60, La, SmB, SmD, RNP-70k, RNP-A, RNP-C, CENP-C, Scl-70, Jo-1, ribosomal RNP and histones was investigated in 193 mothers of children with AV block by immunoblotting and ELISA. Autoantibody reactivity was detected in 48% (93/193) of the mothers of children with AV block. In autoantibody-positive mothers, the vast majority, 95% (88/93), had antibodies against Ro52, while 63% (59/93) had autoantibodies to Ro60 and 58% (54/93) had autoantibodies to La. In addition, 13% (12/93) of the autoantibody-positive mothers had antibodies to other investigated antigens besides Ro52, Ro60 and La, and of these anti-histone antibodies were most commonly represented, detected in 8% (7/93) of the mothers. In conclusion, this Swedish population-based study confirms that maternal autoantibodies may associate with heart block in the child. Further, our data demonstrate a dominant role of Ro52 antibodies in association with AV block.

Comparative effects of permanent biventricular and right-univentricular pacing in heart failure patients with chronic atrial fibrillation

BACKGROUND

One third of chronic heart failure patients have major intraventricular conduction and uncoordinated ventricular contraction. Non-controlled studies suggest that biventricular pacing may improve haemodynamics and well-being by reducing ventricular asynchrony. The aim of this trial was to assess the clinical efficacy and safety of this new therapy in patients with chronic atrial fibrillation.

METHODS

Fifty nine NYHA class III patients with left ventricular systolic dysfunction, chronic atrial fibrillation, slow ventricular rate necessitating permanent ventricular pacing, and a wide QRS complex (paced width >or=200 ms), were implanted with transvenous biventricular-VVIR pacemakers. This single-blind, randomized, controlled, crossover study compared the patients' parameters, as monitored during two 3-month treatment periods of conventional right-univentricular vs biventricular pacing. The primary end-point was the 6-min walked distance, secondary end-points were peak oxygen uptake, quality-of-life, hospitalizations, patients' preferred study period and mortality.

RESULTS

Because of a higher than expected drop-out rate (42%), only 37 patients completed both crossover phases. In the intention-to-treat analysis, we did not observe a significant difference. However, in the patients with effective therapy the mean walked distance increased by 9.3% with biventricular pacing (374+/-108 vs 342+/-103 m in univentricular;P =0.05). Peak oxygen uptake increased by 13% (P=0.04). Hospitalizations decreased by 70% and 85% of the patients preferred the biventricular pacing period (P<0.001).

CONCLUSION

As compared with conventional VVIR pacing, effective biventricular pacing seems to improve exercise tolerance in NYHA class III heart failure patients with chronic atrial fibrillation and wide paced-QRS complexes. Further randomized controlled studies are required to definitively validate this therapy in such patients.

Reduction of hospital days by biventricular pacing

The health care costs for heart failure are substantial. Studies indicate that hospital treatment constitutes 65-75% of these. The aim of this study was to assess total and heart failure related hospital days as well as safety and efficacy of biventricular pacing in 16 patients with severe heart failure and delayed intraventricular conduction (QRS duration >150 ms). They were implanted with a biventricular pacemaker and followed by NYHA class, 6-min walk test and quality of life for a mean of 291+/-76 days. Total number of hospital days and the need for hospitalisations were monitored. Thirteen responders improved by at least one functional class. After 6 months of pacing the 6-min walk test improved from 375+/-83 m to 437+/-73 m (P<0.001) and Minnesota Living with Heart Failure quality of life score from 41+/-19 to 24+/-17 (P<0.001) compared to baseline. The need for hospital care decreased significantly after biventricular pacing. The total number of hospital days in all patients was 253 the year before compared to 45 the year after biventricular pacing (P<0.01). For heart failure related hospital days the corresponding figures were 183 and 39 days, respectively (P<0.01). Biventricular pacing improved 13/16 patients with severe heart failure and wide QRS complexes in this open study. The improvement resulted in a reduced need for hospital care.

