Marcus Ståhlberg

Women have better long-term prognosis than men after cardiac resynchronization therapy

AIMS Cardiac resynchronization therapy (CRT) improves prognosis in patients with moderate-to-severe heart failure, reduced left ventricular ejection fraction, and wide QRS complexes. However, CRT may be under-utilized in women and data on long-term follow-up are still scarce. The aim was to investigate long-term mortality and hospitalization and prognostic impact of gender after CRT. METHODS AND RESULTS Data on 619 consecutive patients (19% women) that received CRT at a single centre between 1998 and 2008 were collected from electronic medical records and national death and hospitalization registries up to 2010. The primary endpoint was death of any cause and the secondary endpoint was combined death of any cause or heart failure hospitalization. Over a mean follow-up of 1320 ± 786 days, 215 (35%) patients reached the primary endpoint and 437 (71%) the secondary endpoint. Overall, 1-, 5-, and 10-year survivals were 91, 63, and 39%, respectively. Female gender was the only independent predictor of all-cause mortality; hazard ratio (HR) 0.44 [95% confidence interval (CI), 0.21-0.90; P= 0.025]. Women also had a trend towards lower risk for the secondary endpoint, HR 0.68 (95% CI, 0.45-1.04; P= 0.072). CONCLUSION In this registry analysis, patients with CRT had similarly high short-term survival to those in controlled trials, and this favourable prognosis was sustained over the long term.Women had lower all-cause mortality than men.

Continuous Monitoring of Intrathoracic Impedance and Right Ventricular Pressures in Patients With Heart Failure

Background—Hemodynamic monitoring using implantable devices may provide early warning of volume overload in patients with heart failure (HF). This study was designed to prospectively compare information from intrathoracic impedance monitoring and continuous right ventricular pressure measurements in patients with HF. Methods and Results—Sixteen patients with HF (age, 63.5±13.8 years; left ventricular ejection fraction, 23.2±11.3%; New York Heart Association, II and III) and a previous HF decompensation received both a cardiac resynchronization therapy defibrillator providing a daily average of intrathoracic impedance and an implantable hemodynamic monitor providing an estimate of the pulmonary artery diastolic pressure. At the end of a 6-month investigator-blinded period, baseline reference hemodynamic values were determined over 4 weeks during which the patient was clinically stable. A major HF event was defined as HF decompensation requiring hospitalization, IV diuretic treatment, or leading to death. Sixteen major HF events occurred in 10 patients. Within 30 days and 14 days before a major HF event, impedance decreased by 0.12±0.21 &OHgr;/d and 0.20±0.20 &OHgr;/d, respectively, whereas estimated pulmonary arterial diastolic pressure increased by 0.10±0.20 mm Hg/d and 0.16±0.15 mm Hg/d, respectively. During these periods, impedance decreased by 3.8±5.4 &OHgr; (P<0.02) and 4.9±6.1 &OHgr; (P<0.007), respectively, whereas estimated pulmonary arterial diastolic pressure increased by 5.8±5.7 mm Hg (P<0.002) and 6.8±6.1 mm Hg (P<0.001), respectively, compared with baseline. In all patients, impedance and estimated pulmonary arterial diastolic pressure were inversely correlated (r=−0.48±0.25). Within 30 days preceding a major HF event, this correlation improved to r=−0.58±0.24. Conclusions—Decompensated HF develops based on hemodynamic derangements and is preceded by significant changes in intrathoracic impedance and right ventricular pressures during the month prior to a major clinical event. Impedance and pressure changes are moderately correlated. Future research may establish the complementary contribution of both parameters to guide diagnosis and management of patients with HF by implantable devices.

Cardiac fatigue in long-distance runners is associated with ventricular repolarization abnormalities

