January 1, 2016International Heart JournalOpen Access

Failing Left Ventricles Have an Enhanced Post-Stimulation Potentiation Despite Their Impaired Force Frequency Relationship

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Idiopathic dilated cardiomyopathy (n=22). Intervention: Idiopathic dilated cardiomyopathy vs. Normal left ventricular ejection fraction. Primary outcome: Increase in LV dP/dtmax of the post-stimulation potentiation beat over pacing beat (ΔPSP) at 120 beats/minute (p=<0.0001).

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Key result

Patients with idiopathic dilated cardiomyopathy exhibited significantly greater post-stimulation potentiation (ΔPSP at 120/minute: 294 vs -152 mmHg/second) despite an impaired force-frequency relationship compared to controls.

Why the study?

Does right atrial pacing alter the force-frequency relationship and post-stimulation potentiation in patients with idiopathic dilated cardiomyopathy compared to controls?

Population

22 patients total: 16 patients with idiopathic dilated cardiomyopathy admitted for heart failure symptoms or…

Comparison

Right atrial pacing using a… vs Control patients with normal left ventricular…

Design

Cross-sectional

Authors

TWToru WatanabeTakasago (Japan)TKTakeshi KashimuraHeart Failure / Cardiomyopathy MKMakoto KodamaKanazawa University

Discussion

Member takes

Implication

Supports contractile reserve in DCM not utilized at high rates; hypothesis-generating and should not yet change practice.

Study Design

Type

Cross-Sectional (n=22)

Multicenter

Structured PICO

Does right atrial pacing alter the force-frequency relationship and post-stimulation potentiation in patients with idiopathic dilated cardiomyopathy compared to controls?

Population

22 patients, comprising 16 with idiopathic dilated cardiomyopathy and 6 controls with normal ejection fraction, underwent right atrial pacing during cardiac catheterization to assess heart rate-dependent contractile properties.

Exposure

Right atrial pacing using a micro-manometer-tipped catheter, starting just above basal heart rate and increasing by increments of 10/minute until 140/minute, with each rate maintained for at least 20 seconds.

Comparator

Control patients with normal left ventricular ejection fraction (≥60%) undergoing the same right atrial pacing protocol.

Outcome

Force-frequency relationship (FFR) measured as the increase of LV dP/dtmax over basal LV dP/dtmax (ΔFFR), and post-stimulation potentiation (PSP) measured as the increase of LV dP/dtmax of the first beat after pacing cessation over LV dP/dtmax during pacing (ΔPSP).surrogate

Main Result

Absolute Event Rate: 294% vs -152%

p-value: p=<0.0001

Failing left ventricles in DCM patients exhibit an impaired force-frequency relationship during tachycardia but enhanced post-stimulation potentiation, suggesting preserved contractile potential that cannot be utilized during rapid heart rates.

Limitations

Left ventricular volume was not measured and the Frank-Starling mechanism was not assessed.
Coupling interval of PSP beats was not controlled and differed among patients and among pacing rates in each patient.
Baseline characteristics (such as age, blood pressure, and medications) were significantly different between the groups.
The numbers of patients in both groups were small, especially in the control group.
Coupling interval of PSP beats was not controlled and differed among patients and pacing rates.
Baseline characteristics (age, systolic blood pressure, medications) were significantly different between groups.
Small number of patients, especially in the control group.

Cite This Study

Watanabe et al. (2016) conducted a cross-sectional in Idiopathic dilated cardiomyopathy (n=22). Idiopathic dilated cardiomyopathy vs. Normal left ventricular ejection fraction was evaluated on Increase in LV dP/dtmax of the post-stimulation potentiation beat over pacing beat (ΔPSP) at 120 beats/minute (p=<0.0001). Patients with idiopathic dilated cardiomyopathy exhibited significantly greater post-stimulation potentiation (ΔPSP at 120/minute: 294 vs -152 mmHg/second) despite an impaired force-frequency relationship compared to controls.

synapsesocial.com/papers/6a846f4a6b6022c7d8c53404 https://doi.org/10.1536/ihj.15-374

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Failing Left Ventricles Have an Enhanced Post-Stimulation Potentiation Despite Their Impaired Force Frequency Relationship

Discussion

Member takes

Implication

Study Design

Structured PICO

Main Result

Limitations

Cite This Study

Failing Left Ventricles Have an Enhanced Post-Stimulation Potentiation Despite Their Impaired Force Frequency Relationship

Discussion

Member takes

Implication

Study Design

Structured PICO

Main Result

Limitations

Cite This Study

Also Consider

Also Consider