[Biventricular pacing as a new therapeutic method in heart failure. An alternative for patients with intraventricular conduction disorders]

Patients with severe heart failure often have interventricular conduction disturbances indicated by wide QRS complexes. The resulting uncoordinated contraction pattern leads to impaired systolic and diastolic function which might be overcome by a new technique, biventricular pacing. The first Swedish clinical trial is reported, an open study where 13 out of 16 patients improved in terms of functional class, walking test and quality of life after six months of treatment. The number of hospital days was markedly reduced after pacemaker implantation.

Significant improvement of quality of life following atrioventricular synchronous pacing in patients with hypertrophic obstructive cardiomyopathy. Data from 1 year of follow-up. PIC study group. Pacing In Cardiomyopathy

AIMS

Atrioventricular synchronous pacing exerts beneficial effects, including reduction of left ventricular outflow tract gradients, in patients with hypertrophic obstructive cardiomyopathy. The Pacing in Cardiomyopathy study was initiated to explore the effects of pacing in a double-blind randomized crossover fashion. The aims were to ascertain the beneficial effects of pacing in a controlled study and to rule out a placebo effect by pacing. This paper deals with the outcome of pacing on quality of life during 1 year of follow-up.

METHODS

Quality of life was evaluated with the Karolinska questionnaire, validated for patients paced for bradyarrhythmias and ischaemic heart disease. Drug-refractory patients with hypertrophic obstructive cardiomyopathy were recruited for the study and after a temporary pacing procedure implanted with permanent pacemakers. Patients were randomized to two study arms defining the sequence of pacemaker programming. In one arm the pacemaker was inactive, in the other active. After 3 months the pacemaker was reprogrammed to the alternate mode and a further 3 months followed. After this period subsequent pacemaker programming corresponded to the mode preferred by the patient. A last assessment was made 1 year after baseline examinations.

RESULTS

Eighty patients completed the first crossover period and 75 completed the full 1 year of follow-up. Active pacing induced significant quality of life improvements, in the order of 9-44%, regardless of programming sequence. Discontinuation of pacing after a first active period resulted in the return of symptoms. Fourteen patients requested early reprogramming after having been programmed to inactive pacing after a first period of active pacing. Seventy-six patients preferred active pacing after the crossover period. A further 6 months of pacing induced progressive improvement in symptoms already favourably influenced.

CONCLUSION

Atrioventricular synchronous pacing has a profound beneficial effect on most domains of quality of life in patients with hypertrophic obstructive cardiomyopathy refractory to drug treatment.

Clinical progress after randomized on/off pacemaker treatment for hypertrophic obstructive cardiomyopathy. Pacing in Cardiomyopathy (PIC) Study Group

BACKGROUND

The therapeutic options for hypertrophic obstructive cardiomyopathy (HOCM) classically include medical treatment with beta-blockers and calcium antagonists or myectomy-myotomy as a surgical possibility for refractory cases. The observation that pacemaker activation of the heart in HOCM reduces the subaortic gradient is well known but less well investigated.

METHODS

Eighty-three patients (33 female and 50 male) mean age 53 (18-82) years, with symptoms refractory to drug treatment and a resting gradient above 30 mmHg, who responded favourably to temporary pacing, were included in this prospective study and had a pacemaker (DDD) implanted. After an initial double-blind crossover phase of 6 months, patients were reinvestigated at 12 months and followed for a mean of 36 months.

RESULTS

As observed during a screening investigation, the obstruction was significantly reduced from 72 +/- 35 mmHg to 29 +/- 24 mmHg (P < 0.01) when the pacemaker was on, while no major effect was seen during the sham phase. The effect was persistent at 1 year with a remaining resting gradient of 28 +/- 24 mmHg. In parallel, we documented an improvement in functional capacity, according to the NYHA classification and by quality of life analysis, and a significant improvement in dyspnoea and angina. Exercise on treadmill improved only in patients with reduced initial tolerance (< 8 min). During the mean follow-up of 36 months, 65 patients remained on pacing alone, with eight patients having additional AV-node ablation and five patients finally having surgery.

CONCLUSION

This controlled multicentre study shows that pacemaker treatment is an option for HOCM patients; it is inoffensive and does not exclude alternative methods, but satisfies 79% of patients beyond 3 years.

