Extraordinarily favorable left ventricular reverse remodeling through long-term cardiac resynchronization: super-response to cardiac resynchronization

The therapeutic effects of upgrade to cardiac resynchronization therapy in pacing-induced cardiomyopathy or chronic right ventricular pacing patients: a meta-analysis

Pacing-induced cardiomyopathy (PICM) or heart failure accompanied with chronic right ventricular pacing (CRVP-HF) has no established treatments. We aimed to carry out a meta-analysis of published studies about the therapeutic effects of the upgrade to cardiac resynchronization therapy (CRT) in patients of PICM/CRVP-HF. The PUBMED, EMBASE, MEDLINE, OVID databases, and Cochrane Library were systemically searched for relevant publications. Data about the improvements of left ventricular ejection fraction (LVEF), NYHA functional class (NYHA-FC), and the CRT response rate was extracted and synthesized. Mean difference (MD), odds ratio, and standard mean difference (SMD) with 95% confidence interval (CI) were calculated as the effect size by both fixed and random effect models. We included sixteen studies (four about PICM and twelve about CRVP-HF). The total sample size of PICM/CRVP-HF patients was 924. Upgrade to CRT improved the LVEF by 10.87% (95%CI, 8.90 to 12.84%) and reduce the NYHA-FC by around one class (MD, -1.25; 95%CI, -1.43 to -1.06) in PICM/CRVP-HF patients overall. Upgrade to CRT seemed to improve LVEF no less than de-novo CRT (SMD 0.24; 95%CI 0.05 to 0.43; P < 0.05). This meta-analysis suggested that upgrade CRT could improve the cardiac function in PICM/CRVP-HF patients. This strategy may be considered in these patients but require more evidence about the efficacy and procedure-related complications from prospective studies or randomized controlled trials.

Novel blood pressure and pulse pressure estimation based on pulse transit time and stroke volume approximation

BACKGROUND

Non-invasive continuous blood pressure monitors are of great interest to the medical community due to their value in hypertension management. Recently, studies have shown the potential of pulse pressure as a therapeutic target for hypertension, but not enough attention has been given to non-invasive continuous monitoring of pulse pressure. Although accurate pulse pressure estimation can be of direct value to hypertension management and indirectly to the estimation of systolic blood pressure, as it is the sum of pulse pressure and diastolic blood pressure, only a few inadequate methods of pulse pressure estimation have been proposed.

METHODS

We present a novel, non-invasive blood pressure and pulse pressure estimation method based on pulse transit time and pre-ejection period. Pre-ejection period and pulse transit time were measured non-invasively using electrocardiogram, seismocardiogram, and photoplethysmogram measured from the torso. The proposed method used the 2-element Windkessel model to model pulse pressure with the ratio of stroke volume, approximated by pre-ejection period, and arterial compliance, estimated by pulse transit time. Diastolic blood pressure was estimated using pulse transit time, and systolic blood pressure was estimated as the sum of the two estimates. The estimation method was verified in 11 subjects in two separate conditions with induced cardiovascular response and the results were compared against a reference measurement and values obtained from a previously proposed method.

RESULTS

The proposed method yielded high agreement with the reference (pulse pressure correlation with reference R ≥ 0.927, diastolic blood pressure correlation with reference R ≥ 0.854, systolic blood pressure correlation with reference R ≥ 0.914) and high estimation accuracy in pulse pressure (mean root-mean-squared error ≤ 3.46 mmHg) and blood pressure (mean root-mean-squared error ≤ 6.31 mmHg for diastolic blood pressure and ≤ 8.41 mmHg for systolic blood pressure) over a wide range of hemodynamic changes.

CONCLUSION

The proposed pulse pressure estimation method provides accurate estimates in situations with and without significant changes in stroke volume. The proposed method improves upon the currently available systolic blood pressure estimation methods by providing accurate pulse pressure estimates.

Comparison of De Novo versus Upgrade Cardiac Resynchronization Therapy; Focused on the Upgrade for Pacing-Induced Cardiomyopathy

PURPOSE

This study aimed to determine whether upgrade cardiac resynchronization therapy (CRT) shows better outcomes than de novo CRT. To do so, we compared the efficacy of CRT between de novo and upgrade groups, focusing particularly on the effect of upgrade CRT on patients with pacing-induced cardiomyopathy (PiCM).