BACKGROUND Prolonged exercise can induce cardiac fatigue, which is characterized by biomarker release and impaired myocardial function. The impact on ventricular electrophysiology is largely unknown. OBJECTIVE The objective of this study was to examine changes in ventricular repolarization after a 30-km cross-country race in runners aged >or=55 years. METHODS Fifteen healthy participants (62 +/- 5 years) were assessed using biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], troponin T [TnT]), tissue Doppler echocardiography, and vectorcardiography at baseline, within 1 hour postrace and on days 1 and 6 postrace. RESULTS During the race, NT-proBNP increased from 42 ng/L (interquartile range 25-117) to 187 ng/L (113-464), and TnT increased from undetectable levels to 0.03 microg/L (0.015-0.05). Global strain (19.1% +/- 2.2%) decreased on day 1 (17.2% +/- 1.8%) and day 6 (17.9% +/- 1.5%; P <.01). QT(c) increased from 431 +/- 15 ms prerace to 445 +/- 22 ms postrace and 445 +/- 15 ms on day 1 (P <.05), mainly because of an increased T(peak-end) interval (prerace 108 +/- 13 ms, postrace 127 +/- 43 ms, day 1 127 +/- 43 ms; P <.05). Postrace, T(area) (baseline 75 +/- 26 microVs) peaked on day 1 (105 +/- 42 microVs) and remained high on day 6 (89 +/- 37 microVs; P <.05). Runners with higher baseline NT-proBNP developed greater impairment of myocardial velocities (rho = -0.68 to -0.54; P <.05) and a larger increase in T(area) (rho = 0.73; P <.01). CONCLUSION Cardiac fatigue induced by prolonged exertion is associated with sustained abnormalities in ventricular repolarization. Runners with higher baseline NT-proBNP are especially liable to such alterations of cardiac function.

Association between demographic, organizational, clinical, and socio-economic characteristics and underutilization of cardiac resynchronization therapy : results from the Swedish Heart Failure Registry.

Cardiac resynchronization therapy (CRT) improves outcomes in heart failure (HF) but may be underutilized. The reasons are unknown.

Gender, underutilization of cardiac resynchronization therapy, and prognostic impact of QRS prolongation and left bundle branch block in heart failure

AIMS It has been suggested that cardiac resynchronization therapy (CRT) is less utilized, dyssynchrony occurs at narrower QRS, and CRT is more beneficial in women compared with men. We tested the hypotheses that (i) CRT is more underutilized and (ii) QRS prolongation and left bundle branch block (LBBB) are more harmful in women. METHODS AND RESULTS We studied 14 713 patients (28% women) with left ventricular ejection fraction (LVEF) <40% in the Swedish Heart Failure Registry. In women vs. men, CRT was present in 4 vs. 7% (P < 0.001) and was absent but with indication in 30 vs. 31% (P = 0.826). Next, among 13 782 patients (28% women) without CRT, 9% of women and 17% of men had non-specific intraventricular conduction delay (IVCD) and 27% of women and 24% of men had LBBB. One-year survival with narrow QRS was 85% in women and 88% in men, with IVCD 74 and 78%, and with LBBB 84 and 82%, respectively. Compared with narrow QRS, IVCD had a multivariable hazard ratio of 1.24 (95% CI 1.05-1.46, P = 0.011) in women and 1.30 (95% CI 1.19-1.42, P < 0.001) in men, and LBBB 1.03 (95% CI 0.91-1.16, P = 0.651) in women and 1.16 (95% CI 1.07-1.26, P < 0.001) in men, P for interaction between gender and QRS morphology, 0.241. CONCLUSIONS While the proportion with CRT was lower in women, CRT was equally underutilized in both genders. QRS prolongation with or without LBBB was not more harmful in women than in men. Efforts to improve CRT implementation should be directed equally towards women and men.

Age, prognostic impact of QRS prolongation and left bundle branch block, and utilization of cardiac resynchronization therapy: findings from 14 713 patients in the Swedish Heart Failure Registry

Age is not a contraindication to cardiac resynchronization therapy (CRT), but the prevalence and prognostic impact of QRS prolongation with intraventricular conduction delay (IVCD) and left bundle branch block (LBBB), as well as CRT utilization, may differ with age. We tested the hypotheses that in the elderly: (i) IVCD and LBBB are more prevalent, (ii) IVCD and LBBB are more harmful, and (iii) CRT is underutilized.

Three Year Outcome of Cardiac Resynchronization Therapy: A Single Center Evaluation

Aims: To evaluate the long‐term clinical outcome and device performance of cardiac resynchronization therapy in a consecutive sample of patients with moderate to severe heart failure.