Placebo effect of pacemaker implantation in obstructive hypertrophic cardiomyopathy. PIC Study Group. Pacing In Cardiomyopathy

This study evaluated a possible placebo effect by pacemaker implantation. The study design was a 3-month multicenter, double-blind, randomized cross-over study to compare the effects of atrioventricular (AV) synchronous pacing with an optimal AV delay to inactive pacing in patients with obstructive hypertrophic cardiomyopathy (HC). Quality of life and left ventricular (LV) outflow tract obstruction were evaluated after the first study period in 40 patients assigned to inactive pacing. Data were compared with the corresponding results among the 41 subjects assigned to a first study period of active pacing. During inactive pacing, there was a significant improvement in perceived chest pain, dyspnea, and palpitations. Moreover, LV outflow tract gradient decreased from 71 +/- 32 mm Hg to 52 +/- 34 mm Hg (p = 0.04). In patients assigned to active pacing the reduction of the gradient was significantly more pronounced (70 +/- 24 mm Hg to 33 +/- 27 mm Hg; p <0.0001). The difference in gradient reduction between the groups was highly significant (p <0.00001). In the group assigned to active pacing there was also significant improvement in perceived symptoms as well as in alertness, the ability to be self-autonomous, and strenuous physical exercise. The improvements in the latter were significantly greater in those paced actively compared with patients paced inactively, whereas the changes in perceived symptoms did not differ between groups. In conclusion, pacemaker implantation had a placebo effect on objective and subjective parameters in this group of patients with obstructive HC.

Rapid return of left ventricular outflow tract obstruction and symptoms following cessation of long-term atrioventricular synchronous pacing for obstructive hypertrophic cardiomyopathy

Atrioventricular (AV) synchronous pacing reduces left ventricular (LV) outflow tract obstruction and symptoms in patients with obstructive hypertrophic cardiomyopathy (HC). The duration of gradient reduction, if pacing is discontinued for a prolonged period of time, is unknown. This question is addressed in the present randomized double-blind crossover study comparing continued with inactivated pacing. Ten patients, successfully paced for > or = 6 months, were randomized to continue pacing or to have their pacemakers inactivated after baseline examinations, including echo-Doppler imaging, exercise testing, and a quality-of-life questionnaire. When entering the study, the patients were in New York Heart Association functional classes I to II. After pacemaker programming, examinations were repeated at 1, 4, and 12 weeks. At the 12-week follow-up the alternate pacing mode was programmed, and the patient entered the second study arm. Premature pacemaker pacing occurred if severe clinical deterioration or a significant increase of the LV outflow tract obstruction were evident. Three patients started in the inactive mode and 7 patients in the active mode. All patients who started with the pacemaker inactivated required early reprogramming due to return of symptoms after 7, 10, and 13 days, respectively. All 7 patients who started in the active pacing mode completed the first period; however, after reprogramming to the inactive mode they required early activation after 1 to 20 days due to reappearance of intolerable subjective symptoms. The LV outflow tract gradient increased significantly after inactivation of pacing in all patients (22 +/- 21 mm Hg to 47 +/- 21 mm Hg). Thus, AV synchronous pacing effectively relieves symptoms and reduces the LV outflow tract gradient in patients with obstructive HC. This improvement, which is rapidly established with the initiation of cardiac pacing, is not persistent after cessation of pacing. Reinitialization of pacing promptly reduces the LV outflow tract obstruction and relieves symptoms to a preexisting extent.

Modification of atrioventricular conduction as adjunct therapy for pacemaker-treated patients with hypertrophic obstructive cardiomyopathy

AIMS

Atrioventricular synchronous pacing offers symptomatic relief for patients with drug-refractory hypertrophic obstructive cardiomyopathy. Successful treatment requires complete right ventricular apical pre-excitation. Enhanced atrioventricular conduction renders this difficult in some patients. The aim of this study was to evaluate whether selective prolongation of atrioventricular conduction is a useful tool for optimization of treatment in patients with hypertrophic obstructive cardiomyopathy primarily refractory to cardiac pacing.

METHODS

Six patients refractory to pacemaker treatment for 3-19 months underwent radiofrequency modification of atrioventricular conduction. Patients were followed with echo-Doppler, exercise testing and clinical evaluation for 6-12 months after modification.