MATERIALS AND METHODS

PiCM was defined as new-onset dilated cardiomyopathy following pacemaker implantation in patients with baseline normal ejection fraction ≥50%. Electro-mechanical reverse remodeling and clinical outcomes were compared among the de novo (n=62), PiCM upgrade (n=7), and non-PiCM upgrade (n=8) CRT groups.

RESULTS

The PiCM upgrade group showed significantly greater electro-mechanical reverse remodeling than the de novo CRT or non-PiCM upgrade groups at 6-month follow-up. The rate of super-responders was significantly higher in the PiCM upgrade group than the other CRT groups. The group factor of the PiCM upgrade was identified as an independent predictor of super-responder in multivariate analysis (odds ratio 10.4, 95% confidential interval 1.08-99.4, p=0.043). During the median follow-up of 15.8 months, the PiCM upgrade group showed the lowest rate of composite clinical outcomes, including cardiac death, heart transplantation, and heart failure-related rehospitalization (p=0.059).

CONCLUSION

The upgrade CRT for PiCM patients showed better performance in terms of electro-mechanical reverse remodeling than de novo implantation or upgrade CRT in non-PiCM patients.

Clinical characteristics and predictors of super-response to cardiac resynchronization therapy: a combination of predictive factors

BACKGROUND

Patients with greater improvement of cardiac function after cardiac resynchronization therapy (CRT) implantation are identified as "super-responders." However, it remains unclear which kind of preimplant assessments could accurately predict outcomes after CRT. Thus, we aimed to examine the essential predicting factors for super-response to CRT, and to construct an accurate predictable model.

METHODS

We retrospectively analyzed the CRT patients who underwent implantation at Nagoya University Hospital. Super-responders are defined as those who show a relative reduction in left ventricular end-systolic volume ≥30% after 6 months of CRT.

RESULTS

Eighty patients (mean age, 67.8 ± 10.2 years) were included. Twenty-two patients received upgrading procedure to CRT implantation. Six months after the implantation, 29 patients (36%) were super-responders. Multiple logistic regression analysis shows that consistent right ventricular pacing with a previous device (odds ratio [OR] 7.28, 95% confidence interval [CI] 1.52-34.9; P = 0.013), lack of prior history of ventricular arrhythmia (OR 5.32, 95% CI 1.52-18.6; P = 0.009), and smaller left atrial diameter (LAD) (OR 0.92, 95% CI 0.86-0.98; P = 0.014) are independent predictors for CRT super-responders. The use of a combination of these predictive factors could increase the certainty with which a greater response to CRT is predicted and the presence of such a combination could improve prognosis.

CONCLUSION

Greater response to biventricular pacing occurs more frequently in patients with consistent right ventricular pacing, lack of prior history of ventricular arrhythmia, and smaller LAD. An association between patient background characteristics and a super-response to CRT was also identified.

Predictors and outcomes of "super-response" to cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) has been shown to improve heart failure (HF) symptoms and survival. We hypothesized that a greater improvement in left-ventricular ejection fraction (LVEF) after CRT is associated with greater survival benefit.

METHODS AND RESULTS

In 693 patients across 2 international centers, the improvement in LVEF after CRT was determined. Patients were grouped as non-/modest-, moderate-, or super-responders to CRT, defined as an absolute change in LVEF of ≤5%, 6-15%, and >15%, respectively. Changes in New York Heart Association (NYHA) functional class and left ventricular end-diastolic dimension (LVEDD) were assessed for each group. There were 395 non-/modest-, 186 moderate-, and 112 super-responders. Super-responders were more likely to be female and to have nonischemic cardiomyopathy, lower creatinine, and lower pulmonary artery systolic pressure than non-/modest- and moderate-responders. Super-responders were also more likely to have lower LVEF than non-/modest-responders. There was no difference in NYHA functional class, mitral regurgitation grade, or tricuspid regurgitation grade between groups. Improvement in NYHA functional class (-0.9 ± 0.9 vs -0.4 ± 0.8 [P < .001] and -0.6 ± 0.8 [P = .02]) and LVEDD (-8.7 ± 9.9 mm vs -0.5 ± 5.0 and -2.4 ± 5.8 mm [P < .001 for both]) was greatest in super-responders. Kaplan-Meier survival analysis revealed that super-responders achieved better survival compared with non-/modest- (P < .001) and moderate-responders (P = .049).

CONCLUSIONS

Improvement in HF symptoms and survival after CRT is proportionate to the degree of improvement in LV systolic function. Super-response is more likely in women, those with nonischemic substrate, and those with lower pulmonary artery systolic pressure.