A 51-year-old man suddenly collapsed while being arrested. He was an abuser of methamphetamine (MP) with a history of previous convictions. The blood MP concentration at autopsy was below the lethal level. The heart revealed hypertrophy and endocardial thickening of the bilateral ventricles. On microscopic examination, the typical findings of hypertrophic cardiomyopathy were not seen, however endocardial thickening with increasing elastic fibres was seen in all the ventricles and in the atria. In the conduction system, the AV node artery with luminal narrowing was longitudinally compressed by circumferential tissue. Severe interstitial fibrosis and small scar formation of the superiorventricular septum were also seen. In addition, diffuse hypertensive pulmonary arteriopathy was seen in the lung parenchyma. We surmise that the AV node artery had been chronically compressed by the circumferential architecture, due to a chronic increase in intracardiac pressure. We believe that the pathological lesions noted in both the cardiac conduction system and the lung in our case may be a complication of MP abuse, and that an MP abuser with such lesions could easily die suddenly upon experiencing emotional stress.