RESULTS

Intrinsic PQ time was significantly prolonged from 175 +/- 18 ms to 253 +/- 22 ms; however, one patient exhibited complete block at one month follow-up. Left ventricular outflow tract obstruction decreased from 74 +/- 17 mmHg to 28 +/- 27 mmHg at the 6-month follow-up. Symptomatic improvement of at least one functional class was recorded in all patients; exercise tolerance remained unchanged, however, less angina and dyspnoea were reported in everyday life.

CONCLUSION

Radiofrequency modification of atrioventricular conduction, with persistent prolongation of the PQ interval, enhances the effects of pacing in patients with hypertrophic obstructive cardiomyopathy. This treatment enhances left ventricular outflow tract gradient reduction and improves symptoms.

Long-term effects of dual chamber pacing in patients with hypertrophic cardiomyopathy without outflow tract obstruction at rest

BACKGROUND

Atrioventricular-synchronous pacing is beneficial in patients with hypertrophic obstructive cardiomyopathy. The effects of pacing in patients without significant left ventricular outflow tract obstruction at rest are, however, less well explored. This study compares the long-term outcome of pacing patients with and without significant left ventricular outflow tract obstruction at rest.

METHODS

Forty-one patients with hypertrophic obstructive cardiomyopathy were studied, 19 with a left ventricular outflow tract gradient < 40 mmHg at rest, but exceeding 50 mmHg during provocation with isoproterenol (group A), and 22 with a left ventricular outflow tract obstruction > 40 mmHg at rest (group B). Before the implantation of a permanent pacemaker, the patients were studied according to a temporary pacing protocol. This included graded isoproterenol provocation of the left ventricular outflow tract obstruction, which was assessed by echo Doppler. Following permanent pacemaker implantation, the patients were regularly followed up with echo Doppler, exercise testing and monitoring of the clinical condition.

RESULTS

Isoproterenol provocation was reproducible and the technique did not cause any clinically important side effects. Left ventricular outflow tract gradient reduction after chronic pacing did not differ between the two groups. In group A, it decreased from 98 +/- 30 mmHg in sinus rhythm to 42 +/- 26 mmHg during pacing. The corresponding values in group B were 87 +/- 40 mmHg to 36 +/- 24 mmHg. The clinical condition improved similarly in the two groups. Exercise capacity increased significantly and perceived dyspnoea and angina pectoris were significantly lower at submaximal levels of exercise after 6 months of pacing.

CONCLUSION

Hypertrophic obstructive cardiomyopathy patients who only exhibit significant left ventricular outflow tract obstruction during provocation benefit as much from pacemaker treatment as do patients who already have significant obstruction at rest. Isoproterenol is a safe and reproducible method for pre-pacing evaluation of hypertrophic obstructive cardiomyopathy patients.

Influence of right ventricular pacing site on left ventricular outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVES

This study was designed to show the influence of right ventricular pacing site on left ventricular outflow tract obstruction during pacing treatment of patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND

Atrioventricular synchronous pacing has been reported to reduce left ventricular outflow obstruction and symptoms in patients with hypertrophic obstructive cardiomyopathy. A paradoxic septal movement induced by right ventricular pacing has been implicated as the mechanism behind the reduced left ventricular outflow tract obstruction; however, the importance of pacing site has not been clarified.

METHODS

Cardiac output, measured invasively, and left ventricular outflow tract gradient, estimated by Doppler echocardiography, were studied in 15 patients with hypertrophic obstructive cardiomyopathy. Measurements were made with the right ventricular electrode in the septal and apical positions during temporary pacing and during sinus rhythm.

RESULTS

Right ventricular apical pacing reduced the outflow tract gradient in all 15 patients to a mean +/- SD of 38 +/- 24 mm Hg from 96 +/- 33 mm Hg during sinus rhythm. During high septal pacing the outflow tract gradient was not reduced, remaining at 93 +/- 44 mm Hg. No significant changes in cardiac output were seen when levels during sinus rhythm (6.4 liters/min), apical pacing (6.4 liters/min) and high septal pacing (5.6 liters/min) were compared.

CONCLUSIONS

The right ventricular pacing site is of crucial importance for reducing left ventricular outflow tract obstruction when patients with hypertrophic obstructive cardiomyopathy are treated with pacing. Cardiac output is not reduced by apical pacing.

