Current Status of Implantable Cardioverter‐Defibrillators ( ICDs )/Cardiac Resynchronization Therapy With Defibrillators ( CRT ‐Ds) for Primary Prevention of Sudden Cardiac Death

Figures

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  FIGURE 1. Positive and negative predictive values of VT/VF inducibility by electrophysiological study (EPS) for predicting arrhythmic events, stratified by LVEF. Arrhythmic events were cardiac arrest or death from arrhythmia (MUSTT), [6] appropriate ICD therapy (MADIT II), [8] appropriate ICD therapy or sudden death (Alternans Before Cardioverter Defibrillator [ABCD] trial), [11] sudden cardiac death, VT/VF or appropriate ICD therapy (PRESERVE EF), [9] appropriate ICD therapy (JCDTR), [10] and sudden death, VT/VF or appropriate ICD therapy (Soris et al.) [12]. The values were estimated at 2 years of each study.

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  FIGURE 2. Relationship between the annual rates of sudden death and overall mortality in randomized controlled trials for patients with heart failure with reduced ejection fraction. The slope of guideline‐directed medical therapy (GDMT, blue circle) and that of cardiac resynchronization therapy with a pacemaker (CRT‐P, gray circle) is nearly identical. Defibrillator therapy (ICD/CRT‐D, orange circle) apparently reduces the slope. The slope was 0.32 for GDMT, 0.38 for CRT‐P, and 0.16 for ICD/CRT‐D, respectively. These values indicate that sudden death accounted for 32%, 38%, and 16%, respectively, of the overall mortality in HFrEF patients treated with GDMT, CRT, and ICD/CRT‐D. ARNI: angiotensin receptor neprilysin inhibitor; Ctrl: control; CRT‐D: cardiac resynchronization therapy with a defibrillator; ICD: implantable cardioverter‐defibrillator. Adapted from MADIT [3], AMIOVIRT [18], DEFINITE [19], COMPANION [20], CARE‐HF [21], SCD‐HeFT [22], EMPHASIS‐HF [23], REVERSE [24], PARADIGM‐HF [25], DANISH [5], and DAPA‐HF [26].

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  FIGURE 3. Kaplan–Meier estimates of event‐free survival in CRT‐D recipients stratified by indication and etiology. Outcome events were appropriate ICD therapy (A) and death from any cause (B) P, primary prevention of sudden cardiac death; S, secondary prevention of sudden cardiac death; Isch, ischemic cardiomyopathy; Non, non‐ischemic cardiomyopathy.

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  FIGURE 4. Annual trends in the number of patients with primary and secondary prevention ICD/CRT‐D implantations with the proportion of primary prevention registered in the JCDTR and New JCDTR. Absolute number of patients with primary prevention ICD/CRT‐D implantations and those with secondary prevention ICD/CRT‐D implantations is given by blue bars and orange bars, respectively. The proportion of primary prevention ICD/CRT‐D implantations (a dark blue line) is 40% range between 2011 and 2020. Adapted from [49].

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  FIGURE 5. Annual trends of ICD/CRT‐D utilization in Japan. A gray line indicates Japanese population (million) (https://www.stat.go.jp/data/jinsui/2023np/index.html, accessed November 25, 2025). An orange line indicates the number of de novo ICD/CRT‐D implantation (hundred) (Japan Arrhythmia Device Industry Association, https://www.jadia.or.jp/medical/crt‐d.html, accessed November 25, 2025). The ICD/CRT‐D utilization per million in Japan is given by blue bars.

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  FIGURE 6. ICD/CRT‐D utilization and Gross Domestic Product (GDP) in the Group of Seven (G7) countries. ICD/CRT‐D utilization (dark blue bars) was expressed as the number of de novo ICD/CRT‐D implantation per million in each country. Adapted from Patel MJ et al. [67], Raatikainen MJP et al. [68], and Canada's Drug Agency, Implantable Cardioverter‐Defibrillator Decision‐Making, (https://www.cda‐amc.ca/implantable‐cardioverter‐defibrillator‐decision‐making, accessed November 25, 2025). Orange bars indicate Gross Domestic Product (GDP) in 2024 (https://eleminist.com/article/3258, accessed November 25, 2025).

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  FIGURE 7. Annual trends of out‐of‐hospital cardiac arrest (OHCA) with cardiac etiology and the outcomes in Japan. Dark blue bars show the absolute number of victims of cardiac OHCA, while orange bars show the absolute number of victims with bystander‐witnessed cardiac OHCA. A gray line indicates the proportion of non‐survivors among victims of bystander‐witnessed cardiac OHCA. A yellow line shows the proportion of victims with favorable neurological outcomes. Adapted from https://www.fdma.go.jp/publication/#rescue, accessed November 25, 2025.