Cardiac output response to changes of the atrioventricular delay in different body positions and during exercise in patients receiving cardiac resynchronization therapy

AIMS The aim of this study was to study the haemodynamic effect of atrioventricular delay (AVD) modifications within a narrow range in different body positions and during exercise in patients receiving cardiac resynchronization therapy (CRT). METHODS The previously optimized AVD was shortened and prolonged by 40 ms in 27 CRT patients and 9 controls without heart failure. Cardiac output (CO) was measured by inert gas rebreathing (Innocor) as the average over different body positions (left-lateral, supine, sitting, standing, and exercise). In eight CRT patients with an implantable haemodynamic monitor, the estimated pulmonary artery diastolic pressure (ePAD) was analysed. RESULTS The magnitude of CO response to AVD changes was greater in CRT patients than in controls (0.25 vs. 0.20 L/min, P<0.05), varied substantially between individuals (range: 0.12-0.56 L/min), and correlated with left atrial size (r=0.61, P<0.001). On average, AVD shortening decreased CO slightly (0.07+/-0.17 L/min) and increased ePAD (1.1+/-0.8 mmHg, both P<0.05), whereas prolongation had no significant effect. CONCLUSION The haemodynamic response to AVD modifications within a narrow range is larger in CRT patients than in normal controls and varies substantially between individuals. These findings suggest that optimal AVD tuning is clinically important in selected patients.

Acute haemodynamic effects of increase in paced heart rate in heart failure patients recorded with an implantable haemodynamic monitor

AIMS The aim of this study was to investigate the acute effects of different biventricularly paced heart rates (pHRs) on right ventricular (RV) haemodynamics in heart failure (HF) patients with an implantable haemodynamic monitor (IHM). METHODS AND RESULTS At rest, seven pHRs, range 60-120 bpm (steps of 10), were randomly programmed and maintained for 60 s in 10 patients (male, 65±12 years, New York Heart Association II-III). Right ventricular systolic (RVSP) and diastolic pressures, estimated pulmonary artery diastolic (ePAD) pressure, and RV+dP/dt were recorded beat-to-beat using the IHM. Cardiac output (CO) was estimated from the RV pressure waveforms and arterial blood pressure was measured (Portapres®). To compare the haemodynamic effects of increased pHR at rest to that of spontaneous, sinus-driven heart rate (HR) increase, patients also performed a symptom-limited bicycle exercise. At rest, RV+dP/dt increased significantly with elevated pHR (P, main effect, <0.001), whereas filling pressures (ePAD and RVSP) decreased significantly in the range 60-100 bpm (P<0.03 and P<0.003, respectively) but tended to increase or level out at pHRs>00 bpm. At a pHR of 100 bpm, ePAD was 1.4 mmHg lower compared with 60 bpm (P<0.01). Cardiac output increased gradually with elevated pHR at rest (P<0.001). Both total peripheral and estimated pulmonary arterial resistance significantly decreased with increased pHR. During exercise-induced maximum HR increase, RV+dP/dt, ePAD, and CO were all significantly higher compared with the corresponding pHR at rest. CONCLUSION During cardiac resynchronization therapy in HF patients, the force frequency relationship is present in the RV, as increasing the pHR in the range 60-100 bpm results in decreased filling pressures and increased CO.

Awareness of indications for device therapy among a broad range of physicians: a survey study

AIMS Cardiac resynchronization therapy (CRT) and primary prophylactic implantable cardioverter-defibrillators (ICDs) are underutilized in heart failure (HF). This may originate from an unawareness of device benefits and indications among physicians responsible for HF care and referral. We aimed to describe the awareness of indications for device therapy in a generalized sample of Swedish physicians. METHODS AND RESULTS A randomly selected sample of Swedish physicians specializing in cardiology, internal medicine, and family medicine and interns (5% of eligible physicians, n = 519) was invited to fill in a 23-item survey, testing their awareness of indications for device therapy and, as comparison, pharmacological therapy. Acceptable awareness (AA) of CRT indication was predefined as recognizing that a left bundle branch block on ECG warrants further evaluation for CRT. Acceptable awareness of ICD indication was predefined as recognizing that ejection fraction ≤35% alone, without a history of ventricular tachycardia, is sufficient to warrant a primary prophylactic ICD. The response rate was 37% (n = 168). Overall, 32% met AA of CRT indication, and significantly less (15%) met AA of ICD indication. Specialist certification in cardiology was the only significant predictor for AA [odds ratio (95% confidence interval): 37 (10-138)]. However, even among cardiologists, awareness of ICD indications was low (61% with AA). Guideline-recommended indications for pharmacological therapy were conceived significantly better (P = 0.02) than device therapy [median (interquartile range) of correct answers: 50% (33-50) compared with 36% (14-57)]. CONCLUSIONS The study identified an important and substantial awareness gap in the medical community that may explain some of the previously reported low referral rates and utilization of device therapy in HF.