Results of atrioventricular synchronous pacing with optimized delay in patients with severe congestive heart failure

To verify that atrioventricular (AV) synchronous pacing (DDD) with short AV delay improves the condition of patients with severe congestive heart failure, we implanted DDD pacemakers in 10 patients with severe heart failure (New York Heart Association [NYHA] class III to IV). One day after pacemaker implantation, the AV delay was optimized by Doppler echocardiographic measurements over the aortic outflow tract. Patients were evaluated regarding NYHA class, stroke volume, cardiac output, ejection fraction, and quality of life at 1, 3, and 6 months after pacemaker implantation. Although the optimized AV delay was associated with short-term improvement in stroke volume and cardiac output (baseline stroke volume = 22 +/- 7 ml, day 1 = 28 +/- 12 ml; p = 0.03: baseline cardiac output = 1.9 +/- 0.6 L/min, day 1 = 2.2 +/- 1.1 L/min; p = 0.10), the mean stroke volume, cardiac output, NYHA class, and ejection fraction did not change significantly after 1, 3, and 6 months of pacing compared with baseline values. Three patients improved in NYHA class during the follow-up. A consistent improvement in stroke volume, cardiac output, NYHA class, and ejection fraction was observed in only 1 patient. In conclusion, we found no beneficial effects of AV-synchronous pacing with optimized AV delay in patients with severe heart failure.

Serum NCA in bone marrow transplant recipients and its metabolism

Normal colon and granulocyte antigen (NCA) in serum from 24 patients undergoing bone marrow transplantation (BMT), mostly for leukemic disease, was studied for a period of 0-60 days before/after transplantation. Out of the 23 patients with a take, 20 acquired elevated serum NCA. One patient had a rejection of the transplantation and never showed a rise of NCA values. Thirteen patients were studied in detail; 7 of them had an NCA rise 1-4 days before take, 4 at the day of take and 2 patients 1-4 days later. To investigate the rate of NCA turnover, 125I-NCA was injected into Macaca irus monkeys. One hour after injection, 87% of the injected substance had left the circulation. The prime site of accumulation was the liver. Thereafter, blood NCA decreased at a slower and linear rate. Of the substance seen at the beginning of the second phase 50% had been eliminated after 30 hours. The data support the theory that NCA is produced by the myeloid cells in bone marrow, that it has a rapid metabolism and therefore is of interest as a marker of bone marrow activity in health and malignant disease.

NCA: a differentiation antigen of myelopoietic cells in humans and hominoid monkeys

NCA, a normal colonic and granulocytic antigen, could be demonstrated in serum and in myelopoietic, but not lymphopoietic or erythropoietic, cells of Homo sapiens and other Primates. The levels of NCA in both serum and myelopoietic cells of Homo and hominoids were higher than those of more distant relatives of the same order. Thus, the classic phylogenetic differences are reflected also by the distribution of NCA. Hyperimmunization of Macaca irus, in which the NCA content of serum and cells is low, led to occurrence of anti-NCA IgG in all animals. The phylogenetic differences may accordingly have to do with slight antigenic NCA differences between Homo and other Primates rather than differences in amount only. Purified NCA did not affect growth and maturation of myelopoietic stem cells in vitro, whereas anti-NCA inhibited development of the majority of myelopoietic clusters and colonies.

Decrease of a normal colon and granulocyte antigen (NCA) in whole lysed blood of myelosuppressed patients

A normal colon and granulocyte antigen (NCA) is found in large amounts in neutrophil granulocytes. A method combining freeze-thawing and ultrasonication of whole blood proved to be the most efficient in recovery of NCA from separated granulocytes or whole blood. NCA in whole blood was studied in healthy persons and in 8 patients with embryonal carcinoma undergoing chemotherapy, with a myelosuppressive effect. A strong correlation (r = 0.96) between the total number of peripheral granulocytes and the amount of NCA in lysed whole blood was found in both healthy persons and myelosuppressed patients. The NCA content per 10(9) granulocytes was equal in granulocytopenic and healthy persons. NCA measurements therefore give information about the total number of granulocytes in peripheral blood within the limits measured (0.5-6.5 x 10(9) granulocytes/l).